A History of Mediaeval Jewish Philosophy

by Isaac Husik

Aristotle's system may be called theistic and dualistic; Plotinus's is pantheistic and monistic. In Aristotle matter is not created by or derived from God, who is external to the universe. Plotinus derives everything from God, who through his powers or activities pervades all. The different gradations of being are static in Aristotle, dynamic in Plotinus. Plotinus assumes an absolute cause, which he calls the One and the Good. This is the highest and is at the top of the scale of existence. It is superior to Being as well as to Thought, for the latter imply a duality whereas unity is prior to and above all plurality. Hence we can know nothing as to the nature of the Highest. We can know only that He is, not what he is. From this highest Being proceeds by a physical necessity, as light from a luminous body or water from an overflowing spring, a second hypostasis or substance, the nous or Reason. This is a duality, constituting Being and Knowledge. Thus Thought and Being hold a second place in the universe. In a similar way from Reason proceeds the third hypostasis or the World-Soul. This stands midway between the intelligible world, of which it is the last, and the phenomenal world, of which it is the first. The Soul has a dual aspect, the one spiritual and pertaining to the intelligible world, the other, called Nature, residing in the lower world. This is the material world of change and decay. Matter is responsible for all change and evil, and yet matter, too, is a product of the powers above it, and is ultimately a derivative of the Absolute Cause, though indirectly. Matter is two-fold, intelligible and sensible. The matter of the lower world is the non-existent and the cause of evil. Matter in a more general sense is the indeterminate, the indefinite and the potential. Matter of this nature is found also in the intelligible world. The Reason as the second hypostasis, being an activity, passes from potentiality to actuality, its indeterminateness being made determinate by the One or the Good. This potentiality and indeterminateness is matter, but it is not to be confused with the other matter of the phenomenal world.

Man partakes of the intelligible, as well as of the sensible world. His body is material, and in so far forth partakes of the evil of matter. But his soul is derived from the universal soul, and if it conducts itself properly in this world, whither it came from without, and holds itself aloof from bodily contamination, it will return to the intelligible world where is its home.

We see here a number of ideas foreign to Aristotle, which are found first in Philo the Jew and appear later in mediæval philosophy. Thus God as a Being absolutely unknowable, of whom negations alone are true just because he is the acme of perfection and bears no analogy to the imperfect things of our world; matter in our world as the origin of evil, and the existence of matter in the intelligible world—all these ideas will meet us again in Ibn Gabirol, in Ibn Daud, in Maimonides, some in one, some in the other.

Alike in respect to Aristotle as in reference to Plotinus, the Jewish philosophers found their models in Islamic writers. The "Theology of Aristotle" which, as we have seen, is really Plotinian rather than Aristotelian, was translated into Arabic in the ninth century and exerted its influence on the Brethren of Purity, a Mohammedan secret order of the tenth century. These men composed an encyclopædia of fifty-one treatises in which is combined Aristotelian logic and physics with Neo-Platonic metaphysics and theology. In turn such Jewish writers as Ibn Gabirol, Bahya, Ibn Zaddik, Judah Halevi, Moses and Abraham Ibn Ezra, were much indebted to the Brethren of Purity. This represents the Neo-Platonic influence in Jewish philosophy. The Arab Aristotelians, Al Kindi, Al Farabi, Avicenna and Averroes, while in the main disciples of the Stagirite, were none the less unable to steer clear of Neo-Platonic coloring of their master's doctrine, and they were the teachers of the Jewish Aristotelians, Abraham Ibn Daud, Moses ben Maimon, Levi ben Gerson.

One other phase must be mentioned to complete the parallelism of Islamic and Jewish philosophy, and that is the anti-philosophic attitude adopted by Judah Halevi and Hasdai Crescas. It was not a dogmatic and unreasoned opposition based simply upon the un-Jewish source of the doctrines in question and their incompatibility with Jewish belief and tradition, such as exhibited itself in the controversies that raged around the "Guide" of Maimonides. Here we have rather a fighting of the philosophers with their own weapons. Especially do we find this to be the case in Crescas who opposes Aristotle on philosophic grounds. In Judah Halevi similarly, though with less rigor and little technical discussion, we have nevertheless a man trained in philosophic literature, who found the philosophic attitude unsympathetic and unsatisfying because cold and impersonal, failing to do justice to the warm yearning after God of the religious soul. He could not abide the philosophic exclusion from their natural theology of all that was racial and national and historic in religion, which was to him its very heart and innermost essence.

In this attitude, too, we find an Arab prototype in the person of Al Gazali, who similarly attacked the philosophers on their own ground and found his consolation in the asceticism and mysticism of the Sufis.

We have now spoken in a general way of the principal motives of mediæval Jewish philosophy, of the chief sources, philosophical and dogmatic, and have classified the Jewish thinkers accordingly as Mutakallimun, Neo-Platonists and Aristotelians. We also sketched briefly the schools of philosophy which influenced the Jewish writers and determined their point of view as Kalamistic, Neo-Platonic or Aristotelian. There still remains as the concluding part of the introductory chapter, and before we take up the detailed exposition of the individual philosophers, to give a brief and compendious characterization of the content of mediæval Jewish philosophy. We shall start with the theory of knowledge.

We have already referred to the attitude generally adopted by the mediæval Jewish thinkers on the relation between religion and philosophy. With the exception of Judah Halevi and Hasdai Crescas the commonly accepted view was that philosophy and religion were at bottom identical in content, though their methods were different; philosophy taught by means of rational demonstration, religion by dogmatic assertion based upon divine revelation. So far as the actual philosophical views of an Aristotle were concerned, they might be erroneous in some of their details, as was indeed the case in respect to the origin of the world and the question of Providence. But apart from his errors he was an important guide, and philosophy generally is an indispensable adjunct to religious belief because it makes the latter intelligent. It explains the why's and the wherefore's of religious traditions and dogmas. Into detailed discussions concerning the origin of our knowledge they did not as a rule go. These strictly scientific questions did not concern, except in a very general way, the main object of their philosophizing, which was to gain true knowledge of God and his attributes and his relation to man. Accordingly we find for the most part a simple classification of the sources of knowledge or truth as consisting of the senses and the reason. The latter contains some truths which may be called innate or immediate, such as require no experience for their recognition, like the logical laws of thought, and truths which are the result of inference from a fact of sensation or an immediate truth of the mind. To these human sources was added tradition or the testimony of the revealed word of God in the written and oral law.

When Aristotle began to be studied in his larger treatises and the details of the psychology and the metaphysics became known especially through Averroes, we find among the Jews also an interest in the finer points of the problem of knowledge. The motives of Plato's idealism and Aristotle's conceptualism (if this inexact description may be allowed for want of a more precise term) are discussed with fulness and detail by Levi ben Gerson. He realizes the difficulty involved in the problem. Knowledge must be of the real and the permanent. But the particular is not permanent, and the universal, which is permanent, is not real. Hence either there is no knowledge or there is a reality corresponding to the universal concept. This latter was the view adopted by Plato. Gersonides finds the reality in the thoughts of the Active Intellect, agreeing in this with the views of Philo and Augustine, substituting only the Active Intellect for their Logos. Maimonides does not discuss the question, but it is clear from a casual statement that like Aristotle he does not believe in the independent reality of the universal (Guide III, 18).

In theoretical physics the Arabian Mutakallimun, we have seen (p. [xxii]), laid great stress on the theory of atom and accident as opposed to the concepts of matter and form by which Aristotle was led to believe in the eternity of the world. Accordingly every Mutakallim laid down his physical theory and based on it his proof of creation. This method was followed also by the early Jewish thinkers. The Karaites before Maimonides adopted the atomic theory without question. And Aaron ben Elijah, who had Maimonides's "Guide" before him, was nevertheless sufficiently loyal to his Karaite predecessors to discuss their views side by side with those of the Aristotelians and to defend them against the strictures of Maimonides. Saadia, the first Rabbanite philosopher, discusses no less than thirteen erroneous views concerning the origin and nature of the world, but he does not lay down any principles of theoretical physics explicitly. He does not seem to favor the atomic theory, but he devotes no special treatment to the subject, and in his arguments for creation as opposed to eternity he makes use of the Kalamistic concepts of substance and accident and composition and division. The same is true of Bahya Ibn Pakuda. Joseph Ibn Zaddik is the first who finds it necessary to give an independent treatment of the sciences before proceeding to construct his religious philosophy, and in so doing he expounds the concepts of matter and form, substance and accident, genesis and destruction, the four elements and their natures and so on—all these Aristotelian concepts. Ibn Daud follows in the path of Ibn Zaddik and discusses the relevant concepts of potentiality and actuality and the nature of motion and infinity, upon which his proof is based of the existence of God. Maimonides clears the ground first by a thorough criticism and refutation of the Kalamistic physics, but he does not think it necessary to expound the Aristotelian views which he adopts. He refers the reader to the original sources in the Physics and Metaphysics of Aristotle, and contents himself with giving a list of principles which he regards as established. Aristotle is now the master of all those who know. And he reigns supreme for over a century until the appearance of the "Or Adonai" of Hasdai Crescas, who ventured to deny some of the propositions upon which Maimonides based his proof of the existence of God—such, for example, as the impossibility of an infinite magnitude, the non-existence of an infinite fulness or vacuum outside of the limits of our world, the finiteness of our world and its unity, and so on.