Fazlur Rahman (essay date 1963)

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SOURCE: "Ibn Sīna," in A History of Muslim Philosophy, with Short Accounts of Other Disciplines and the Modern Renaissance in Muslim Lands, Vol. One, edited by M. M. Sharif, Otto Harrassowitz, 1963, pp. 480-506.

[ In the following excerpt, Rahman surveys Avicenna's metaphysics, philosophy of mind, epistemology, and philosophy of...

(The entire section contains 43402 words.)

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SOURCE: "Ibn Sīna," in A History of Muslim Philosophy, with Short Accounts of Other Disciplines and the Modern Renaissance in Muslim Lands, Vol. One, edited by M. M. Sharif, Otto Harrassowitz, 1963, pp. 480-506.

[In the following excerpt, Rahman surveys Avicenna's metaphysics, philosophy of mind, epistemology, and philosophy of religion, and briefly discusses Avicenna's influence in the East and West.]

In the history of philosophical thought in the Medieval Ages, the figure of ibn Sīna (370/980-428/1037) is, in many respects, unique, while among the Muslim philosophers, it is not only unique but has been paramount right up to modern times. He is the only one among the great philosophers of Islam to build an elaborate and complete system of philosophy—a system which has been dominant in the philosophical tradition of Islam for centuries, in spite of the attacks of al-Ghazāli, Fakhr al-Dīn al-Rāzi, and others. This ascendancy has been possible, however, not merely because he had a system but because that system had features of remarkable originality displaying a type of geniuslike spirit in discovering methods and arguments whereby he sought to reformulate the purely rational and intellectual tradition of Hellenism, to which he was an eminent heir, for and, to an extent, within the religious system of Islam. The exact terms of this reformulation and their relation to Islam we shall discuss presently …; it is only to be noted at the outset that it was this kind of originality which rendered him unique not only in Islam but also in the medieval West where the reformulations of the Roman Catholic theology at the hands of Albert the Great, and, especially, of Thomas Aquinas, were fundamentally influenced by him.

Since … we are mainly concerned with ibn Sīnā's interpretation of Greek philosophical doctrines, we need not give an account of his sources in the Greek and Muslim philosophers. To be sure, the elements of his doctrines are Greek, and certain reformulations of Greek doctrines in his writings are also to be found in al-Fārābi (to whom ibn Sīnā's debt is immense) in varying degrees of development; but our task here is to state, analyse, and appreciate ibn Sīnā's teaching. And, indeed, ibn Sīnā's system, taken as a whole, is such that it is his, bearing the unmistakable impress of his personality. This is proved by the fact that he states his cardinal doctrines over and over again in his different works and often gives cross references, which are unmistakable signs of systematic thinking and not of random borrowing from heterogeneous sources.

The most fundamental characteristic of ibn Sīnā's thought is that of arriving at definitions by a severely rigorous method of division and distinction of concepts. This lends an extraordinary subtlety to his arguments. It can often give his philosophical reasoning a strongly scholastic complexity and intricacy of structure which can annoy the modern temperament, but it is doubtlessly true that it is also this method which has resulted in almost all the original doctrines of our philosopher. It has enabled him to formulate his most general and basic principle, viz., to every clear and distinct concept there must correspond a distinctio in re, a principle on which later Descartes also based his thesis of the mind-body dualism. The fecundity and importance of this principle of analysis in ibn Sīnā's system are indeed striking: he announces it recurrently and at all levels, in his proof of the mind-body dualism, his doctrine of universals, his theory of essence and existence, etc. Examples of this principle are: "that which is affirmed and admitted is different from that which is not affirmed and admitted," and "a single conceptual (lit. specific) entity cannot be both known and unknown at the same time except with regard to different aspects."

This [essay] will deal mostly with those concepts and doctrines of ibn Sīna which are not only capital and bring out the nature of his system, but have also both been influential and originally elaborated by him to a greater or lesser extent. …

Ibn Sīnā's doctrine of Being, like those of earlier Muslim philosophers, e.g., al-Fārābi, is emanationistic. From God, the Necessary Existent, flows the first intelligence alone, since from a single, absolutely simple entity, only one thing can emanate. But the nature of the first intelligence is no longer absolutely simple since, not being necessary-by-itself, it is only possible, and its possibility has been actualized by God. Thanks to this dual nature which henceforth pervades the entire creaturely world, the first intelligence gives rise to two entities: (i) the second intelligence by virtue of the higher aspect of its being, actuality, and (ii) the first and highest sphere by virtue of the lower aspect of its being, its natural possibility. This dual emanatory process continues until we reach the lower and tenth intelligence which governs the sublunary world and is called by the majority of the Muslim philosophers the Angel Gabriel. This name is applied to it because it bestows forms upon or "informs" the matter of this world, i.e., both physical matter and the human intellect. Hence it is also called the "Giver of Forms" (the dator formarum of the subsequent medieval Western scholastics). We shall return later to these intelligences and these spheres to examine more closely their nature and operations; meanwhile we must turn to the nature of Being.

The procession of the immaterial intelligence from the Supreme Being by way of emanation was intended to supplement, under the inspiration of the Neo-Platonic Theory of Emanation, the meagre and untenable view of God formulated by Aristotle according to whom there was no passage from God, the One, to the world, the many. According to Muslim philosophers, although God remained in Himself and high above the created world, there were, nevertheless, intermediary links between the absolute eternity and necessity of God and the world of downright contingency. And this theory, besides, came very close to satisfying the Muslim belief in angels. This is the first occasion to remark how Muslim philosophers, by a re-elaboration of the Greek tradition of philosophy, not only sought to build a rational system, but a rational system which sought to integrate the tradition of Islam. But what about the Theory of Emanation itself? Would it not destroy the necessary and all-important gulf between the Creator and the creation and lead to a downright pantheistic world-view—tat tvam Asi—against which Islam, like all higher religions, had warned so sternly? No doubt, this type of pantheism, being dynamic, is different from the absolutist and static forms of pantheism; yet it could lead to anthropomorphism, or, by a reverse process of ascent, to the re-absorption of the creature's being into the being of God. Now, the guarantee against any such danger shall be ibn Sīnā's doctrine of essence and existence. This celebrated theory again is designed to fulfil equally both religious and rational needs and, once again, to supplement Aristotle.

Early in this section we said that God and God alone is absolutely simple in His being; all other things have a dual nature. Being simple, what God is and the fact that He exists are not two elements in a single being but a single atomic element in a single being. What God is, i.e., His essence, is identical with His existence. This is not the case with any other being, for in no other case is the existence identical with the essence, otherwise whenever, for example, an Eskimo who has never seen an elephant, conceives of one, he would ipso facto know that elephants exist. It follows that God's existence is necessary, the existence of other things is only possible and derived from God's, and that the supposition of God's non-existence involves a contradiction, whereas it is not so with any other existent. A cosmological argument, based on Aristotle's doctrine of the First Cause, would be superfluous in establishing God's existence. Ibn Sīna, however, has not chosen to construct a full-fledged ontological argument. His argument, which, as we shall see later, became the cardinal doctrine of the Roman Catholic dogmatic theology after Aquinas, is more like the Leibnizian proof of God as the ground of the world, i.e., given God, we can understand the existence of the world. Here cause an effect behave like premises and conclusion. Instead of working back from a supposed effect to its cause, we work forward from an indubitable premise to a conclusion. Indeed for ibn Sīna, God creates through a rational necessity. On the basis of this rational necessity, ibn Sīna also explains the divine pre-knowledge of all events, as we shall see in his account of God. The world, as a whole, is then contingent, but, given God, it becomes necessary, this necessity being derived from God. This is ibn Sīnā's principle of existence stated in brief; we shall now analyse it according to the complex materials which ibn Sīna has left us. It involves more than one point of view.

From the metaphysical point of view, the theory seeks to supplement the traditional Aristotelian analysis of an existent into two constituent elements, as it were, viz., form and matter. According to Aristotle, the form of a thing is the sum total of its essential and universalizable qualities constituting its definition; the matter in each thing is that which has the potentiality of receiving these qualities—the form—and by which the form becomes an individual existent. But there are two major difficulties in this conception from the point of view of the actual existence of a thing. The first is that the form is universal and, therefore, does not exist. Matter too, being pure potentiality, does not exist, since it is actualized only by the form. How then shall a thing come into existence by a non-existent form and an equally non-existent matter? The second difficulty arises from the fact that, although Aristotle generally holds that the definition or essence of a thing is its form, he nevertheless says in certain important passages that matter is also to be included in the essence of a thing, otherwise we shall have only a partial definition of it. If, then, we regard both form and matter as constitutive of definition, we can never arrive at the actual existence of a thing. This is the rock against which the whole scheme of Aristotle to explain Being threatens to break.

This is why ibn Sīna holds that from form and matter alone you would never get a concrete existent, but only the essential and accidental qualities. He has analysed at some length the relation of form and matter in K. al-Shifā', where he concludes that both form and matter depend on God (or the active intellect) and, further, that the composite existent also cannot be caused by form and matter alone but there must be "something else." Finally, he tells us, "Everything except the One who is by His essence One and Existent acquires existence from something else.… In itself it deserves absolute non-existence. Now, it is not its matter alone without its form or its form alone without its matter which deserves non-existence but the totality (of matter and form)." This is why ibn Sīna substitutes a three-term analysis of the existent matèrial objects instead of the traditional Greek dyadic formula. It must be noted that it is Aristotle's doctrine which is being developed here. Many scholars have held that ibn Sīna is here following a Neo-Platonic line instead of the Aristotelian one, but, from this point of view, the Neo-Platonic doctrine is the same as that of Aristotle, viz., the dyadic scheme of form and matter, except that, according to Plotinus, under the influence of Plato, the forms have a higher ontological status and exist in God's mind who then proceeds to make them existent in matter. It should also be borne in mind that existence is not really a constituent element of things besides matter and form; it is rather a relation to God: if you view a thing in relation to the divine existentializing agency, it exists, and it exists necessarily and, further, its existence is intelligible, but when out of relation with God, its existence loses its intelligibility and meaning. It is this relational aspect which ibn Sīna designates by the term "accident" and says that existence is an accident.

Ever since the criticism of ibn Sīnā's doctrine by ibn Rushd who, among other things, accused ibn Sīna of having violated the definition of substance as that which exists by itself, and of Aquinas who, although he adopts the distinction between essence and existence under the direct influence of ibn Sīna, nevertheless follows ibn Rushd in his criticism, the unanimous voice of the Western historians of medieval philosophy has been to the effect that existence, according to ibn Sīna, is just an accident among other accidents, e.g., round, black, etc. We have said that when ibn Sīna talks of existence as an accident with relation to objects (as distinguished from essence) he just means by it a relation to God; it is, therefore, not an ordinary accident. Further, if existence were an accident, one could think it away and still go on talking of the object just as one can do in the case of other accidents and, indeed, in that case ibn Sīna would have been forced to hold something like the Meinongian view held by many Muslim Mutakallims that non-existents must also "exist" in some peculiar sense of that word. But this is the very doctrine which ibn Sīna ridicules.… [ibn Sīna] criticizes the view of those who hold that a non-existent "thing" must, nevertheless, "exist" in some sense so that we can talk about it. He says, "Those people who entertain this opinion hold that among those things which we can know (i. e., be acquainted with) and talk about, are things to which, in the realm of non-being, non-existence belongs as an attribute. He who wants to know more about this should further consult the nonsense which they have talked and which does not merit consideration." Indeed, according to ibn Sīna, the ideas of existence and unity are the primary ideas with which we must start. These underived concepts are the bases of our application of other categories and attributes to things and, therefore, they defy definition since definition must involve other terms and concepts which are themselves derived.

It will be seen that this problem now is not a metaphysical one but has to do with logic. Ibn Sina has attempted to give his own answer to the question: How is it possible that we can talk of non-existents and what do these latter mean? His answer is that we can do so because we give to these objects "some sort of existence in the mind." But, surely, our individual images cannot constitute the meanings of these entities for the obvious reason that when we talk, e.g., of a space-ship, it must have an objective meaning. It is, nevertheless, true that ibn Sīna has seen the basic difficulty of the logic of existence. And our modern logic itself, despite its superior techniques and some valuable distinctions, seems nowhere nearer the solution. It has tried hard to contend that whenever I talk of a space-ship, although none exists, I am not talking of a "thing," of an individual object, but only of a generic object or a conglomeration of properties. But is this really so? Is it absurd to say that the "individual space-ship I am talking of now has this and this property"? Besides, the crux is the phrase "conglomeration or set of properties"—what is it to which they belong and of which I profess to be talking?

Besides this meaning of "accident" as a peculiar and unique relation of an existent to God, the term "accident" in ibn Sīna has another unorthodox philosophic meaning. This concerns the relationship of a concrete existent to its essence or specific form, which ibn Sīna also calls accidental. This use of the term "accident" is quite pervasive in ibn Sīnā's philosophy and, without knowing its correct significance, one would be necessarily led to misinterpret some of his basic doctrines. Now, whenever two concepts are clearly distinguishable from each other, they must refer to two different ontological entities, as we said above, and, further, whenever two such concepts come together in a thing, ibn Sīna describes their mutual relationship as being accidental, i.e., they happen to come together, although each must be found to exist separately. This is the case, for example, between essence and existence, between universality and essence.

According to ibn Sīna, essences exist in God's mind (and in the mind of the active intelligences) prior to the individual existents exemplifying them in the external world and they also exist in our minds posterior to these individual existents. But these two levels of the existence of an essence are very different. And they differ not only in the sense that the one is creative, and the other imitative. In its true being, the essence is neither universal nor particular, but it is just an essence. Hence he holds that both particularity and universality are "accidents" which happen or occur to the essence. Universality occurs to it in our minds only, and ibn Sīna takes a strictly functional view of the universals: our mind abstracts universals or general concepts whereby it is enabled to treat the world of infinite diversity in a summary and scientific manner by relating an identical mental construction to a number of objects. In the external world the essence does not exist except in a kind of metaphorical sense, i.e., in the sense in which a number of objects allow themselves to be treated as being identical. Existents in the external world are the individual concrete objects, no two of which are exactly the same. He says, "It is impossible that a single essence should exist identically in many", and again, "It (i.e. absolute manness) is not the manness of 'Amr; it is different from it, thanks to the particular circumstances. These particular circumstances have a role in the individual person of Zaid … and also a role in the 'man' or 'manness' inasmuch as it is related to him." It is clear especially from this last statement that the "essence" virtually undergoes a change in each individual. That is why we must say that if we regard essence as a universal, that concrete determinate existence is something over and above the essence; it is something added to the essence, or it is an "accident" of the essence.

Two things must be specially noted here. First, that existence is something added not to the existent objects—this would be absurd—but to the essence. This is because everything whether it exists or not—indeed whether it is existable or not—in fact every concept is "something" of which assertions can be made, whether positive or negative. Indeed, even non-existence is "something," since one can talk about it. But a positive individual existent is more than just "something." (This distinction between "something" and an existent, treated by ibn Sīna which has confusedly returned in present-day logic, was originally made by the Stoics.) Hence ibn Sīna says that when existence is attributed to essences, this existence is equivalent to "is something" and, therefore, such statements are not "profitable." But statements about existents are informative and profitable, since they add to the essence something that is new. Secondly, we must note that although ibn Sīna speaks in several places of matter as the principle of multiplicity of forms or essences, he never says that matter is the principle of individual existence. The sole principle of individual existence is God—the Giver of existence; matter is the occasional cause of existence, supplying external attributes of multiplicity.

We have given a considerable number of quotations from ibn Sīna in the treatment of this problem not only because it is of capital importance for ibn Sīnā's philosophy, but also because there has been such a great deal of fundamental confusion in the traditional treatment of the subject that a clarification of the terms "existence," "accident" in this relation, and "essence" is absolutely necessary.…

With Aristotle, ibn Sīna stresses the intimate connection of mind and body; but whereas Aristotle's whole trend of thought rejects a two-substance view, ibn Sīna holds a form of radical dualism. How far these two aspects of his doctrine are mutually compatible is a different question: ibn Sīna certainly did not carry his dualism through to develop a parallelistic, occasionalistic account of mind-body relationship. His remarks, nevertheless, on either side are both interesting and profound. We shall first state his arguments for the two-substance view and then discuss their close interconnection. To prove that the human soul is a substance capable of existing independently of the body, our philosopher employs two different arguments. One appeals to direct self-consciousness, the other seeks to prove the immateriality of the intellect. We can postpone his teaching on the intellect till we discuss his theory of knowledge; here we shall state and discuss his first argument. Indeed, according to him, this is the more direct way of proving the incorporeal substantiality of the soul acting not as an argument but as an eye-opener.

The argument is stated by ibn Sīna in the first chapter of the psychological book of the K. al-Shifā' and then re-stated and discussed in the last but one chapter of the same book. Let us suppose, as he says, that a person is created in an adult state, but in such a condition that he is born in a void where his body cannot touch anything and where he cannot perceive anything of the external world. Let us also suppose that he cannot see his own body and that the organs of his body are prevented from touching one another, so that he has no sense-perception whatsoever. Such a person will not affirm anything of the external world or even the existence of his own body but will, nevertheless, affirm the existence of his self as a purely spiritual entity. Now, that which is affirmed is certainly not the same as that which is not affirmed. The mind is, therefore, a substance independent of the body. Our philosopher is here describing an imaginary case impossible of realization, but his real point, as of Descartes, is that we can think away our bodies and so doubt their existence, but we cannot think away our minds.

The affinity of ibn Sīnā's argument with that of Descartes' cogito ergo sum has been justly pointed out by historians of philosophy. Actually, this whole trend of thought is inspired by the argument of Plotinus for the separateness of the mind from the body. But there is an important difference between ibn Sīnā's and Descartes' formulations. With regard to Descartes, the question can be and has been raised: Is the existence of the self a matter of inference or an immediate datum of consciousness? Whatever the answer to this question may be, there is no doubt that consciousness or "I think" is constitutively and necessarily involved in Descartes' "I am." This is so much so that "I think" and "I am" have the same meaning in Descartes. This being the position, it is obvious that in this case the consciousness of the self and its existence cannot be logically disengaged from each other. In ibn Sīnā, however, although the element of consciousness is present since one can "affirm one's own existence," it is nevertheless present only as a way of locating the self: it is a contingent fact and not a logical necessity. In fact, ibn Sīna presents a medial position between Descartes and Plotinus, for, according to the latter, consciousness, being a relation, signifies not utter self-identity but a kind of otherness; in complete self-identity, consciousness must cease altogether.

This argument, which seeks to establish dualism by doubting or denying the existence of the body, may be called the argument from abstraction in that it abstracts psychical functions from the total functions of the organism. Its fundamental weakness obviously is to insist that by thinking away the body, the body ceases to play a role in one's total consciousness. If the problem could be solved by a simple inspection of the self in this manner, nothing would be easier. Ibn Sīna seems to be aware that the position is liable to objections. He says: (If my self were identical with any bodily members) "say, the heart or the brain or a collection of such members and if it were their separate or total being of which I were conscious as being my self, then it would be necessary that my consciousness of my self should be my very consciousness of these members, for it is not possible that the same thing should be both cognized and uncognized in the same sense." He then goes on to say that "in fact I do not know by self-consciousness that I have a heart and a brain but I do so either by sense-perception (experience) or on authority." "I mean by what I know to be my self that which I mean when I say: 'I perceived, I intellected, I acted,' and all these attributes belong to me." But, ibn Sīna pauses to consider the possible objection: if you are not aware of your self being a bodily member, you are neither directly aware that it is your soul or mind.

Ibn Sīnā's answer to this objection is: "Whenever I present bodily attributes to this something which is the source of my mental functions, I find that it cannot accept these attributes," and thus this incorporeal entity must be the soul. Here we clearly see that the argument has taken a new turn and the phenomenon of direct consciousness is being supplemented by a further consideration to the effect that the disparateness between the mental and physical qualities is such that both cannot belong to one substance. And this is the perennial argument for the two-substance theory, viz., that the mental and the physical attributes are of qualitatively disparate genré.

From the acceptance of the view, that the mind is a substance, the conclusion that the mind is a unity follows tautologically and ibn S na lays great stress on it. Indeed, once again, both doctrines, viz., the reality of faculties and the unitary nature of the soul, are stated with equal emphasis by him. The reality of mental faculties was established by Aristotle but was further pursued by his commentators, notably Alexander of Aphrodisias. Ibn Sīna has devoted a special chapter to the question where he bases the multiplicity of faculties on the qualitative differences among mental operations. Nevertheless, he repeatedly stresses the necessity of an integrative bond (ribāt) for the diverse operations. Indeed, he declares that even the vegetative and perceptual functions in man, for example, are specifically different from those in plants and animals, thanks to the rationality present in man which pervades and changes the character of all his functions. This integrative principle is the mind itself.

The soul in its real being is then an independent substance and is our transcendental self. We shall return to its transcendence when we discuss ibn Sīnā's theory of knowledge.… Here we shall note only that Ibn Sīnā's arguments for the immortality of the soul are based on the view that it is a substance and that it is not a form of the body to which it is attached intimately by some kind of mystical relation between the two. There is in the soul which emerges from the separate substance of the active intelligence simultaneously with the emergence of a body with a definite temperament, a definite inclination to attach itself to this body, to care for it, and direct it to the mutual benefit. Further, the soul, as being incorporeal, is a simple substance and this ensures for it indestructibility and survival, after its origination, even when its body is destroyed.

But if at the transcendental level the soul is a pure spiritual entity and body does not enter into its definition even as a relational concept, at the phenomenal level the body must be included in its definition as a building enters into the definition of a (definite) builder. That is why ibn Sīna says that the study of the phenomenal aspect of the soul is in the field of natural science, while its transcendental being belongs to the study of metaphysics. Now, since at the phenomenal level there exists between each soul and body a mystique which renders them exclusively appropriate for each other—whether we understand this mystique or not—it follows that the transmigration of souls is impossible. (Transmigration is rejected by Aristotle who does not hold the two-substance view.) Indeed, this mystique is both the cause and the effect of the individuality of the self. Ibn Sīna, therefore, totally rejects the idea of the possible identity of two souls or of the ego becoming fused with the Divine Ego, and he emphasizes that the survival must be individual. It is a primary fact of experience that each individual is conscious of his self-identity which cannot be shaken by any kind of argument. Indeed, our philosopher is so keen to affirm the individuality of personality that he says that even the qualitative nature of the intellectual operations in different individuals may be different— a statement which would have shocked not only the Platonists and Neo-Platonists, but even perhaps Aristotle, since, according to the universal Greek doctrine, the intellect represents, at least, the qualitative identity of mankind, a doctrine which was later pushed to its logical extremes by ibn Rushd.

The relationship, then, between soul and body is so close that it may affect even the intellect. It goes without saying that all the other psycho-physical acts and states have both aspects—mental and physical. This was emphasized by Aristotle himself. But Aristotle's doctrine, even if it is not outright materialistic, is quasi-materialistic and, whereas it either emphasizes the double aspect of each state or operation, or tends strongly to point out the influence of the body on the mental phenomena, exactly the reverse is the case with ibn Sīina. Indeed, his insistent stress on the influence of the mind on the body constitutes an outstanding and one of the most original features of his philosophy. Whereas in Aristotle, life and mind give a new dimension to the material organism, in ibn Sina, under the inspiration of the Neo-Platonic thought and the influence of his own metaphysically spiritual predilections, this no longer remains a mere dimension. The material side of nature is both pervaded and overshadowed by its mental and spiritual side, even though, as a medical man, he is keen to preserve the importance of the physical constitution, especially in the case of the character of the emotions and impulses. Indeed, as we shall see, his medical art helped him to gauge the extent of mental influence on apparently bodily states.

At the most common level, the influence of the mind on the body is visible in voluntary movement: whenever the mind wills to move the body, the body obeys. In his detailed account of animal motion, ibn Sina has enumerated four stages instead of Aristotle's three. The three stages according to Aristotle are: (1) imagination or reason, (2) desire, and (3) movement of the muscles. Ibn Sina has split up the second into (1) desire and (2) impulsion (ijma') for, he says, not every desire can move to action but only when it is impulsive, whether consciously or unconsciously. The second, and more important difference between ibn Sina and the traditional view is that according to the latter the initiation of bodily movement must always lie in a cognitive state, whether it is imagination or reason. Ibn Sina holds that, while in most cases the cognitive act precedes the affective and the conative ones, this is not true of all cases. We read: "All (the appetitive and conative) faculties also follow imaginative faculties.… But sometimes it happens, e.g., in cases of physical pain, that our natural impulse tries to remove the cause of pain and thus initiates the process of stirring up imagination. In this case, it is these (appetitive) faculties which drive the imagination to their own purpose, just as, in most cases, it is the imaginative faculty which drives the (appetitive and conative) faculties towards the object of imagination." Thus, according to ibn Sina, the initiation of the animal motion can lie in the affections as well as in the cognitive states. Psychologically, this is of great significance and marks an advance over the purely and one-sidedly intellectual accounts of traditional philosophy.

Here we reach the second level of the influence of the mind on the body, viz., that of emotions and of the will. Ibn Sina tells us from his medical experience that actually physically sick men, through sheer will-power, can become well and, equally, healthy men can become really ill under the influence of sickness-obsession. Similarly, he says, if a plank of wood is put across a well-trodden path, one can walk on it quite well, but if it is put as a bridge and down below is a chasm, one can hardly creep over it without an actual fall. "This is because he pictures to himself a (possible) fall so vividly that the natural power of his limbs accords with it." Indeed, strong emotions like fear can actually destroy the temperament of the organism and result in death, through influencing the vegetative functions: "This happens when a judgment takes place in the soul; the judgment, being pure belief, does not influence the body, but rather when this belief is followed by joy or grief." Joy and grief too are mental states, ibn Sina goes on, but they affect the vegetative functions. Again, "We do not regard it as impossible that something should occur to the soul, in so far as it is embodied, and be then followed by affections peculiar to the body itself. Imagination, inasmuch as it is knowledge, is not in itself a physical affection, but it may happen that, as a result, certain bodily organs, sexual for example, should expand.… Indeed, when an idea becomes firmly established in the imagination, it necessitates a change in the temperament.…" Just as, we are told, the ideas of health present in the doctor's mind produce actual health in a patient, so the soul acts on the body; only the doctor produces cure through media and instruments, but the soul does it without any instruments.

If, indeed, the soul were strong enough, it could produce cure and illness even in another body without instruments. And here ibn Sina produces evidence from the phenomena of hypnosis and suggestion (al-wahm al-'amil). He uses these considerations in order to show the possibility of miracles which are a part of the discussion of the question of prophethood. Here we will recall what we said before that, according to ibn Sina, a soul becomes exclusively attached to one body. Our newer consideration shows that it can transcend its own body to affect others. This would become possible only when the soul becomes akin to the universal soul, as it were.

It is on these grounds that ibn Sina accepts the reality of such phenomena as the "evil eye" and magic in general. We may note that the influence of the emotions on the body was known and discussed in later Hellenism. Especially since the Stoic conception of the principle of "Sympathy" in nature and Plotinus' elaboration of that principle, the mind-body interaction was explained on these lines. What is scientifically new in ibn Sina is that he also explains phenomena like magic, suggestion, and hypnosis, and, in general, the influence of one mind on other bodies and minds on these lines, i.e., by referring them to the properties of the influencing mind. In Hellenism, these phenomena were accepted, but were regarded as exceptionally occult. And in the mystery-mongering superstition of later Hellenism, "Sympathy" was given an occult twist. Magical properties were assigned to special objects: metals, animals, etc., through which the magician or the hypnotizer worked or pretended to work on the gods or spirits to intervene in the realm of nature and to produce occult effects. But the only principle which ibn Sina will accept—and here he strikes a very modern note—is to refer efficacy to the special constitution of the mind itself. This rests on the premise that it is of the nature of mind to influence matter and it belongs to matter to obey the mind, and ibn Sina will have no theurgic magic: "This is because the soul is (derived from) certain (higher) principles which clothe matter with forms contained in them, such that these forms actually constitute matter.… If these principles can bestow upon matter forms constitutive of natural species … it is not improbable that they can also bestow qualities, without there being any need of physical contact, action, or affection.… The form existing in the soul is the cause of what occurs in matter." The reason for this great change is that in later Hellenism the human soul had lost its dignity and people relied more and more for the explanation of the "para-natural" phenomena on the intervention of the gods.…

In accordance with the universal Greek tradition, ibn Sina describes all knowledge as some sort of abstraction on the part of the cognizant of the form of the thing known. His chief emphasis, elaborated most probably by himself, is on the degrees of this abstracting power in different cognitive faculties. Thus, sense-perception needs the very presence of matter for its cognitive act; imagination is free from the presence of actual matter but cannot cognize without material attachments and accidents which give to the image its particularity, whereas in intellect alone the pure form is cognized in its universality. It is very probable too that ibn Sina elaborated this theory "of the grades of abstraction" to avoid the objection to which Aristotle's doctrine of cognition (according to which all cognition is the abstraction of form "without its matter") was liable, viz., if perception is the knowledge of form alone, how do we know that this form exists in matter? Or, indeed, how do we know that matter exists at all?

Ibn Sina's position on perception is generally that of naive realism, like that of Aristotle and his commentators, holding a representational view of perception. But under criticism from scepticism and relativism which point out the relativity of perceived qualities, this representational view becomes seriously modified and ibn Sina finally accepts a quasi-causal or, rather, relational view of perceptual qualities, i.e., objects, which have certain real qualities in themselves, appear as such-and-such under such-and-such circumstances and from such-and-such a position. This is responsible for several subjectivist statements in ibn Sina, who comes to distinguish between "primary" and "secondary" perceptions: the "primary" perception being subjective or of the state of the percipient's own mind, the "secondary" perception being that of the external world. He did not clearly see, as we moderns do, the basic difficulties in this position. But his conception reappears in Western medieval philosophy as the distinction between the psychological or "intentional" object and the real object, a distinction which was much later developed by Locke into that of primary and secondary perceptual qualities.

But the great key-stone of ibn Sina's doctrine of perception is his distinction between internal and external perception. The external perception is the operation of the external five senses. Ibn Sina also divides the internal perception formally into five faculties, although he shows a great deal of hesitation on the subject. His chief aim is to separate the different functions or operations on a qualitative basis, and, of course, we once again remember his principle that to every clear idea there must correspond a distinction in reality. Indeed, his doctrine of the internal senses has no precedent in the history of philosophy. The first internal sense is sensus communis which is the seat of all the senses. It integrates sense-data into percepts. This general sense must be internal because none of the external five senses is capable of this function. The second internal sense is the imaginative faculty in so far as it conserves the perceptual images. The third faculty is again imagination in so far as it acts upon these images, by combination and separation. In man this faculty is pervaded by reason so that human imagination can deliberate and is, therefore, the seat of the practical intellect. The fourth and the most important internal faculty is called wahm which passed into the West as vis estimativa: it perceives immaterial motions like usefulness and harmfulness, love and hate in material objects, and is, in fact, the basis of our character, whether influenced or uninfluenced by reason. The fifth internal sense conserves in memory those notions which are called by him "intentions" (ma'ani).

The doctrine of wahm is the most original element in ibn Sina's psychological teaching and comes very close to what some modern psychologists have described as the "nervous response" of the subject to a given object. In Aristotle, this function is performed by imagination or perception itself, but ibn Sina contends that perception and imagination tell us only about the perceptual qualities of a thing, its size, colour, shape, etc.; they tell us nothing about its character or "meaning" for us, which must be read or discerned by an internal faculty of the organism. In the Stoics, again, we have the perceptual-moral theory of the oikeiosis or "appropriation," according to which whatever is perceived by the external senses is interpreted internally by the soul as the bearer of certain values. But the Stoics, in this doctrine, were primarily concerned with the development of a moral personality in man. Ibn Sina's doctrine of wahm, on the other hand, despite its moral significance, is primarily a purely psychological doctrine, explaining our instinctive and emotional response to the environment.

This "nervous response" operates at different levels. At one level it is purely instinctive as when a sheep perceives a wolf for the first time and flees from it, or as the mother instinctively feels love for her baby. This occurs without previous experience and hence through some kind of "natural inspiration" ingrained in the constitution of the organism. Secondly, it also operates at a "quasi-empirical" level. This occurs through association of ideas or images of memory. A dog which has suffered pain in the past from being beaten by a stick or a stone, associates the image of the object and the "intention" of pain and, when it sees the object again, at once runs away. This phenomenon of direct association can also become indirect and irrational. This happens in the case of animals and also in the case of less reasonable human beings. Some people who have irrationally associated the yellow colour of honey with both the colour and the bitter taste of gall, do not eat honey and in fact at its sight exhibit symptoms of gall-like taste. This principle of association appeared later in Leibniz; and the principle of irrational or automatic association has appeared more thoroughly worked out in recent experimental psychology under the name of the "conditioned reflex." Since wahm makes perceptual predictions on the basis of association of ideas, for which, says ibn Sina, there are innumerable causes (contiguity, similarity, etc.), its perceptual judgments may sometimes be false. Aristotle had noticed this failure of perception but could not explain it since he did not discern the influence of past experience on present perceptual judgments.

We come next to the doctrine of the intellect which ibn Sina has elaborated in great detail. He has taken over in his doctrine the theory of the development of human intellect announced by Aristotle very briefly and rather obscurely and then elaborated by Alexander of Aphrodisias and later by al-Farabi. But he has added quite new and original interpretations of his own. The doctrine, in brief, distinguishes between a potential intellect in man and an active intellect outside man, through the influence and guidance of which the former develops and matures. Basically, the problem is that of the origin of human cognition and it is explained on the assumption of a supra-human transcendent intellect which, when the human intellect is ready, bestows knowledge upon it.

As against Alexander, al-Farabi, and probably Aristotle, ibn Sina holds that the potential intellect in man is an indivisible, immaterial, and indestructible substance although it is generated at a definite time and as something personal to each individual. This has important religious consequences, for, whereas according to al-Farabi only men of developed intellect survive and others perish for ever at death, ibn Sina holds the immortality of all human souls. (According to Alexander of Aphrodisias, even the actualized intellect is perishable so that no soul is immortal.) The immateriality of the intellect is proved by ibn Sina in an unprecedented, elaborate, and scholastic manner, the basic idea being that ideas or "forms," being indivisible, cannot be said to be localized in any material organ.

But it is in his account of the intellectual operation and the manner of the acquisition of knowledge that the most original aspect of his doctrine of the intellect lies. Whereas, according to the Peripatetic doctrine, accepted by al-Farabi, the universal, which is the object of the intellective act, is abstracted from the particulars of sense-experience, for ibn Sina it issues directly from the active intellect. The Peripatetic tradition has given the following account of the rise of the universal from perceptual experience: First, we perceive several similar individuals; these are stored up in memory and after this constant operation the light of the active intellect "shines" upon them so that the essential nature common to all the particulars emerges from them. This theory is neither nominalistic nor realistic: it does say that the universal is more than what the instances of experience have given to the mind, but it holds that the universal lies somehow in these instances. For ibn Sina, the universal cannot emerge from the images of sense because it does not lie there. Further, as we have seen already, the essence, according to ibn Sina, is not really a universal: it only behaves as such when it is in our minds. Besides, no amount of particular instances would actually suffice to produce the universal essence which is applicable to infinite instances. He, therefore, declares that the task of our minds is to "consider" and reflect upon the particulars of sense-experience. This activity prepares the mind for the reception of the (universal) essence from the active intellect by an act of direct intuition. The perception of the universal form, then, is a unique movement of the intellective soul, not reducible to our perceiving the particulars either singly or totally and finding the common essence among them, for if so, it would be only a spurious kind of universal.

There is, besides, another vital consideration which leads to this view. If the perception of the individual instances and the noting of their resemblance (which latter, indeed, itself presupposes the possession of the universal by the mind) were sufficient to cause the universal, then acquisition of knowledge would become mechanical and this mechanism would operate necessarily.

It is, however, in fact not true that cognition can be so mechanically and deterministically produced. The origin of knowledge is mysterious and involves intuition at every stage. Of all intellectual knowledge, more or less, it is not so much true to say "I know it" as to admit "It occurs to me." All seeking for knowledge, according to ibn Sina (even the emergence of the conclusion from the premises), has this prayer-like quality: the effort is necessary on the part of man; the response is the act of God or the active intellect. We are, indeed, often not aware as to what it is we want to know, let alone go ahead and "know it." A theory of knowledge which fails to notice this fundamental truth is not only wrong but blasphemous.

All ideas or forms then come from outside. The precise sense of the "outside" we shall try to work out [later]. But in the meantime we should notice certain other important characteristics of our knowledge. The first is that it is piecemeal and discursive, not total: it is also mostly "receptive" in the sense noted just above. In our normal consciousness we are not fully aware of the whence and whither of our cognition. True, there are people who are receptive in the ordinary sense of the word in that they do not discover either anything, or much that is new and original: they only learn for the most part; while there are others who discover new things. But even these latter are only "receptive" in the sense that, not being fully conscious of the whence and whither of their knowledge—not aware of the total context of reality—they do not know the full meaning of their discoveries. This is because, in the common run of thinkers ideas come and go in succession and, therefore, their grasp of reality is not total. Hence ibn Sina rejects the general and especially later Greek doctrine of the absolute identity of subject and object in intellectual operation, for, he argues, in the case of normal consciousness, there being a succession of ideas, if the mind became identical with one object, how could it then become identical with another? In this connection he rebukes Porphyry for his "mystical and poetical statements." Why he should single out the pupil of Plotinus, is not quite clear, for the doctrine is both Peripatetic and Neo-Platonic, although there are, it must be admitted, moderate representatives like Alexander of Aphrodisias just as there are extremist champions of the doctrine like most Neo-Platonists.

Ideas in this detailed, discrete, and discursive form of knowledge, as we have said, come into the mind and go out of it. Ibn Sina is insistent that when an idea is not actually being used in intellection, it does not remain in the mind, or, in other words, there is, properly speaking, no intellectual memory as there is a memory of sensible images. There is nothing in the mind which can conserve intelligibles just as there is a conservatory in the soul for sensibles, for the existence of an intelligible in the mind means nothing else than the fact that it is actually being intellected. Absolutely speaking, it should be remarked that the word memory, when applied to sensible objects and individual events of the past, is radically different from the memory of universals and universal propositions, for in the former case there is a reference to the past. Aristotle himself had indicated this doctrine in his De Memoria et Reminiscentia where he says that universals are remembered only per accidens. The ordinary human thinking mind, says ibn Sina, is like a mirror upon which there is a succession of ideas reflected from the active intellect. This does not mean that a truth once acquired, because it "goes out of the mind," has to be relearnt all over again when it is remembered. By our initial acquisition we acquire a skill to contact the active intellect and in remembering we simply use that skill or power. Resuming the analogy of the mirror, ibn Sina says that, before acquisition of knowledge, the mirror was rusty; when we re-think, the mirror is polished, and it only remains to direct it to the sun (i.e., the active intellect) so that it should readily reflect light.

Even so is the ordinary philosophic (or mystic) consciousness: it is mostly partial (in varying degrees) even when it is original and creative (again in varying degrees) and it is, therefore, obviously not in total contact with reality, or, as ibn Sina puts it, "is not one with the active intellect." But even in our ordinary cognitive processes, there are serious pointers to the existence of a type of consciousness in which this partiality and discursiveness may be overcome and which may be wholly creative, with the pulse of the total reality in its grasp. These pointers are illustrated by ibn Sina by the example of a man who is confronted suddenly with a questioner who asks him a question which he has never asked himself before and, therefore, to which he cannot give a detailed answer on the spot. He is sure, however, that he can answer it because the answer has just "occurred" to him and lies within him. He then proceeds to the details and formulates the answer. "The strange thing is," says ibn Sina, "that when this man begins to teach the questioner the answer to his question, he is simultaneously teaching himself as well" the detailed and elaborated form of knowledge even though he previously possessed this knowledge in a simple manner. This simple, total insight is the creator of that detailed, discursive knowledge which ensues. Now, this simple, total insight (the scientia simplex of the medieval Latin scholastics comes from ibn Sina) is the creative reason (or the active intellect); the formulated and elaborate form is the "psychic" knowledge, not the absolutely intellectual cognition. A person possessed of this simple creative agency, if such a one exists, may well be said to be one with the active intellect; and since he possesses a total grasp of reality, he is sure, absolutely sure, of the whence and whither of knowledge (ibn Sina puts a great emphasis on this self-confidence, certainty, conviction, or faith); he alone is aware of the total context of truth and, therefore, in him alone there is the full awareness of the meaning of each term in the process of reality; and, therefore, finally, only such a person can enter (and must enter) most significantly into temporal history, moulding it and giving it a new meaning. This is the prophet; but how to ascertain his existence? …

The necessity of the phenomenon of prophethood and of divine revelation is something which ibn Sina has sought to establish at four levels: the intellectual, the "imaginative," the miraculous, and the socio-political. The totality of the four levels gives us a clear indication of the religious motivation, character, and direction of his thinking. Indeed, from our description and partial interpretation of his central philosophical theses so far, his deeply religious spirit has emerged very clearly. His theory of "Being" has led to the dependence of every finite being on God; and his doctrines of mind-body relationship and of the genesis and nature of knowledge have both culminated in the religious conception of miracles in the one case, and of a creative revelatory knowledge in the other. And there is not the slightest suggestion that religiosity is something artificially grafted upon his purely rational thinking; on the contrary, it has organically grown out of a rigorous process of ratiocination, and goes down to the very kernel of his thought.

It may be said that ibn Sīna is a citizen of two intellectual-spiritual worlds; the Hellenic and the Islamic. In his own mind he has so intrinsically unified the two worlds that they are identical; the question of disloyalty to either, therefore, does not arise for him at all. Under this circumstance, both traditional Islam and the heritage of Hellenism were inevitably interpreted and modified to a greater or lesser extent. This is apparent in the whole of his philosophy which enters into the technically religious field, but is most palpably so in his doctrine of prophecy. In this doctrine, ibn Sīna drastically modifies the Muslim dogmatic theology by declaring that the Qur'anic revelation is, by and large, if not all, symbolic of truth, not the literal truth, but that it must remain the literal truth for the masses (this does not mean that the Qur'an is not the Word of God; indeed, as we shall see, it is in a sense literally the Word of God); further, that the Law, although it must be observed by everyone, is also partly symbolic and partly pedagogical and, therefore, an essentially lower discipline than philosophic pursuits. (This again does not mean that we can dispense with the Law at any stage of our individual or collective development, for to be social belongs to the essence of man.) The interpretation and modification of Hellenism in this doctrine is obvious: although most elements of the Muslim philosophic doctrine of prophethood exist in Hellenism, they nevertheless exist in a nebulous and sometimes in a crude form; further, they are scattered. Indeed, the Greeks had no conception of prophethood and prophetic revelation as the Muslims knew it. In fact, the Muslim conception of prophethood is new and unique in the history of religion. For the Muslim philosophers (especially ibn Sina, for although al-Farabi had pioneered the way, we do not find all the elements in him, notably, the intellectual and the miraculous), to have evolved out of these nebulous, crude, and disjointed elements an elaborate, comprehensive, and refined theory of prophecy to interpret the personality of Muhammad, is nothing short of the performance of a genius.

At the intellectual level, the necessity of the prophetic revelation is proved by an argument elaborated on the basis of a remark of Aristotle that some people can hit upon the middle term without forming a syllogism in their minds. Ibn Sina constructs a whole theory of total intuitive experience on the basis of this scanty remark. Since, he tells us, people differ vastly with regard to their intuitive powers both in quality and quantity, and while some men are almost devoid of it, others possess it in a high degree, there must be a rarely and exceptionally endowed man who has a total contact with reality. This man, without much instruction from outside, can, by his very nature, become the depository of the truth, in contrast with the common run of thinkers who may have an intuitive experience with regard to a definite question or questions but whose cognitive touch with reality is always partial, never total. This comprehensive insight then translates itself into propositions about the nature of reality and about future history; it is simultaneously intellectual and moral-spiritual, hence the prophetic experience must satisfy both the philosophic and the moral criteria. It is on the basis of this creative insight that the true prophet creates new moral values and influences future history. A psychologicomoral concomitant of this insight is also the deep and unalterable self-assurance and faith of the prophet in his own capacity for true knowledge and accurate moral judgment: he must believe in himself so that he can make others believe in him and thus succeed in his mission to the world.

This insight, creative of knowledge and values, is termed by ibn Sina the active intellect and identified with the angel of revelation. Now, the prophet qua prophet is identical with the active intellect; and in so far as this identity is concerned, the active intellect is called 'aql mustafad (the acquired intellect). But the prophet qua human being is not identical with the active intellect. The giver of revelation is thus in one sense internal to the prophet, in another sense, i.e., in so far as the latter is a human being, external to him. Hence ibn Sina says that the prophet, in so far as he is human, is "accidentally," not essentially, the active intellect (for the meaning of the term "accidental," see the first section of this essay). God can and, indeed, must come to man so that the latter may develop and evolve, but the meaning of God can at no stage be entirely exhausted in man.

But although the intellectual-spiritual insight is the highest gift the prophet possesses, he cannot creatively act in history merely on the strength of that insight. His office requires inherently that he should go forth to humanity with a message, influence them, and should actually succeed in his mission. This criterion leads the Muslim philosophers, although they admit the divineness of the leading Greek thinkers and reformers, to fix their minds upon Moses, Jesus, and, above all, Muhammad who, undoubtedly, possesses the requisite qualities of a prophet to the highest degree. These requisite qualities are that the prophet must possess a very strong and vivid imagination, that his psychic power be so great that he should influence not only other minds but also matter in general, and that he be capable of launching a socio-political system.

By the quality of an exceptionally strong imagination, the prophet's mind, by an impelling psychological necessity, transforms the purely intellectual truths and concepts into lifelike images and symbols so potent that one who hears or reads them not only comes to believe in them but is impelled to action. This symbolizing and vivifying function of the prophetic imagination is stressed both by al-Farabi and ibn Sina, by the latter in greater detail. It is of the nature of imagination to symbolize and give flesh and blood to our thoughts, our desires, and even our physiological inclinations. When we are hungry or thirsty, our imagination puts before us lively images of food and drink. Even when we have no actual sexual appetite but our physical condition is ready for this, imagination may come into play and by stirring up suitable vivid images may actually evoke this appetite by mere suggestion. This symbolization and suggestiveness, when it works upon the spirit and the intellect of the prophet, results in so strong and vivid images that what the prophet's spirit thinks and conceives, he actually comes to hear and see. That is why he "sees" the Angel and "hears" his voice. That is why also he necessarily comes to talk of a paradise and a hell which represent the purely spiritual states of bliss and torment. The revelations contained in the religious Scriptures are, for the most part, of the figurative order and must, therefore, be interpreted in order to elicit the higher, underlying, spiritual truth.

It is the technical revelation, then, which impels people to action and to be good, and not the purely intellectual insight and inspiration. No religion, therefore, can be based on pure intellect. However, the technical revelation, in order to obtain the necessary quality of potency, also inevitably suffers from the fact that it does not present the naked truth but truth in the garb of symbols. But to what action does it impel? Unless the prophet can express his moral insight into definite enough moral purposes, principles, and indeed into a socio-political structure, neither his insight nor the potency of his imaginative revelation will be of much use. The prophet, therefore, needs to be a Lawgiver and a statesman par excellence—indeed the real Law-giver and statesman is only a prophet. This practical criterion throws into still bolder relief the personality of Muhammad in the philosopher's mind. The Law (Shari'ah) must be such that it should be effective in making people socially good, should remind them of God at every step, and should also serve for them as a pedagogic measure in order to open their eyes beyond its own exterior, so that they may attain to a vision of the true spiritual purpose of the Lawgiver. The Law is not abrogated at any stage for anybody, but only the philosophic vision of the truth gives to the Law its real meaning; and when that vision is attained, the Law seems like a ladder which one has climbed but which it would still be unwise to discard. For those relatively unfortunate souls which cannot see through the Law its philosophic truth, the technical revelation and the letter of the Law must remain the literal truth.…

We have learnt [earlier] that God is unique in that He is the Necessary Being; everything else is contingent in itself and depends for its existence upon God. The Necessary Being must be numerically one. Even within this Being there can be no multiplicity of attributes— in fact, God has no other essence, no other attributes than the fact that He exists, and exists necessarily. This is expressed by ibn Sina by saying that God's essence is identical with His necessary existence. Since God has no essence, He is absolutely simple and cannot be defined. But if He is without essence and attributes, how can He be related to the world in any way? For Aristotle, who held this conception of the Deity, the world presented itself as a veritable other— it was neither the object of God's creation, nor of care, not even of knowledge. His God led a blissful life of eternal self-contemplation and the world organized itself into a cosmos out of love and admiration for Him, to become like Him.

The Muslim philosophical tradition finds the solution under the influence of the Neo-Platonic example which combines God's absolute simplicity with the idea that, in knowing Himself, God also knows in an implicit, simple manner the essence of things. The system is worked out and systematized by ibn Sina, who strives to derive God's attributes of knowledge, creation, power, will, etc., from His simple unchanging being, or, rather, to show that these attributes are nothing but the fact of His existence. This is done by an attempt to show that all the attributes are either relational or negative; they are, thus, identical with God's being and with one another. The Deity is, therefore, absolutely simple. That God is knowing, is shown by the fact that being pure from matter and pure spirit, He is pure intellect in which the subject and object are identical.

But God's self-knowledge is ipso facto knowledge of other things as well, since, knowing Himself, He also inevitably knows the rest of the existents which proceed from Him. Here ibn Sina strikes an original note. According to the philosophical tradition of Hellenism, God, at best, can know only the essences (or universals) and not the particular existents, since these latter can be known only through sense-perception and, therefore, in time; but God, being supra-temporal and changeless and, further, incorporeal, cannot have perceptual knowledge. This doctrine of the philosophers was especially repugnant to Islam, for it not only made God's knowledge imperfect, but it made God Himself useless for those whose God He is to be. Ibn Sina devises an argument to show that although God cannot have perceptual knowledge, He nevertheless knows all particulars "in a universal way," so that perceptual knowledge is superfluous for Him. Since God is the emanative cause of all existents, He knows both these existents and the relations subsisting between them. God knows, for example, that after such a series of events a solar eclipse would occur, and knowing all the antecedents and consequences of this eclipse, He knows in a determinate manner its qualities and properties; He knows, therefore, what this particular eclipse will be, and can differentiate it completely from all other events even of the same species, viz., eclipse in general. But when the particular eclipse actually occurs in time, God, not being subject to temporal change, cannot know it. But He also need not know it in this way, for He knows it already. Very ingenious though this theory is and, we think, successful in showing that sense-perception is not the only way to know the particulars, it is obvious that it cannot avoid the introduction of time factor, and, therefore, change in divine knowledge. Al-Ghazali's criticism of the theory in the thirteenth discussion of his Tahafut al-Falasifah certainly finds the target at this point, although his view that according to ibn Sina God cannot know individual men but only man in general, is obviously mistaken, for if God can know a particular sun-eclipse, why can He not know, in this manner, an individual person? Indeed ibn Sina declares in the Qur'anic language that "not a particle remains hidden from God in the heavens or on the earth."

As regards God's attributes of volition and creation, ibn Sina's emanationist account renders them really pointless as al-Ghazali has shown. In a thoroughly intellectualist-emanationist account of the Deity, will has no meaning. For ibn Sina, God's will means nothing but the necessary procession of the world from Him and His self-satisfaction through this. Indeed, he defines it in purely negative terms, viz., that God is not unwilling that the world proceed from Him; this is very different from the positive attributes of choice and the execution of that choice.

Similarly, the creative activity of God, for ibn Sina, means the eternal emanation or procession of the world, and since this emanation is grounded finally in the intellectual nature of God, it has the character of unalterable rational necessity. Even though al-Ghazali's criticism which assimilates the divine activity of ibn Sina to the automatic procession of light from the sun and, thus, rejects the appellation of "act" to God's behaviour, is not quite correct (since according to ibn Sina, God is not only conscious of the procession of the world from Him, but is also satisfied with and "willing" to it), the term "creation" is nevertheless used only in a Pickwickian sense, and the term "act" (in the sense of voluntary action) is also seriously modified, since, as we have said, there is no question of real choice. Rationally determined, activity is, of course, compatible with will and choice and can also be said to be done with choice, but this choice has to be brought in as an additional element both initially and finally. For, suppose, a man chooses to think about a certain problem. Now, the initial choice is his own to think about this rather than that problem and then at any moment he can also choose or will to terminate this process of thinking. What goes on between the beginning and the end will be a rationally determined process of thought, and not a series of choices, though the process as a whole is also chosen and voluntary. But in the philosophical account of God there is just no room for this additional factor either at the end or at the beginning.

The world, then, exists eternally with God, for both matter and forms flow eternally from Him. But although this concept was abhorrent to Islamic orthodoxy, ibn Sina's purpose in introducing it was to try to do justice both to the demands of religion and of reason and to avoid atheistic materialism. For the materialists, the world has existed eternally without God. For ibn Sina, too, the world is an eternal existent, but since it is in itself contingent, in its entirely it needs God and is dependent upon Him eternally. We see here the double purpose of the doctrine of essence and existence. Unlike atheism, it requires God who should bestow being upon existents; and in order to avoid pantheism, it further requires that the being of God should be radically differentiated from the being of the world.

The chief crux of the eternity of the world, which has been stressed by the opponents of the doctrine throughout the history of thought, is that it involves an actual infinite series in the past. In answer, it has been said, ever since Kant, that it is not impossible at all to imagine an infinite in the past, just as it is not impossible to imagine it in the future, i.e., there is no absurdity involved in starting from any given moment backwards and traversing the past and at no point coming to the beginning of the past. The fallacy of this answer consists in assimilating the past to the future, for the past is something actual in the sense that it has happened and is, therefore, determinate once and for all. But the same fallacy, we think, is implied in the objection itself, and it seems that the application of the term "infinite" is inappropriately used for the past: the term "infinite" is used either for a series which is endless or which is both beginningless and endless. According to the thesis, the series is beginningless in the past, and endless in the future, whereas the objection seeks to put an end to the series at a given moment of time and then argues for an infinity in the past. Also, whereas beginning is a temporal concept, beginninglessness is a negation and need not be a temporal concept, but the objection obviously implies "infinity in the past" as a temporal concept.…

The influence of ibn Sina's thought has been enormous. In the East, indeed, his system has dominated the Muslim philosophical tradition right down to the modern era when his place is being given to some modern Western thinkers by those who have been educated in modern universities. In the madrasahs run on traditional lines, ibn Sina is still studied as the greatest philosopher of Islam. This is because no subsequent philosopher of equal originality and acuteness produced a system after him. Ibn Rushd, the last great philosophical name in the medieval tradition of Muslim philosophy, did not formulate his thought systematically, but chose to write commentaries on Aristotle's works. These commentaries, because of their superb scholarliness and acuteness, had a tremendous impact on the medieval West (which received Aristotle first through him) but were not only not influential in the Muslim East, but most of them are even lost in the original Arabic. His comparative lack of influence, of course, is chiefly due to the destruction of his works. For the rest, the subsequent philosophical activity was confined to the writing of commentaries on ibn Sina or polemics against him. Rare exceptions, like Sadr al-Din al-Shirazi, who wrote works on systematic philosophy, became less philosophical and more mystical in their intellectual, if not spiritual, temper. Nevertheless, these commentaries and polemics against and for ibn Sina and later systems have never yet been studied to any appreciable extent by modern students.

Now, let us determine more exactly the influence of ibn Sina within the Islamic tradition. To say that he has dominated the philosophical tradition in Islam is certainly not to say that he has dominated the Islamic tradition itself. On the contrary, the influence of ibn Sina—which is equivalent to the influence of philosophy—within Islam suddenly and sharply dwindled after the polemics of al-Ghazali and later on of al-Razi and then declined and became moribund. He continued to be read in the madrasahs merely as an intellectual training ground for theological students, not to philosophize anew but to refute or reject philosophy. The chief contributory factors to this situation were the formal rigidity of dogmatic theology and the fact that human reason itself became suspect due to the incompatibility of certain tenets of ibn Sina with this theology (besides, of course, social, political, educational, and economic causes). Not only did the philosopher's concept of the eternity of the world give affront to orthodoxy but also to those doctrines of his own which were developed with an especial regard for Islam, like the doctrine of prophethood. But perhaps the greatest theological objection was to his rejection of the bodily resurrection. On this point, although he maintains in the K. al-Najat (and the Shifa') that the resurrection of the flesh, while not demonstrable by reason, ought to be believed on faith; in his expressly esoteric work called Risalat al-Adwiyyah he rejects it in totality and with vehemence.

Ibn Slna's works were translated into Latin in Spain in the middle of the sixth/twelfth century. The influence of his thought in the West has been profound and farreaching. We have, while discussing ibn Slna's individual theories, alluded time and again to certain definite influences of his. But as it is impossible to do justice to this aspect fully within the space at our disposal, we shall be content with certain general remarks. Ibn Slna's influence in the West started penetrating palpably since the time of Albert the Great, the famous saint and teacher of St. Thomas Aquinas. Aquinas' own metaphysics (and theology) will be unintelligible without an understanding of the debt he owes to ibn Sina. No one can fail to observe ibn Sina's influence even in Aquinas' later and bigger works like the Summa Theologica and the Summa contra Gentiles. But the influence of the Muslim philosopher in the earlier formative period of the Christian Saint is overwhelming; he is mentioned by the latter, e.g., on almost each page of his De Ente et Essentia which is, indeed, the foundation of Aquinas' metaphysics. No doubt, ibn Sina is also frequently criticized by Aquinas and others, but even the amount of criticism itself shows in what esteem he was held in the West.

But the influence of ibn Sina is not restricted to Aquinas, or, indeed, to the Dominican Order or even to the official theologians of the West. The translator of his De Anima, Gundisalvus, himself wrote a De Anima which is largely a wholesale transporation of ibn Slna's doctrines. Similar is the case with the medieval philosophers and scientists, Robert Grosseteste and Roger Bacon. Duns Scotus and Count Zabarella, the finest of the late medieval commentators of Aristotle, also bear testimony to ibn Slna's enduring influence.…

But it would be futile to go on giving a mere catalogue of individual authors. In fact, the historic influence of this rich personality is a phenomenon which is being realized only now in the West.…

Herbert A. Davidson (essay date 1979)

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SOURCE: "Avicenna's Proof of the Existence of God as a Necessarily Existent Being," in Islamic Philosophical Theology, edited by Parviz Morewedge, State University of New York Press, 1979, pp. 165-87.

[In the following essay, Davidson insists that, although Avicenna purports to prove God's existence based on the concept of a necessarily existent being, his ontological argument is rather a kind of cosmological proof]

1. The cosmological proof of the existence of God may be characterized as a proof that begins by recognizing the actual existence of something in the universe; then it employs the principle of causality to establish that that thing and the universe as a whole have a cause. The a priori or ontological proof, in contrast, operates in the realm of thought without assuming the actual existence of anything. It begins with a concept of the nature of God, such as "that than which nothing greater can be conceived"; the "best"; the "absolutely simple"; "most perfect being"; "immeasurably powerful being"; "inifinite being"; or "substance" par excellence. Then, as the proof is generally understood, merely by analysis the concept, it undertakes to demonstrate that such a being must exist. It does their either directly, by showing that actual existence can be logically deduced from the concept; or indirectly, by showing that a self-contradiction would result from assuming that the being in question does not exist.

The term necessary being echoes through much of the history of the ontological proof. This term is not defined by every writer using it, but it seems, in ontological proofs, to have been used in one of two senses: (a) Necessary being may be understood in the sense of a being whose existence is established as a necessary truth, in the way that necessary truth is defined by Leibniz. According to Leibniz: "When a truth is necessary, its reason can be found by analysis, resolving it into more simple ideas and truths until we come to those that are primary … Truths of reasoning are necessary and their opposite is impossible." (b) A necessary being may also be understood as that which exists "through itself or "through its essence," as that "which has in its essence the sufficient reason of its existence."

There have been instances of ontological proofs employing the term necessary being in one sense or the other, as well as instances employing the term without specifying which sense is intended or whether both are. In fact, however, whether a given argument does happen to use the term necessary being in one sense or the other, every ontological proof should, it would seem, make both points. That is to say, every ontological proof attempts to show that the existence of God follows by logical necessity from an analysis of the concept of God's nature; such simply is what we mean by an ontological proof. And, it would further seem, an ontological proof can infer the existence of God from a concept of His nature only if the essence of God, as reflected in the concept, should somehow contain the "sufficient reason" of His existence. Thus the ontological proof assumes that the existence of God can (a) be proved by a priori, logical necessity; and by virtue of this assumption it further assumes that (b) God exists through His essence, that He has in His essence a sufficient reason of His existence.

Ontological proofs formulated with the aid of the term necessary being or necessary existence are known from the time of Descartes, and that term can appear in different stages of given argument. Descartes, in the course of elucidating his ontological proof, introduces necessary existence as a middle term, to justify passing from the concept of God as a perfect being to the actual existence of God: "Because actual existence is necessarily and at all times linked to God's other attributes, it follows certainly that God exists." In a number of philosophers, the thesis that God is necessarily existent is the conclusion of an ontological proof. Thus Spinoza, More, Leibniz, perhaps Christian Wolff, Baumgarten, and Moses Mendelssohn offer ontological proofs establishing the existence of a "necessary being," a "necessarily existent being," or a being that "necessarily exists." There also are at least two instances of proofs that start with necessary existence. That is to say, rather than beginning with a concept such as perfect being or infinite being or the like, they begin with the concept of necessary being, and then, by analyzing the concept, they establish that such a being does in fact exist. One of several formulations of the ontological argument in Leibniz consists in the following bare syllogism: "necessary being exists," which, Leibniz explains, is equivalent to saying that "being to whose essence existence belongs, exists; or being per se exists." This "is evident from the terms." "But God is such a being.… Therefore God exists," Mendelssohn reasoned, also as one of several formulations: "It is clear that necessary being … must possess all perfections in the highest degree … The concept of the necessary must accordingly also include within itself the perfection of existence. Therefore the necessary must also actually exist."

In addition to its role in the ontological proof, which must undertake to establish the existence of God as a necessary being in both senses of the term distinguished earlier, necessary being also plays a role in the cosmological proof. Now whatever sense the term necessary being may have in a given cosmological argument, the first of the two senses distinguished earlier would presumably be excluded. A cosmological proof could hardly establish the existence of a necessary being in the sense of a being whose existence is established merely by analyzing concepts: for the characteristic of this proof is precisely that it does not restrict itself to the mere analysis of concepts. On the other hand, every cosmological proof, whether or not it happens to use the term necessary being, must explicitly or virtually establish that God exists as a necessary being in the second sense. For the cosmological proof undertakes to establish the existence of God as an uncaused cause, consequently as a being that exists through itself, a being that as a sufficient reason of its existence in itself. Thus the cosmological proof—whether or not a given instance of the argument happens to use the term necessary being—cannot establish the existence of God in the first sense of necessary being affirmed by the ontological proof; and it must undertake to establish the existence of God in the second sense.

Leibniz gave perhaps the best known instance of a cosmological argument using the term necessary being By the side of his ontological argument, Leibniz offered another wherein he begins by considering the actual existence of objects in the external world. Then, employing the principle of sufficient reason, a form of the principle of causality, Leibniz establishes that "contingent things … can have their final or sufficient reason only in the necessary being," that is to say, in a being "which has the reason of its existence in itself—the second sense of necessary being. Wolff, Baumgarten, and Mendelssohn all repeat, with minor variations, Leibniz's cosmological proof, concluding in the existence of a necessary being. Thus Leibniz, perhaps Wolff, Baumgarten, and Mendelssohn give parallel proofs, one ontological and the other cosmological, of the existence of a necessary being. The contention of these philosophers is that the ontological and cosmological proofs lead independently to the same result, the existence of a necessary being in some such sense as that which exists "through its essence."

The two proofs were not, however, always kept distinct. At least one philosopher, Samuel Clarke, intentionally or inadvertently combined the two into a single overall demonstration. Clarke presents a cosmological argument in the spirit of Leibniz, contending that the changeable and dependent beings in the universe must have their "ground or reason of existence" in an eternal being which is "self-existent, that is, necessarily existing." But the only meaning of "self-existent" recognized by Clarke is that whose "necessity … must be antecedent in the natural order of our ideas to our supposition of its being"; whose necessary existence "must antecedently force itself upon us whether we will or no, even when we are endeavoring to suppose that no such being exists"; "the supposition of whose non-existence is an express contradiction." That is to say, the cosmological argument, which begins with the actual existence of things in the external world, establishes a being which is necessarily existent in the sense that its existence can be discovered merely by examining its concept "antecedently" and without considering the existence of anything in the external world, a being such that assuming it not to exist gives rise to a self-contradiction. This, however, is the sense of necessary being that can be established only through an ontological argument. Thus Clarke has intentionally combined or inadvertently confused two arguments, following the reasoning of the cosmological, but giving the conclusion of the ontological.

Clarke is of particular interest because he inspired Section IX of Hume's Dialogues Concerning Natural Religion. In Section IX of the dialogue, Hume allows the conservative participant to have his say. This participant maintains that the most effective way of establishing the existence of God is the "simple and sublime argument a priori." The argument, it turns out, has three steps, the first two of which correspond to the cosmological part of Clarke's demonstration. The third step then concludes that in order to explain the existence of the world "we must … have recourse to a necessarily existent being who carries the reason of his existence in himself; and who cannot be supposed not to exist without an express contradiction." That is to say, we must have recourse to a first "necessary" cause—a proper conclusion of the cosmological argument—whose concept is such that a self-contradiction results from assuming it not to exist—the conclusion of an ontological argument. If there should be any doubt, Hume's critique reveals that two arguments are in fact present here. The critique begins by showing that the existence of nothing at all can be established a priori, merely by examining its concept; that is a criticism appropriately directed against the ontological method. But then Hume goes on to argue that perhaps the universe as a whole has no cause, a criticism appropriate for refuting a cosmological argument.

Whereas Hume's critique blurs the distinction between the cosmological and ontological proofs of a necessarily existent being, Kant's critique, as is well known, clearly distinguishes the two, and then proceeds to establish an intrinsic connection between them. The cosmological proof, Kant argued, ultimately reduces itself to the ontological. Kant gives a concise statement of a cosmological argument establishing the existence of an "absolutely necessary being," and then contends: "What properties this being must have, the empirical premise cannot tell us." Consequently, human reason is led to "abandon experience altogether and endeavors to discover from mere concepts what properties an absolutely necessary being must have." The only means human reason can discover for pouring content into absolutely necessary being is to identify this being with ens realissimum, being possessing the fullness of perfection. But in order to show that ens realissimum is identical with the necessary being established by the cosmological argument, human reason must first analyze the concept of ens realissimum and derive necessary existence from it. Since ens realissimum is a necessarily existent being and in fact the only one, so human reason proceeds, it must be identical with the necessarily existent being established by the cosmological argument. Thus the absolutely necessary being whose existence is established through the cosmological argument acquires meaning only on the assumption that necessary existence can also be analyzed out of the concept of ens realissimum—which, according to Kant, amounts to the assumption that the concept of ens realissimum can serve as the basis for an ontological argument. Hence Kant concludes that the cosmological argument inevitably reduces itself to an ontological argument.

The foregoing survey shows that an ontological argument, whether it explicitly says so or not, must establish the existence of God as a necessary being in two senses: as a being whose existence can be established by a prior, logical necessity; and as a being that exists through itself, whose essence contains sufficient reason for its existence. Individual instances of the ontological proof have used the term necessary being at different stages of their argument. A cosmological argument, whether explicitly or not, should establish the existence of God in the second of the two senses of necessary being. And individual instances of the cosmological proof, it was seen, did undertake to prove the existence of God as a necessary being in this sense. In at least one instance, Clarke, a cosmological and an ontological argument were combined or confused: from a cosmological argument, Clarke concludes the existence of a necessary being in the sense that can be established only by the ontological proof. Of the two best known critiques of the cosmological argument, Hume's deals with the combined or confused version, and Kant's contends that the cosmological argument for a necessary being must inevitably reduce itself to an ontological argument.

The first philosopher known to use the concept of necessary existence in order to construct a proof of the existence of God was Avicenna. Avicenna's proof, it will appear, neither is, nor inevitably reduces itself to, an ontological proof. It is rather a certain kind of cosmological proof.

2. The concept of necessary existence is used by Avicenna to prove the existence of God in two works, at length in the Najat, briefly and somewhat obscurely in the Isharat. The concept is also discussed fully in two other works, the Shifa and Danesh Namesh, but there Avicenna employs it only to define the nature of God, not, as far as I can see, to establish His existence.

Avicenna gave thought to the method of his proof. The proof, he explains, consists in "examining nothing but existence itself; by "considering … the nature (hal) of existence," the proof has "exitence qua existence testify to the first [cause]." This method pursued by Avicenna is contrasted by him with another whereby the existence of God is established not from a consideration of existence in general, but rather from a consideration of one segment of existence: God's "creation and effect." Although the latter method, which takes its departure from "creation and effect," is also recognized by Avicenna as legitimate, his own method, he claims, is "more certain and more exalted."

The difference between the two is stated here in language that is deliberately allusive, but easily deciphered. Metaphysics was defined in the Aristotelian tradition as the science that "examines the existent qua existent and what belongs to it by virtue of itself." Accordingly, when Avicenna claims to have constructed a proof exclusively by examining "existence itself and by considering "existence qua existence," he means that he has constructed a proof using philosophic principles drawn only from the science of metaphysics. This he contrasts with the proof that begins with God's "creation and effect" and reasons back from them to the existence of God as a first cause. Avicenna cannot mean that his proof uses absolutely no data drawn from God's "creation and effect." For, as we shall see, his proof does require at least one datum from the external world; and the parts of the world accessible to man are himself and physical nature, both of which belong to God's "creation and effect." Avicenna does mean that his proof considers no peculiar properties of God's creation, that is, no properties of physical nature, but instead considers the attributes belonging to physical nature or anything else solely insofar as it is existent. He is thus claiming to have constructed a metaphysical proof which is superior to proofs that do use principles drawn from physical science, such as—to take the most notable example—Aristotle's proof from motion does. Averroes was later to attack Avicenna for this presumption. At every possible opportunity, Averroes undertook to refute the claim that the existence of God can be established by nothing more than metaphysical principles; and in opposition he defended the position, represented as truly Aristotelian, that the proof of the existence of God is at least in part a subject for the science of physics.

It is easy to point out advantages Avicenna could have perceived in the metaphysical proof, rendering it "more certain and more exalted" than the physical proof. Aristotle's proof from motion rested on a set of physical principles: motion in place underlies all other kinds of change; everything moved has the cause of its motion outside itself; nothing can maintain itself in motion unless it is continuously moved by an agent, only circular motion is continuous; only an infinite force can maintain the heavens in motion for an infinite time. Using all these physical principles, Aristotle undertook to establish the existence of an unmoved incorporeal cause solely of the motion of the universe. Avicenna, although not rejecting Aristotle's physical principles, dispenses with them in his metaphysical proof. And yet, without them, he is confident that he can prove the existence of a cause not merely for the motion, but for the very existence of the universe. The metaphysical proof requires fewer premises and is thus "more certain." And it is "more exalted," for it establishes a cause of the very existence of the universe. With less fuel it travels, or attempts to travel, further.

Avicenna found two passages in Aristotle especially suggestive. One of them appears in Aristotle's Metaphysics, Book XII. There Aristotle gives a version of his proof from motion, then adds a postscript: Since the prime mover "can in no way be otherwise than as it is," it "is an existent … of necessity." Avicenna's proof, particularly the fuller version in the Najat, can be understood as starting just where Aristotle left off. Avicenna sets aside all the physical arguments leading up to Aristotle's prime mover, which is an "existent … of necessity." He begins afresh by analyzing the concept "existent … of necessity" or, as he calls it, necessarily existent, working out everything contained in the concept. Then he undertakes to establish that something corresponding to the concept actually exists. He does this, however, without using the principles of physical motion employed by Aristotle, and also without relying exclusively on his analysis of the concept, as an ontological proof would.

The second Aristotelian passage underlying Avicenna's proof appears in another part of the Metaphysics, in Book V. Metaphysics V is a philosophic glossary that strikes a modern scholar as "evidently out of place" in the totality of the Metaphysics. Avicenna, however, read Aristotle differently. The subject matter of metaphysics was after all understood to be the existent qua existent and its attributes, and Metaphysics V consists precisely in an analysis of existence and of attributes of existence such as unity, plurality, necessity, potentiality, actuality, and the like. Book V can therefore be understood as a philosophic analysis of the subject matter lying at the heart of metaphysics. Avicenna must have read it that way, for he used Book V of Aristotle's Metaphysics as a cadre for a good half of his own Metaphysics, the subject of the remainder of his Metaphysics being the existence of God, His attributes, and the incorporeal realm.

Among the terms analyzed by Aristotle in the section in question is necessary; necessary, he explains, has three senses, of which the most fundamental is "what cannot be otherwise." Then, Aristotle observes: "For certain things, something else is a cause of their being necessary, but for some nothing is [a cause of their being necessary]; rather it is through them that others exist of necessity." That is to say, there is a class of things that are necessary without having a cause of their being necessary; and a second class of things that are necessary through a cause, this cause to be found in the former class. The Aristotelian distinction was to be mirrored in the painstaking distinction Avicenna drew between the necessarily existent by reason of itself and the necessarily existent by reason of another.

Avicenna for his part begins his analysis of metaphysical concepts by showing that primary concepts cannot truly be defined. Definitions in Aristotelian logic are framed by taking a wider and already known concept, the genus, and setting apart a segment of it through a specific difference. Accordingly, Avicenna writes, primary concepts such as existent, and thing, which are not "subsumed under anything better known," cannot be defined; they are rather "imprinted in the soul in a primary fashion." And among the concepts that cannot be "made known … in a true sense" are necessary, possible, and impossible.

Because necessary, possible, and impossible are not definable, ostensible definitions of them lead to a vicious circle. Avicenna considers two ostensible definitions of necessary: "That which can (yumkin) not be assumed [to be] absent (ma 'dum)"; "that which is such that an impossibility would result if it should be assumed to be other than it is." The first of the two definitions employs the term possible (mumkin)—"can (yumkin)"—and the second uses impossible. But, Avicenna observes, when we consider ostensible definitions of possible we find that they in their turn employ either necessary or impossible; possible is defined as "that which is not necessary" or as "that which is absent (ma'dum), but is such that its existence is not impossible if it should be assumed to occur at any time in the future." Ostensible definitions of impossible, finally, include either necessary or possible. Thus attempts to define the triad chase one another in a circle. Yet, although primary concepts are not explicable by anything wider and better known and are thus inaccessible to true definition, there is, according to Avicenna, a way of explaining them to the man who for some reason does not have them imprinted in his soul. We may "direct attention" to the primary notions and "call them to mind" through a "term or an indication." On this basis, Avicenna ventures an explanation of necessary: "It signifies certainty of existence."

When Avicenna turns from necessary and possible to "necessarily existent being" and "possibly existent being," he offers the following explications: A necessarily existent being is a being that "perforce exists"; alternatively, it is "such that when it is assumed not to exist, an impossibility results." A "possibly existent being" is a being that "contains no necessity … for either its existence or nonexistence ('adam)"; alternatively it is "such that whether assumed not to exist or to exist, no impossibility results." These obviously are not definitions by Avicenna's standard, since they do not explain the concepts by anything wider and better known. They are in fact merely adaptations of the blatantly circular definitions of possible and necessary that Avicenna has just been seen to criticize.

The distinction between possibly existent being and necessarily existent being is supplemented by the distinction, originating in Aristotle's Metaphysics V, between two ways in which a thing can be necessary. Reflecting Aristotle's distinction, Avicenna writes that we can conceive of a being as necessarily existent either by reason of itself or by reason of something else. The former would be something "such that because of itself and not because of anything else whatsoever, an impossibility follows from assuming its nonexistence." The latter would be a being "such that should something other than itself be assumed [to exist], then it becomes necessarily existent." The illustrations Avicenna adduces for the latter category are "combustion," which is "necessarily existent … when contact is assumed to take place between fire and inflammable material," and "four," which is "necessarily existent … when we assume two plus two." If some thing is necessarily existent only by reason of something else, it must— since it will not exist by virtue of itself without that other thing—be possibly existent by reason of itself. Thus Avicenna distinguishes three categories: (a) the necessarily existent by reason of itself; (b) the necessarily existent by reason of another, but possibly existent by reason of itself; and (c) the possibly existent by reason of itself, which is not rendered necessarily existent by reason of another.

What Avicenna calls necessarily existent by reason of itself is the same as necessary being in the sense of that which exists "through itself and "has in its essence the sufficient reason of its existence." What Avicenna calls necessarily existent by reason of another is the same as the category of things having, in the terminology of Leibniz, "physical or hypothetical necessity"; physical or hypothetical necessity" consists in "things, happening in the world just as they do" because "the nature of the world is such as it is." However, the necessity characterizing these two categories of necessarily existent being was already seen to be indefinable for Avicenna; it is a primary concept to be grasped by the human mind immediately. As a mere "indication" of its meaning, Avicenna wrote that necessity "signifies certainty of existence." The necessarily existent by reason of itself would accordingly be that which has certainty of existence by reason of itself; the necessarily existent by reason of another would be that which has certainty of existence by reason of another. And the impossibility involved in supposing such a being not to exist would consist in contradicting the certainty of its existence, the fact that it does exist. If no more than this can be said about the meaning of necessarily existent, it is difficult to see just how necessary existence differs from actual existence; not surprisingly, Ghazali was later to accuse Avicenna of vagueness in his use of the term.

These remarks relate to the meaning of necessity and of necessarily existent: Avicenna rules out any definition of necessarily existent and we can only infer that its meaning amounts virtually to actually existent When Avicenna subsequently comes to delimit the class of necessarily existent beings, that class turns out, in fact, to coincide exactly with the class of actually existent beings. For the two categories of necessarily existent being—that which is so by virtue of itself and that which is so by virtue of another—are, according to Avicenna, the only two conceivable categories of actual existence. To put this in another way, the possibly existent does not actually exist unless rendered necessary by something else; and conversely, everything actually existing, including whatever occurs in the physical world, such as combustion, is necessary in one sense or the other. To justify the point, Avicenna reasons that as long as something is merely possible, nothing is present to "prefer" its existence over its nonexistence. The possibly existent can enter the realm of actual existence only if a factor distinct from itself should "select out" its existence. But whenever that factor is present, the existence of the possibly existent being is rendered necessary. The proper way of construing possible existence, according to Avicenna, is therefore to say that during the time the possible existent actually exists, its existence is necessary, and during the time it does not exist, its existence is impossible. but that necessity and that impossibility are both conditioned, due not to the thing itself, but only to the presence or absence of an external condition which necessitates its existence or nonexistence. Considered in itself, in isolation from the external conditions, the possibly existent at all times remains possible.

Actual existent is thus either: (a) Necessarily existent by reason of itself; this is something "such that if assumed not to exist an impossibility results," with the proviso that it has that character "by reason of itself." Or (b) necessarily-existent by reason of another, but possibly existent by reason of itself; this is something, again, such that if assumed not to exist, an impossibility results, with the proviso that it has that character only inasmuch as "something else is assumed" to exist. In distinguishing these categories, it must be stressed, Avicenna is operating exclusively in the realm of concepts, without committing himself to the actual existence of anything: He is saying that if something should be assumed to exist, then it has to be classified in one of the two categories of necessarily existent being.

3. Avicenna, it appears, rejects a true definition of (a) the necessarily existent by reason of itself, (b) the necessarily existent by reason of another but possibly existent by reason of itself, or (c) the possibly existent by reason of itself which is not rendered necessarily existent by anything else. Still, he writes, the "properties" of these three can be set forth. His proof of the existence of God consists in analyzing the concept of the necessarily existent by reason of itself and establishing its attributes; then analyzing the concept of the possibly existent and showing that if anything actually exists, something necessarily existent by reason of itself must also exist.

Avicenna's analysis of the necessarily existent by reason of itself was not original with him. Proclus had analyzed the concept of the "self-existent" (qa 'im bidhdtihi) and "self-sufficient (mustaghniyya bi-nafsiha) first cause" and shown that it must be eternal, uncaused, and free of composition. Alfarabi subsequently applied the same type of analysis to the concept of the "First," as he called the Deity, arriving at a wider set of attributes than did Proclus. And the set of attributes deduced by Alfarabi from the concept of the "First" parallels the set Avicenna now derives from the concept of the necessary by reason of itself. Significantly, neither Proclus nor Alfarabi required the concept of necessity for their analysis. This supports the suggestion that the concept of necessity adds nothing to Avicenna's proof, and that his proof could have as well been based on an analysis of the actually existent by reason of itself instead of on an analysis of the necessarily existent by reason of itself.

Avicenna's analysis runs as follows: The necessarily existent by reason of itself clearly can "not have a cause." If it did have a "cause of its existence," its existence would be "by virtue of something" and therefore not solely by virtue of itself. Aristotelian philosophy distinguished no less than four senses of cause, including causes internal to the effect as well as those working on the effect from without, yet Avicenna does not specify which sense he is using here. However, the omission is apparently intentional, for Avicenna understands that the necessary by reason of itself is incompatible not only with an external cause—an agent upon which its existence depends—but also with internal causes—elements within itself making it what it is.

The denial of internal causes means that the necessarily existent by reason of itself can have no "principles which combine together and in which the necessarily existent consists." The full argument for this rests on a distinction between a given entity as a whole and the parts of which it is composed. Any composite entity, Avicenna contends, exists by virtue of its parts and not by virtue of itself as distinct from its parts. Accordingly, considered as a whole, it does not exist by virtue of what it is in itself but only by virtue of something else—by virtue of the components that constitute it. And it is therefore not necessarily existent by reason of itself. The implications of the thesis are far reaching. For if the necessarily existent by reason of itself can contain no parts whatsoever, it is simple in every conceivable way. It is incorporeal, inasmuch as it is not composed of matter and form. It is unextended and immaterial, inasmuch as it is free of quantitative parts. It is indefinable, inasmuch as it is not composed of genus and specific difference. And it is free of the distinction of essence and existence. The argument for simplicity also gives an implied answer to a much repeated object later to be directed against the proof of the existence of God as a necessary being. Perhaps, that objection runs, the physical world is itself the necessary being. Avicenna would by implication reply that the physical world cannot be conceived as necessarily existent by reason of itself, since the physical world cannot be assigned the attributes deducible from the concept of the necessarily existent by reason of itself: The physical world is not simple, unextended, and incorporeal.

There can, Avicenna further contends, be only one being necessarily existent by reason of itself. To prove this thesis, he argues basically that assuming two such beings amounts to assuming two beings that are similar in one respect—their necessary existenceȔbut different in another—the respect whereby they can be distinguished and called two. But that situation would be conceivable only if at least one of the two things should be composite, containing both the element in common with its counterpart and another element whereby it can be distinguished and by virtue of which two distinct beings can be enumerated. Thus at least one of the two would have to be composite, and consequently, as already seen, not necessarily existent by virtue of itself. It follows that not more than one being necessarily existent by reason of itself is conceivable.

Avicenna derives other attributes from the concept of necessarily existent by reason of itself. It must be pure intellect, for such is the nature of beings free of matter. It must be true, for truth consists in the highest grade of existence, and the necessarily existent by reason of itself would have the highest grade of existence. It must be good, for evil consists in privation, whereas the necessary by reason of itself has fullness of being and therefore suffers no privation. It must constitute the highest beauty, be the highest object of desire, be possessed of the greatest pleasure, and so forth. Avicenna's analysis of the concept of necessarily existent by reason of itself thus establishes that such a being must be uncaused, simple, incorporeal, one, pure intellect, true, good, beautiful, an object of desire, possessed of the greatest pleasure.

But is there anything in the external world corresponding to that concept? Does such a being actually exist? Its existence, Avicenna writes, is surely not self-evident. Nor can its existence be established through a syllogistic "demonstration" (burhan). For a demonstrative syllogism must be constructed with propositions that are "prior to," and the "causes" of the conclusion, whereas there is nothing prior to existence, and the cause of the presence of actual existence in the necessarily existent is accepted by reason of itself. What can be provided is an indirect "proof (dalil) of the existence of a being necessary by reason of itself, and that is what Avicenna undertakes.

To accomplish his proof, Avicenna leaves the conceptual realm for a single empirical datum: "There is no doubt that something exists (anna huna wujudan)." It makes no difference what it is that exists or what its peculiar properties might be; for the purpose of his proof Avicenna considers merely the "existent qua existent" and therefore all he needs is the fact that something does indeed exist. Applying the proposition that there are only two conceivable categories of actual existing beings, Avicenna proceeds: "Everything that exists is either necessary [by reason of itself] or possible [by reason of itself and necessary by reason of another]. On the first assumption, a necessarily existent [by reason of itself] has immediately been established, and that was the object of our demonstration. On the second assumption, we must show that the existence of the possible [by reason of itself but necessary by reason of another] ends at the necessarily existent [by reason of itself]." If the first alternative were accepted, the proof would be complete; the being conceded to be necessarily existent by reason of itself would simply be assigned all the attributes already shown to belong to such a being. But the real issue is of course posed by the second alternative, the assumption that the random existent object with which the proof started is necessarily existent only by reason of another, and possibly existent by reason of itself. The heart of the proof therefore lies in showing that anything possibly existent by reason of itself must ultimately depend for its actual existence upon something necessary by reason of itself.

Professor Wolfson has pointed out that two philosophic principles underlie Avicenna's proof, as well as other cosmological proofs of the existence of God in the Aristotelian tradition: (a) the principle of causality, and (b) the impossibility of an infinite regress of causes. Avicenna does not posit the two principles in their own right, but ingeniously derives them from his analysis of necessarily existent by reason of itself and possibly existent by reason of itself

In formulating his version of the principle of causality, Avicenna employs a distinction between the cause of the "generation" (huduth) of an object and the cause of its "maintenance" (thabat). The cause of generation is more obvious since no one, Avicenna is certain, can doubt that whenever an object comes into existence, it does so by virtue of something else. But Avicenna's proof cannot pursue a first cause of the generation of every possibly existent being, both because Avicenna believed that some possible beings are eternal and not generated, and also because his proof requires causes that exist together with their effect, whereas the cause of generation may perish after the effect comes into existence. Therefore Avicenna gives his attention to the maintaining cause. If, he contends, we consider any object possible by reason of itself, irrespective of whether it is generated or eternal, we may legitimately ask what maintains it in existence. The factor maintaining the object in existence must be distinct from the object, for in itself the latter is only possible and does not exist by virtue of itself. And that factor must exist as long as the object exists; for even when the object is actual, it never ceases to be possible by reason of itself and dependent on something else for its existence. Thus the analysis of the concept possibly existent by reason of itself— or, to be more precise, merely asking what possibly existent means—establishes that if anything possibly existent should exist, it must at all times depend on a cause distinct from itself to maintain it in existence.

The second proposition required by Avicenna is formulated by him as the impossibility that "causes go to infinity"—the impossibility of an infinite regress of causes. In fact, unlike other philosophers, Avicenna does not argue that an infinite regress, specifically, is absurd. He rather argues for the more general principle that whether all actually existent possible beings are "finite or infinite," they must ultimately depend on a being necessarily existent by reason of itself; and from this more general principle he derives the impossibility of an infinite regress as a corolary.

Avicenna's reasoning here too is conducted solely through an analysis of concepts, in the present instance both the necessarily existent and the possibly existent. He is considering a situation wherein Z, for example, depends for its existence upon Y, which exists simulataneously with it; Y then depends upon X, which also exists simultaneously; ad infinitum. To show that such a situation is inconceivable, he mentally collects into a single group all possible beings actually existing at a single moment. Then he reasons as follows: The totality of possibly existent beings, considered as a whole, must be either (a) necessarily existent by reason of itself or (b) possibly existent by reason of itself. The former alternative would involve the absurdity that the "necessarily existent [by virtue of itself] is composed of possibly existent beings." Avicenna does not give any reason why that thesis is absurd. He presumably means that assuming the necessarily existent by reason of itself to be composed of possibly existent beings amounts to assuming that the necessarily existent is composite, whereas his earlier analysis showed that the necessary by reason of itself cannot be composite.

If the totality of possibly existent beings cannot (a) constitute a group that is necessarily existent by reason of itself, there remains (b) the second alternative, according to which the totality of possibly existent beings, taken collectively, is possible by reason of itself. On this alternative, Avicenna proceeds, "whether the group is finite or infinite," it stands in need of a factor that will continually "provide [it] with existence." That factor must be either (b-1) within the group or (b-2) outside of it. Assuming (b-1) that one [or more] of the members maintains the whole group is equivalent to assuming that the member in question is a cause of itself. For to be a cause of the existence of a group is "primarily" to be the cause of the individual members, and since the supposed cause is itself one of the members, it would be a cause of itself. Yet the supposed cause has already been assumed to be possibly existent, and the possibly existent is precisely what does not exist by virtue of itself. Therefore it could not be the cause of the collection of which it is one member.

If the totality of possibly existent beings cannot form a group that is necessarily existent by reason of itself, and if, further, that totality cannot be maintained by one of its own members, the sole remaining alternative is that what does maintain the totality of possibly existent beings in existence is (b-2) outside the group. Since, by hypothesis, all possibly existent beings were included inside, anything left outside is not possibly existent; it must accordingly be necessarily existent by reason of itself. Avicenna was able to reach this result, it should be observed, through the device of considering all possibly existent beings as a single group and then asking what maintains the group in existence; and the cogency of his argument depends upon the legitimacy of that procedure. Once he has established that the series of all possibly existent beings does depend on a necessarily existent being, Avicenna infers, as a sort of corollary, that the series must be finite; for the possibly existent beings must "meet" their necessarily existent cause and "terminate" there. Thus an infinite regress of causes would be impossible—a regress, however, of only one type, that wherein all the causes exist together.

Avicenna's complete proof now proceeds as follows: Something clearly exists, and it must be either necessary by reason of itself, or necessary by reason of another and possible by reason of itself. On the former assumption the proof is immediately complete: There is a being necessarily existent by reason of itself, which is to be assigned all the attributes of such a being. On the other assumption, the possible by reason of itself must be maintained in existence by something else, which exists as long as it exists. That other factor, in turn, must be either necessary by reason of itself or possible by reason of itself. If it is assumed to be necessary by reason of itself, the proof is again at once complete. If, on the other hand, it is assumed to be possible by reason of itself, it too must depend on a further factor distinct from it and existing as long as it exists. Once again, Avicenna asks whether the new factor is necessary by reason of itself or possible by reason of itself. It is inconceivable, he has contended, that the series of all possible beings existing simultaneously, whether finite or infinite, should be maintained in existence by part of itself or by itself as a whole. The series must be maintained in existence by something outside, something which can only be necessarily existent by reason of itself. The latter is to be assigned all the attributes shown to belong to the necessary by reason of itself, and it is the Deity in Avicenna's system.

4. Avicenna thus offers a proof of the existence of God that he characterizes as metaphysical since the proof considers the attributes of what exists solely insofar as it is existent and not insofar as it is a certain type of existent. The proof begins by distinguishing that which is necessarily existent from that which is possibly existent, and that which is necessarily existent by reason of itself from that which is necessarily existent by reason of something else; it analyzes those concepts; and it shows that the possibly existent can actually exist only if ultimately dependent on something necessarily existent by reason of itself. Necessarily existent, as far as I can see, means nothing more than actually existent for Avicenna, and the proof could be executed unchanged using the distinction between what is actually existent by reason of itself, and what is possibly existent by reason of itself but actually existent by reason of something else.

Avicenna has not given an ontological proof, for although his proof depends on an analysis of the concept necessarily existent by reason of itself the analysis alone is not intended to show that anything exists in the external world corresponding to the concept. In deriving various attributes from the concept of necessary existence, Avicenna in fact follows a procedure later to be sanctioned explicitly by Kant, not for necessary existence, but for the concept of God. The proposition "God is omnipotent," Kant granted, is a "necessary judgment," inasmuch as "omnipotence cannot be rejected if we posit a deity, that is, an infinite being; for the two concepts are identical." Only the derivation of actual existence from a concept gives an ontological proof, subject to the several objections raised by critics of that proof. What Kant sanctions for the concept of God but rules out for the concept of necessary being, Avicenna does undertake with the concept necessarily existent by reason of itself; he derives a set of attributes from the concept, but does not pretend to derive actual existence from it.

Like other cosmological proofs of the Aristotelian type, Avicenna's proof employs the principles of causality and the impossibility of an infinite regress of causes. Avicenna's proof goes beyond Aristotle's, however, in establishing a first cause of the very existence of the universe rather than just a first cause of motion. His proof, further, is original in basing even the philosophical principles needed for the argument exclusively upon an analysis of concepts. Merely by analyzing the concept possibly existent by reason of itself Avicenna establishes that if such a being actually exists, it must have a cause. And merely by analyzing the concepts possibly existent by reason of itself and necessarily existent by reason of itself Avicenna shows that actual existence cannot consist solely in a series of possibly existent beings. Since Avicenna derives the philosophic principles used in the proof from an analysis of those concepts, the only proper way of refuting the proof would be to go back and question the analysis. In other words, the critic would have to go back and question Avicenna's dichotomy of what exists by virtue of itself and what exists by virtue of something else; and, more importantly, he would have to question whether what exists by virtue of another can indeed at no time in its career be self-sufficient, and whether what exists by virtue of itself cannot be composed of internal factors. Criticisms along these lines were directed against the proof by Ghazali, Averroes, and Hasdai Crescas.

Avicenna's proof was widely used, less as a whole than in parts or in adaptations. The methodological insistence that a proof of the existence of God is a subject for metaphysics, not physics, was, for example, taken up by the Latin writer Henry of Ghent, although the proof Henry gives is different from Avicenna's. The analysis of necessary and possible being on which the proof rests was employed by Kalam writers and there even appeared an adaptation of the proof as a proof of creation. A watered down version of the proof is given in 'Uyun al-Masa'il, and related works; these are works mistakenly attributed to Alfarabi but in fact dependent on Avicenna. The proof was reformulated by Maimonides, from whom it was copied by Thomas Aquinas. Another reformulation was offered by Crescas. Avicenna's analysis of necessary and possible existence enriched one of Spinoza's ontological arguments. The proof is central for Leibniz and his followers, who—although the historical filiation is unclear—reveal striking similarities with Avicenna. The two best known critiques of the cosmological proof are directed against versions of this proof as formulated by the followers of Leibniz. Despite the critiques, the proof is accepted by such widely-read twentieth century writers as Mohammed Abduh and F. Copleston.

A. I. Sabra (essay date 1980)

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Last Updated on May 5, 2015, by eNotes Editorial. Word Count: 6866

SOURCE: "Avicenna on the Subject Matter of Logic," in The Journal of Philosophy, Vol. LXXVII, No. 10, October, 1980, pp. 746-64.

[Here, Sabra outlines Avicenna's influential conception of logic as a part of philosophy that can lead one to "knowledge of the unknown. "]

I think it is true to say that modern logicians have no great interest in the ancient debate about whether logic was a part or an instrument of philosophy. They are of the opinion that the debate, at least in the form it took in the ancient schools of Greek philosophy, raised a question the solution of which was largely a matter of convention. Avicenna would readily agree, and for the same reason; in one place at least he characterized the question as nothing more than a quibble about the meaning of words. But in both ancient and medieval discussions the question was often linked with another concerning the subject matter of logic. If, as the Platonists and the Stoics maintained, logic is a part of philosophy and the various parts of philosophy are studies of various portions or aspects of being, then what portion or aspect of being should be assigned to logic? This was not a verbal question. And since Avicenna decided to come down on the side of the Academy and not on the side of his "friends" the Peripatetics who maintained that logic was only an instrument, it is not surprising that he should take the trouble in his Kitab al-Shifa' to expound his views on these two interrelated questions.

The dispute as to whether logic was a theory or an instrument has a further significance for the historian of Islamic thought: it became part of a continuing struggle of far-reaching consequences between the champions of Arabic and Islamic learning and the followers of an imported Hellenistic tradition. It should be remembered that in Islam the trivium was not an accepted category; logic and grammar stood on opposite sides of the fence, supported by rival groups. The word chosen by the translators of Aristotle for the art of logic, mantiq (speech), could naturally be used, and was sometimes used, as a title of works on grammer; and this alone was bound to impose the question as to which group, the grammarians or the logicians, was to be regarded as the true custodian of sound discourse. The ensuing controversies may have been motivated in part by religious or nationalistic impulses, but they were not devoid of philosophical interest—being ultimately concerned with the relation between language and thought. The documents that have survived from the early period of this debate appear to indicate that it was the grammarians who had the better of the argument. Logicians were content at first to claim that they were concerned with meanings whereas grammar was competent to deal only with words. This was too simple a view of the task that the grammarians had set for themselves. In the famous debate that took place in the tenth century between the logician Matta ibn Yunus and the grammarian Abu Sa'id al-Sirafi, both recognized leaders in their respective disciplines, the case for logic appears to be vulnerable and lacking in sophistication. With regard to the logicians' view of grammar, Sirafi cites example after example of how subtle shades of meaning are reflected in linguistic features which it was the business of the grammarian to identify. It is true that Matta—whose translations of Greek philosophical works into Arabic were done not directly from the Greek but from Syriac—is being repeatedly put on the defensive by being reminded of his ignorance of Greek, the original language of the logic he now claims to explicate in another language (Arabic) which he has not mastered. The audience is clearly unsympathetic to him, and he is rarely given the chance to answer the questions put to him. But even with the admission that this was perhaps not a fair trial, one comes away from reading it with the clear impression that it was Sirafi who had a deeper appreciation than his adversary of the incongruences generated by the "creation of a language within a language," as he aptly described the logicians' enterprise.

Abu Nasr al-Farabi, at one time a student of Matta, was the first Arabic logician to take seriously the questions of the relation of logic to grammar and of language to thought. His Enumeration of the Sciences briefly formulates the idea of logic as universal grammar (grammar furnishes the rules proper to the utterances of a given language; logic furnishes the rules common to the utterances of all languages), and states some of the implications of the connection between "inner" and "outer" speech. His book on The Utterances Employed in Logic can be viewed as an attempt to face the problems of introducing an artificial mode of speaking into natural Arabic. In his so-called Short Commentary on Aristotle's Prior Analytics, he tried to convince other Muslims of the usefulness of Greek logic by illustrating Aristotelian forms of inference in terms taken from Islamic theology and jurisprudence. He thus preceded al-Ghazali in formulating the kind of argument that finally succeeded in securing for Aristotelian logic a permanent place in Muslim education.

It is one of the paradoxes of Islamic intellectual life that the man most responsible for admitting Aristotelian logic into the scheme of traditional learning was an opponent of Greek philosophy who wrote a powerful book in its refutation. The great religious thinker Abu Hamid al-Ghazali (d. 1111) not only rejected the metaphysical doctrines of Peripateticism and Neoplatonism but also warned against the dangers of studying astronomy and mathematics. Nevertheless he wrote several books on Aristotelian logic and, what was more crucial for the history of logic in Islam, prefaced his influential work on Islamic jurisprudence (al-Mustas-fd) with a lengthy introduction in which he went so far as to say that without logic one could not be sure of any part of knowledge (whether secular or religious, theoretical or practical). Al-Ghazali was able to do this because he understood logic as a mere instrument, a kind of "balance" for weighing arguments which did not commit its user to any doctrine or belief.

Ghazali's attitude was in great contrast to that of another religious thinker who lived some two hundred years after him. Ibn Taymiyya was a strict jurisconsult who had no use for mystical or speculative approaches to religion, let alone an unbridled habit of thought such as philosophy. He could not tolerate the fact that Greek logic had appeared to gain a firm foothold in the field of religious learning, and he singled it out for a concentrated and persistent attack. Unlike Ghazali, Ibn Taymiyya believed that Aristotelian logic was committed to certain metaphysical doctrines from which it could not be detached. One could not adopt Aristotelian logic without being contaminated by its false presuppositions. One of these was a pervasive belief in universals or essences. According to Ibn Taymiyya, only individuals exist, and what is called "essence" is nothing but a conventional device for grouping individuals together for practical or theoretical purposes of our own. A universal term like 'man' does not refer to something shared by individuals, for no such thing exists. The inevitable conclusion was a total rejection of Aristotle's theories of definition and syllogism.

Ibn Taymiyya's criticisms, often acute and original, constituted the most radical critique of Aristotelian logic in the Arabic language. But they were not the work of a concerned logician; their aim was not to reform logic but to destroy it. They came too late in history to achieve that aim on a wide scale; the trend initiated by Ghazālī had taken root and was already well established. But the logic that Ghazālī had made acceptable was not a part of philosophical inquiry, a search for new truths, but an instrumental discipline consisting of a fairly fixed set of rules that one learned in order to apply them in other disciplines.

Avicenna, too, appreciated the instrumental character of logic, but his perspective differed from that of any of the thinkers I have mentioned. In broad terms he belonged to the same philosophical tradition to which al-Fārābī and al-Kindī before him also belonged. But he was more independent of mind than either of his two predecessors, and he spoke more often than they with an individual voice of his own. He was frequently critical or skeptical of the Aristotelianism he embraced and modified, and openly dissociated himself from the Peripatetic school of Baghdad, feeling himself the equal of the ancient commentators whom he read of course in translation. In matters of logic, as in other parts of his philosophy, he helped himself more freely than members of that school to Platonic (and Stoic) doctrines which had already been fused together in the late Greek writings that became the common heritage of Islamic philosophers. He did not always do this in the spirit of eclecticism, but often as the work of an independent thinker who felt able and obliged to make up his own mind.

Logic occupies a major part of Kitāb al-Shifā', the huge philosophical summa which Avicenna completed just before he reached the age of forty. It is known from Avicenna's own account and from a supplementary account provided by his pupil al-Jūzjānī, that the book was composed in varying and sometimes difficult circumstances which had their effect on the character of its various parts. Al-Jūzjānī says, for example, that Avicenna dictated most of the Physics and the Metaphysics during a period of only twenty days without referring to other writings. When he came to write the Logic, however, he was able to consult the books of others "whose order [of treatment] he followed and whose objectionable views he discussed"—a fact which the historian of Avicenna's logic must bear in mind. The logical part of the Shifā' is divided into sections corresponding generally to the parts of Aristotle's Organon. Only the first section, the Introduction paralleling Porphyry's Isagoge, was translated into Latin in the middle ages. It happens to be the section in which Avicenna directly addresses the question of the subject matter of logic. Avicenna's discussions thus continue a tradition that goes back to the Greek commentators, and his own treatment of these questions entered into the stream of philosophical thought in the West. In this [essay] I shall not in general be concerned to reconstruct the complex process of transmission of Greek ideas into Arabic, or follow Avicenna's discussions into the writings of medieval thinkers; my main object will be to identify and clarify Avicenna's views. I hope that the following remarks, despite their preliminary character, will not fail to show that Avicenna's style of thinking and writing does lend itself profitably to the kind of analytical approach attempted here.

To avoid confusion I shall refer to sections of Avicenna's Logic in the Shifā' by English titles, such as "Introduction" or "Interpretation," reserving for Greek works their commonly used titles in Latin or Greek.

Chapter 2 of the Introduction, on the chief divisions of the sciences, ends with a longish passage giving Avicenna's first statement in the Shifā' on the nature of logic and its relation to the other sciences. The essences of things (māhiyyāt al-ashyā'māhiyya …) may exist in the actual things (a'yān al-ashyā') or in thought (fīal-tasawwur.) Certain accidents (a'rād) attach themselves to the essences when these possess one or the other of the two modes of existence. We may therefore examine the essences in themselves, without reference to their existence in individuals or in thought, or our examination of them may involve those adventitious properties which accrue to them in consequence of their external or mental existence. Avicenna here gives some examples of the kind of accidents that may attach to essences as mental entities: being subject or predicate, universality or particularity of predication, essential or accidental predication. He explains his examples by briefly remarking that "in external things there is no essential or accidental predication, nor is a thing a subject or a predicate, a premiss or a syllogism or the like."

These opening sentences are misleading in that they give the impression that the accidents exemplified here come into being simply as a result of bringing the essences into one's mind. But Avicenna seems to be struggling to dispel this misunderstanding in the following words:

If we wish to investigate things and gain knowledge of them we must conceive them; thus they necessarily acquire certain states (ahwāl) that come to be in conception: we must therefore consider those states which belong to them in conception, especially as we seek by thought to arrive at things unknown from those that are known. Now things can be unknown or known only in relation to a mind; and it is as concepts that they acquire what they do acquire in order that we move from what is known to what is unknown regarding them, without however losing what belongs to them in themselves; we ought, therefore, to have knowledge of these states and of their quantity and quality and of how they may be examined in this new circumstance (emphasis added).

I take this to mean that, although the properties of being a subject or a predicate or the like can attach only to concepts and not to external things, they do so only when the concepts are manipulated for the purpose of arriving at (or conveying) a piece of knowledge. Thus, in addition to the two varieties of investigation whose aim is to gain knowledge of external and mental things as such, there exists an inquiry whose aim is to be of use in carrying out the other two investigations. Such an inquiry is called "logic."

Avicenna is thus arguing that logic has its own subject matter which it does not share with any other science. But because of the very nature of this subject matter (properties acquired by concepts when organized for the purpose of attaining or transmitting knowledge), he maintains at the same time that the goal of logical investigation is to help in other investigations. He concludes this passage by saying that if philosophy is understood as the investigation of external and conceptual things as such, then logic is not a part of philosophy, but, as an aid in other investigations, it is an instrument of philosophy. If, however, the term 'philosophy' is applied to "all manner of theoretical investigation," then logic is a part of philosophy and a tool for the other parts. To Avicenna's mind, the question whether logic is a part or an instrument of philosophy is both false and futile—false because it presupposes a nonexistent contradiction between the two roles and futile because "to busy oneself with such matters serves no purpose." But this brief discussion at least allows him to offer something like a definition of logic: it is an inquiry into concepts, and into their properties, insofar as they can be made to lead to knowledge of the unknown.

In the Introduction Avicenna has no name for those concepts which, on account of certain properties that attach to them in the context of proof, he sets apart as the proper object of logic. He does, however, provide such a name in his Metaphysics, in a passage which [William and Martha Kneale, in their The Development of Logic] believed to be "the origin of that discussion of first and second intentions which continued until the end of medieval logic":

As you have known, the object of logic was the secondary intelligible concepts (al-ma'ānī al-ma'gūla al-thāniya)—those that depend upon (tastanid ilā) the primary intelligible concepts— insofar as they may be of use in arriving at the unknown from the known, and not insofar as they are thoughts (ma'gūla) having an intellectual existence that is not attached to matter at all or attached to non-corporeal matter.

As has been noted more than once, Avicenna's doctrine had a precursor in the Porphyrian distinction between terms in first position and terms in second position …, a distinction which we do find in Arabic writers before and contemporary with Avicenna. A look at some of these writers will show the wider scope of Avicenna's remarks, brief though they are.

Al-Fārābī's Commentary on Aristotle's De interpretatione makes the standard observation: 'name' and 'verb' are terms in second position, whereas, he implies, the categories are terms in first position. The notes (ta'liqāt) that Ibn Bājja (Avempace, d. 1138) wrote on Fārābī's account (?the same as the just-mentioned Commentary or rather a separate paraphrase of Aristotle's De int.) furnish a longer list of terms in second position including 'particle', 'definite' …, 'indefinite' …, 'straight', …, 'oblique' …, 'derivative' as well as 'name' and 'verb'.

Let us look next at the relevant sentences in the notes that a late tenth-century translator and commentator of Aristotle, the Syrian Christian al-Hasan ibn Suwār, has written on the Categories. He states first that Aristotle's aim in the Categories is to discuss those "single utterances in first position (fīal-wad' al-awwal) which signify the highest genera of things (al-umūr) by means of the affections (āthār) [produced] by them in the soul, and [to discuss] things insofar as they are signified by the utterance." In regard to the expression 'first position' al-Hasan explains:

We say utterances in the first position in order to distinguish them from utterances in second position; for utterances in first position are those names and labels (?) that are first applied to things as signs (simāt, 'alāmāt) that signify them in a general way (dalāla mujmala,) such as calling this "silver" and this "copper" and this "gold," while utterances in second position are those that signify what we have set apart as utterances in first position, such as calling ["name"] every utterance signifying something definite, without time, as "Zayd" and "'Amr," and calling "verb" everything that additionally signifies time, as "stood up" and "will stand up." These are utterances in second position because we have posited them subsequent to the existence of the others.

Finally, here are two examples of what a leading logician and teacher of logic in eleventh-century Baghdad, Abū al-Faraj ibn al-Tayyib (d. 1043), had to say about the two expressions in question. In his Commentary on Porphyry's Isagoge, Abū al-Faraj wrote:

… utterances are investigated in two ways, as utterances in first position and as utterances in second position. Utterances in first position are those that signify things (al-umūr), such as "Zayd," "'Amr," and "has struck." Utterances in second position are those that signify utterances in first position.… And [Porphyry's] concern here is with utterances in first position.

The only examples given by Abū al-Faraj of words in second position are 'name' and 'verb', which, as he also observes, are discussed at the beginning of Aristotle's De interpretatione.

What is lacking in all these examples is any statement to the effect that terms (or concepts) in second position constitute the specific subject matter of logic.

Al-Fārābī in his Commentary on Aristotle's De interpretatione does employ the phrase "secondary concepts" (al-ma'qūlāt al-thawānī), the very same expression which we encountered in Avicenna's Metaphysics. I shall here paraphrase Fārābī's text without attempting to do full justice to his rather difficult arguments, my aim being simply to indicate the context in which he introduces that phrase. The occasion is Aristotle's statement at 16b 19 ff which prompts Fārābī to speculate about the combinative function of "existential verbs" (is, exists). An existential verb, he says, indicates three things: a time, a combination or connection, and an unspecified subject. A question may arise as to how an existential verb, whether used existentially or copulatively, can perform the combination. The problem (as presented by Fārābī) is that a non-existential verb like 'walks' is analyzable into 'is walking', so that "man walks" is equivalent to "man is walking," where 'is' performs the combinative function. Should we then say that "man is (exists)" is also analyzable into "man is existing," where existence would occur twice—once as a connector and again as a predicate?

Fārābī answers that in the case of the existential 'is' ("when 'is' is predicated by itself") no absurdity would result from such a repetition. But no repetition would need to be involved in the case of the copulative 'is' (when the latter is "predicated for the sake of something else"). In this last case 'is' signifies only time, an (unspecified) subject, and "the notion of a copulative existence," the predicate (say, white) being something apart from that.

Fārābī then goes on to pose the unexpected question of whether the copulative 'is' did not itself require a connector which in turn required a connector and so on to infinity—to which question he gives the following enigmatic answer in terms of "secondary concepts":

There would be nothing impossible or absurd in this consequence [of an infinite series of connectors], for the notion of connector is here one of the secondary concepts, and it is neither impossible nor absurd for secondary concepts to go on to infinity, as you have heard me say many times and as I have set down in writing.

He finally adds that repetition of one and the same secondary concept is not necessary, but does no harm if it occurs.

All this is rather baffling. But the character of Fārābī's arguments, the sudden but surprisingly brief appearance of the idea of an infinite chain of connectors regarded as secondary concepts, and the reference to his previous teachings and writings, all this is clear indication that we do not yet possess all we need to have to penetrate the thoughts of early Arabic logicians on the subject that has concerned us. Avicenna's remarks in the Introduction and in the Metaphysics thus remain the clearest and fullest statement on the topic of the subject matter of logic which has come down to us from the period between the translation of Aristotle's logical works into Arabic and the middle of the eleventh century. It is remarkable that they also seem to have become henceforward the standard doctrine to which later Arabic logicians turned for a ready answer to the question of what logic was about. To illustrate this last point I shall quote a passage [from 'Alā' ibn 'Alī al-Tahānawī's Kashshāf istilāhāt al-funūn] that describes the situation as it appeared to an erudit living in the eighteenth century:

The authorities are of the opinion that the subject matter [of logic] comprises the secondary concepts (al-ma'qūlāt al-thāniya), not in respect of what they are in themselves, nor insofar as they exist in the mind (for this [inquiry] is a function of philosophy), but insofar as they lead or can be of use in leading to the unknown. Thus a universal concept in the mind, when compared to the particulars under it, will be considered essential or accidental to them according as it enters into or lies outside their essences, and it will be considered a species if it coincides with those essences.… Now for a universal concept to be essential, accidental or a species or the like, is not something external but something that arises in universal natures when they exist in the mind. It is so with a proposition's being predicative or conditional and with an argument's being a syllogism, an induction or an example.… The logician [also] investigates tertiary and higher-level concepts, for these are essential attributes of secondary concepts. "Proposition," for example, is a secondary concept which may be investigated in regard to its division, conversion, or conclusiveness when combined with other propositions. Thus "conversion," "conclusiveness," "division," "contradiction" are concepts on the third level of thought; and if, in a logical inquiry, something is judged to be one of the divided parts or contradictories, then that thing will belong to the fourth level of thought, and so on.

The gist of all this had already been said by Avicenna; only the idea of a multi-level hierarchy of concepts is lacking in Avicenna's writings. When and in what context did that idea become articulated; and with what consequences, if any? These are questions that must await further search of the enormous bulk of logical writings that relentlessly piled up in the centuries separating Avicenna from the author of the above passage.

Avicenna further develops his views in chapters 3 and 4 of the Introduction, on the utility and the subject matter of logic, respectively. His discussion in chapter 3 begins with the famous distinction between taṣawwur and taṣdīq which we find in almost every Arabic writer on logic after Avicenna. The same terms have been found in the logical writings of al-Fārābī, but their ultimate provenance remains somewhat uncertain. Paul Kraus suggested [in Recherches Philosophiques V, 1935-36] in 1936 that they translated the Stoic terms ραντασία and σヅγκατάθϵσιϛ, and, on the basis of this suggestion, M.-D. Chenu has argued [in "Un Vestige du stoïcisme," "Revue des Sciences philosophiques et théologiques XXVII (1938)] for a Stoic infiltration of medieval Latin thought by way of translating into Latin certain Arabic texts containing the words taṣawwur and taṣdīq.

Literally, taṣawwur is the act of grasping or receiving a form (ṣūra …) in the mind, and taṣdīq is the act of taking or believing something to be true (ṣādiq). Both are described by Arabic logicians as acts of knowledge ('ilm), but truth and falsity are said to have to do only with the second. Often the two words are also applied, respectively, to the form received or the proposition believed to be true. 'Concept' and 'conception' usually do well as translations of 'taṣawwur', ('thought' is also appropriate in some contexts); for rendering "taṣdīq" one has to oscillate between a number of words such as 'assertion', 'belief', 'judgment', 'proposition'. The medieval Latin translation of Avicenna's Introduction has intellectus for taṣawwur and credulitas for taṣdīq.

Whatever the origin of these two terms, Stoic or otherwise, a similar distinction to what they are meant to convey can be easily found in Aristotle, and it appears that Avicenna at least conflated the two distinctions. We read in Aristotle's De interpretatione:

Just as some thoughts in the soul are neither true nor false while some are necessarily one or the other, so also with spoken sounds. For falsity and truth have to do with combination and separation. Thus names and verbs by themselves—for instance 'man' or 'white' when nothing further is added—are like the thoughts that are without combination and separation; for so far they are neither true nor false.

The ninth-century Arabic translation of this passage (by Ishāq ibn Hunayn) does not use the words taṣawwur and taṣdīq. But in the corresponding chapter in Avicenna's Interpretation the plural taṣawwurāt is used interchangeably with āthār, the equivalent in Ishāq's translation of Aristotle's παθήματα and in a passage of the same chapter that parallels the lines just quoted from Aristotle, ma'qūl … and i'tiqād (belief) are made to stand for taṣawwur and taṣdīq: a single thought (ma'qūl), says Avicenna, is neither true nor false; only the belief (i'tiqād) associated with relating one thought to another affirmatively or negatively is true or false. Now there is no term in Aristotle's text that corresponds to Avicenna's i'tiqād (a word which usually rendered the Greek πίστιϛ); only combination and separation of thoughts are said by Aristotle to have truth or falsity. But Avicenna clearly understands Aristotle's remarks in terms of a distinction between acts of conceiving single thoughts and acts of belief applied to the conceived relations between thoughts. How Avicenna himself understood the distinction is made abundantly clear in chapter 3 of the Introduction:

… a thing is knowable in two ways: one of them is for the thing to be merely conceived (yutaṣawwar: intelligatur) so that when the name of the thing is uttered, its meaning (ma'na: intentio) becomes present in the mind without there being truth or falsity, as when someone says 'man', or 'do this!' For when you understand the meaning of what has been said to you, you will have conceived it. The second is for the conception to be [accompanied] with belief (taṣdīq: credulitas), so that if someone says to you, for example, "every whiteness is an accident," you do not only have a conception (taṣawwur) of the meaning of this statement, but [also] believe it (ṣaddagta) to be so. If, however, you doubt whether it is so or not, then you have conceived what is said, for you cannot doubt what you do not conceive or understand, but what you have gained through conception in this [latter] case is that the form of this composition and what it is composed of, such as "whiteness" and "accident," have been produced in the mind. Assertion (taṣdīq), however, occurs when there takes place in the mind a relating (nisba: comparatio) of this form to the things themselves as being in accordance with them; denial (takdhīb: mentiri) is the opposite of that.

It is clear from this text that taṣdīq is not the relation between subject and predicate in a predicative proposition. Such a relation is here called "form of composition" which (as in the case of doubting) can be entertained in the mind without truth or falsity being applied to it; that is, it can be the subject of mere conception (although, of course, unlike the conception of a single thought, it is capable of being described as true or false). Taṣdīq is the attribution of this relation or form to the things themselves.

The role of belief or assertion is again emphasized by Avicenna in his Interpretation, in an account of what a predicative statement is made of. "A predicative proposition (qaḍiyya ḥamliyya), he says, consists of three things, a subject-concept, a predicate-concept, and a relation (nisba) between the two. Concepts (ma'ānī) do not, however, become subjects and predicates by being gathered together in the mind; in addition to this mind must believe (ya'taqid) affirmatively or negatively the relation between the two concepts." He goes on to insist that mere concatenation (tatālī) of terms does not make up a statement. To be a complete expression of a predicative preposition a sentence must therefore contain, in addition to the terms indicating the subject and predicate, a sign that indicates the relation or connection between these. Such a sign is of course the copula (rābita: connector) which, he says, may take the form of a verb (as in Greek or Persian or, sometimes, Arabic), or a noun (the Arabic pronoun huwa,) or a vowel change (modifying the predicate term or both subject and predicate terms). In any case, three linguistic elements are needed to correspond, one to one, with the three essential components of a predicative proposition.

But if assertion is something apart from the relation to which it is applied in predicative propositions, should not such propositions be analyzed into four, rather than three, components, and should not their complete verbal expressions contain four, rather than three, elements? As far as I can see, the question is nowhere broached by Avicenna himself, but it was raised by later Arabic logicians, no doubt led to do so by Avicenna's own remarks. Some argued that since a "relation of judgment" (nisba ḥukmiyya) is found equally in the affirmation and negation of that relation, it must be clearly distinguished from both; four components must therefore be recognized in the make-up of a predicative proposition. Others maintained that the copula would not be able to perform its function as a connector unless it signified both the judgment relation and its affirmation or negation. The copula would thus give expression to both the assertion (taṣdīq) made and the concept (taṣawwur) to which the assertion is applied, and there would thus be no need for a separate assertion sign. This is not the occasion to pursue this discussion in the various writers, but it seems that it was the latter view that finally prevailed. It was also the latter view that very likely expressed Avicenna's own implicit opinion.

I have dwelt at some length on the distinction between taṣawwur and taṣdīq because it became the accepted doctrine of all Arabic logicians. As pointed out earlier, taṣawwur and taṣdīq divided between them the whole sphere of knowledge, the first being attainable by definition, the second by argument. Logic, being concerned with the appropriate means of acquiring knowledge, therefore divided into two parts: a theory of definition (mabḥath al-taṣawwurāt) and a theory of proof (mabḥath al-taṣdīqāt). The following passage succinctly expresses this pervasive doctrine. It comes from Avicenna's Kitāb al-Najāh, a summary account of Kitāb al-Shifā':

Every knowledge is either conception (taṣawwur) or belief (taṣdiq). Conception is the prior knowledge (al-'ilm al-awwal) and it is acquired by means of definition or the like.… Belief is acquired only by means of syllogism or the like.… Thus definition and syllogism are two instruments by means of which knowledge of unknown things is acquired through discursive thought (al-rawiyya).… Now every syllogism and every definition is made up by bringing intelligible notions (ma'ānī ma'qūla) into a definite composition so that each would have a matter from which it is composed and by means of which the composition is effected. And just as a house or seat cannot properly be made from any chance matter or in any chance form, but rather every thing has its own matter and form which are proper to it, so also there belong to every object of knowledge (ma'lūm) which is knowable by means of discursive thought a proper matter and form by means of which that object may be grasped (taḥaqquq). And just as a house may be improperly built because of deficient matter or form or both, so also discursive thought may be vitiated (fasād) on account of its matter even if the form is valid (ṣāliḥa), or on account of the form even if the matter is appropriate (ṣāliḥa), or on account of both.

Fārābī had said in his Enumeration of the Sciences that the objects with which the rules of logic are concerned are "the thoughts (ma'qūlāt) in so far as they are indicated by the utterances, and the utterances in so far as they indicate the thoughts." We establish an opinion in ourselves by setting up in our minds those thoughts which are apt to verify it. This process is called by the ancients "inner speech" (al-nuṭq al-dākhil). To impart the truth of an opinion to someone else we employ the forms of speech (aqāwīl) suitable for achieving that purpose. This is called "outer speech" (nuṭq khārij bi-al-ṣawṭ). It is the function of logic to provide the rules (qawānīn) that guide us toward the proper conduct (called "qiyās," reasoning) of both kinds of speech.

Avicenna seems to have had some such statements in mind when he wrote in chapter 3 of the Introduction (= chapter 4 in the Latin edition) that "there is no value in the doctrine of those who say that the subject of logic is to investigate utterances in so far as they indicate notions (al-ma'ānī.)" It is noticeable that in the two previous chapters the question of language and its relation to logic is nowhere brought into the discussion. Now that Avicenna has put forward in those chapters his own view of the subject and use of logic, he feels he can settle that question without much belaboring of words. Unfortunately his remarks are much too brief. The logician, he says, would have been able to dispense with utterances only if it were possible to learn logic by means of "pure thought." But we are forced to use utterances,

… especially as it is not possible (muta'adhdhir: non potest) for the reasoning faculty (al-rawiyya: ratio) to arrange notions (al-ma'ānī: intellecta) without imagining the utterances corresponding to them, reasoning being rather a dialogue with oneself by means of imagined utterances. It follows that utterances have various modes (aḥwāl) on account of which the modes of the notions corresponding to them in the soul vary so as to acquire qualifications (aḥkām) which would not have existed without the utterances [seguitur ut verba habeant diversas dispositiones per guas differant dispositiones intentionum gue concomitantur esse in anima, ita quod fiant eis indicia gue non haberentur nisi per verba]. It is for this reason that the art of logic must be concerned in part with investigating the modes of utterances.… But there is no value in the doctrine of those who say that the subject of logic is to investigate utterances in so far as they indicate notions … but rather the matter should be understood in the way we described.

The modes mentioned here are of course those secondary properties which concepts acquire when they constitute definitions and arguments. They are thoughts (ma'qūlāt) of a second order, twice removed from the things of the material world to which outward speech belongs. Avicenna now tells us that reasoning is impossible without utterances, whether spoken or imagined. By itself this is not a new thing to say. But the consequence he draws from this statement is not the simple language-thought parallelism noted by the writers whose views he found inadequate. He clearly says that the conceptual modifications are brought about by modifications in the utterances. This means that the secondary concepts, the proper object of logic, not only are reflected in language but are generated by it. Is this so because logical concepts arise only in the context of a process, reasoning, which is dependent on language in a peculiar way? In any case, however one interprets his words, and I am not sure I quite understand them, he seems to be making a stronger claim for the role of utterance in logic than I have encountered in any writer before and up to his time. Avicenna is not just saying that utterances are important in the study of logic. Having already pointed out that logic was not a (psychological) inquiry concerned with mental entities as such, he is now telling us that it is an inquiry primarily concerned with language. The reason is, or seems to be, that the properties constituting the subject matter of logic would be inconceivable without the exercise of a particular function of language.

Avicenna returns to the question of the relation of logic to philosophy and the related question of the subject matter of logic in other parts of the Logic in Kitāb al-Shifā'. In the section on Categories, for example, he again asserts his independence from the Peripatetics (including Fārābī and Ibn al-Tayyib) by emphatically excluding the doctrine of categories from the proper domain of logic. This agrees with his understanding of logic as concerned with second-order concepts. And in the section of Syllogism he devotes a chapter to showing how the function of logic as an instrument is to be understood. His interesting views in these and in other places are, however, too detailed and too complex to be dealt with adequately here.

Charles E. Butterworth (essay date 1983)

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SOURCE: "Ethics in Medieval Islamic Philosophy," in The Journal of Religious Ethics, Vol. 11, No. 2, Fall, 1983, pp. 224-39.

[In the following excerpt, Butterworth discusses Avicenna's moral and political philosophy.]

[Avicenna's] writing takes the form of essays about Aristotelian treatises and themes, essays which explore the subject of the treatise or the theme itself in such a manner that one learns far more about Avicenna's opinions than about what he thinks Aristotle was trying to explain. For example, in his multi-volume Shifā (or Healing)—a work divided into four major sections, somewhat along the lines of Aristotle's account of the sciences, and each section further divided into parts which frequently bear the names of Aristotelian treatises—Avicenna explains what he understands of these sciences or arts with nary a reference to Aristotle. Much of the rest of his writing presupposes the importance of the Shifā insofar as it summarizes or enumerates in abbreviated form the themes discussed there. And Avicenna indicates his differences from Aristotle in yet another way: whereas Aristotle presented his moral and political teaching as belonging to practical science and as independent of as well as distinct from theoretical science, Avicenna frequently blurs that distinction. Though he does admit that morals and politics belong to practical science, he elaborates upon them only in the course of his theoretical discussions, that is, either in his On the Soul of the Shifā (a treatise which takes up the theme and many of the discussions of Aristotle's De Anima) or in his Metaphysics, also a part of the Shifā.

It is in Book Ten of his Metaphysics that Avicenna provides his fullest account of moral virtue. He begins by explaining the superiority of the prophet to all other men, indicating thereby that both philosophy and politics are subordinate to religion. The prophet is the best of men because he has acquired the practical moral habits by which he can manage his own affairs as well as provide for those of the people for whom he sets down laws and establishes justice, and because he has developed his soul to the point that it has become a free intellect. Such an explanation tacitly suggests that the prophet completes the partial lives of the philosopher and the virtuous ruler—the philosopher having a fully developed intellect, but not the practical moral virtues whose mastery would allow him to rule people well, and the virtuous ruler having the latter but not the former.

Whereas the opinions and actions Farabi's virtuous first ruler set before the people were clearly such as to help them acquire the moral habits and dispositions which would allow them to live together harmoniously, and in such living to move towards ultimate happiness, Avicenna's prophet dwells more on beliefs which have no such immediate political relevance. Some even have an anti-political or ascetic bent, as though the highest goal towards which thoughtful humans should strive were to weaken the ties between their soul and their body in order to achieve separation from the body. In this sense, ultimate happiness is not acquired through political association, but through a turning away from political life and all other bodily concerns. Running throughout Avicenna's writings, this tension between the demands of political life and the demands of complete spiritual life derives from the subordination of philosophy and politics to religion, from the claim that the highest human achievement is the pure intellectual or spiritual perception proper to a disembodied soul which has gone beyond the concerns of the practical intellect. Unfortunately, Avicenna never explains what prompts the prophet to turn aside from this all-important goal of untrammeled spiritual perception in order to legislate for a political community. Nor, in spite of his repeated insistence on the need to do away with or go beyond the practical intellect in order to develop fully the theoretical or spiritual intellect, does he ever make clear why the prophet's mastery of the practical moral virtues should constitute his superiority over the philosopher.

This tension or unclarity notwithstanding, Avicenna's prophet does set down laws for a political community, laws which provide for its administration and survival as well as for the moral and physical well-being of its citizens. Avicenna pictures human beings as first coming together in order to survive. Initially no more than a basic response to nature's inattentiveness, it leads, under the best of circumstances, to their spiritual betterment as well. Their immediate need for someone who will set down laws and thereby establish justice so that they might live together harmoniously points beyond mere physical concerns because justice, properly conceived, provides for all human good. Avicenna's reasoning is that justice is a balance or mean acquired by means of moral habits and character traits and sought either to break the hold of the passions so that the soul may be purified and liberated from the body or to use the passions with respect to the concerns of this world.

One way men should make use of the passions for what pertains to this world is to take pleasure in their natural appetites for things like food, clothing, and sex in order to preserve their bodies and to have children. Avicenna also suggests another way, namely, giving vent to those passions like anger, hate, and pride in order to be courageous enough to preserve the city. With respect to this proper use of the appetitive passions (or temperance) and of the irascible passions (or courage), Avicenna speaks of the need to observe a mean between vices of excess and deficiency. Though he does no more than hint at the consequences, he must have in mind that men can harm one another by pursuing the bodily pleasures to excess or by being rash and foolhardy; on the other hand, if they are so insensitive to pleasure that they do not eat adequately and fail to engage in sexual intercourse or shy away from protecting what is their own as do those who are overly fearful, the city will be harmed.

Avicenna says little here, or in the treatise which discusses these same issues—On the Science of Moral Habits—about practical wisdom. We are told that it is to be used for administrative affairs and is opposed to the vices of discernment, nothing more.

These three moral habits and character traits (temperance, courage, and practical wisdom—also referred to by Avicenna as moral virtues), by means of which justice is acquired, are for the well-being of human beings in this world. They can be pursued adequately without theoretical wisdom, even though it is superior to them. At the end of his account, Avicenna presents theoretical wisdom as being so important that one can attain happiness only by acquiring it as well as these three virtues, all of which add up to justice. Clearly, one cannot be happy—however virtuous one is—without having theoretical wisdom, but Avicenna says nothing about the converse. Instead he indicates that the only thing to be desired more than justice plus theoretical wisdom is "to win, in addition, the prophetic qualities" [1960: X, 455: 14-16].

The communal basis of Avicenna's ethical teaching can now be stated as follows. Adherence to the laws set down by the prophet will permit the citizens to acquire the moral virtues, which together are tantamount to justice, and thus to live harmoniously in this world. If the citizens also embrace the beliefs about God and the life to come as set down by the prophet (the non-political beliefs alluded to above), they can aspire to happiness in the hereafter. Those able to acquire theoretical wisdom as well as justice may aspire to happiness in this life, but to a happiness inferior to that of the prophet—presumably because the prophet alone is able to purify his soul so that it becomes liberated from the body and thus achieves intellectual or spiritual perception.…

Michael Marmura (essay date 1986)

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SOURCE: "Avicenna's 'Flying Man' in Context," in The Monist, Vol. 69, No. 3, July, 1986, pp. 383-95.

[In the essay below, Marmura discusses the three instances of Avicenna's "Flying Man" scenario, which illustrates Avicenna's philosophy of mind.]

The psychological writings of the Islamic philosopher Avicenna (Ibn Sīnā) (d. 1037) are noted for the hypothetical example he gives of the man suspended in space—the "Flying Man." This example, which left its impress on the Latin scholastics and has engaged the attention of modern scholars, occurs thrice in his writings in contexts that are closely related, but not identical. Its third occurrence, which represents a condensed version, conveys the general idea. It states, in effect, that if you imagine your "entity," "person," "self" (dhātaka) to be created at birth fully mature, sound in mind and body, but suspended in temperate air in such a manner that this "self" is totally unaware of its body and physical circumstances, "you will find that it will be unaware of everything except the 'fixedness' (thubūt) of its individual existence (anniyyatihā)."

What Avicenna intends to show by this hypothetical example is not as obvious as it might initially seem. For one thing, the roles the "Flying Man" plays in its three appearances, although closely related and complementary, are not identical. More to the point is the difficulty of Avicenna's texts, both in terms of language and thought. The "Flying Man" and the arguments it includes or relates to in the texts are problematic.

But whatever the difficulties it poses, the example remains an expression of its author's Neoplatonic soul-body dualism. Before attending to its three versions for a clearer idea of what they are all about, some remarks about its relation to other psychological theories—particularly in medieval Islam—may help place it in its historical setting. Similarities between it and the Cartersian cogito have been discussed by scholars. The notion that we have certain knowledge of our individual existence is one of the things inherent in the example. This notion, as will be seen, is part of Avicenna's paradoxical belief that we have constant, intimate knowledge of the existence of our individual selves, even if we do not know this. The primary concern here, however, is psychology, not metaphysics. Avicenna is not seeking in this example the certainty of his existence as a premise on which to build a philosophical system. His metaphysical starting point is not doubt. It is the certainty "that there is here existence."

That we have certain knowledge of our individual existence was also the prevalent view among the Islamic speculative theologians, the mutakallimūn. Both the Muctazilite and the Ashcariate rival schools of speculative theology (kalām) held this. They included knowledge of the existence of ourselves among those cognitions that are "necessary" or "compulsory." Now Avicenna opposed the doctrine of the self held by these theologians, but not because they maintained that we have indubitable knowledge of the existence of ourselves. His disagreement with them was on the question of the nature of the self, or, as the issue was sometimes expressed, about the referent of the personal pronoun, 'I'. Is this the immaterial rational soul, as Avicenna held, or a material entity as the theologians and other Muslims maintained? Thus he begins [Ahwāl al-Nafs] as follows:

We say: what is intended by "the soul" is that which each of us refers to by his saying, 'I.' Scholars have differed as to whether what is being referred to is this body, observed and experienced by the senses, or something else. As regards the first [alternative], most people and many of the speculative theologians (almutakallim n) have thought that the human being is this body and that everyone refers to it when saying, 'I.' This is a false belief as we shall show.

The vast majority of the mutakallimūn, it should be remarked, were atomists, upholding a materialist concept of the human soul. There were exceptions and variations, to be sure. The Mucazilite al-Naẓẓām (d. 845), for example, rejected atomism. He maintained that the soul is a subtle material substance that is diffused throughout the body, rendering it animate. Another ninth century Muctazilite, Mucammar (d. 835), did not reject atomism, but maintained that the human soul is immaterial, a spiritual atom. Most of the mutakallimūn, however, were atomists and materialists. They maintained either the doctrine that the soul is an individual material atom to which life, a transient accident, attaches, or else, the doctrine that the soul and the transient accident, life, that attaches to an organic body, are one and the same.

The more traditional Islamic doctrine of the soul accords with what the ninth century al-Naẓẓām held. Accordingly, life meant the conjunction of soul and body. The soul is a subtle substance that spreads throughout the body making it alive. Death is the separation of soul from body. The soul, though a material substance, is immortal and rejoins the body at the resurrection. This traditional concept is summed up by the fourteenth century, Ibn Qayyim al-Jawziyya (d. 1350). He states that the human soul "differs in quiddity (al-māhiyya) from the sensible body, being a body that is luminous, elevated, light, alive and in motion. It penetrates the substance of the body organs, flowing therein as water flows in roses, oil in olives and fire in charcoal."

Avicenna is also opposed to this traditional doctrine of the soul. This concept of the soul as a subtle substance has a striking resemblance to what he conceived to be "spirit" (al-rūh), namely "the subtle body" that pervades the living body, acting as the substratum for the vegetative and animal soul. This spirit, however, is material and, for Avicenna, what is material (in the terrestrial realm) is corruptible. The rational soul, on the other hand, is immaterial and hence immortal. Avicenna's "Flying Man", as will be seen, is intended, among other things, to indicate the immateriality of this soul—by implication, its immortality.

The "Flying Man's" first version occurs at the end of Psychology, I, 1, an intricately argued chapter whose objective—as its heading proclaims—is to establish the existence of the soul and to define it "inasmuch as it is soul." This latter phrase suggests that Avicenna is referring to the soul's essence or quiddity. This, however, is not the case. He is only referring to its functional relation to the body, a relation, he repeatedly tells us, which is other than the quiddity and which does not indicate the category of existence, namely, substance, to which the soul belongs.

He states this, for example, at the beginning of the chapter where he argues in Aristotelian terms for the existence of the soul: The observed animate activities of organic bodies cannot be due to their sheer corporeality, but to principles within them. "Soul" is the name for "whatever is a principle for the issuance of activities that are not of the uniform pattern that negates volition." This, he goes on, "is the name of the thing, not inasmuch as it is substance, but by way of some relation it has." Again, in a lengthy discussion where he differentiates between entelechy and form ("every form is an entelechy but not every entelechy is a form") and where he maintains that "entelechy" rather than "form" is the more comprehensive term referring to the soul, he writes:

If we have come to know that the soul is an entelechy,… we still do not know the soul and its quiddity, but have only known it inasmuch as it is soul. The term, "soul," does not apply to it by way of its substance, but by way of its being governor over bodies and in relation to them.… Indeed, we ought to set aside another investigation for knowing the essence of the soul.

After further discussion of "entelechy," leading to the Aristotelian definition of the soul as the first entelechy of a living, acting natural organ, and a discussion of the difficulty of applying this definition univocally to both terrestrial and celestial souls, Avicenna gives a last reminder that this relational definition of the soul does not refer to the quiddity. It is with this reminder that the last part of the chapter devoted to the "Flying Man" is introduced:

We have now known the meaning of the name that applies to the thing termed soul because of a relation it has. It thus behoves us to occupy ourselves with apprehending the quiddity of this thing which through the above consideration has become spoken of as soul.

Avicenna continues:

We must indicate in this place a manner of establishing (ithbāt) the existence of the soul we have by way of alerting (tanbih) and reminding (tadhkīr), giving an indication (ishāra) that has a strong impact on someone who has the power of noticing (mulāḥaẓa) the truth himself, without the need of having to educate him, constantly prod him, and divert him from what causes sophistical errors.

The example of the "Flying Man" immediately follows this statement. But before turning to the example, we must pause to consider the above statement, which is quite basic for understanding the first (and most problematic) version of the example. The statement, though structurally complex (and difficult to translate), is quite clear in expressing its intention, namely, to indicate a way of establishing the soul's existence by means of "alerting" and "reminding."

But what does Avicenna mean by "alerting" and "reminding"? Some light is shed on his meaning by Psychology, V, 7, where he criticizes and rejects various psychological theories, two of which involve the concepts of "alerting" and "reminding." The first maintains that the human soul by its very nature knows all things: the activities of perceiving and reasoning simply "alert" it to the knowledge it already has but from which it has been distracted. The second theory also maintains that the soul has knowledge of all things, knowledge, however, which it has acquired "previously." Avicenna does not identify this theory. But the Platonic theory of reminiscence seems an obvious candidate. At any rate, knowledge is reminiscence, the activities of perceiving and reasoning acting as reminders of what is already known.

Avicenna's philosophical system can accommodate neither theory and he rejects them and their claim that the soul has within it, so to speak, knowledge of "all" things. But he does not reject the view that the soul by its very nature has self-knowledge. The main intention of the third version of the "Flying Man," as will be seen, is to state and illustrate the soul's constant knowledge of itself. Another statement about "natural" self-knowledge occurs in al-Taclīqāt, comments Avicenna dictated to his student Bahmanyār:

The human soul is [so constituted that] it is by nature aware of existents. It is aware of some of them naturally; with others, it gains the power to become aware of them by acquisition. That which is attained for it naturally is realized for it actually and always. Thus its awareness of itself is by nature, this being a constituent of it and hence belongs to it always and in actuality. Its awareness that it is aware of itself is by acquisition.

In this work, Avicenna does not elaborate: he does not explain how one is always aware of one's self and yet has to "acquire" awareness of this awareness. Elsewhere, he offers an answer to the related question of why should one seek after knowing one's self (and its immateriality) if one already has such knowledge. In Psychology, V, 7, he writes:

It is not the case that if you are seeking the existence [of the self] and its being non-corporeal you are therefore ignorant of this in an absolute sense. Rather, you are oblivious of it. Many a time knowledge of a thing is near at hand, but one is oblivious of it. It becomes within the bound of the unknown and is sought after from a more distant place. Often knowing that it is near at hand is of the order of alerting (al-tanbīh).

To return to the statement immediately preceding the first version of the "Flying Man," it clearly states that the intention of what is to follow is to indicate "a manner of establishing the existence of the soul … by way of alerting and reminding, giving an indication that leaves a strong impact on someone who has the power of noticing the truth himself." This first version is as follows:

We say: The one among us must imagine himself as though he is created all at once and created perfect (kāmil), but that his sight has been veiled from observing external things, and that he is created falling in the air or the void in a manner where he would not encounter air resistance, requiring him to feel, and that his limbs are separated from each other so that they neither meet nor touch. He must then reflect as to whether he will affirm the existence of his self (dhātahu).

He will not doubt his affirming his self existing, but with this he will not affirm any limb from among his organs, no internal organ, whether heart or brain, and no external thing. Rather, he would be affirming his self without affirming for it length, breadth and depth. And if in this state he were able to imagine a hand or some other organ, he would not imagine it as part of his self or a condition for its existence.

You know that what is affirmed is other than what is not affirmed and what is acknowledged (al-muqarr bihi) is other than what is not acknowledge. Hence the self whose existence he has affirmed has a special characteristic (khāṣṣiyya) of its being his very self, other than his body and organs that have not been affirmed.

Hence the one who affirms (al-muthbit) has a means (lahu sabīl) to be alerted (yatannabah) to the existence of the soul as something other than the body—indeed, other than body—and to his being directly acquainted (cārif) with [this existence] and aware of it. If he is oblivious to this, he would require educative prodding.

The last paragraph brings home the point that the process of imagination and contemplation Avicenna asks us to undertake alerts us ultimately to the experiential knowledge of our immaterial selves. More specifically, it states that the one who in the example affirms (al-muthbit) his existence without affirming the existence of his body "has a means" (lahu sabīl) "to be alerted" (an yatanabbah) to the existence of the self as immaterial and subsequently to the experiential knowledge of this immaterial existence. (The use of the term, cārif, the active participle of the verb carafa, is very significant. In Avicenna's vocabulary (and that of the mystics of Islam) it means "to know" in the sense of having experiential, intimate knowledge, gnosis.) In other words, we discern here two stages of knowing. The first is knowing that the self is immaterial, leading to the second, the experiential knowledge of one's self as an immaterial entity.

When Avicenna speaks of the "means" for alerting the self to this knowledge, he is referring to the argument immediately preceding the final paragraph which can be summed up as follows: In the circumstances of the example where the self is totally unaware of the physical and the bodily, it is still aware of its existence, not doubting this. It thus affirms its existence without affirming the existence of the body. But since what is affirmed is other than what is not affirmed, the self whose existence is being affirmed is not the body.

This argument, however, so very central to the first version of the "Flying Man," is problematic. It operates within an imagined, hypothetical framework and hence one expects its conclusion to be hypothetical and tentative. But an unwarranted swerve from the hypothetical to the categorical seems to take place. For the language of its conclusion is categorical. That Avicenna intended this conclusion to be categorical is also indicated by the example's other two versions. In this connection, it should be noted that there are instances in Avicenna's logical writings where he uses a similar hypothetical example for categorical ends. Thus, he tells us, if a person is created fully mature and rational, having, however, had no contact with other humans and human institutions, and is confronted with a commonly accepted moral dictum and a self-evident logical truth, he will be able to doubt the first, but not the second. The example here is used as a criterion for self-evidence. Again, he uses this example to define natural knowledge. This is the knowledge, he states, that a person born fully mature and rational but having had no human contact will have.

Moreover, the argument begs the question. This brings us to its assumptions which perhaps may help explain how Avicenna treats its conclusion in categorical terms. As indicated earlier, he holds that the self has natural, constant knowledge of itself. In the third version of the "Flying Man," as we shall see, he elaborates on this. Provided the self is able to "discern a thing correctly," then whatever the circumstances, it will have this constant knowledge of itself. Now Avicenna includes as one of these circumstances in which the self is still able "to discern a thing correctly" the state of its being totally unaware of the bodily and the physical, exemplified by the "Flying Man." But once he includes this, then he is already assuming the very thing to be proven—an immaterial self capable of self-awareness while totally oblivious of the body and anything physical.

Our concern, however, is not so much with the shortcomings of this argument as it is with the role it plays in the example. As already hinted at in passing, it really performs two tasks, not one. The first is to prove that the soul is immaterial; the second, by showing this, to awaken the self to the experiential knowledge of itself as an immaterial entity. Since the argument's conclusion that the self is immaterial is in agreement with the experiential knowledge it helps "trigger off," so to speak, the distinction between these two related tasks is easily blurred.

[The second version of Avicenna's "Flying Man"], which is very short, occurs in Psychology, V, 7. As mentioned earlier, this is a chapter in which Avicenna criticizes and rejects a number of psychological theories. One of these is the theory that the human soul cannot be one entity, that the vegetative, animal and rational souls are three numerically distinct souls. In rejecting this theory, he argues for two points: (1) that the different psychological faculties require something that binds and unifies them; (2) that this binding entity cannot be corporeal but must be the immaterial rational soul. In the course of arguing for the second point, the "Flying Man" reappears, playing a related but different role than the one it played in its first apperance.

Avicenna argues that there must be a binding entity for the psychological faculties, relating to them in the way the Aristotelian common sense relates to the various senses. For each faculty is restricted to its own kind of act. The sensory acts are other than the appetitive and irascible. Yet these faculties interact. It is thus that we can make such true statements as "when we perceived, we desired," and "when we saw such a thing, we were angered." We can say such true things because there is an entity that binds and links the various faculties. This entity, Avicenna concludes, "is the thing which each of us perceives to be his self."

To show that this binding entity is the immaterial rational soul, Avicenna advances three arguments. The first and shortest is that body qua body cannot be this binding entity. Otherwise every corporeal thing would be performing this task, which is clearly not the case. The second argument harkens back to an earlier chapter where Avicenna had given lengthy arguments to show that the faculty receptive of the abstract intelligibles must be immaterial. Thus at least one of the human psychological faculties is immaterial. Now the binding entity, he argues, is the one from which the power emanates on the rest of the psychological faculties. This entity cannot be material because matter is not the source of emanation, but the recipient of it. The third argument is the longest. It reintroduces the "Flying Man."

If one supposes the binding entity to be a body, then it would have to be either the whole of the body or only part of it. Avicenna then proceeds to show that it is neither, concluding that this binding entity is immaterial. The "Flying Man" is used as part of the refutation of the first alternative. This refutation begins with the argument that if the binding entity is the whole body, then if a part is missing, it follows that what we perceive to be our selves would not exist. But this is not the case:

For, as we've mentioned in other places, I know that I am myself even if I do not know that I have a leg or one of the organs. Rather, I believe these things to be attachments to my self and believe that they are instruments of mine which I use for certain needs. Were it not for such needs, I would dispense with them. I will still be 'I', when they are not [existing].

The second version of the "Flying Man" follows immediately, giving further support to what has just been uttered:

Let us repeat what we've said earlier. We say: If a human is created all at once, created with his limbs separated and he does not see them, and if it so happens that he does not touch them and they do not touch each other, and he hears no sound, he would be ignorant of the existence of the whole of his organs, but would know the existence of his individual being (anniyyatihi) as one thing, while being ignorant of all the former things. What is itself the unknown is not the known.

This brief appearance of the "Flying Man" is followed by an elaboration on the idea that the bodily organs are mere attachments to the self, akin to garments:

These organs belong to us in reality only as garments which due to constant adherence to us have become as parts of our selves. When we imagine our selves, we do not imagine ourselves unclothed, but imagine them possessing covering garments. The reason for this is constant adherence, with the difference that with [real] clothes we have become accustomed to taking them off and laying them aside—something we have not been accustomed to with the bodily organs. Thus our belief that the organs are parts of us is more emphatic than our belief that garments are parts of us.

Avicenna then gives a spirited argument to disprove the second alternative, namely that the binding psychological entity cannot be one organ or a combination of some organs. For if an organ (or a combination of some organs), then when one is aware of one's self, one must be aware of the particular organ or organs. This is not the case. For even our knowledge of the heart, if we suppose it to be the binding entity, comes through experiment. It is not the thing one perceives to be the self when one has self-awareness. This argument, as it appears in this chapter, stands on its two feet, quite independently of the hypothetical example. We meet it elsewhere in Avicenna's writings without any reference to the "Flying Man."

To return, then, to the brief second entry of the example, we notice that it is used conjointly in support of another independent argument for disproving an alternative statement in a larger argument. We also notice that its conclusion is categorical. Thus, once again, we encounter Avicenna's arriving at the categorical conclusion from hypothetical premises. This version reechoes the first, but there is no indication here that it is intended to awaken the soul to its self-knowledge. Its task is quite limited—to help disprove an alternative statement in a larger argument.

Avicenna's third (and also very short) version of the "Flying Man" occurs in his al-Ishārāt wa al-Tanbīhāt, one of his late works that sums up his philosophy. In the title, the term ishārāt is the plural of ishāra, "indication," "hint," "directive," "sign," "signal"; tanbīhāt, the plural of tanbīh, "alerting," "awakening," "drawing attention to," or, as recently translated, "admonition." Avicenna presents his ideas in short paragraphs each bearing the heading of either ishāra or tanbīh, although other related terms are also sometimes used. The paragraph containing the "Flying Man" has the heading tanbīh. Each of the three subsequent paragraphs that constitute an argument for the soul's immateriality also bear this heading. As we have seen with the first version of the example, the term tanbīh is used in a special epistemological sense of arousing the self to the self-knowledge it already possesses. The heading, tanb h, for the third version of the "Flying Man" and the related paragraphs that follow suggests that the term is meant to convey the same idea.

The example appears as part of the first paragraph, a first tanbīh, introducing a chapter entitled, "On the Terrestrial and Celestial Soul." The paragraph is as follows:

Return to your self and reflect whether, being whole, or even in another state, where, however, you discern a thing correctly, you would be oblivious to the existence of your self (dhātaka) and would not affirm your self (nafsaka)? To my mind, this does not happen to the perspecacious—so much so that the sleeper in his sleep and the person drunk in the state of his drunkenness will not miss knowledge of his self, even if his presentation of his self to himself does not remain in his memory.

And if you imagine your self (dhātaka) to have been at its first creation mature and whole in mind and body and it is supposed to be in a generality of position and physical circumstance where it does not perceive its parts, where its limbs do not touch each other but are rather spread apart, and that this self is momentarily suspended in temperate air, you will find that it will be unaware of everything except the "fixedness" (thubūt) of its individual existence (anniyyathihā).

Thus, according to the opening statement of this tanbīh, introspection shows that as long as the self is able to "discern a thing correctly," then whatever other circumstance it happens to be in, it will have self-knowledge. Commenting on this tanbīh as a whole, the philosopher-scientist Naṣīr al-Dīn al-Tūsī (d. 1274) writes: "Hence the absolutely first and clearest apprehension is a human being's apprehension of his self. It is clear that this kind of apprehension can neither be acquired through definition (hadd) or description (rasm), nor established by argument (hujja) or demonstration (burhān)."

The main intention of this version of the "Flying Man" is not to prove or demonstrate. Rather, it is to point out and illustrate that self-knowledge is the most primary of human cognitions. Thus, as noted earlier, it states explicitly what is implicit in the first version. Unlike the latter, it does not contain the explicit argument that the self is immaterial. An argument for the immateriality of the self, different from the one encountered in the first version, however, comes immediately after. This argument, no less than the one in the first version, is open to the criticism that it assumes the point at issue and that it makes a shift from the hypothetical to the categorical. For it uses the "Flying Man" as a premise. But this example, as we have tried to show, already assumes that the self is immaterial. Furthermore, it appeals to this hypothetical example as though it has established the factual. The argument, spread over three tanbīhs, is expressed in cryptic language. Its essentials can be paraphrased as follows:

In the first tanbīh, Avicenna argues that self-knowledge is direct, not mediated, on the basis that the example excludes awareness of anything other than the self. In the second tanbīh, he argues that the self cannot be the body since the body is apprehended by the external senses. Now, he continues, the body has apparent external parts seen and felt by our senses and internal organs known to us only through dissection. The external parts cannot be the self. This is because we can be "stripped" of these parts and because these parts undergo growth and change without our losing our identity. Moreover, in "the supposition" (al-fard), that is, the "Flying Man," the senses are not operative and the activities of dissection enabling us to have knowledge of our inner organs is likewise excluded. The self hence is not the body. In the third tanbīh, Avicenna raises the question of whether self-knowledge is mediated through one's action. This, he argues, is not the case because, once again, "the supposition" excludes any action. Moreover action is either general or specific. General action does not lead to the knowledge of the particular self. The action would have to be particular; for example, my own individual act. But when I state that I am performing an act, the "I" is prior to my act. My act presupposes the existence of my self; otherwise I would not refer to it as my act.

One notices in this argument, not only the appeal to the hypothetical example as though it has established what is factual, but two other things. The first is Avicenna's reference to it as "the supposition" (al-fard), a concrete indication that he is only too well aware of its hypothetical nature. The second is that there are parts of the argument, more specifically, in the second and third tanbīhs, that are quite independent of the "Flying Man." One must also recall that the second version of the example was introduced conjointly with an argument that is independent of it. To this one must add that in the Psychology he devotes a whole chapter in an attempt to give a rigorous demonstration for the immateriality of the rational soul, quite independently of the "Flying Man" and without once referring us back to this example. All these considerations raise the question: Was Avicenna using the "Flying Man" to prove in the rigorous sense of "to prove" the existence of the self as an immaterial entity?

The indications are that he was not. In introducing the first version, as we have seen, he makes it quite plain that he intends to indicate "a manner of establishing the existence of the soul we have by way of alerting and reminding" and that this way is effective only with those capable of seeing the truth themselves. Underlying this approach is not only the conviction that experiential knowledge of ourselves is the most basic of our cognitions, but that the real object of this knowledge is an immaterial entity, an 'I' that is totally other than the body. Some who have this proper knowledge are inattentive to it, distracted from it. A thought experiment, not intended, however, as a rigorous proof, will awaken them to this knowledge. Others, the mutakallimūn would be an example of this, have been so accustomed to associating the body with the 'I' that they believe that this primary self-knowledge we have is knowledge of the body. Such people require a rigorous rational argument to show them their error.

Turning to the condensed third version of the example, its appearance in the Ishārāt wa al-Tanbīhāt is itself significant. This is a very intimate, personal work, written at the end of Avicenna's life, that gives the quintessence of his philosophy. Its mood is meditative, its tone religious, climaxed in the moving chapter on the stations of the mystics. The work is intended for kindred spirits, its contents, as he tells us, not to be divulged to anyone. If we read Avicenna aright, the "Flying Man" reappears in this work intended once again for "someone who has the power to see the truth himself, without the need of having to educate him, constantly prod him, and divert him from what causes sophistical errors."

Nancy G. Siraisi (essay date 1987)

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Last Updated on May 5, 2015, by eNotes Editorial. Word Count: 8454

SOURCE: "The Canon of Avicenna," in Avicenna in Renaissance Italy: The Canon and Medical Teaching in Italian Universities after 1500, Princeton University Press, 1987, pp. 19-40.

[In the following essay, Siraisi outlines the main ideas of Avicenna's Canon of Medicine, focusing on the Latin translation by Gerard of Cremona, and comparing it with its Galenic sources.]

The encyclopedic medical work written by Avicenna (d. 1037) is far too lengthy and, as the massiveness of the Latin commentaries on short sections of it testifies, far too complex to be adequately characterized in brief. The following comments are intended only to draw the reader's attention to certain features of the organization and content of the Canon that seem particularly relevant to its reception in the schools of the West and the emergence of a tradition of Latin commentary and, especially, to the adoption of Canon 1.1 as a textbook for the teaching of medical theory. Beginning with a brief overview of the Canon as a whole, I shall then pass to a somewhat more detailed, but still highly compressed, account of the physiological treatise in Book 1, Part 1. In the absence of full studies of Avicenna's relationship to his sources and of the relationship of the Latin to the Arabic text of the Canon, a summary of Canon 1.1 can only be, at best, sketchy and impressionistic. The immediate goal is, however, merely to indicate some of the main features of that treatise as its appears in its Latin form. A few comparisons with other ancient and medieval treatments of somewhat similar material illustrate the distinguishing characteristics of Canon 1.1.

The following description refers to the Latin translation of the Canon attributed by his pupils to Gerard of Cremona (d. 1187), since, although revisions of the Gerard translation and retranslations of parts of the work began to circulate in the sixteenth century, the twelfth-century Latin text was the original basis of Western understanding of Avicenna's book. Furthermore, as we shall see, various of the later revised Latin versions retained much of Gerard's work. Given the length, complexity, and technical nature of the Canon, the translation attributed to Gerard of Cremona is a remarkable accomplishment. Certainly the long history of the use of this version attests that by and large Gerard or his pupils managed to produce a generally understandable rendering of Avicenna's opus. Nonetheless, even though comprehensive studies of the translation have yet to appear, various scholars in the sixteenth century and the twentieth have pointed out that it is characterized by a high proportion of both errors and obscurely rendered passages. It also retains numerous transliterated Arabic words, especially for names of plants and minerals in the pharmacological sections and for anatomical terms. But whatever its merits or defects, the Gerard translation was the means whereby the Canon reached all its readers in western European medical schools up until the early sixteenth century, and a good many of them thereafter.

Considered as an encyclopedia of Greco-Arabic medicine, the Canon is in many respects distinguished by comprehensiveness and good organization. Praise of Avicenna's work for these qualities became, indeed, a commonplace among Latin commentators. As G. B. Da Monte put it [in his 1554 commentary on the Canon], Avicenna was moved to write the Canon when he saw that "neither among the Greeks nor among the Arabs was there any single, complete, continuous book that taught the art of medicine," the Hippocratic writings being enigmatic and obscure, Galen extremely prolix, and Rasis confusing. [In his Preface to Galeni opera ex sexta Juntarum editione, 1586], the same author asserted that Avicenna "intended to reduce all the monuments of medical art scattered at large in various works of Galen into one, as it were, corpus.… Indeed, he collected much dispersed information into appropriate and defined places and arranged it in sequence." One may certainly agree that the Canon is comprehensive. Few aspects of traditional Greek and Arabic medicine are left untouched in its five books, which together amount to about a million words in length. However, the Canon is at least as much a collection of essentially separate and distinct manuals and reference works as it is an architectonic summa of medicine. Moreover, while individual sections are as a rule clearly organized and succinctly expressed, the overall arrangement is somewhat confusing and involves a certain amount of overlapping. The reader turns with gratitude to the lengthy analytic table of contents found in the early printed editions of Gerard's translation immediately after Avicenna's preface to the whole work and before each of its subsequent books.

Book 1 is divided into four main parts, or fen, to use the term adapted from the Arabic by the Latin translator. It opens with the statement of principles and handbook of physiology. The second fen of Book 1 classifies varieties, efficient causes, and symptoms of disease. Diseases are divided primarily into those caused by imbalance of the four elementary qualities of hot, wet, cold, and dry in the body, those caused by faulty composition, or conformation of bodily parts, and those caused by solutio continuitatis or continui, which may be rendered, more or less, as trauma. The efficient causes of disease are categorized as either connected with environment, regimen, and psychology (among them are included the factors embraced in the traditional scheme of the "non naturals"—air, food, and drink; repletion and inanition; motion and rest; sleep and waking; and passions of the soul) or as due to any of a wide range of individual physical events, some of which (for example, pain and swelling) the modern reader might be inclined to consider symptoms rather than causes. The section on symptomology both lists an array of individual signs of imbalance of complexion, of solutio continuitatis, of obstruction, and so on, and reviews the standard means of diagnosis by pulse and urine. The third fen of Book 1 concerns the conservation of health: separate sections on pediatric, adult, and geriatric regimen are followed by regimes for the delicate and complexionally imbalanced, and for travelers. The fourth and final fen of Book 1 deals with principles of therapy and forms of treatment appropriate for different conditions. Therapies discussed include emetic, cathartic, sedative, and other medications, bleeding, cauterization, blistering, and enemas.

Book 2 is on the subject of medicinal simples; most of it is given over to a list—arranged more or less in Latin alphabetical order, presumably by the translator—of individual substances, their properties, and the conditions for which they are supposedly remedies. In his third book, Avicenna provided twenty-one fen on ailments peculiar to each major organ of the body— arranged from head to toe—and their treatment. Most of the sections are preceded by one or two chapters on the anatomy and aspects of the physiology of the organ in question. Book 4 suveys diseases and injuries that either affect the whole body or may occur in any part of it, and their treatment; of its seven fen, the most notable is probably the first, on fevers, which provided a famous and influential account of the subject. The remaining fen of Book 4 concern the concept of crisis or critical days in illness; tumors and pustules; solutio continuitatis in the form of wounds, bruises, sprains, and ulcers; dislocations and fractures; poisons of mineral, vegetable, and animal origins (including animal bites and stings); and skin conditions. The fifth and final book of the Canon is an antidotarium, or manual on the preparation of compound medicines.

If one wishes to use the Canon as a reference tool, the arrangement of material just summarized works well for some subjects, but a good deal less well for others. A reader who is primarily interested in disease, for example, finds a sequence of more or less self-contained treatises offering complementary information. He or she can begin with classification, efficient causes, and symptoms of disease in general in Book 1, Fen 2, and proceed to the survey arranged by varieties of treatment in Book 1, Fen 4. Then, moving from the general to the particular, there is the account of diseases affecting different parts of the body in Book 3 and of diseases affecting the body as a whole in Book 4. Yet the division of the material into separate sections, and the provision of the analytical table of contents, means that anyone who is interested only in one particular topic—lepra, say, or diseases of the eyes—can easily turn to a few chapters on that subject alone.

The results are also fairly satisfactory if one considers the material available to a reader primarily interested in therapy. There is a self-contained survey of treatment methods (1.4) and a dictionary of medicinal simples (2); much discussion of treatments appropriate for disease of particular bodily parts is found in Book 3, and of ills affecting the entire body in Book 4; Book 5 provides guidance for compounding medicines. The arrangement has the merit of making it possible to approach the subject of therapy from a variety of different standpoints. One can, for example, relatively easily find an answer to any of the following questions: When and in what conditions is bleeding an appropriate treatment? What are the medicinal powers of cinnamon? What treatments are recommended for deafness? For various kinds of fevers? How is theriac compounded? However, although no systematic survey has been attempted for present purposes, it is clear that consistency throughout the whole, whether in terms of therapeutic recommendations or of properties attributed to substances, is not always achieved.

Least satisfactory, in some respects, is the arrangement of the physiological and anatomical material. Principles of physiology and the anatomy of bones, muscles, nerves, veins, and arteries are discussed in the first fen of Book 1; but the accounts of the anatomy and some further discussion of the physiology of other major organs (brain, lungs, heart, digestive and reproductive organs, for example) are scattered through the opening chapters of the twenty-one fen of Book 3. This separation, which is the result both of Avicenna's division of medicine into theory and practice and of the classification of bodily parts that he adopted, was, as we shall see, further accentuated by the curricula and practices of medieval university faculties of medicine. But in order to understand both the basis for Avicenna's treatment of physiology and anatomy and the principles underlying the organization of the Canon as a whole, it is necessary to turn to the content of the fīrst fen of Book 1.

The easiest way to describe Canon 1.1 is as a manual of Galenic physiology, although such a description is slightly misleading because the work also contains other elements of considerable importance. Furthermore, although the subject matter of the treatise is primarily physiological, the discipline with which it is concerned is not coterminous with even the loosest and most general modern definition of the science of physiology. Instead, Fen 1, along with other parts of Book 1, deals with the theoretical part of medicine, a subject that embraced the definition of medicine and of its place among the arts and sciences, and the fundamental principles of medical learning. Canon 1.1 is subdivided into six doctrinae, the last four of which are mainly physiological in content. The first two sections concern the definition, subdivisions, and subject of medicine and the theory of the elements, the last being considered to provide the basis in physical science for physiological theory.

The first section (doctrina) of Fen 1 opens with a definition of medicine: "Medicine is the science by which we learn the various states of the human body, when in health and when not in health, whereby health is conserved and whereby it is restored, after being lost." Medicine is thus presented from the outset as a science in the Aristotelian sense of a body of knowledge derived by demonstrative reasoning from true premises, but a science with a practical purpose. Implicit in the definition is the repudiation of any notion that medicine is merely a practical art, technology, or craft. Avicenna next asserts that medicine is divided into theory and practice, rebutting the counterclaim that any true science must of necessity be entirely theoretical with the example of philosophy, also, in his view, divided into theoretical and practical parts. Furthermore, it is not the theoretical part of medicine alone that is categorized as scientia; the practical part is also scientia, since it too involves formally organized knowledge, in this case the knowledge of how the tasks of healing should be carried out.

The subject of medical science, we learn in the following chapter, is the human body, insofar as it is subject to health and sickness. Since complete knowledge only comes with knowledge of causes, the physician must know the causes of health and sickness, these being classified in the Aristotelian manner into material, efficient, formal, and final causes. The subject of Fen 1 is announced to be the material, formal, and final causes of the human body as it is subject to health and sickness (efficient causes Avicenna identified with external factors affecting the body and discussed, as already noted, in Book 1, Fen 2). The medicus, who must also know regimen, symptoms, and medications, should investigate these causes by sense and anatomy, but he should take the fundamentals of physical science (for example, that the elements exist and are four in number) from natural philosophy without himself engaging in natural philosophical investigation.

The second doctrina of Fen 1, on the elements, is an admirable illustration of this last principle, since it provides a highly compressed account of those, and only those, parts of a mainly Aristotelian element theory necessary to establish the human body as an object in the physical world and to provide the foundations for an understanding of two central concepts of Greco-Arabic medical theory, namely humoral physiology and the idea of complexio, temperament, or krasis (that is, the balance of the elementary qualities of hot, wet, cold, and dry in living bodies). We read that the human body, like all other bodies, is compounded of the elements. The two heavy elements, earth and water, contribute chiefly to the formation of its members; and the two light elements, air and fire, contribute mostly to the generation of spiritus and motion of the members (although only the soul actually moves the members). In addition to learning the natural place and qualities of each element (earth in the center, cold and dry, and so on), the reader is also reminded that earth preserves shapes and forms; that water receives all shapes but does not preserve them, that air helps in rarefying and elevating substances; and fire assists in processes of maturation, mixing, and making subtle. When one recalls, for example, the notion frequently expressed by medieval authors that a good memory is due to the physical retention of images by relatively dry (that is, earthy) brain tissue, or the frequency with which the heating of mixtures plays a part in medical recipes, the medical and physiological relevance of the latter information becomes readily apparent.

The first two doctrina of Fen 1 thus constitute an important statement about the nature of medical learning. The definition of medicine is broad enough to include the study of all aspects of physical function. The status of medicine as a science is defended. Moreover, the subject is placed in the context of Aristotelian natural philosophy, through insistence on medicine's scientific character, the application to it of the concept of the four causes, and the assertion that the fundamental physical principles on which medicine rests are drawn from natural philosophy. The human body studied by the physician exists as part of the sublunary world of Aristotelian physics and is subject to its laws. At the same time the independence of medicine as a discipline is safeguarded by the warning that the medicus should not, qua medicus, investigate issues in natural philosophy. The significance of these assertions was not to escape Avicenna's Latin commentators.

In addition, the second of the two introductory sections, that on the elements, fulfills a transitional function. While it continues the Aristotelian and philosophical themes of Doctrina 1, it also leads directly into the mainly Galenic and physiological material of the rest of the treatise. The topics surveyed in the last four subdivisions of Fen 1 are complexio or temperament, the humors or bodily fluids, the parts of the body, and the virtues and operations, which include sensation, motion, pulsation, and so on. These categories, together with the elements and spiritus (discussed by Avicenna along with the virtues and operations), constitute the ancient scheme of the things natural. In composing Fen 1, Avicenna superimposed the Aristotelian scheme of the four causes upon the set of seven things natural, redefining the latter as a sequence that proceeded from the most remote to the most immediate material causes, and ended with the final causes of the human body. Thus Doctrina 1 informs the reader that the body's material causes are the elements (remote), the humors (somewhat remote), and the members and spiritus (immediate). The virtues and operations, which usually come last in the scheme of things natural, Avicenna regarded, appropriately enough, as the final or teleological causes of the human body. These definitions accounted for the things natural except complexio, which Avicenna proclaimed the body's formal cause. He discussed complexio in its accustomed place in the sequence of things natural between the elements and the humors. This position, somewhat awkward in terms of his arrangement according to the four causes, had perhaps to be retained because of the presence of another implied progression in the traditional order of the first four of the things natural (elements, complexio, humors, members), namely an ascending hierarchy of perceptibility to sense.

Within this whole scheme, each section leads logically to its successor, and all major bodily functions are neatly fitted into the system. Having learned that the human body, like all other sublunary bodies, is fundamentally composed of the four elements, each with its pair of qualities, the reader proceeds next to Doctrina 3 on complexio. The balance of the elementary qualities produces, in plant and animal species, in human individuals, in parts of the body, and in medicinal compounds, the complexio, which Avicenna, as transmitted by Gerard, defined as itself a quality. Complexion, used in this special sense, is either balanced or unbalanced, temperate or intemperate; in reality, however, complexion never achieves perfect balance, although in man it can come very close. A given complexion can only be identified by comparison with one of a series of norms (such as with the ideal for the species or the individual). According to Avicenna, eight varieties of temperate and eight varities of distemperate complexion can be identified in this way. Medicines, too, can only be described as, for example, temperate, hot, or cold, with regard to their effect on a particular body or kind of body. The same medicine may be hot in regard to a scorpion and cold in regard to a man, or hotter for Peter than it is for Paul. Whereas the elements in the human body were conceived of as not individually or directly perceptible to sense, complexion was supposedly to some extent detectable by physical means; in human beings, the skin of the palm of the hand is the most temperate organ and hence serves as the measure of the complexion of the other parts of the body and the manifestation of the complexion of the body as a whole. As is apparent from the foregoing, all the organs and humors of the body were thought of as individually complexionate. Avicenna accordingly provided his readers with four lists of bodily parts, each list being arranged in descending order from the extreme of hotness, coldness, wetness, or dryness to the palm of the hand.

Since complexion in human beings was considered both as a kind of individual constitution and as sex-linked and subject to change in scientifically predictable ways over time (as well as in response to climatic and other conditions), discussion of complexion necessarily involved consideration of growth and aging as well as sex differences. Avicenna devoted a chapter to these topics, in which he considered some of the implications of the doctrine that life involves a process of diminution of heat and moisture from infancy to old age and ultimately death. A long section of this chapter weighs the relative complexional heat of children and youths; the problem was of interest because the theory just mentioned implied that infants ought to be the hotter, but the vigor of youth seemed to suggest the contrary.

Doctrina 4 defines the humors as liquids into which nutriment is converted. In addition to the four primary humors (blood, phlegm, red bile, and black bile), four secondary humors are identified. All are said to be found in both good and bad varieties. The good varieties of the primary humors are absorbed into and nourish the substance of the body; the bad are "superfluities," which are either excreted or damaging to the body if retained. Thus, discussion of the humors and their role in the body's economy involves attention to digestion, nutrition, and excretion, processes treated in a chapter on the generation of the humors. Topics covered include the stages of digestion and functions of mastication, saliva, stomach, intestines, liver, kidneys, and bladder.

The topic of the humors is succeeded in Doctrina 5 by that of the membra, or parts of the body, which are here described as generated by the humors and sustained by their nutritive activity. The introductory chapter of this section contains generalizations about the members paralleling those about the humors and complexions in the two preceding parts of the work; it is, however, followed by five summae containing a total of seventy-six chapters on the anatomy of the bones, muscles, nerves, arteries, and veins. Well over half of Fen 1, in fact, consists of these chapters on anatomy. However, … the only part of Doctrina 5 normally taught in European universities was the introductory chapter, and this is all that will be considered here. It is mainly concerned with various ways of classifying bodily parts. The first distinction made is between membra similia or simplicia (for example, bones, cartilage, nerves, ligaments, arteries, and veins) and composite or instrumental members (for example, the hands or the face); it will be observed that this distinction is not quite the same as that between tissues and organs, which it is sometimes said to resemble. Brief definitions of the nature and function of the more important membra similia follow. It is, of course, only such members that are treated in the subsequent anatomical chapters; for an account of the chief composite members as such the reader has to turn to the introductory chapters of each section of Book 3.

The next classification of members is according to whether they receive or emit virtue: examples of members that both receive and emit (suscipiens et tribuens) are the brain and the liver; a member that receives and does not emit is the flesh; one that emits and does not receive is, according to some, the heart, although others disagree. This allusion to the difference between the teaching of Aristotle and that of Galen on the role of the heart leads, appropriately enough, to consideration of the Galenic doctrine of the three, or four, primary or principal members. The discussion divides the parts into principal members and members that serve the principal members. The former are heart, brain, liver, and testicles; the subsidiary organs of the heart are the arteries and lungs, those of the liver the stomach and veins, and so on. Again, the members may be divided into those in whose generation the paternal sperm played a larger part (all membra similia other than flesh and blood) and those generated primarily from the retained menstrual blood of the mother (flesh and blood); discussion of this distinction leads into a brief excursus on embryology. Members may also be classified as fibrous (villosa) or nonfibrous in composition, the membra villosa being the stomach, intestines, urinary bladder, and gall bladder.

Discussion of the principal members leads naturally to consideration of the virtues, or powers, associated with each of them. These were divided into "natural," "vital" and "animal" virtues, a classification ultimately connected with the philosophical concept of the three-fold character of the soul. Hence, Doctrina 6, the concluding section of Fen 1, opens (after a brief introductory chapter) with an account of the natural virtues (or in other terminology, powers of the vegetative soul) associated with liver and testicles: growth, the ability to convert and assimilate nutriment, and reproduction. Avicenna then proceeded to a description of the role of spiritus in preparing the body for the reception of the animal virtues (that is, the powers associated with the sensitive soul possessed by all animals, including humankind) of motion and sensation. Spiritus in the Galenic tradition here followed by Avicenna was a highly refined bodily substance formed in part from inspired air; in Avicenna's version it was first generated in the liver from the vaporous part of the humors (to which, presumably, inspired air had contributed) and then received a second generation in the heart. Pervading the entire body, spiritus, which manifests itself in pulsation, serves as the vehicle of virtus vitalis, which keeps life itself in being. Specialized functions attributed to spiritus—the refinement of animal spirits in the brain and the role of visual spirits in seeing—were also briefly mentioned by Avicenna. The account of the animal virtues focuses mainly on the process whereby messages from the senses are received and interpreted in the brain. For the Latin Middle Ages and Renaissance, Avicenna was of course a leading authority on psychology, although his reputation in this field was chiefly based on his De anima rather than the Canon. Nonetheless, in the latter work, too, he weighed the validity of such classifications of brain function as sensus communis, phantasia, and imaginative, cogitative, estimative, and rational powers (the last of these being associated with the rational soul and reserved for humankind alone). Fen 1 finally concludes with a chapter in which it is pointed out that many of the body's actual operations require the cooperation of both natural and animal powers.

As will have become apparent from the foregoing summary, the first fen of Book 1 of the Canon is a compendium based almost entirely upon ancient Greek sources, chiefly Aristotle and Galen. Yet Avicenna's selection, organization, and interpretation of his material resulted in a work with a distinctive character of its own. Investigation of the relationship of Fen 1 to its sources is beyond the scope of the present work; however, consideration of the way in which a few somewhat arbitrarily chosen examples of Aristotelian and Galenic doctrines appear in Avicenna's treatise may serve to throw light upon the special characteristics and apparent goals of that work.

Avicenna was both physician and philosopher, although he distinguished quite sharply between the two roles. Repeatedly, he warned the readers of Fen 1 that the medicus should not himself investigate natural philosophy, but should rather accept the conclusions of experts in that field. However, information and ideas derived from philosophy in general and from Aristotle in particular in fact play quite a large part in Fen 1. The Aristotelian framework provided for the whole work in its opening sections has already been noted. In addition, Avicenna took every opportunity that offered itself to point out specific differences between the physiological and psychological views of Galen and his followers and those of Aristotle and his. The most important differences between Aristotle and Galen on the subject of physiology were those relating to the functions of heart and brain and to conception. Regarding heart and brain, Aristotle usually held the heart to be the primary organ of the whole body, whereas the Galenists, as already noted, considered the heart only one of several primary organs (namely, heart, brain, and liver, a triad to which the testicles were often added as a fourth). The differing doctrines had extensive ramifications in that they also entailed differing views on sensation and motion, the blood vessels, and other topics. As regards conception, Aristotle held that the active or formative principle was contributed entirely by the male, whereas Galen maintained that both sexes contributed actively to the formation of the fetus and that females as well as males therefore emitted sperm.

Hence, in the first general chapter on the members, Avicenna informed his readers, according to the version attributed to Gerard, that the brain was held to be the principium of sense absolutely by some (the Galenists), but only intermediately by others (the Aristotelians). A little farther on, he remarked that

… the medici differ from a great man among the philosophers. For this great man among the philosophers said that the heart is the member that gives out and does not receive. For it is the first root of all the virtues, and it gives to all the other members their virtues by which they are nourished and live and by which they know and move. But the medici and some of the first philosophers shared out these virtues among the members and they do not say that [the heart] gives out and does not take in. And the opinion of the philosopher is indeed more subtly proved and truer. But the opinion of the medici when it is attended to in the first place (in primis) is more obvious.

Later in the same chapter, referring to the simile used by "he who gave truth (verificavit) to the wise," likening the male contribution in conception to rennet and the female contribution to that of the milk passively acted upon by rennet, Avicenna observed:

This word is to no small, nay, to a large extent, contrary to the words of Galen. For it seems to him that both the power of coagulating and the power of being coagulated is in each of the two [that is, male and female] sperms.…

In several passages of Doctrina 6, on the virtues, Avicenna returned at some length to the topic of the differences between the physiology of Aristotle and that of Galen, explaining that their differences over heart and brain were reflected in varying accounts of the vital, animal, and natural powers (associated with heart, brain, and liver, respectively). In one of these passages the medicus was instructed that though the Aristotelian view was correct, it was not his business in his capacity as medicus to investigate the issue, since whether or not a particular organ was or was not the principium of one of the powers made no difference from the standpoint of medical treatment.

Doctrina 6 also warns of differences between philosophical and medical terminology. Galenic medical writers normally described motion and sense as animal, and growth and reproduction as natural, powers. Avicenna, as Gerard represented him, pointed out that "the philosophers when they say anima mean anima terrena, the perfection of the natural instrumental body. And they mean the principium of every power, that principle indeed from which motion and diverse operations come." Hence, the powers of growth and reproduction termed natural by medical writers might be described as animales in philosophical texts, although on other occasions animalis might be used to refer to the power of comprehending and moving. Furthermore, the reader is also instructed that philosophers use the term natural for "every power (virtus) through which operation occurs in a body according to the diversity of its form," and this usage refers to a higher faculty than the powers of reproduction and growth designated by the medical term virtus naturalis. Finally, yet other passages in the same doctrina point out differences between philosophers and medical writers over the proper classification of the internal powers of the brain.

In Fen 1, the various discussions of the relationship of philosophical and medical teachings carry a double message. On the one hand, the medicus is repeatedly warned off philosophizing. He is, in effect, told on a number of occasions that although the Aristotelian teaching is true, he should for all practical purposes follow Galen and not worry about the discrepancy. On the other, the reader gets a good many tantalizing glimpses of philosophical views, and hints are not lacking that the dual roles of philosopher and physician may be combined in one person. That Avicenna himself had functioned in both capacities was, of course, well known to medieval and Renaissance readers of the Canon in Latin. Furthermore, in Canon 1.1 Avicenna referred readers of Fen 1 to his own philosophical writings; and he drew attention to Galen's philosophical interests with the remark that if Galen is to be attacked for his views on the division of medicine "he ought not to be attacked insofar as he is a medicus but insofar as he is a philosopher."

For the strictly physiological, as distinct from the natural philosophical, material in Canon 1.1, Galen is by far the most important source. Almost all the physiological concepts schematized and abbreviated in Avicenna's treatise can be found in Galen's works. Except for the instances noted above, in which Galen's views are weighted against those of Aristotle, to the ultimate advantage of the latter, the Latin text of Canon 1.1 contains few or no examples of clearly intentional divergence from Galen's teaching. Moreover, Galen is several times cited by name, and is always mentioned with respect, even in instances when Aristotle's opinions are preferred from the standpoint of philosophy. Yet the spirit and approach of Avicenna in Canon 1.1 seems very different from that of Galen.

Avicenna's apparent goal in writing Canon 1.1 was to present a highly compressed yet comprehensive account of the whole of physiological theory; the work teaches a set of principles that have been, to a very large extent, effectively abstracted from any context of experience. Unified organization, clarity (usually), and brevity are achieved, but at a certain cost. Lacking, for the most part, are illustrative examples, admissions of uncertainty or limited knowledge, indications of divergence of views among ancient physicians, or acknowledgement of the presence of inconsistencies within the body of Galen's writings. By contrast, Galen's major treatises embody, as a rule, a leisurely and discursive investigation of a particular aspect of a unified science of medicine that is not sharply divided into theory and practice. Moreover, in Galen's writings physiological theory is generally interwoven into a context rich in detailed anatomical description, records of personal experience and observation, and, often, polemic against the holders of different scientific views. Without undertaking any detailed investigation of the way in which Avicenna used his Galenic sources (or the form in which these reached him), we may illustrate some of the ways in which the teaching of Galen is transformed by its presentation in the Latin text of Canon 1.1 by means of a comparison of a few passages therein with sections of three works of Galen that Canon 1.1 to some extent parallels in subject matter—namely, De complexionibus (De temperamentis), De naturalibus facultatibus, and De usu partium.

Let us take our first example from the treatment of the subject of complexio. Most of the main ideas expressed in Doctrina 3 of Canon 1.1 can also be found in Books 1 and 2 of Galen's De complexionibus. Among the themes present in Galen's work that are also treated in Canon 1.1 are the relation of complexion to the elementary qualities; the notion that the physician considers complexion not as a balance of weight (ad pondus) but ad justitiam, in terms of appropriateness for the species, individual, etc., under consideration; the idea that complexion can only be expressed in relative terms and that the point of reference must always be specified; the related idea that a given complexion may be cold in regard to one point of reference and hot in regard to another; the assertion that man is the most temperate of all complexionate beings and that the skin of the hand is the most temperate part of man; and discussions of the different complexions of various ages and sexes, of the inhabitants of different regions, and of the individual organs of the human body.

De complexionibus 1, however, also contains extensive passages of exposition of differing views and polemic against them that have no parallel in Canon 1.1.3; furthermore, Book 3 of De complexionibus is devoted to detailed exposition of the complexion of various medicinal substances and the therapeutic applications of complexion theory, topics excluded from Canon 1.1. But the characteristic that most significantly distinguishes Galen's treatment from Avicenna's handling of some of the same material is the inclusion throughout Book 2 of De complexionibus of lengthy descriptions of the physical manifestations of different kinds of complexion. In Galen's treatise, the whole subject is closely related to anatomical experience, to observation of the patient, and to medical care; in Avicenna's, summary of the topic is explained by means of clearly stated but abstract and apparently arbitrarily determined rules, and examples are deliberately deferred until later in the Canon. Thus, Galen's remarks on the complexion of the various organs relate the complexional characteristics of each part to its physical characteristics and especially to its consistency; the flesh of the heart is drier than that of the spleen, kidneys, and liver because it is harder. The reader is urged to find out for himself that the heat of the heart is greater than that of any other organ by thrusting his fingers into an incision in the chest of a living animal. By contrast, Canon 1.1' s neatly schematized and readily memorable lists of organs in descending order of dryness and heat provide essentially the same information as that given by Galen—and a few gaps are fi̵lled in— but supporting references to physical experience are absent. In general, in Galen's much more than in Avicenna's account one is constantly reminded that complexion, and secondary characteristics dependent thereon, are to a significant extent accessible to sense.

Nowhere is this contrast more evident, perhaps, than in the treatment of the issue of whether the complexion of children or youths is hotter. In Canon 1.1, in one of the relatively few places in that treatise where a diversity of opinion among ancient physicians is acknowledged, otherwise unidentified medici antiqui are described as having been divided on the issue. Galen is said to have dissented from both views, and to have maintained that the heat of children and youths was in radice equal, but that the heat of children was greater in quantity and that of youths greater in quality. The rest of the passage is devoted to an explanation of Galen's supposed views, which turns on the two assertions: it is impossible to increase innate heat, and humidity declines throughout life. Thus, the heat of youths is conserved by less humidity than that of infants; they are at a stage of life in which the humidity is sufficient to preserve heat at a level that is qualitatively high, but not of such quantity as to permit further augmentation of the body in the form of growth.

Turning to the Galenic account as presented in De complexionibus, one is immediately struck by the much less abstract character of most of the discussion. Galen pointed out that the physician's evaluation of actual (as distinct from potential) complexional heat depended on touch, which with the aid of memory was indeed a satisfactory way of detecting changes in the heat of a single individual. However, if different individuals or whole categories of individuals were to be compared, then it was essential to compare like with like in regard to as many characteristics and conditions as possible—body type, diet, environment, and so on. These remarks, interesting for the adumbration of the idea of controlled observation of numerous exemplars, find no echo in the Latin Canon 1.1.3. Moreover, Galen's conclusion in De complexionibus was firmly rooted in his clinical experience; he stated that having touched the bodies of numerous children and adolescents, he found it impossible to assert on the basis of the sense of touch that either group was simply and unequivocally hotter than the other. However, the perspiration (a manifestation of heat, evidently) of children, was, owing to their greater humidity, greater in quantity, and that of adolescents more acrid in quality. This difference is because children have more innate heat, but the heat of adolescents is drier. Comparing this chapter with the passage in the Canon, one notes that the latter, characteristically, elaborates on Galen's conclusion, but does not contain those of his supporting arguments that depend upon clinical experience and sense perception. (Canon does, however, also explain a few perceptible characteristics of small children in complexional terms.)

One more illustration of the way in which Avicenna handled Galenic material may be drawn from his treatment of the topic of digestion and the digestive organs. We have seen that in Canon 1.1 there is a short narrative of the digestive process as a whole in the chapter on the generation of the humors (; to this must be added the description of the coats of the stomach and intestines in the section on membra villosa in the general chapter on the members (, and the account of the four nutritive powers (attractive, retentive, digestive, and expulsive) in the third chapter of Doctrina 6. Among the most important Galenic accounts of this part of physiology are Books 4 and 5 of De usu partium on the digestive organs and digestive process, and the lengthy discussion of nutritive power in De naturalibus facultatibus.

In its main outline, the brief summary of digestion in Avicenna's chapter on the generation of the humors is fairly similar to the much longer account presented by Galen in De usu partium and with parts of the account in De naturalibus facultatibus. Missing from Avicenna's highly compressed version are, however, both the emphasis on functional teleology and the richness of detail characteristics of De usu partium and the context of polemic against Erasistratus and his followers found in De naturalibus facultatibus. It is really only the opening generalities of De usu partium 4.1-4 that are paralleled in Canon Any attempt at more detailed description of the individual digestive organs and their functions, similar to that occupying the remainder of Books 4 and 5 of Galen's work, is postponed in the Canon until scattered chapters of Book 3. Furthermore, even in passages that do closely parallel one another in Galen's account and in the Canon, Avicenna's version is greatly simplified. In some instances, the process of simplification, and the stripping away or deemphasis of the metaphors freely used by Galen to clarify his descriptions and render them more vivid, resulted in a presentation of Galenic ideas in the Canon in a form that was simultaneously both cryptic and perhaps more literal than Galen intended. One example will suffice. In both De usu partium and De naturalibus facultatibus Galen compared the concoction of the chyle in the liver to the fermentation of wine. In the former work, he said:

Let us, then, compare the chyle to wine just pressed from the grapes and poured into casks, and still working, settling, fermenting, and bubbling with innate heat. The heavy, earthy part of its residues, which I think is called the dregs, is sinking to the bottom of the vessels and the other, light, airy part floats. This latter part is called the flower and forms on the top of light wines in particular, whereas the dregs are more abundant in heavy wines. In making this comparison, think of the chyle sent up from the stomach to the liver as bubbling and fermenting like new wine from the heat of the viscus and beginning to change into useful blood; consider too that in this effervescence the thick, muddy residue is being carried downward and the fine, thin residue is coming to the top and floating on the surface of the blood.

In De naturalibus facultatibus the same idea is presented as follows:

What else, then, remains but to explain clearly what it is that happens in the generation of the humors, according to the belief and demonstration of the Ancients? This will be more clearly understood from a comparison. Imagine then some new wine which has been not long ago pressed from the grape, and which is fermenting and undergoing alteration through the agency of its continued heat. Imagine next two residual substances produced during this process of alteration, the one tending to be light and air-like and the other to be heavy and more of the nature of earth; of these the one, as I understand, they call the flower and the other the lees. Now you may correctly compare yellow bile to the first of these, and black bile to the latter.…

In the Canon the presentation of its idea runs as follows:

In every concoction of this sort there is to be found foam and sediment.… The foam is red [yellow] bile; and the sediment is melancholy [black bile].

Avicenna's drastic condensation of Galenic material is accompanied on occasion not only by oversimplification, as in the instance just noted, but also by inconsistency, the latter sometimes merely echoing Galen's own. Thus, in the account of the membra villosa in the Gerard version of Canon 1.1, the urinary bladder is said in passing to have a single tunic; but in the account of the bladder's anatomy in Book 3 it is described as having two tunics. This discrepancy presumably stems from the fact that Galen had assigned the bladder one tunic in De usu partium and in one passage of De naturalibus facultatibus, but in a second passage of the latter work had given it two. Moreover, while the details of Galen's—and Avicenna's own— experience were excised from Canon 1.1, certain concepts adumbrated in Galen's works in Canon 1.1 were elaborated to the point where they may be regarded as original contributions. A case of this kind that has been the subject of modern scholarly attention is Avicenna's development of the concept of so-called radical moisture as an explanation of the process of aging. It must be emphasized, however, that the focus in the physiological sections of Canon 1.1 upon the systematic presentation and explanation of principles, at the expense of detail and supporting evidence, is unquestionably part of the deliberate strategy of that treatise; other parts of the Canon are rich in material pertaining to the experience of the physician and the treatment of patients.

Avicenna was neither the first nor the earliest available in Latin among authors who had written in Arabic to produce a schematic general summary of Greco-Arabic medicine structured around a division into theory and practice. The collection of brief medical opinions attributed to Joannitius and known as the Isagoge begins with the assertion that medicine is divided into theoretical and practical branches and proceeds to a consideration of the naturals, the nonnaturals, and the things against nature (that is, diseases). Avicenna has been shown to have drawn some of his material from the medical encyclopedia of Rasis (d. 925); another predecessor and possible partial source of the Canon was the survey of medicine written by Haly Abbas (d. 994). As compared with these other works, the Canon offers a fuller and more intellectually demanding account of its subject matter than the highly abbreviated Isagoge, and its organization is somewhat easier to grasp than that of the work of Rasis. The work of Haly Abbas is fully comparable to the Canon in scope and sophistication as well as structure. It is divided into ten books on theory and ten books on practice, of which the first four books on theory roughly parallel Canon 1.1 in content. In organization, the Liber totius medicinae is in at least one respect superior to the Canon: Haly's entire account of physiology and anatomy is presented as a coherent unit in his opening books, whereas in the Canon, as we have seen, the treatment of internal organs is excluded from the physiological and anatomical material in Book 1, Fen 1. Like Canon 1.1, of which it may well have been one of the sources, the Liber totius medicinae contains lengthy passages summarizing Galenic concepts. But the Aristotelian element, which plays so marked a part in Canon 1.1 seems not to be found in the corresponding parts of the Latin version of Haly's work. It was precisely Avicenna's philosophical interests that gave Canon 1.1 its distinctive cast. In Canon 1.1, as in Avicenna's philosophical writings, elements of diverse origin were drawn together. It seems likely that, indeed, Avicenna's well-known readiness to incorporate both Aristotelian and Neoplatonic elements into his philosophical system stimulated his interest in considering the relationship between Aristotelian and Galenic thought, which also contained Platonic elements.

Such, in barest outline, was the Canon as translated by Gerard of Cremona or his associates. The scope and organization of the work, the mass of practical information it contained, the author's summaries of Galenic thought (inadequate though these might sometimes be in detail), and the philosophical context in which Avicenna succeeded in placing medicine while preserving its independence as a distinct science—all initially secured for the Canon a place of honor in medieval western European medicine.…

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