SOURCE: "Albert's Influence on Late Medieval Psychology," in Albertus Magnus and the Sciences: Commemorative Essays 1980, edited by James A. Weisheipl, Pontifical Institute of Mediaeval Studies, 1980, pp. 501-35.

[In the following excerpt, Park discusses Albert's theory of the soul and its importance to Medieval psychological theory, including that of his student Thomas Aquinas.]

Albert wrote four major works on the soul: a commentary on De anima; Summa de homine (Book II of his Summa de creaturis); De natura et origine animae; and De intellectu et intelligibili. The first two were the most important for later psychology. In these, as in Albert's other writings on the subject, the most frequently cited philosopher, apart from Aristotle, was Avicenna, whose De anima seu Sextus de naturalibus was Albert's principal source. Albert depends on Avicenna for many of his particular doctrines and for much of his method.

Concerning his method, Albert distinguishes two approaches to the study of the soul.

On this subject, Avicenna says in Sextus de naturalibus that there are two ways of defining a sailor: in one he is considered in himself and is called a worker governing a boat by skill; in the other he executes his functions through the instruments of the boat, namely the yard, mast, sail, and oars. In the same way, the soul has two definitions: one according to which it performs the operations of life in the body and its organs. The other is given of the soul in itself and as it is separable from the body.

Thus, says Albert, one may study the soul a priori, in itself, or a posteriori, as it performs its various operations in and through the body. Considered in the first sense, the human soul is in its essence a separable spiritual substance which differs from the angels only in its affinity for the human body. Because it is, in principle, independent of matter, it should be thought of as the body's motor, perfection, or act, not as its form. It is joined to the body only incidentally by the lower functions of nutrition and sensation.

From this point of view, the human soul is not simple: it contains a lower part which performs the corporeal functions, and a higher which performs these and the intellectual ones as well. The two enter the foetus at different times and in different ways. The lower vegetative and sensitive faculties are drawn out from the matter of the embryo by the formative power (virtus formativa) in the seed of the parents. They remain incomplete, however, until God, the First Cause, illuminates the composite by infusing into it from outside the higher part, individually created. As soon as this happens, the "intrinsic" lower parts are transformed by their association with the "extrinsic" higher ones, and the product is a substantial whole—entirely human, rather than vegetable or animal, in nature. In more technical terms, "the powers are faculties which fol-low the constitutive species." For example, although the faculty of vision is the same in a man and an ass with respect to object and operation, nonetheless in the man it belongs to a different species—the human— because it is completed and "denominated" by the intellectual soul.

As a result, the intellectual soul becomes united to the body, depending on the lower parts, such as sensation, for all its operations. This is why, in Aristotle's maxim, "the soul never thinks without an image." Despite its association with the body, however, the intellectual soul remains fundamentally separable from it and closely allied with the other spiritual substances: with the angels and God himself. Therefore, while relying on sense images for its initial stimulation, the intellect may proceed beyond them to contemplate first itself, then the celestial intelligences, and finally God. Albert calls this intellectual state "assimilative":

the assimilative intellect is that in which man, as much as is possible or permitted, springs up analogically toward the divine intellect, which is the light and cause of all things… Therefore from the light of its own agent intellect, it reaches the light of the intelligence, and from that extends itself toward the intellect of God.

Thus the soul ascends to virtue, wisdom, and prophetic powers.

In his a priori discussion of the soul as substance, Albert depends heavily, as many scholars have shown, on the neoplatonic elements in Avicenna's version of Aristotle; using them, he can integrate Aristotle's psychology into the Augustinian tradition of the separable and immortal soul. In his a posteriori inquiry into the soul as revealed through its various operations, he takes as the center of his analysis Avicenna's transformation of the Aristotelian notion of faculty.

Aristotle considered the faculties as potentialities of the soul for different kinds of action and used them mainly as convenient categories to classify different levels of living things. Albert, following Avicenna, visualizes them as really existing and distinct powers which possess, in some sense, continuous actuality. For all practical purposes, the study of the soul a posteriori reduces to the study of the faculties as powers of the soul. In Albert's image, the soul is divided into diverse powers as a potestative whole. Like the organs of the body, the faculties are separate from each other, but mutually dependent and arranged in a hierarchy of nobility and command which resembles the chain of authority in a well-ordered monarchy.

The element of order is central for Albert. He takes the division of the soul into faculties as the organizing principle of his psychological works. In De anima and Summa de homine, after introductory sections which define the soul, each tractate or question is devoted to a different power or group of powers. These are of great importance in the history of medieval psychology. At the time Albert wrote the Summa de homine, his first extended discussion of the soul, Latin psychological theory was in chaos. The powers were acknowledged as central to any account of the soul, but there was no consensus as to what they were and how they should be divided, since the various Greek, Arabic, and Christian authorities had all proposed different models. Most earlier Latin writers, like Jean de la Rochelle, were content to give several different classifications without attempting to reconcile them.

Albert transforms the situation with his Summa de homine. He replaces the chaos of authorities and opinions with a coherent system based on Avicenna and incorporates elements from earlier Latin writers. In the first place, he rationalizes the enumeration of the powers of the soul by establishing a single system derived from Avicenna's interpretation of Aristotle and by relegating the faculties according to Augustine and Lombard to an appendix as motive powers "according to the Platonists and theologians." The result is a complex but coherent scheme of faculties divided into four main groups—vegetative, sensitive, motive, and intellectual. These correspond to three types of soul: vegetative, sensitive (or animal), and intellectual (or human). Albert's divisions and subdivisions, with minor variations, remain standard in Latin psychological theory through the end of the fifteenth century, and they persist in many authors well past 1600.

In the second place, Albert establishes the general philosophical terms in which the powers will be discussed throughout the later Middle Ages. As actual operative principles, the powers demanded a much more rigorous and systematic discussion than was found either in earlier literature or in Aristotle himself. Albert is the first adequately to provide such a discussion, and he does so by drawing on both Avicenna and earlier Latin sources, notably Boethius. Applying Aristotelian logical and philosophical principles, he develops a coherent explanation of the faculties which addresses the issue of their ontological status.

For Albert, the central questions are the following: In what sense can the soul be said to be composed of parts? What are the logical and ontological relations between the soul as a single substance and its multiple powers and sub-powers? He takes his answer, as he takes his image of the soul as hierarchy of authority, from Boethius' De divisione. Although physical objects may be divided into essential or integral parts, a spiritual entity like the soul has only "potestative" parts—natural powers—which flow from it; it must be considered as a whole composed of powers, or what Boethius and Albert call a "potential whole" (totum potestativum, potentiate, or virtuale). If the faculties of the soul are natural powers, then they lie, according to Aristotle's Categories, in the category of quality.

Albert uses Boethius not only to establish the logical status of the faculties, but also to answer a question which had plagued psychological theory for more than a century: Is the soul identical with its faculties? The Augustinian tradition, dominant through the end of the twelfth century, had argued that the distinction between the powers was only verbal; the different powers were in fact various names given to the soul as it performed various actions, but in essence identical to the soul With the new translations, it became clear that both Avicenna and Averroes accepted a real distinction between the soul and its powers and that Latin psychologists would have somehow to accommodate this position. Albert is the first to do so in a satisfactory manner. Rejecting the strained compromises of his earlier contemporaries, he demonstrates that, if the soul is truly a totum potestativum, it is a substance, while the powers are qualities which function as its powers. Logic thus demands a real distinction between them.

Albert's significance for the history of medieval Latin psychology mirrors his significance for medieval science in general. His influence extended beyond that of a generalized Aristotelianism, however; many specific aspects of his thought on the soul entered the tradition of medieval psychology. He took over two particular strains of Avicenna's theory: the Platonic strain which emphasized that nature of the soul as a separable substance—the "perfection" rather than the form of the body—and the scholastic strain which manifested itself in the elaborate hierarchical subdivisions of the faculties. Using concepts from the logical writings of Aristotle and Boethius, he developed a clear and reasonably consistent explanation of the way in which the faculties could be really distinct from the soul and from each other, but still of the same essence and substance. Later Latin writers often reject or alter Albert's conclusion, but they remain interested in Al-bert's questions, asked in his own terms.

The psychological theory of Thomas Aquinas, once a student of Albert, is both an index and a vehicle of his master's influence on late medieval psychology. Thomas' principal philosophical concerns are different from Albert's: for him metaphysics and theology replace natural philosophy and physiology as the center of attention. Nonetheless, his thought on the soul and its faculties clearly reflects that of his early teacher. On the one hand, he is very similar to Albert in his account of the faculties. He describes them as composing a hierarchy of authority like that in a monarchy, and his list of them in the Summa theologiae follows Albert's quite closely. The soul is a virtual whole and its powers are its natural properties—accidents flowing from its essence—and therefore really different from the soul itself. Thomas elaborates on Albert's conclusions by noting that the faculties, as natural powers, must lie in the second species of quality.

On the other hand, Thomas explicitly rejects the a priori discussion of the soul as separable substance that Albert took over from Avicenna and other Arabic sources. For Thomas, the soul is first and foremost the substantial form of the body. This leads him to reject a number of Albert's other claims. In the first place, he denies that the developing foetus derives its vegetative and sensitive powers from the formative power of the semen and is only later perfected by the infusion of a rational soul. This would mean, he argues, that

the substantial form would be continuously perfected. It would further follow that the substantial form would be drawn not all at once, but progressively from potency into act, and further that generation would be a continuous motion, like alteration. All of these things are naturally impossible.

What really happens, according to Thomas, is that the embryo receives a succession of increasingly perfect forms: it is first animated by a purely vegetative soul. At a certain point, this is wholly corrupted and replaced by a sensitive soul and, later, through God's direct creation, by a rational soul.

By the same token, Thomas rejects Albert's apparent contention that in this life the human intellect, as a separable spiritual substance, can know itself directly or the other separable substances—God and the celestial intelligences. As the substantial form of the body, the human soul is bound inextricably to corporeal modes of cognition. To know immaterial reality it must rely on what it can abstract from sense images, and as a result may understand this reality only reflectively and by analogy. Albert's "assimilative" intellect does not exist: "according to the state of present life, neither by the possible nor by the agent intellect can we understand the separate immaterial substances in themselves."

While in actual fact both Albert and Thomas insist that the proper object of the human intellect is the essence of material things and that everything above man can be known only by analogy to what is proper to man, Albert seems to stress the self-sufficiency of the hu-man intellect in self-knowledge more than does Thomas. But even Thomas admitted with Albert that the human intellect can through discourse know itself as an intellectual substance.

These differences were later exaggerated by opposing camps of Albertists and Thomists, and they became central to the debates over Albert's authority in fifteenth-century discussions of the soul.