A History of Mediaeval Jewish Philosophy

by Isaac Husik

These discussions of the fundamental principles of physics were applied ultimately to prove the existence of God. But there was a difference in the manner of the application. During the earlier period before the "Emunah Ramah" of Abraham Ibn Daud was written, the method employed was that of the Arabian Mutakallimun. That is, the principles of physics were used to prove the creation of the world in time, and from creation inference was made to the existence of a Creator, since nothing can create itself. The creation itself in time as opposed to eternity was proved from the fact of the composite character of the world. Composition, it was said, implies the prior existence of the constituent elements, and the elements cannot be eternal, for an infinite past time is unthinkable. This method is common to Saadia, Bahya, Joseph Ibn Zaddik, and others.

With the appearance of Ibn Daud's masterpiece, which exhibits a more direct familiarity with the fundamental ideas of Aristotle, the method changed. The existence of God is proved directly from physics without the mediation of the doctrine of creation. Motion proves a mover, and to avoid an infinite regress we must posit an unmoved mover, that is, a first mover who is not himself moved at the same time. An unmoved mover cannot be corporeal, hence he is the spiritual being whom we call God. Ibn Daud does not make use of creation to prove the existence of God, but neither does he posit eternal motion as Aristotle does. And the result is that he has no valid proof that this unmoved mover is a pure spirit not in any way related to body. This defect was made good by Maimonides. Let us frankly adopt tentatively, he says, the Aristotelian idea of the eternity of the world, i. e., the eternity of matter and motion. We can then prove the existence of an unmoved mover who is pure spirit, for none but a pure spirit can have an infinite force such as is manifested in the eternal motion of the world. Creation cannot be demonstrated with scientific rigor, hence it is not safe to build so important a structure as the existence of God upon an insecure foundation. Show that eternity of the world leads to God, and you are safe no matter what the ultimate truth turns out to be concerning the origin of the world. For if the world originated in time there is no doubt that God made it.

Thus Maimonides accepted provisionally the eternity of matter and motion, but provisionally only. No sooner did he prove his point, than he takes up the question of the world's origin and argues that while strict demonstration there is as yet none either for or against creation, the better reasons are on the side of creation.

Gersonides, on the other hand, was a truer Aristotelian than Maimonides and he decided in favor of the eternity of matter, though not of this our world.

The Jewish Mutakallimun, as we have seen, proved the existence of God from the fact that a created world implies a creator. The next step was to show that there is only one God, and that this one God is simple and not composite, and that he is incorporeal. The unity in the sense of uniqueness was shown by pointing out that dualism or pluralism is incompatible with omnipotence and perfection—attributes the possession of which by God was not considered to require proof. Maimonides, indeed, pointed out, in his opposition to the Mutakallimun, that if there is a plurality of worlds, a plurality of Gods would not necessarily be in conflict with the omnipotence and perfection of each God in his own sphere (Guide I, 75), and he inferred the unity of God from his spirituality.

The simplicity of God was proved by arguing that if he is composite, his parts are prior to him, and he is neither the first, nor is he eternal, and hence not God; and the incorporeality followed from his simplicity, for all body is composite. Maimonides proved with one stroke God's existence, unity and incorporeality. For his argument from motion leads him to conceive of the first mover as a "separate" form or intellect. This clearly denotes incorporeality, for body is composed of matter and form. But it also denotes unity, for the immaterial is not subject to numerical distinction unless the one be the cause and the other the effect. But in that case the cause alone is God.

Next in importance to the proof of God's existence, unity and incorporeality, is the doctrine of attributes. We have seen (p. [xxiii]) how much emphasis the Arabian Mutakallimun placed upon the problem of attributes. It was important to Jew, Christian and Mohammedan alike for a number of reasons. The crude anthropomorphism of many expressions in the Bible as well as the Koran offended the more sophisticated thinkers ever since Alexandrian days. Hence it was necessary to deal with this question, and the unanimous view was that the Biblical expressions in question are to be understood as figures of speech. The more difficult problem was how any predicates at all can be applied to God without endangering his unity. If God is the possessor of many qualities, even though they be purely spiritual, such as justice, wisdom, power, he is composite and not simple. The Christian theologians found indeed in this problem of attributes a philosophical support for the doctrine of the Trinity. Since God cannot be devoid of power, reason and life, he is trinitarian, though he is one. The difficulty was of course that the moment you admit distinctions within the Godhead, there is no reason for stopping at three. And the Jewish critics were not slow to recognize this weakness in the system of their opponents. At the same time they found it necessary to take up a positive attitude toward the question of attributes so as to harmonize the latter with God's absolute unity. And the essence of the solution of the problem was to explain away the attributes. Saadia says that the ascription of life, power and knowledge to God does not involve plurality in his essence. The distinction of three attributes is due to our limited mind and inadequate powers of expression. In reality the essence of which we predicate these attributes is one and simple. This solution did not seem thoroughgoing enough to Saadia's successors, and every one of the Jewish philosophers tried his hand at the problem. All agreed that the attributes cannot apply to God in the same signification as they have when we use them in our own experience. The meaning of the term attribute was investigated and the attributes were divided into classes, until finally in the system of Maimonides this question too received its classical solution. God is conceived as absolutely transcendent and unknowable. No positive predicate can apply to him so as to indicate his essence. We can say only what he is not, we cannot say what he is. There is not the faintest resemblance between him and his creatures. And yet he is the cause of the world and of all its happenings. Positive attributes signify only that God is the cause of the experiences denoted by the attributes in question. When we say God is just we mean that he is not unjust, and that he is the cause of all justice in the world. Hence Maimonides says there are no essential attributes, meaning attributes expressive of God's essence, and the only predicates having application are negative and such as designate effects of God's causal activity in the world. Gersonides was opposed to Maimonides's radical agnosticism in respect of the nature of God, and defended a more human view. If God is pure thought, he is of the nature of our thought, though of course infinitely greater and perfect, but to deny any relation whatsoever between God's thought and ours, as Maimonides does, is absurd.

From God we pass to man. And the important part of man is his soul. It is proved that man has a soul, that the soul is not material or corporeal, that it is a substantial entity and not a mere quality or accident of the body. Both Plato and Aristotle are laid under contribution in the various classifications of the soul that are found in Saadia, in Joseph Ibn Zaddik, in Judah Halevi, in Abraham Ibn Daud, in Maimonides. The commonest is the three-fold division into vegetative, animal and rational. We also find the Platonic division into appetitive, spirited and rational. Further psychological details and descriptions of the senses, external and internal, the latter embracing the common sense, memory, imagination and judgment, are ultimately based upon Aristotle and are found in Judah Halevi, Abraham Ibn Daud and Maimonides, who derived them from Avicenna and Alfarabi. In the Neo-Platonic writers, such as Isaac Israeli, Solomon Ibn Gabirol, Joseph Ibn Zaddik, Moses Ibn Ezra, Pseudo-Bahya, Abraham Bar Hiyya, and so on, we also find reference to the World Soul and its emanation from Intelligence. In the conception of the human soul the Jewish philosophers vary from the Platonic view, related to the Biblical, that the soul is a distinct entity coming into the body from a spiritual world, and acting in the body by using the latter as its instrument, to the Aristotelian view that at least so far as the lower faculties of sense, memory and imagination are concerned, the soul is the form of the body, and disappears with the death of the latter. The human unit, according to this opinion, is body-and-mind, and the human activities are psycho-physical and not purely psychical as they are according to Plato. Some writers occupying intermediate positions combine unwittingly the Platonic and Aristotelian views, or rather they use Aristotelian expressions and interpret them Platonically (Saadia, Joseph Ibn Zaddik, Hillel ben Samuel).

As the influence of the Arab Aristotelians, Alfarabi, Avicenna and especially Averroes, began to make itself felt, the discussions about the Active Intellect and its relation to the higher Intelligences on the one hand and to the human intellect on the other found their way also among the Jews and had their effect on the conception of prophecy. Aristotle's distinction of an active and a passive intellect in man, and his ideas about the spheral spirits as pure Intelligences endowing the heavenly spheres with their motions, were combined by the Arabian Aristotelians with the Neo-Platonic theory of emanation. The result was that they adopted as Aristotelian the view that from God emanated in succession ten Intelligences and their spheres. Thus the first emanation was the first Intelligence. From this emanated the sphere of the fixed stars moved by it and the second Intelligence. From this emanated in turn the sphere of Saturn and the third Intelligence, and so on through the seven planets to the moon. From the Intelligence of the lunar sphere emanated the Active Intellect and the sublunar spheres of the four elements. These Intelligences were identified with the angels of Scripture. With some modifications this theory was adopted by the Jewish Aristotelians, Abraham Ibn Daud, Maimonides, Levi ben Gerson.

The Active Intellect was thus placed among the universal Intelligences whose function it is to control the motions of the sublunar world, and in particular to develop the human faculty of reason which is in the infant a mere capacity—a material intellect. Sensation and experience alone are not sufficient to develop the theoretical reason in man, for they present concrete, individual material objects, whereas the reason is concerned with universal truth. The conversion of sense experience into immaterial concepts is accomplished through the aid of the Active Intellect. And at the end of the process a new intellect is produced in man, the Acquired Intellect. This alone is the immortal part of man and theoretical study creates it. Averroes believed that this Acquired Intellect exists separately in every individual so long only as the individual is alive. As soon as the individual man dies, his acquired intellect loses its individuality (there being no material body to individuate it) and there is only one acquired intellect for the entire human species, which in turn is absorbed into the Active Intellect. There is thus no individual immortality. Maimonides, it would seem, though he does not discuss the question in his "Guide," shared the same view. Gersonides devotes an entire book of his "Milhamot Adonai" to this problem, but he defends individuation of the acquired intellect as such and thus saves personal immortality.