Gersonides Criticism - Essay

Nima H. Adlerblum (essay date 1926)

(Classical and Medieval Literature Criticism)

SOURCE: Adlerblum, Nima H. “Gersonides—His Life and Works,” “Gersonides as a Scholastic,” “Gersonides in His Proper Perspective Setting.” In A Study of Gersonides in His Proper Perspective, pp. 22-126. New York: Columbia University Press, 1926.

[In the following excerpt, Adlerblum examines what little is known of Gersonides's life; explains his interest in astronomy, philosophy, and metaphysics; analyzes his writing style; summarizes the arguments of his opponents; and attempts to describe the historical setting in which his work was created.]


Of all Jewish philosophers, Gersonides is the one in whom scholasticism reached its highest articulation. We are here treating of Gersonides only in so far as a study of him would illustrate our chief contentions. Even with scholasticism at its best, a reversing of the historical method is bound to yield more fruitful results. It is therefore our aim to seek for the Jewish element underneath the scholastic garb, rather than for scholasticism in itself. An account of Gersonides' life and work will make us better understand his mental and emotional struggles. The gist of his metaphysics contained in Chapter III of this monograph, will reproduce to us the scholastic world with which he had to grapple. Into his Jewish world we can enter only indirectly, since the Jewish marks are not on the surface, and it is no easy task to disentangle the Jewish from the non-Jewish elements in the course of philosophical development. However, by a comparison with Judah Halevi, in whom ancient Jewish thought remained unalloyed, we may succeed in determining Gersonides' radius within the Jewish circle. As we shall later see, Judah Halevi's philosophy is a translation of Jewish life into thought terms, a blending of the content of history with that of metaphysics. A diagram constructed on the basis of Halevi's philosophy might help determine the degree of Jewishness in each medieval Jewish philosopher.

Even though we know little of Gersonides' life, a picture of it, inadequate as it may be, will help us penetrate better into his abstract metaphysics. When it comes to a philosopher whose contribution has already been incorporated in human thought we cannot read him with the same eagerness as we would one of our moderns, unless there is awakened in us an emotional interest in the personality of the author, in his strivings and yearnings, to a point where our attention is absorbed even in what has become irrelevant to our present mode of thinking. As soon as we transport ourselves into the respective worlds of our philosophers, those things which appear irrelevant loom up before us as living realities in the drama of thought. The Intelligibles, the Active Intellect, the separate Intelligences, and the spheres above were more thrilling to the scholastics than the dramatic incidents of here below.

De Rossi,1 Steinschneider,2 Munk,3 and Renan,4 tried to make out a biography of Gersonides from scanty references, both in the author's own writings and in those of his contemporaries. Munk thought that the dates of Gersonides' life were not ascertainable. Renan, basing his conclusion on a series of deductions, states that Gersonides must have been born in 1288 and that he died in 1344.5 The author of the Sefer Ha-Johsin (Book of Geneology) quotes the astronomer David Poel, who in his astronomical tables of 1361 refers to Gersonides as dead already. On the other hand, it is certain that in 1343 Gersonides was still alive, as he completed then his manuscript De Numeris Harmonicis.

His Hebrew name was Levi ben Gershon or Gershom. In his biblical commentaries as well as in most of the books where mention is made of him, he is referred to as Levi ben Gershon. But in his own introduction to the Milhamoth, as well as in a Hebrew work entitled Sha'arei Zion by Isaac Lattes, the name appears as Levi ben Gershom. In the rabbinical literature, he is referred to as Gershuni or R'l'b'g (Ralbag), the latter being the initials of Rabenu Levi ben Gershon. He was also surnamed Ari, meaning lion, because of his great mental acumen. In medieval Latin works, he is referred to as Leo Hebraeus or Maestro Leon de Bagnols, because he originated from Bagnols, France.6

Bartolocci speaks of him as having been born in Spain. But this is such an erroneous statement that the scholars did not deem it necessary even to refute it. It has been established beyond doubt that Gersonides was born in Bagnols, died in Perpignan and spent his days between Orange and Avignon where the Jews seem to have lived under greater tolerance than in Provence proper. However, from allusions in his writings, it seems that he was lacking the necessary tranquillity of mind. He writes somewhere that he could not go on with his writings “on account of the calamities of the times which interfered with clear thinking.” In a manuscript of his biblical commentaries he mentions that he did not have a Bible at his command, and in a remark written in 1338 he says that he could not revise his commentary on the Pentateuch, as there was no copy of the Talmud available at Avignon.

Renan directs attention to a few allusions made by Gersonides to some historical facts of the time, such as, e.g., the feud between Colonna and Orsini, and the practice of flagellation.

Gersonides was a physician by profession. We also know that he was married, and came from a family of great learning. In his biblical commentaries he often quotes his father who seems to have been a great scholar,7 and he also mentions a certain Rabbi Levi Ha-Cohen as his grandfather, probably his mother's father, known as R. Levi ben Chayim Ha-Cohen of Villefranche.8 The latter is the one whom Ibn Adrath persecuted for commenting on the Torah in an allegorical and philosophical manner. Perhaps, it was on account of him that the ban was launched by Ibn Adrath and other Barcelonean scholars against the study of philosophy, Greek literature and secular sciences, except medicine, before the age of twenty-five. On the other hand, Jacob ben Makir and one hundred other scholars of the Provence launched a counter ban against those who would refrain from teaching science to their sons. It was but natural, therefore, that Gersonides' father, who was the son-in-law of the persecuted Ha-Cohen, should have been more mindful of the ban against the non-teaching of science, than of the ban condemning the teaching of it. Gersonides must have been introduced to the sciences long before the age of twenty-five, for at 20 he had already gathered material for most of his works.9

Gersonides was an exceptionally rapid writer. It took him but seven days10 to write the fourteen chapters of the third section of the fifth part of his chief work, the Milhamoth. In one month, he wrote the twenty chapters of the first section of the sixth part. Another seven days saw the completion of the second section of the sixth part, consisting of fourteen chapters. The commentaries on Numeri and Deuteronomy took him one month each, as did his commentary on the book of Samuel, and the books of Ezra, Nehemiah, and the two Chronicles. Regarding the book of Numeri, he writes, “We have completed it in a very short time, without books at our disposal and there will be need of revision.” This shows that he required less even than a month's time for the completion of this commentary.

Gersonides' literary activity covers a period of twenty-three years. He started his chief philosophical work, the Milhamoth, about the year 1317 as can be inferred from his closing words at the end of Part I of Book 6.

An idea of the fertility and versatility of the author's mind can be gained from the list of his writings given in chapter V of this monograph. The list of his works comprises logic, metaphysics, psychology, physiology, commentaries on Averroes, mathematics, physics, meteorology, talmudic treatises, biblical commentaries, and astronomy.

Gersonides distinguished himself not only in philosophy, but also in astronomy. It is in his astronomy that one has to seek for the completion of his metaphysics. He was renowed in his time as the most famous astronomer, on whose hypotheses other astronomers based their further investigations. He corrected the astronomical hypotheses of his predecessors, and made interesting investigations about the heavenly bodies and their orbits. He also invented an instrument with which to fix the situation of the stars with greater exactitude. Pope Clement VI ordered a Latin translation of his chapter describing this instrument. This translation was made in 1342, during Gersonides' lifetime. Subsequently, in 1377, his whole work on astronomy was translated into Latin.11 Keppler made attempts to obtain a copy. At the request of Jewish and Christian scholars, Gersonides composed astronomical tables which were highly praised by Pico de Mirandola. Moses Ferussol Botarel commented on these tables.

It must have been his interest in astronomy that led Gersonides to philosophy. His first philosophical essay was on the question of the creation and the eternity of the world. Even though he incorporated this essay as the final chapter of his Milhamoth, he had written it ten years before conceiving his masterwork. His investigation on the constitution of the world must have led him into a further research of the relation of this world,—primarily the astronomic world, the planets, the active intellect,—to man, as well as their common inter-relations with God.

Aristotle, through the medium of Averroes, was of great help to him. Gersonides approaches Aristotle with impartial scrutiny. Before Gersonides, Aristotle met with either strong opponents or blind followers among the Jews. But in Gersonides are combined the faithful scholar as well as the keen critic. He admires Aristotle, accepts his premises, but works out his own conclusions. History cites Ibn Daud as the first Jewish Aristotelian; Maimonides as the one who adapted Aristotle to Judaism; Hillel de Verona as the first who reached Aristotle through Latin channels; and Gersonides as the most faithful follower of Aristotle. Indeed, at prima facie, he is a stauncher Aristotelian than Maimonides, who did not always dare face the ultimate conclusions. But in spite of this Aristotelian garb, Gersonides' philosophy is as far from Aristotelianism as it is from Platonism. But his insight into Aristotle is deeper than that of his predecessors, because he was careful to get a more correct version of Aristotle, by checking up the various commentators. Though he had no knowledge, or at best a limited knowledge of Latin and Arabic, he often discovered both errors of expression and misinterpretation in the Aristotelian commentators. Hillel de Verona had already before Gersonides attempted to analyze and discuss the Aristotelian vocabulary. But his chief aim in this was to ply Aristotle to his own views. In Gersonides the motive was only the discovery of the objective scientific truth.

The study of Aristotle led Gersonides to his work on metaphysics. He started with supercommentaries to all of Averroes' commentaries on Aristotle. Then he sought to supplement and reconstruct Maimonides' Guide for the Perplexed in the light of these commentaries.12 Once he started on this task, the scope of his work became enlarged. He was not satisfied to rely on Averroes alone, but studied the other Aristotelian commentators as well. He weighs every argument; tests its logical consistency; discusses the pros and cons, and cites as many philosophical opinions as he finds available. He writes that when we understand the inner reasonings of the argument, we shall better be able to judge of its veracity.13 In matters so difficult as to baffle a satisfactory solution, his method is to eliminate the most erroneous opinion. He thus hopes ultimately to arrive at the right solution. And so Gersonides becomes engrossed in a multitude of arguments to such an extent that the reader is at a loss to discover the author's own thread of thought amidst this labyrinth.

Gersonides' chief work in philosophy is the Milhamoth Adonai [Text references in this monograph are to the Leipzig edition of the Milhamoth, published 1866.] (Wars of the Lord) but the thoughts expressed in his biblical commentaries must also be taken into account. The Milhamoth is divided into six books, treating of the following subjects:

Book I—Immortality: Psychology and immortality of the soul; the hylic, the acquired, and the active intellect; the relation of the active intellect to the human intellect; reconciliation of philosophical conclusions with the biblical and talmudic views. (Chapters 1-14.)
Book II—Dreams, Divination and Prophecy: The psychology of prescience and its relation to the contingent. (Chapters 1-8.)
Book III—Of God's Knowledge: The well known dilemma of God's knowledge and the question of freedom. (Chapters 1-6.)
Book IV—Of Providence: The nature of providence and its relation to God's knowledge. (Chapters 1-7.)
Book V—The Heavenly Bodies: A study of the intelligibles, of the divine attributes, and of the rôle of the active intellect in the sublunary world. (Part I, omitted from this edition, 136 chapters; Part II, 9 chapters; Part III, 14 chapters.)
Book VI—The Creation of the World: Time, space, motion, potentiality, actuality, eternity, as well as other problems of medieval metaphysics. (Part I, 29 chapters.) The relation of his philosophical views on creation to the story of Genesis; miracles and their relation to prophecy. (Part II, 14 chapters.)

Gersonides does not enter into an investigation about the existence of God, nor into the essence and content of this concept, such as unity or negation of matter. This subject was much discussed by Gersonides' predecessors. It is possible that he didn't touch upon it, either because he thought that Maimonides had exhausted the subject, or because he feared to apply his usual method of treating a subject which required the citation of proofs for the negative as well as for the affirmative side. And Maimonides had declared that the negative thought of the existence of God must not even enter one's mind.14 It is true that Bahya Ibn Pakuda, Maimonides and other Jewish philosophers, as well as Thomas Aquinas and the Christian scholastics did not evade the subject. But their religious piety was never questioned; while the family of Gersonides, even back to his grandfather, was regarded with suspicion in this regard, because they were avowed champions of scientific research.

Gersonides also omits discussing in his Milhamoth the questions of revelation and resurrection, because, presumably, these rest entirely on faith, and are not amenable to scientific investigation and proof. Their affirmation or negation depend entirely on an interpretation of the meaning of passages in the Torah, the Prophets and the Rabbis. They do not properly belong in the realm of metaphysical investigation. Gersonides refers us for these questions to his biblical commentaries. In his Milhamoth he treats only of those principles of faith which lend themselves to scientific treatment.

At the time when Gersonides started his speculations, medieval philosophy had reached its maturity. The material was there; the problems had been formulated. The work of the philosophers consisted in their weaving of the material, or in their solutions of the problems. But Gersonides did not content himself merely with following the footsteps of his predecessors. Although in appearance the mold of his work seems to be the same as that of the others, his philosophy may be said to mark an epoch in medieval intellectual history. In its scholastic aspect it is a forerunner of Spinoza, and in its Jewish aspect it points towards a beginning of Bible criticism.

In psychology, too, Gersonides marks a distinct advance over his Jewish contemporaries. With them, the desire was not so much to know the inherent nature of the soul, as the theological curiosity of what the soul was and what would become of it. They touched on psychology only in so far as it involved the study of immortality. The psychology of the intellect was undertaken from the standpoint of the immortality of the intellect. Those who were interested to extend immortality to the whole of psychic life carried their psychological investigations a step further. But the science of psychology per se did not interest the Jewish philosophers.

The first Jewish Aristotelian, Abraham Ibn Daud (ca. 1110-1180) devoted only two chapters of his philosophical work Emunah Ramah (Exalted Faith) to what he called the science of the soul. He lays down certain principles regarding the soul, and finds in them a support for the theory of the existence of the Separate Intelligences. He regards these intelligences as the necessary intermediaries between God and material substance.

From Maimonides we have only incomplete fragments on psychology embodied in his morals of the soul. This is found in the Eight Chapters comprising the introduction to his commentary on the Tractate Abboth, (Ethics of the Fathers). Elsewhere he seems to have dealt more directly with the nature, essence and functions of the soul. But the only part of that work extant is in a quotation by Gerson ben Solomon in Chapter XI of his Shaar Ha-Shomayim. It is possible that this quotation as well as the introduction to Abboth were originally a single treatise on psychology. But when Maimonides thought of prefacing it as an introduction to Abboth, he left out such subjects as the psychology of prophecy, and such part as borders on physiology,—topics which have no bearing on the Tractate Abboth. In this connection, the following excerpt from Maimonides' Introduction is significant. “I have brought here from the study of the soul as much as was necessary for our purpose.”

Shem Tob ben Joseph Ibn Falaquera (13th century) attempted to collect the various opinions of Jewish philosophers on the soul. It is a mere collection. The compiler made no attempt to make a critical analysis of the opinions quoted.

The most complete Jewish work on psychology prior to Gersonides is the Tagmule Ha-Nefesh (Rewards of the Soul) of Hillel ben Samuel de Verona (1220-1295). It is hard to determine whether Gersonides saw this book or not. The two authors approach each other in logical arrangement, but they differ in their opinions.

With Gersonides, the study of psychic activities assumes a far greater importance than with his predecessors. He devotes the whole of the first book of the Milhamoth to the study of the soul, and even submits prophecy and the nature of God's knowledge to a psychological analysis.

His scientific temperament, acute logical mind and independence of spirit led Gersonides to transcend his own time. He felt the dawn of science and was transported by it. He felt such great joy at inventing an astronomical instrument that he composed a poem in honor of the event. He believed sincerely that the questions with which he concerned himself were of the utmost importance, and that their solution would be a great factor in human happiness. Similarly, he dreaded an erroneous solution on the ground that it would estrange man from real happiness.15 The chief motive which prompted him to compose his philosophical work was the desire to remove the obstacles from the path of those interested in these important questions.16 For this reason, Gersonides was happy with his Milhamoth and proud of it. He writes: “It must not be overlooked by those interested in our words that this book contains nothing which is not scientific. To eliminate all doubt, we have also cited and discussed various views, after thorough investigation. We have also solved many points of general interest in science, as will be clear to any one who knows the difficulties connected with them.”

Gersonides stresses the importance of the science of Astronomy. He writes a whole chapter in praise of Part V of Milhamoth dealing with this science. Astronomy is superior to all sciences. “The end of scientific research is the knowledge of the science of the stars.”17 It would be unjust to assume that Gersonides praised his treatment of astronomy out of vanity and boastfulness. It was rather because of his joy at contributing to human progress. Judah Messer Leon (1450-1490) did him an injustice in accusing him of conceit.18 Gersonides himself speaks of conceit as a very bad trait. In his commentary on Daniel IV, 27, he states that Nebuchadnezzar was changed to a beast in punishment for his conceit. “It is not worthy of a man to boast of his comprehension and achievements, or to think that he has acquired much knowledge. One should be conscious of one's deficiencies, as such a state of mind is an incentive for the striving after perfection.”19


The style of Gersonides' writings varies with the nature of their contents. His biblical commentaries have a pleasant style, attractive and easy to grasp. Writers on the history of Jewish literature familiar only with his commentaries, have inferred that in his metaphysics, his style is of the same nature. But this is not the fact. His profuse ramifications into lengthy pro and con arguments, throw the reader into confusion, and make it difficult to discover the bases and axes around which his arguments turn. His meaning in certain passages becomes apparent only after laborious analysis. Gersonides' contemporaries often mistook for his own the thoughts of others which he tried to discuss, and they made such views the basis of criticism against him. With all that, however, his style is simple, concise and logical. It is not the attractive style of Halevi's Alkhazari, nor of the Guide for the Perplexed, but it has qualities of strength and frankness and a conscious attempt at clearness. He writes in his introduction that he has used neither rhetorical nor deep and obscure language. “The depth of the meaning is sufficient, and one should not add the difficulty of language to that of the subject. The logic of the arrangement and of the language must be apparent. If this method is not followed, the authors lose the aim of their writings, and thereby render harder things which are easy in themselves. Not only are such writers of no help to those interested in their subjects, but they throw the reader into greater confusion. Through their lack of order and obscurity of language, they add mystery and deepen misunderstanding. However, sometimes the author might endeavor purposely to make himself clear to a few only, in the fear that the deeper meaning of his words might be misconstrued by the cruder mind of the masses.20 On the other hand, sometimes an author resorts to this subterfuge in order to hide an inherent shortcoming in the treatment of his theme by trying to hide it in deep language, flowery style and dragging in a number of other themes.21 In this manner the reader will attribute the difficulties to his own inability to understand, and the author's shortcomings will be hidden.” But, continues Gersonides, his aim in this book is just the contrary. He wants to have order and make use of a simple, clear style; clarify and not let depth of language and bad order hide the weakness of the meaning. (p. 8.)

However, in spite of his consciousness of the importance of simplicity and order in style, his work does not bear out his intentions in this respect. He goes back and forth from one subject to another. Before completing a topic under discussion, he starts a new subject and then reverts to the old. Not all of his views on a given subject are contained in the particular part or chapter dealing with the theme. For example, the Active Intellect is treated in Part I of the Milhamoth; but for the completion of this topic we must go to Book V where he discusses the heavenly bodies and their prime movers. Gersonides must have felt that the execution of his work fell short of his ideal, for he found it desirable to give in his introduction, (pp. 7-9), a kind of key to the principles of logical sequence that he followed. He enumerates seven principles of precedence:

  • (1) Premises before conclusions.
  • (2) The general before the particular.
  • (3) The easily understood before the more difficult.
  • (4) The sequence of number, both ordinal and quantitative; for example, the discussion of the triangle should precede that of the quadrangle, etc.
  • (5) Where two or more conclusions follow from one principle, the more obvious conclusion should precede the less obvious.
  • (6) The refutation of a conflicting opinion should precede the proof of the acceptable opinion.
  • (7) Where the writer's views differ from the accepted notions of the reader, the topics of lesser divergence should be discussed before those of greater divergence, so as to keep the interest of the reader and to prepare him gradually for a change in his notions. Gersonides adds also about the need of short summaries as the work progresses.


At a time when a new idea was looked upon with suspicion and regarded as heresy, when the controversy about Maimonides had not yet lost its bitterness, it was but natural that Gersonides, too, should be the object of attacks. It is even surprising that the opposition was not more vehement than it actually was. The explanation may be sought in the fact that in Gersonides' time, philosophy began to be less in vogue. His talmudical writings may have attracted more attention among the contemporary Rabbis, and may have warded off the suspicions of heresy arising from a reading of his philosophical works. This probably was the reason why he encountered no opposition from such renowned talmudical authorities as the disciples of Ibn Adrath, whose opposition to philosophy was almost fanatical. It should be noted, however, that their fight was not so much against philosophy per se, as against the allegorical interpretation of the Torah which the medieval philosophers introduced. The conservatives feared that the Jewish philosophers meant to rob the Torah of its original meaning, and uproot the halachic and historical principles of Judaism. But they could not suspect Gersonides of such motives, since he himself objected to allegorical interpretations wherever the scriptures were not allegorical in themselves. The excellent moral lessons and practical laws and suggestions that he deduced from every biblical story and incident were sufficient proof for them of his profound understanding of the spirit of the Bible and of the Talmud.

But if Gersonides met with no opposition from the talmudists, he was not spared by the philosophers. Already in his lifetime he was attacked by Samuel ben Judah ben Mesulam of Marseilles.

The greatest opponent of Gersonides was Crescas (1340-1410). The chief aim of his Or Adonai was to criticize Gersonides' philosophy; but once started, he extended his criticism also against Maimonides, the other scholastics, as well as against Aristotle himself. However, although Crescas appears as the critic of Gersonides, as a matter of fact, he appropriated Gersonides' thoughts. At prima facie Gersonides appears a most faithful follower of Aristotle, and Crescas chose to present him as such. A closer study, however, shows that while Gersonides starts with Aristotelian premises, he reaches different conclusions. But Crescas chooses to lay stress on the apparent meaning of Gersonides' words, while appropriating as his own Gersonides' deeper and truer meaning. Crescas uses Gersonides' own thoughts to criticize his alleged interpretation of Gersonides.

One is rather puzzled as to the cause which could have led Crescas to such plagiarism. He was known as a righteous man and was greatly beloved. He was a Court favorite even in the reign of John I. when Jewish persecutions were renewed. Nothing but a religious motive could have been responsible for such diplomacy on the part of Crescas. It seems that medieval scholars would leave all scruples behind them when it came to religion. Crescas must have been alarmed by Gersonides' free conceptions of miracles and of creation. He probably feared that with his great talmudic learning, Gersonides would win the people over to his views. Therefore he must have been anxious to destroy Gersonides' authority at all costs.

It is rather surprising that the historians looked upon Crescas as the antipode of Gersonides when at bottom the two systems stand so closely together. Their closeness might have come nearer to the surface had an attempt been made to get at the heart of these respective philosophies instead of merely analyzing them. That Crescas borrowed from Gersonides is testified to by his frequent inconsistencies on the one hand, and by his points in common with Gersonides on the other. Crescas appropriates Gersonides' premises and arguments, but arbitrarily rejects his conclusions whenever they are not sufficiently orthodox.

A number of inconsistencies which we meet in Crescas could be traced to this cause. Take, for instance, Crescas' discussion of the unity of God. Crescas posits the infinite potence of God, hence he must reject the possibility of the existence of another God. If there were two Gods, they would limit each other. Yet, Crescas tells us that it is still possible that there should be a second God who is not active. But a passive God contradicts Crescas' own conception of God, who possesses infinite potence. That other being which is neither active nor potential could not at all be explained in Crescas' scheme of the universe. But by a passive God, Crescas had in mind Gersonides' primary eternal matter which occupies such a great place in Gersonides' system. When it comes to the attributes of God,—such a vital item of scholasticism,—Crescas again contradicts himself because he refutes Gersonides in appearance, but in reality holds on to Gersonides' views. He defends Maimonides' homonymy theory which is so opposed to that of Gersonides, and at the same time he appropriates Gersonides' theory of attributes, namely that attributes are a relation of degree,—that of priority and posteriority. Inconsistently with Crescas' chief original contribution—the autonomy of morality—he makes morality preparatory to the happiness of the soul. The happiness of the soul is the supreme end in Gersonides, and Crescas combats it in some other connection. Crescas' conclusion in favor of creation is most inconsistent with his premises and analysis of the problem, which closely approaches that of Gersonides. Gersonides does not shrink from the logical conclusion of his premises, and declares himself in favor of eternity.

Many are the points of similarity between Crescas and Gersonides, but we shall mention only a few. Crescas' conception of God as the cause and law of all beings is literally taken from Gersonides. Crescas' criticism of the current view of emanation, his theory of attributes, and his solution of the problem of prescience are all taken from Gersonides. In his discussion of knowledge and prescience, Crescas follows Gersonides even in the order and logical arrangement. A digression used by Gersonides regarding the conception of the particular is textually copied by Crescas who substitutes merely the word “matter” for “sense”. In Gersonides this digression occurs in his first objection against the current theory of God's knowledge; in Crescas we meet with the same digression in his third objection.22 The same distinction that Gersonides makes between the act of knowledge in God, and the process of knowledge in man is also adopted by Crescas. They both maintain that God's knowledge is prior, and ours is derivative. Through the knowledge of God known existing things have acquired their existence. God knows through the general order of things, the law of which is in Himself. Crescas' reckoning the natural laws as a part of providence, his theory of reward and punishment as a cause and effect necessity, are all taken from Gersonides. Even what is considered to be Crescas' chief contribution, namely his theory of freedom and necessity, is also Gersonidian. Both Gersonides and Crescas maintain that from the aspect of general order, events are determined. But from the aspect of human choice they are indeterminate. In Gersonides' scheme of the universe even human freedom is guided by the general order so that all should lead to the ultimate perfection.

These similarities as well as many others are too fundamental and could not be taken for mere coincidences or for current thoughts of the time. There are many indications pointing to Crescas' adoption of Gersonides' system, even though we may remain ignorant of the reasons which brought Crescas to attack Gersonides on the one hand, and on the other to embody his fundamental views in his own system.

Through Crescas' influence, a few others rose against Gersonides. Among them was the great talmudist Isaac ben Shesheth of Saragossa. He speaks, however, of Gersonides in a respectful manner, and mentions him as a great talmudic scholar who has made fine commentaries on the Torah and the Prophets. He writes: “Although Gersonides followed in the path of Maimonides, the many sciences turned him away from the true path. He contradicted the opinions of our venerated Moses in certain subjects, such, e.g., as God's knowledge as related to future possibilities. About the miracle of Joshua he wrote things which are forbidden to be heard. In the same vein he wrote about immortality, providence and theodicy. And now, if these two kings (Maimonides and Gersonides) did not step on firm ground, their glory will abide with them. They are to be reckoned among the great ones of the world. But how could we expect a safe footing, we who, etc.” These are very mild words, and they show that in spite of all his love for Crescas, Bar Shesheth meant less to enter into war on Gersonides than to warn against philosophy in general. If he had been more in earnest to enter into controversy, this great talmudic scholar would have referred to Gersonides' theories with more precision and not in such a vague manner. For he is very accurate and precise in his talmudic and other discussions.

Don Isaac Abarbanel (1437-1508) complains that Gersonides should not have spoken so openly of his free views. Merely to listen to them is a sin, and how much more sinful is it to believe in them. Isaac ben Moses Arama (1420-1494) in his Akedath Yizhak, though agreeing with Gersonides on immortality, criticizes his views on God's knowledge, providence, and creation. He twists the title of Gersonides' work Wars of the Lord into “Wars against the Lord.”

Shem Tob ben Joseph Ibn Shem Tob (15th Century), author of Emunot, characterizes Gersonides as stupid for styling as prophets the angels that appeared to Abraham. He also attacked the other Jewish philosophers, such as Maimonides and Ibn Ezra. He merely repeats Crescas' words, without even understanding them. He was not taken seriously, however. One writer, Alashakar, calls Shem Tob a fool for speaking disrespectfully of the great ones of Israel.

In the 17th Century, Manasseh ben Israel seemed to have felt quite upset by Gersonides' philosophy. He expressed himself vehemently even against Isaac Arama for agreeing with Gersonides on immortality. He writes: “Would to God that such views had not been written, and that they should not come into the community of Israel.” (Nishmath Hayim, II, Ch. 2.)

But if Gersonides had opponents, he also had staunch admirers who tried to refute the criticisms against him. These defenders, moreover, were among the greatest Jewish scholars.

Isaac Lattes (14th Century) in his preface to Scha'are Zion (MS.) speaks of Gersonides as the great prince “our master.” He writes, “Gersonides does not have his equal in the world. He has commented on the Bible most profoundly, and has enlightened the world by his science, and especially by his famous work Milhamoth, the great value of which can be appreciated only by the initiated.”

Simon ben Zemach Duran (1361-1444) at the age of seventy-six and a half, wrote a book “Or Ha-Hayim” (Light of Life) in which he refutes all of Crescas' criticisms against Gersonides. He divided his work into fifty-five chapters, but the book has never been printed, and no manuscripts of it are known to be extant.

Even as late as the 19th Century we find an attempt to defend Gersonides. The Kabalist Abraham Shalom ben Israel in his Neve Shalom (Peaceful Habitations) attacks Crescas for having criticized the two great Jewish philosophers Maimonides and Gersonides. However, this author is not always in full sympathy with Gersonides' radical views.

A more detailed discussion of the criticisms against Gersonides would carry us beyond the scope of this monograph. We have merely referred to them here in so far as they helped us bring Gersonides' personality into relief.



Gersonides' philosophy is an attempt at constructing the world through the physics and astronomy then available, with the underlying hope of discovering that the indisputable truth of the present also lay hidden in the past. His system is not formulated, but scattered piecemeal through his writings. Interspersed in his discussions of Aristotle's commentators, there pierce through his own opinions which, if pasted together, would give us a picture of his world. This world is the reflection of a scholastic prism, and the reproduction of it would be no more than an additional colour to the endless kaleidoscope of philosophy.

The basis of Gersonides' metaphysics is Platonic and the structure is Aristotelian. According to Gersonides, there are two eternal existences. The one existence is infinite and of the highest perfection, which we term God. In Him are the ground and order of perfection of all beings throughout all generations. He is the only fundamental Being, (essential existence). The rest of existences acquired existence from Him, and are but a faint copy of Him. The attribute “existence” is predicated of God and the other beings in the relation of priority and posteriority.

The second eternity is finite, without any attribute of perfection whatever. It is so imperfect that it is devoid even of the ordinary dimensions.23 However, it has one redeeming feature, namely the possibility of perfecting itself within a certain degree24 through the aid of the perfect existence.25 And on the other hand, among the infinite number of perfections of the perfect being is his inherent goodness to perfect and complete the imperfect26 to the highest extent, comporting with the latter's capacity.27 And upon the varying degree of this receiving capacity, God classified this “imperfect existence” into three parts out of which he created the world. To two of those parts He gave the form of dimension and of motion and they thus became the hylic matter. One of these two parts is that which the Greeks called the hyle and it has constituted the low matter of the sublunary world. God has infused into it the possibility of receiving all kinds of forms. He invested it with the fundamental elements and gave to these the power of combination.28 The other part of the matter, God made most wonderfully pure and it constitutes the heavenly body. Therein God created the stars and the spheres that move them; and this motion produces the power of combination in the sublunary world. As a consequence to motion was created time which is an incident attached to motion.29 The heavenly body would never cease to exist30 because it does not contain within itself the cause of perishment, namely the combination of struggling opposites.31

As to the third part, the existence which has not been perfected, God put it between one sphere and the other, so that the motion of one sphere should not penetrate into the motion of another.32 The spheres which are already endowed with dimensions cannot penetrate into this formless matter.

Furthermore God has caused to emanate some of His perfection on the heavenly bodies and made them to be living intelligences33 that have a perfect knowledge of themselves and of their effects. And having a perfect knowledge of themselves, they necessarily know that they are caused by a being more perfect than themselves.34

The highest perfection into which the two parts of the primary matter have the capacity to evolve is the intelligibles. These are the universal nature of all existing things. The universal nature of the heavenly bodies is the motion of each sphere according to its particular nature, the effects resulting from it, the comprehension of itself and its effects. The universals of the sublunary matter are the many universals which we know and comprehend in all the existences. All these universals within the existing sensuous things35 are intelligibles which have an existence in themselves.36 And by themselves they are substances, separate intelligences which have emanated from the real perfection.37 In the heavenly bodies these universals are the movers of the spheres; here below they are the universals which have emanated from the heavenly movers. The latter effectuate all the natural effects of the sublunary world through a desire implanted in them by God to reproduce each its own respective share of the perfection arranged in God's mind.38

These intelligibles contribute to form the monistic system of the world. On the one hand the intelligibles appear to us many and separate according to the various conceptions, but on the other, they unite and form the order of perfection of here below, for all the intelligibles help each other and form each other's perfection. The more they unite, the more they perfect themselves by approaching nearer to the perfect existence wherein all the perfections are united into one infinite perfection.39

All the universals here below unite into one perfection termed the “Active Intellect”. The content of the Active Intellect is the unification of all the sublunary universals in so far as they form a unity.40 This is why the Active Intellect is the order and ground of all the perfections of here below in so far as the matter here below is capable of perfecting itself. In the Active Intellect must be the order and law of all the perfections of here below, also some of the perfection of the heavenly bodies, and of all the spheres in so far as they affect the nature of the things below and become united into one with all the other perfections. In this respect the Active Intellect stands above the movers of the spheres even though it emanated from them. For the movers of the spheres are each but the respective universal of its particular sphere and each conceives only itself and what is emanated from itself on the sublunary matter,41 while the Active Intellect contains whatever is emanated by all the spheres and the combination of the various effects upon the sublunary world.42 That is why Aristotle calls the Active Intellect the soul that has been emanated out of the spheres.43 The Active Intellect also gives the forms to all sublunary things,44 and preserves their existence in various ways.45

Another function of the Active Intellect is its important role in the act of human knowledge. It helps us to bring out all the intelligibles from potentiality into actuality.46 The main task of knowledge is to find in every particular its universal which unites several particulars into one. And the more our knowledge progresses, the more we discover the unity between the universals themselves. If one had the possibility of comprehending all the universals of here below in their completeness, one would see them all united into one; and this constitutes the Active Intellect.47 The universals are but intelligibles, and the Active Intellect is the intelligible of all the sublunary existences, that is, therein all the intelligibles, after completing each other, form a unity. This could be compared, for instance, to the construction of a house wherein the various processes, such as wood-cutting, stone-cutting, etc., all unite for the fundamental work, namely, the construction of the house. The house, which is the culmination of all these works, is in the mind of the architect who controls all those subordinate processes until they become coordinated into a house.48 If the intelligibles would not unite or supplement each other until they reach one perfection, our hylic intellect would not be able by itself to conceive any intelligible at all, and it would remain in a mere state of potentiality without ever becoming actual. It is only the acquired intellect that, through the connection of intelligibles, abstracts the universal from the particulars and comprehends them.49

The Active Intellect plays the same rôle in prophecy, dreams and divination as in knowledge. Just as with the help of the Active Intellect, our intellect passes from potentiality to actuality, so also the instincts of the soul, the feelings and the imagination, through the help of the Active Intellect, comprehend the future and the mysterious.50

In turn, all the intelligibles which are in the Active Intellect as well as in the other heavenly spheres unite into an eternal unity in the mind of God, the perfect eternity.51 Hence Gersonides' opinion is that all resides within God. He expresses it in a still stronger language. “God is the law of all intelligibles. He is their order and system. He arranged and ordered them all.52 He is the intelligible of all the existences.”53 In other words, the latter are part of His content. But they form His content only through their unification, that is, they complete each other and become one in God.54 But in their existence they are emanated from God. Nor are the intelligibles a complete unity in their act of conceiving. For their conception is composed of their perfect self-conception, of what is emanated from them, as well as of the imperfect conception of their cause. Such is not the case with the process of God's conceiving. He is the perfect unity, conceiving only Himself, and what emanates from Him, as He has no cause above Him.55

Human perfection, according to Gersonides, consists not in conceiving the separate intelligences and the Active Intellect. This is impossible for man to conceive. But genuine perfection lies in the comprehension of existence and in the better understanding of the unity of intelligibles. The more intelligibles we acquire, the more we approach their unity through the acquired intellect.56 But man is an inherently defective being, and he cannot comprehend the universal of anything without the intermediary of the senses which put before him the sensuous perceptions. Hence we can reckon it as a perfection for man if he at least realizes that through the process of comprehension he abstracts the universal from the sensuous perceptions. For the sensuous perceptions originate in the inherent defectiveness of matter which is incapable of carrying its perfection to the extent of becoming a full intelligible. It is only capable to receive this definite measure from the universal. But it is within this matter that the perfect, genuine and infinite universal lies. The latter attempts to perfect even that very matter to the extent of the matter's capacity. In comprehending the universal, one approaches a knowledge similar to that of God. For, God comprehends the universal of the things. The sensuous things do not belong to the definition of knowledge; they have not attained such grade.57 Man needs the senses only for their presentation of things to the mind, so that the latter should abstract the universal. God's knowledge does not require the intermediary of the senses. He does not acquire His knowledge from the existences; the latter acquire their existence from God.58 He comprehends all the existences. For, every intelligible and every intellect include the act of comprehension, the more so God who is the intellect—the intelligible—of the whole of existence.

Through the very act of comprehension, the universal nature of comprehension which is inherent in man passes from potentiality into actuality; it enters into the height of perfection. It joins with the perfection of the Active Intellect, and joins with the perfection of God in whom all the intelligibles unite into one. Through this process the potential intellect passes into the acquired intellect which constitutes the immortality and eternity of the soul, because the universals are eternal. The supreme beatitude, however, lies not only in the eternity, but in the unique delight which the soul experiences during comprehension.59

The question of freedom and necessity is also interconnected with the order of the intelligibles. It is Gersonides' opinion that a certain order is prescribed even for the things that happen by mere accident.60 For all things that happen in the world, whether they are essential or accidental, must all come through their respective causes arranged in the system and law of things in the mind of the Active Intellect, in the organized nature of the spheres, and in the unification of all in God's mind. But two factors, the two forces of the world, namely God and man, have each according to their respective capacity the power of transforming the necessary into the possible. They can change everything that has been arranged. Through the intelligibles all things become necessary, but through the freedom which is inherent in the universal nature of man the necessary things may become possible.61 Even this very possibility is recorded within the system of intelligibles in the mind of God.

The power of possibility is allowed in the order of perfection so that everything should finally come back to the unifying perfection which unites all into one.62

On account of the coexistence of possibility and necessity as well as on account of Providence which takes care that the whole of existence should reach its perfection and that nothing should be omitted, there must necessarily exist the power of prophecy in nature. It is necessary that man should be notified of the arrangement of future events with their respective causes, so as to be able to control them for his good.63 The knowledge of the future comes either through an instinctive feeling,64 or through a strong imagination,65 or through intellectual conception reached either by a natural66 or supernatural calculation. The imagination or the intellect might be endowed with an additional power of conceiving the future results of most remote causes,67 and thus know them beforehand. Prophecy belongs to the same category as knowledge. Knowledge as well as prophecy are an emanation from God, from the ground of intelligibles arranged in God's mind. The emanation takes place through the Active Intellect68 in which are all the systems of here below. The phenomenon of prophecy is but the act of knowing and discovering in a miraculously rapid way chains of events which in the natural course would have required much thought and a number of years in time.

The existence of...

(The entire section is 21811 words.)

Seymour Feldman (essay date 1967)

(Classical and Medieval Literature Criticism)

SOURCE: Feldman, Seymour. “Gersonides's Proofs for the Creation of the Universe.” Proceedings of the American Academy for Jewish Research 35 (1967): 113-37.

[In the following essay, Feldman analyzes Gersonides's ideas regarding time, motion, and the creation of the universe.]

One of the more lively speculative issues in medieval thought was the question of the creation of the universe. Once Aristotle's physics had become part of the intellectual heritage of the medieval world, a philosopher committed to a Biblical conception of the universe had to cope with Aristotle's claim that the universe is eternal. Although the majority of medieval philosophers rejected this...

(The entire section is 9150 words.)

J. David Bleich (essay date 1973)

(Classical and Medieval Literature Criticism)

SOURCE: Bleich, J. David. “Life and Works,” “Gersonides's Discussion of Providence.” In Providence in the Philosophy of Gersonides, pp. 9-17, 30-43. New York: Yeshiva University Press, 1973.

[In the following excerpt, Bleich compares Gersonides's writings on providence with those of Maimonides.]

Gersonides, a leading personality of the medieval period, was certainly one of the most significant figures to arise in Jewish philosophic thought after the death of Maimonides and may be described as the greatest of the post-Maimonidean Aristotelians. Although known to us primarily as a philosopher his written works reflect broad scholarly interests. Gersonides was...

(The entire section is 9836 words.)

Seymour Feldman (essay date 1974)

(Classical and Medieval Literature Criticism)

SOURCE: Feldman, Seymour. “Platonic Themes in Gersonides's Cosmology.” In Salo Wittmayer Baron: Jubilee Volume, On the Occasion of His Eightieth Birthday, English Section, Vol. 1, pp. 383-405. New York: Columbia University Press, 1974.

[In the following essay, Feldman analyzes Gersonides's argument against the ex nihilo doctrine of creation and his defense of the idea of the incorruptibility of the universe.]

In his opening presentation of the controversy concerning creation Maimonides cites three distinct cosmological theories, the second of which he attributes to Plato and some other Greek philosophers.1 The chief characteristic that...

(The entire section is 8544 words.)

Menachem Marc Kellner (essay date 1977)

(Classical and Medieval Literature Criticism)

SOURCE: Kellner, Menachem Marc. “Maimonides and Gersonides on Mosaic Prophecy.” Speculum 52, no. 1 (January 1977): 62-79.

[In the following essay, Kellner compares Gersonides's understanding of the nature of the prophecies of Moses with Maimonides's interpretation of them.]

Gersonides1 and Maimonides2 shared many ideas concerning the possibility and nature of prophecy. This is hardly surprising; not only were they both Jewish Aristotelians, but Gersonides clearly implies that the problems he raises in his major philosophic work, Milhamot Hashem, are those problems and only those problems to which Maimonides failed to provide adequate...

(The entire section is 9537 words.)

T. M. Rudavsky (essay date 1982)

(Classical and Medieval Literature Criticism)

SOURCE: Rudavsky, T. M. “Individuals and the Doctrine of Individuation in Gersonides.” New Scholasticism 56, no. 1 (winter 1982): 30-50.

[In the following essay, Rudavsky explores the nature of individuals and of prime matter as posited by Gersonides and his contemporary Johns Duns Scotus.]

The attention in 14th century philosophical writings accorded to the status of individuals developed for several reasons. For many scholastics, the problem of individuals arose out of specific theological considerations surrounding the doctrine of the Trinity, as well as out of more ontological and logical issues resulting from commentaries on Porphyry's...

(The entire section is 6973 words.)

Seymour Feldman (essay date 1984)

(Classical and Medieval Literature Criticism)

SOURCE: Feldman, Seymour. “Composition and Style of The Wars of the Lord.” In The Wars of the Lord, Book One: Immortality of the Soul, by Levi ben Gershom (Gersonides), translated by Seymour Feldman, pp. 55-60. Philadelphia: The Jewish Publication Society of America, 1984.

[In the following excerpt, Feldman summarizes the literary history of The Wars of the Lord and defends Gersonides's monotonous style by explaining that he sought clarity, not literary flourish.]


Even a superficial reading of The Wars of the Lord could give the impression that this work was written at the...

(The entire section is 2464 words.)

T. M. Rudavsky (essay date 1988)

(Classical and Medieval Literature Criticism)

SOURCE: Rudavsky, T. M. “Creation, Time, and Infinity in Gersonides.” Journal of the History of Philosophy 26, no. 1 (January 1988): 25-44.

[In the following essay, Rudavsky explains Gersonides's approach to problems involving infinite divisibility and the continuum.]


In this paper I should like to examine Gersonides' theory of time and the infinite as developed against the backdrop of his views on creation. Two questions are of paramount importance: the creation of the universe, and the notion of the continuum. Before proceeding to an examination of these two issues, let me first say something about their importance in...

(The entire section is 8615 words.)

Charles H. Manekin (essay date 1992)

(Classical and Medieval Literature Criticism)

SOURCE: Manekin, Charles H. “Logic, Science, and Philosophy in Gersonides.” In Studies on Gersonides, edited by Gad Freudenthal, pp. 285-303. Leiden, The Netherlands: E. J. Brill, 1992.

[In the following essay, Manekin explains Gersonides's views on logic, particularly those ideas which run counter to Aristotle's understanding of the subject.]


The contributions of Levi ben Gershom (Gersonides) to the fields of science and philosophy are well-known, but his logical writings, though of some influence in the Middle Ages, have only begun to be studied. To these writings belong two major works: the...

(The entire section is 7538 words.)

Amos Funkenstein (essay date 1992)

(Classical and Medieval Literature Criticism)

SOURCE: Funkenstein, Amos. “Gersonides's Biblical Commentary: Science, History, and Providence (or: The Importance of Being Boring).” In Studies on Gersonides, edited by Gad Freudenthal, pp. 305-15. Leiden, The Netherlands: E. J. Brill, 1992.

[In the following essay, Funkenstein contends that Gersonides's undramatic style properly reflects his scholastic, logical nature.]

1. Gersonides' biblical commentary does little to ingratiate itself to its readers—be they medieval or modern. It has nothing of Rashi's charm, his unique blend of correct grammatical readings with pedagogically instructive homilies.1 It lacks the grammatical acumen of Ibn-Ezra, who...

(The entire section is 4213 words.)

Robert Eisen (essay date 1995)

(Classical and Medieval Literature Criticism)

SOURCE: Eisen, Robert. “Conclusions.” In Gersonides on Providence, Covenant, and the Chosen People: A Study in Medieval Jewish Philosophy and Biblical Commentary, pp. 169-83. Albany: State University of New York Press, 1995.

[In the following excerpt, Eisen analyzes Gersonides's arguments concerning providence and his thoughts about whether the covenant between God and the Jewish people is conditional or unconditional.]

In my introduction, I set out a number of reasons for exploring the theme of the Chosen People in Gersonides' thought. First and foremost, this doctrine is one of Judaism's cardinal principles and is therefore a key issue in any comprehensive...

(The entire section is 7328 words.)

Menachem Kellner (essay date 1998)

(Classical and Medieval Literature Criticism)

SOURCE: Kellner, Menachem. “Translator's Introduction.” In Commentary on “Song of Songs,” by Levi ben Gershom (Gersonides), translated by Menachem Kellner, pp. xv-xxxi. New Haven: Yale University Press, 1998.

[In the following excerpt, Kellner contends that Gersonides addressed his biblical commentaries to amateurs in philosophy and notes that, since the so-called secrets of the Torah had already been revealed, he had no reason to avoid discussing them in his works.]

In June or July 1325, at the age of thirty-seven, Levi ben Gershom wrote his commentary on Song of Songs. He had already written a large number of works, beginning with his Wars of the Lord...

(The entire section is 9441 words.)