# A History of Mediaeval Jewish Philosophy/Introduction

INTRODUCTION
The philosophical movement in mediæval Jewry was the result of the desire and the necessity, felt by the leaders of Jewish thought, of reconciling two apparently independent sources of truth. In the middle ages, among Jews as well as among Christians and Mohammedans, the two sources of knowledge or truth which were clearly present to the minds of thinking people, each claiming recognition, were religious opinions as embodied in revealed documents on the one hand, and philosophical and scientific judgments and arguments, the results of independent rational reflection, on the other. Revelation and reason, religion and philosophy, faith and knowledge, authority and independent reflection are the various expressions for the dualism in mediæval thought, which the philosophers and theologians of the time endeavored to reduce to a monism or a unity.
Let us examine more intimately the character and content of the two elements in the intellectual horizon of mediæval Jewry. On the side of revelation, religion, authority, we have the Bible, the Mishna, the Talmud. The Bible was the written law, and represented literally the word of God as revealed to lawgiver and prophet; the Talmud (including the Mishna) was the oral law, embodying the unwritten commentary on the words of the Law, equally authentic with the latter, contemporaneous with it in revelation, though not committed to writing until many ages subsequently and until then handed down by word of mouth; hence depending upon tradition and faith in tradition for its validity and acceptance. Authority therefore for the Rabbanites was two-fold, the authority of the direct word of God which was written down as soon as communicated, and about which there could therefore be no manner of doubt; and the authority of the indirect word of God as transmitted orally for many generations before it was written down, requiring belief in tradition. By the Karaites tradition was rejected, and there remained only belief in the words of the Bible.
On the side of reason was urged first the claim of the testimony of ​the senses, and second the validity of logical inference as determined by demonstration and syllogistic proof. This does not mean that the Jewish thinkers of the middle ages developed unaided from without a system of thought and a Weltanschauung, based solely upon their own observation and ratiocination, and then found that the view of the world thus acquired stood in opposition to the religion of the Bible and the Talmud, the two thus requiring adjustment and reconciliation. No! The so-called demands of the reason were not of their own making, and on the other hand the relation between philosophy and religion was not altogether one of opposition. To discuss the latter point first, the teachings of the Bible and the Talmud were not altogether clear on a great many questions. Passages could be cited from the religious documents of Judaism in reference to a given problem both pro and con. Thus in the matter of freedom of the will one could argue on the one hand that man must be free to determine his conduct since if he were not there would have been no use in giving him commandments and prohibitions. And one could quote besides in favor of freedom the direct statement in Deuteronomy 30, 19, "I call heaven and earth to witness against you this day, that I have set before thee life and death, the blessing and the curse: therefore choose life, that thou mayest live, thou and thy seed." But on the other hand it was just as possible to find Biblical statements indicating clearly that God preordains how a person shall behave in a given case. Thus Pharaoh's heart was hardened that he should not let the children of Israel go out of Egypt, as we read in Exodus 7, 3: "And I will harden Pharaoh's heart, and multiply my signs and my wonders in the land of Egypt. But Pharaoh will not hearken unto you, and I will lay my hand upon Egypt, and bring forth my hosts, my people, the children of Israel, out of the land of Egypt by great judgments." Similarly in the case of Sihon king of Heshbon we read in Deuteromony 2, 30: "But Sihon king of Heshbon would not let us pass by him: for the Lord thy God hardened his spirit, and made his heart obstinate, that he might deliver him into thy hand, as at this day." And this is true not merely of heathen kings, Ahab king of Israel was similarly enticed by a divine instigation according to I Kings 22, 20: "And the Lord said, Who shall entice Ahab, that he may go up and fall at Ramoth-Gilead?"
​The fact of the matter is the Bible is not a systematic book, and principles and problems are not clearly and strictly formulated even in the domain of ethics which is its strong point. It was not therefore a question here of opposition between the Bible and philosophy, or authority and reason. What was required was rather a rational analysis of the problem on its own merits and then an endeavor to show that the conflicting passages in the Scriptures are capable of interpretation so as to harmonize with each other and with the results of rational speculation. To be sure, it was felt that the doctrine of freedom is fundamental to the spirit of Judaism, and the philosophic analyses led to the same result though in differing form, sometimes dangerously approaching a thorough determinism, as in Hasdai Crescas.
If such doubt was possible in an ethical problem where one would suppose the Bible would be outspoken, the uncertainty was still greater in purely metaphysical questions which as such were really foreign to its purpose as a book of religion and ethics. While it was clear that the Bible teaches the existence of God as the creator of the universe, and of man as endowed with a soul, it is manifestly difficult to extract from it a rigid and detailed theory as to the nature of God, the manner in which the world was created, the nature of the soul and its relation to man and to God. As long as the Jews were self-centered and did not come in close contact with an alien civilization of a philosophic mould, the need for a carefully thought out and consistent theory on all the questions suggested was not felt. And thus we have in the Talmudic literature quite a good deal of speculation concerning God and man. But it can scarcely lay claim to being rationalistic or philosophic, much less to being consistent. Nay, we have in the Bible itself at least two books which attempt an anti-dogmatic treatment of ethical problems. In Job is raised the question whether a man's fortunes on earth bear any relation to his conduct moral and spiritual. Ecclesiastes cannot make up his mind whether life is worth living, and how to make the best of it once one finds himself alive, whether by seeking wisdom or by pursuing pleasure. But here too Job is a long poem, and the argument does not progress very rapidly or very far. Ecclesiastes is rambling rather than analytic, and on the whole mostly negative. The Talmudists were visibly puzzled ​in their attitude to both books, wondered whether Job really existed or was only a fancy, and seriously thought of excluding Ecclesiastes from the canon. But these attempts at questioning the meaning of life had no further results. They did not lead, as in the case of the Greek Sophists, to a Socrates, a Plato or an Aristotle. Philo in Alexandria and Maimonides in Fostat were the products not of the Bible and the Talmud alone, but of a combination of Hebraism and Hellenism, pure in the case of Philo, mixed with the spirit of Islam in Maimonides.
And this leads us to consider the second point mentioned above, the nature and content of what was attributed in the middle ages to the credit of reason. It was in reality once more a set of documents. The Bible and Talmud were the documents of revelation, Aristotle was the document of reason. Each was supreme in its sphere, and all efforts must be bent to make them agree, for as revelation cannot be doubted, so neither can the assured results of reason. But not all which pretends to be the conclusion of reason is necessarily so in truth, as on the other hand the documents of faith are subject to interpretation and may mean something other than appears on the surface.
That the Bible has an esoteric meaning besides the literal has its source in the Talmud itself. Reference is found there to a mystic doctrine of creation known as "Maase Bereshit" and a doctrine of the divine chariot called "Maase Merkaba." The exact nature of these teachings is not known since the Talmud itself prohibits the imparting of this mystic lore to any but the initiated, i. e., to those showing themselves worthy; and never to more than one or two at a time. But it is clear from the names of these doctrines that they centered about the creation story in Genesis and the account of the divine chariot in Ezekiel, chapters one and ten. Besides the Halaka and Agada are full of interpretations of Biblical texts which are very far from the literal and have little to do with the context. Moreover, the beliefs current among the Jews in Alexandria in the first century B. C. found their way into mediæval Jewry, that the philosophic literature of the Greeks was originally borrowed or stolen from the Hebrews, who lost it in times of storm and stress. This being the case, it was believed that the Bible itself cannot be without some allusions to philosophic doctrines. That the Bible does not clearly teach philosophy is due to the fact that it was intended for the ​tion of all men, the simple as well as the wise, women and children as well as male adults. For these it is sufficient that they know certain religious truths within their grasp and conduct themselves according to the laws of goodness and righteousness. A strictly philosophic book would have been beyond their ken and they would have been left without a guide in life. But the more intellectual and the more ambitious are not merely permitted, nay they are obligated to search the Scriptures for the deeper truths found therein, truths akin to the philosophic doctrines found in Greek literature; and the latter will help them in understanding the Bible aright. It thus became a duty to study philosophy and the sciences preparatory thereto, logic, mathematics and physics; and thus equipped to approach the Scriptures and interpret them in a philosophical manner. The study of mediæval Jewish rationalism has therefore two sides to it, the analysis of metaphysical, ethical and psychological problems, and the application of these studies to an interpretation of Scripture.
Now let us take a closer glance at the rationalistic or philosophic literature to which the Jews in the middle ages fell heirs. In 529 A. D. the Greek schools of philosophy in Athens were closed by order of Emperor Justinian. This did not, however, lead to the extinction of Greek thought as an influence in the world. For though the West was gradually declining intellectually on account of the fall of Rome and the barbarian invasions which followed in its train, there were signs of progress in the East which, feeble at first, was destined in the course of several centuries to illumine the whole of Europe with its enlightening rays.
Long before 529, the date of the closing of the Greek schools, Greek influence was introduced in the East in Asia and Africa. The whole movement goes back to the days of Alexander the Great and the victories he gained in the Orient. From that time on Greeks settled in Asia and Africa and brought along with them Greek manners, the Greek language, and the Greek arts and sciences. Alexandria, the capital of the Ptolemies in Egypt after the death of Alexander, and Antioch, the capital of Syria under the empire of the Seleucidæ, were well-known centres of Greek learning.
When Syria changed masters in 64 B. C. and became a Roman province, its form of civilization did not change, and the introduction ​of Christianity had the effect of spreading the influence of the Greeks and their language into Mesopotamia beyond the Euphrates. The Christians in Syria had to study Greek in order to understand the Scriptures of the Old and the New Testaments, the decrees and canons of the ecclesiastical councils, and the writings of the Church Fathers. Besides religion and the Church, the liberal arts and sciences, for which the Greeks were so famous, attracted the interests of the Syrian Christians, and schools were established in the ecclesiastical centres where philosophy, mathematics and medicine were studied. These branches of knowledge were represented in Greek literature, and hence the works treating of these subjects had to be translated into Syriac for the benefit of those who did not know Greek. Aristotle was the authority in philosophy, Hippocrates and Galen in medicine.
The oldest of these schools was in Edessa in Mesopotamia, founded in the year 363 by St. Ephrem of Nisibis. It was closed in 489 and the teachers migrated to Persia where two other schools became famous, one at Nisibis and the other at Gandisapora, A third school of philosophy among the Jacobite or Monophysite Christians was that connected with the convent of Kinnesrin on the left bank of the Euphrates, which became famous as a seat of Greek learning in the beginning of the seventh century.
Christianity was succeeded in the Orient by Mohammedanism, and this change led to even greater cultivation of Greek studies on the part of the Syrians. The Mohammedan Caliphs employed the Syrians as physicians. This was especially true of the Abbasid dynasty, who came into power in 750. When they succeeded to the Caliphate they raised Nestorian Syrians to offices of importance, and the latter under the patronage of their masters continued their studies of Greek science and philosophy and translated those writings into Syriac and Arabic. Among the authors translated were, Hippocrates and Galen in medicine, Euclid, Archimedes and Ptolemy in mathematics and astronomy, and Aristotle, Theophrastus and Alexander of Aphrodisias in philosophy. In many cases the Greek writings were not turned directly into Arabic but as the translators were Syrians, the versions were made first into Syriac, and then from the Syriac into Arabic. The Syrian Christians were thus the mediators between the Greeks and the Arabs. The latter, however, in the course of time ​far surpassed their Syrian teachers, developed important schools of philosophy, became the teachers of the Jews, and with the help of the latter introduced Greek philosophy as well as their own development thereof into Christian Europe in the beginning of the thirteenth century.
We see now that the impulse to philosophizing came from the Greeks,—and not merely the impulse but the material, the matter as well as the method and the terminology. In the Aristotelian writings we find developed an entire system of thought. There is not a branch of knowledge dealing with fundamental principles which is not there represented. First of all Aristotle stands alone as the discoverer of the organon of thought, the tool which we all employ in our reasoning and reflection; he is the first formulator of the science and art of logic. He treats besides of the principles of nature and natural phenomena in the Physics and the treatise on the Heavens. He discusses the nature of the soul, the senses and the intellect in his "Psychology." In the "History of Animals" and other minor works we have a treatment of biology. In the Nikomachean and Eudemian Ethics he analyzes the meaning of virtue, gives a list and classification of the virtues and discusses the summum bonum or the aim of human life. Finally in the Metaphysics we have an analysis of the fundamental notions of being, of the nature of reality and of God.
The Jews did not get all this in its purity for various reasons. In the first place it was only gradually that the Jews became acquainted with the wealth of Aristotelian material. We are sure that Abraham Ibn Daud, the forerunner of Maimonides, had a thorough familiarity with the ideas of Aristotle; and those who came after him, for example Maimonides, Gersonides, Hasdai Crescas, show clearly that they were deep students of the ideas represented in the writings of the Stagirite. But there is not the same evidence in the earlier writings of Isaac Israeli, Saadia, Joseph Ibn Zaddik, Gabirol, Bahya Ibn Pakuda, Judah Halevi. They had picked up Aristotelian ideas and principles, but they had also absorbed ideas and concepts from other schools, Greek as well as Arabian, and unconsciously combined the two.
Another explanation for the rarity of the complete and unadulterated Aristotle among the Jewish thinkers of the middle ages is that people in those days were very uncritical in the matter of historical ​facts and relations. Historical and literary criticism was altogether unknown, and a number of works were ascribed to Aristotle which did not belong to him, and which were foreign in spirit to his mode of thinking. They emanated from a different school of thought with different presuppositions. I am referring to the treatise called the "Theology of Aristotle," and that known as the "Liber de Causis." Both were attributed to Aristotle in the middle ages by Jews and Arabs alike, but it has been shown recently that the former represents extracts from the works of Plotinus, the head of the Neo-Platonic school of philosophy, while the latter is derived from a treatise of Proclus, a Neo-Platonist of later date.
Finally a third reason for the phenomenon in question is that the Jews were the pupils of the Arabs and followed their lead in adapting Greek thought to their own intellectual and spiritual needs. It so happens therefore that even in the case of Abraham Ibn Daud, Maimonides and Gersonides, who were without doubt well versed in Aristotelian thought and entertained not merely admiration but reverence for the philosopher of Stagira, we notice that instead of reading the works of Aristotle himself, they preferred, or were obliged as the case may be, to go to the writings of Alfarabi, Avicenna and Averroes for their information on the views of the philosopher. In the case of Gersonides this is easily explained. It seems he could read neither Latin nor Arabic and there was no Hebrew translation of the text of Aristotle. Averroes had taken in the fourteenth century the place of the Greek philosopher and instead of reading Aristotle all students read the works of the Commentator, as Averroes was called. Of course the very absence of a Hebrew translation of Aristotle's text proves that even among those who read Arabic the demand for the text of Aristotle was not great, and preference was shown for the works of the interpreters, compendists and commentators, like Alfarabi and Avicenna. And this helps us to understand why it is that Ibn Daud and Maimonides who not only read Arabic but wrote their philosophical works in Arabic showed the same preference for the secondhand Aristotle. One reason may have been the lack of historical and literary criticism spoken of above, and the other the difficulty of the Arabic translations of Aristotle. Aristotle is hard to translate into any language by reason of his peculiar technical terminology; ​and the difficulty was considerably enhanced by the fact that the Syriac in many cases stood between the original Greek and the Arabic, and in the second place by the great dissimilarity between the Semitic language and its Indo-European original. This may have made the copies of Aristotle's text rare, and gradually led to their disuse. The great authority which names like Alfarabi, Avicenna and Averroes acquired still further served to stamp them as the approved expositors of the Aristotelian doctrine.
Among the Arabs the earliest division based upon a theoretical question was that of the parties known as the "Kadariya" and the "Jabariya." The problem which was the cause of the difference was that of free will and determinism. Orthodox Islam favored the idea that man is completely dependent upon the divine will, and that not only his destiny but also his conduct is determined, and his own will does not count. This was the popular feeling, though as far as the Koran is concerned the question cannot be decided one way or the other, as it is not consistent in its stand, and arguments can be drawn in plenty in favor of either opinion. The idea of determinism, however, seemed repugnant to many minds, who could not reconcile this with their idea of reward and punishment and the justice of God. How is it possible that a righteous God would force a man to act in a certain manner and then punish him for it? Hence the sect of the "Kadariya," who were in favor of freedom of the will. The Jabariya were the determinists.
This division goes back to a very early period before the introduction of the Aristotelian philosophy among the Arabs, and hence owes its inception not to reason as opposed to religious dogma, but to a pious endeavor to understand clearly the religious view upon so important a question.
From the Kadariya, and in opposition to the Aristotelian movement which had in the meantime gained ground, developed the school of theologians known as the "Mutakallimun." They were the first among the Arabs who deliberately laid down the reason as a source of knowledge in addition to the authority of the Koran and the "Sunna" or tradition. They were not freethinkers, and their object was not to oppose orthodoxy as such. On the contrary, their purpose was to purify the faith by freeing it from such elements as obscured ​in their minds the purity of the monotheistic tenet and the justice of God. They started where the Kadariya left off and went further. As a school of opposition their efforts were directed to prove the creation of the world, individual providence, the reality of miracles, as against the "philosophers," i. e., the Aristotehans, who held to the eternity of motion, denied God's knowledge of particulars, and insisted on the unchanging character of natural law.
For this purpose they placed at the basis of their speculations not the Aristotelian concepts of matter and form, the former uncreated and continuous, but adopted the atomistic theory of Democritus, denied the necessity of cause and effect and the validity of natural law, and made God directly responsible for everything that happened every moment in life. God, they said, creates continually, and he is not hampered by any such thing as natural law, which is merely our name for that which we are accustomed to see. Whenever it rains we are accustomed to see the ground wet, and we conclude that there is a necessary connection of cause and effect between the rain and the wetness of the ground. Nothing of the kind, say the Mutakallimun, or the Mu'tazila, the oldest sect of the school. It rains because God willed that it should rain, and the ground is wet because God wills it shall be wet. If God willed that the ground should be dry following a rain, it would be dry; and the one is no more and no less natural than the other. Miracles cease to be miracles on this conception of natural processes. Similarly the dogma of creation is easily vindicated on this theory as against the Aristotelian doctrine of eternity of the world, which follows from his doctrine of matter and form, as we shall have occasion to see later.
The Mu'tazila were, however, chiefly known not for their principles of physics but for their doctrines of the unity of God and his justice. It was this which gave them their name of the "Men of Unity and Justice," i. e., the men who vindicate against the unenlightened views of popular orthodoxy the unity of God and his justice.
The discussion of the unity centered about the proper interpretation of the anthropomorphic passages in the Koran and the doctrine of the divine attributes. When the Koran speaks of God's eyes, ears, hands, feet; of his seeing, hearing, sitting, standing, walking, being angry, smiling, and so on, must those phrases be understood ​literally? If so God is similar to man, corporeal like him, and swayed by passions. This seemed to the Mu'tazila an unworthy conception of God. To vindicate his spirituality the anthropomorphic passages in the Koran must be understood metaphorically.
The other more difficult question was in what sense can attributes be ascribed to God at all? It is not here a question of anthropomorphism. If I say that God is omniscient, omnipotent and a living God, I attribute to God life, power, knowledge. Are these attributes the same with God's essence or are they different? If different (and they must be eternal since God was never without them), then we have more than one eternal being, and God is dependent upon others. If they are not different from God's essence, then his essence is not a strict unity, since it is composed of life, power, knowledge; for life is not power, and power is not knowledge. The only way to defend the unity of God in its absolute purity is to say that God has no attributes, i. e., God is omniscient but not through knowledge as his attribute; God is omnipotent but not through power as his attribute, and so on. God is absolutely one, and there is no distinction between knowledge, power, and life in him. They are all one, and are his essence.
This seemed in opposition to the words of the Koran, which frequently speaks of God's knowledge, power, and so on, and was accordingly condemned as heretical by the orthodox.
In the tenth century a new sect arose named the "Ashariya" after Al-Ashari, its founder. This was a party of moderation, and tended to conciliate orthodoxy by not going too far in the direction of rationalistic thinking. They solved the problem by saying, "God knows through a knowledge which is not different from his essence."
The other problem to which the Mu'tazila devoted their attention was that of the justice of God. This was in line with the efforts of the Kadariya before them. It concerned itself with the doctrine of free will. They defended man's absolute freedom of action, and insisted on justice as the only motive of God's dealings with men. God must be just and cannot act otherwise than in accordance with justice. In reference to the question of the nature of good and evil, the orthodox position was that good is that which God commands, evil that which God forbids. In other words, nothing is in itself good or ​evil, the ethical character of an act is purely relative to God's attitude to it. If God were to command cannibalism, it would be a good act. The Mu'tazila were opposed to this. They believed in the absolute character of good and evil. What makes an act good or bad is reason, and it is because an act is good that God commands it, and not the reverse.
The foregoing account gives us an idea of the nature of the Mu'tazilite discussions of the two problems of God's unity and God's justice. Their works were all arranged in the same way. They were divided into two parts, one dealing with the question of the unity, and the other with that of justice. The proofs of the unity were preceded by the proofs of God's existence, and the latter were based upon a demonstration that the world is not eternal, but bears traces of having come to be in time. These are the earmarks by which a Mu'tazilite book could be recognized, and the respect for them on the part of the philosophers, i. e., the Aristotelians, was not great. The latter did not consider them worthy combatants in a philosophical fight, claiming that they came with preconceived notions and arranged their conceptions of nature to suit the religious beliefs which they desired to defend. Maimonides expresses a similar judgment concerning their worthlessness as philosophical thinkers.
This school of the Mutakallimun, or of the more important part of it known as the Mu'tazila, is of great interest for the history of Jewish rationaHsm. In the first place their influence on the early Jewish philosophers was great and unmistakable. It is no discovery of a late day but is well known to Maimonides who is himself, as has just been said and as will appear with greater detail later, a strong opponent of these to him unphilosophical thinkers. In the seventy-first chapter of his "Guide of the Perplexed," he says, "You will find that in the few works composed by the Geonim and the Karaites on the unity of God and on such matter as is connected with this doctrine, they followed the lead of the Mohammedan Mutakallimun. . . . It also happened, that at the time when the Mohammedans adopted this method of the Kalam, there arose among them a certain sect, called Mu'tazila. In certain things our scholars followed the theory and the method of these Mu'tazila."
Thanks to the researches of modern Jewish and non-Jewish scholars ​we know now that the Rabbanite thinker Saadia and the Karaite writers, like Joseph Al Basir and Jeshuah ben Judah, are indebted far more to the Mohammedan Mu'tazilites than would appear from Maimonides's statement just quoted. The Rabbanites being staunch adherents of the Talmud, to the influence of which they owed a national and religious self-consciousness much stronger than that of the Karaites, who rejected the authority of tradition, did not allow themselves to be carried away so far by the ideas of the Mohammedan rationalists as to become their slavish followers. The Karaites are less scrupulous; and as they were the first among the Jews to imitate the Mu'tazila in the endeavor to rationalize Jewish doctrine, they adopted their views in all details, and it is sometimes impossible to tell from the contents of a Karaite Mu'tazilite work whether it was written by a Jew or a Mohammedan. The arrangement of the work in the two divisions of "Unity" and "Justice," the discussion of substance and accident, of the creation of the world, of the existence, unity and incorporeality of God, of his attributes, of his justice, and of human free will, are so similar in the two that it is external evidence alone to which we owe the knowledge of certain Karaite works as Jewish. There are no mediæval Jewish works treating of religious and theological problems in which there is so much aloofness, such absence of theological prepossession and religious feeling as in some Karaite writings of Mu'tazilite stamp. Cold and unredeemed logic gives the tone to the entire composition.
Another reason for the importance of the Mu'tazilite school for the history of Jewish thought is of recent discovery. Schreiner has suggested that the origin of the Mu'tazilite movement was due to the influence of learned Jews with whom the Mohammedans came in contact, particularly in the city of Basra, an important centre of the school. The reader will recall that the two main doctrines of the Mu'tazila were the unity of God and his justice. The latter really signified the freedom of the will. That these are good Jewish views would of course prove nothing for the origin of similar opinions among the Mohammedans. For it is not here a question simply of the dogmatic belief in Monotheism as opposed to polytheism. Mohammedanism is as a religion Monotheistic and we know that Mohammed was indebted very much to Jews and Judaism. We are here concerned ​with the origin of a rationalistic movement which endeavors to defend a spiritual conception of God against a crude anthropomorphism, to vindicate a conception of his absolute unity against the threatened multiplication of his essence by the assumption of eternal attributes, and which puts stress upon God's justice rather than upon his omnipotence so as to save human freedom. Another doctrine of the Mu'tazila was that the Koran was not eternal as the orthodox believed, but that it was created. Now we can find parallels for most of these doctrines. Anthropomorphism was avoided in the Aramaic translations of the Pentateuch, also in certain changes in the Hebrew text which are recorded in Rabbinical literature, and known as "Tikkune Soferim," or corrections of the Scribes. Concern for maintaining the unity of God in its absolute purity is seen in the care with which the men of the Agada forbid any prayer which may have a semblance, however remote, of dualism. The freedom of the will is clearly stated in the Rabbinic expression, "All is in the hands of God except the fear of Heaven." And an apparently deterministic passage in Job 23, 13, "But he is one and who can turn him, and what his soul desireth, even that he doeth," is explained by Rabbi Akiba in the following manner, "It is not possible to answer the words of him who with his word created the world, for he rules all things with truth and with righteousness." And we find a parallel also for the creation of the Koran in the Midrashic statement that the Torah is one of the six or seven things created before the world.
These parallels alone would not be of much weight, but they are strengthened by other considerations. The Mu'tazilite movement seems to have developed among the ascetic sects, with the leaders of whom its founders were in close relation. The ascetic literature bears unmistakable traces of having been influenced by the Halaka and the Agada. Moreover, there is a Mohammedan tradition or two to the effect that the doctrine of the creation of the Koran and also of the rejection of anthropomorphism goes back to a Jew, Lebid-ibn Al-A'sam.
More recently still C. H. Becker proved from a study of certain Patristic writings that the polemical literature of the Christians played an important rôle in the formation of Mohammedan dogma, ​and he shows conclusively that the form in which the problem of freedom was discussed among the Mohammedans was taken from Christianity. The question of the creation or eternity of the Koran or word of Allah, is similarly related to the Christian idea of the eternal Logos, who is on the one hand the Word and the Wisdom, and is on the other identified with Jesus Christ. And the same thing holds of the doctrine of attributes. It played a greater rôle in Christian dogma than it ever did in Judaism prior to the philosophic era in the middle ages. To be sure, the Patristic writers were much indebted to Philo, in whose writings the germ of the mediæval doctrine of attributes is plainly evident. But the Mohammedan schools did not read Philo. It would seem, therefore, that Schreiner's view must be considerably modified, if not entirely rejected, in view of the later evidence adduced by Becker.
The more extreme doctrines, however, of the more orthodox Ashariya, such as the denial of natural law and the necessity of cause and effect, likewise the denial of man's ability to determine his actions, none of the Jews accepted. Here we have again the testimony of Maimonides, who, however, is not inclined to credit this circumstance to the intelligence and judgment of his predecessors, but to chance. His words are, "Although another sect, the Ashariya, with their own peculiar views, was subsequently established among the Mohammedans, you will not find any of these views in the writings of our authors; not because these authors preferred the opinions of the first named sect to those of the latter, but because they chanced first to become acquainted with the theory of the Mu'tazila, which they adopted and treated as demonstrated truth."
The influence of the Kalam is present in greater or less degree in the philosophers up to Abraham Ibn Daud and Maimonides. The latter gave this system its death blow in his thoroughgoing criticism, and thenceforth Aristotelianism was in possession of the field until that too was attacked by Hasdai Crescas.
Another sect of the Mohammedans which had considerable influence on some of the Jewish philosophical and ethical writers are the ascetics and the Sufis who are related to them. The latter developed their mode of life and their doctrines under the influence of the Christian monks, and are likewise indebted to Indian and Persian ideas. ​In their mode of life they belong to the class of ascetics and preach abstinence, indifference to human praise and blame, love of God and absolute trust in him even to the extent of refraining from all effort in one's own behalf, and in extreme cases going so far as to court danger. In theoretical teaching they adopted the emanatistic doctrine of the Neo-Platonic School. This has been called dynamic Pantheism. It is Pantheism because in its last analysis it identifies God with the universe. At the same time it does not bring God directly in contact with the world, but only indirectly through the powers or δυνάμεις hence dynamic Pantheism. These powers emanate successively from the highest one, forming a chain of intermediate powers mediating between God and the world of matter, the links of the chain growing dimmer and less pure as they are further removed from their origin, while the latter loses nothing in the process. This latter condition saves the Neo-Platonic conception from being a pure system of emanation like some Indian doctrines. In the latter the first cause actually gives away something of itself and loses thereby from its fulness. The process in both systems is explained by use of analogies, those of the radiation of light from a luminous body, and of the overflowing of a fountain being the most common.
The chief exponent of the ethics of the Sufis in mediæval Jewish literature is Bahya Ibn Pakuda. In his ethical work "The Duties of the Hearts," he lays the same stress on intention and inwardness in religious life and practice as against outward performance with the limbs on the one hand and dry scholasticism on the other, as do the Sufis. In matters of detail too he is very much indebted to this Arab sect from whose writings he quotes abundantly with as well as without acknowledgment of his sources except in a general way as the wise men. To be sure, he does not follow them slavishly and rejects the extremes of asceticism and unworldly cynicism which a great many of the Sufis preached and practiced. He is also not in sympathy with their mysticism. He adopts their teachings only where he can support them with analogous views as expressed in the Rabbinical writings, which indeed played an important rôle in Mohammedan ascetic literature, being the source of many of the sayings found in the latter.
The systems of thought which had the greatest influence upon Jewish as well as Mohammedan theology, were the great systems of ​Plato (especially as developed in Neo-Platonism) and Aristotle. These two philosophies not merely affected the thinking of Jew and Mohammedan but really transformed it from religious and ethical discussions into metaphysical systems. In the Bible and similarly in the Koran we have a purely personal view of God and the world. God is a person, he creates the world—out of nothing to be sure—but nevertheless he is thought of doing it in the manner in which a person does such things with a will and a purpose in time and place. He puts a soul into man and communicates to him laws and prohibitions. Man must obey these laws because they are the will of God and are good, and he will be rewarded and punished according to his attitude in obedience and disobedience. The character of the entire point of view is personal, human, teleological, ethical. There is no attempt made at an impersonal and objective analysis of the common aspects of all existing things, the elements underlying all nature. Nor is there any conscious effort at a critical classification of the various kinds of things existing in nature beyond the ordinary and evident classification found in Genesis—heaven and earth; in heaven, sun, moon and stars; on earth, grass, fruit trees, insects, water animals, birds, quadrupeds, man. Then light and darkness, the seasons of the year, dry land and water.
In Greek philosophy for the first time we find speculations concerning the common element or elements out of which the world is made—the material cause as Aristotle later called it. The Sophists and Socrates gave the first impulse to a logical analysis of what is involved in description or definition. The concept as denoting the essence of a thing is the important contribution Socrates made to knowledge. Plato objectified the concept, or rather he posited an object as the basis of the concept, and raised it out of this world of shadows to an intelligible world of realities on which the world of particulars depends. But it was Aristotle who made a thoroughgoing analysis of thing as well as thought, and he was the master of knowledge through the middle ages alike for Jew, Christian and Mohammedan.
First of all he classified all objects of our experience and found that they can be grouped in ten classes or categories as he called them. Think of any thing you please and you will find that it is either an object in the strict sense, i. e., some thing that exists independently ​of anything else, and is the recipient of qualities, as for example a man, a mountain, a chair. Or it is a quantity, like four, or cubit; or a quality, like good, black, straight; or a relation like long, double, master, slave; and so on throughout the ten categories. This classification applies to words and thoughts as well as to things. As an analysis of the first two it led him to more important investigations of speech and thinking and arguing, and resulted in his system of logic, which is the most momentous discovery of a single mind recorded in history. As applied to things it was followed by a more fundamental analysis of all real objects in our world into the two elements of matter and form. He argued as follows: nothing in the material world is permanent as an individual thing. It changes its state from moment to moment and finally ceases to be the thing it was. An acorn passes a number of stages before it is ripe, and when it is placed in the ground it again changes its form continually and then comes out as an oak. In artificial products man in a measure imitates nature. He takes a block of marble and makes a statue out of it. He forms a log into a bed. So an ignorant man becomes civilized and learned. All these examples illustrate change. What then is change? Is there any similarity in all the cases cited? Can we express the process of change in a formula which will apply to all instances of change? If so, we shall have gained an insight into a process of nature which is all-embracing and universal in our experience. Yes, we can, says Aristotle. Change is a play of two elements in the changing thing. When a thing affected with one quality changes into a thing with the opposite quality, there must be the thing itself without either of the opposite qualities, which is changing. Thus when a white fence becomes black, the fence itself or that which undergoes the change is something neither white nor black. It is the uncolored matter which first had the form of white and now lost that and took on the form of black. This is typical of all change. There is in all change ultimately an unchanging substratum always the same, which takes on one quality after another, or as Aristotle would say, one form after another. This substratum is matter, which in its purity is not affected with any quality or form, of which it is the seat and residence. The forms on the other hand come and go. Form does not change any more than matter. The changing thing is the composite of matter and form, and change means ​separation of the actual components of which one, the form, disappears and makes room for its opposite. In a given case, say, when a statue is made out of a block of marble, the matter is the marble which lost its original form and assumed the form of a statue. In this case the marble, if you take away both the previous form and the present, will still have some form if it is still marble, for marble must have certain qualities if it is to be marble. In that case then the matter underlying the change in question is not pure matter, it is already endowed with some primitive form and is composite. But marble is ultimately reducible to the four elements, fire, air, water, earth, which are simpler; and theoretically, though not in practice, we can think away all form, and we have left only that which takes forms but is itself not any form. This is matter.
Here the reader will ask, what kind of thing is it that has no form whatsoever, is it not nothing at all? How can anything exist without being a particular kind of thing, and the moment it is that it is no longer pure matter. Aristotle's answer is that it is true that pure matter is never found as an objective existence. Point to any real object and it is composed of matter and form. And yet it is not true that matter is a pure figment of the imagination; it has an existence of its own, a potential existence. And this leads us to another important conception in the Aristotelian philosophy.
Potentiality and actuality are correlative terms corresponding to matter and form. Matter is the potential, form is the actual. Whatever potentialities an object has it owes to its matter. Its actual essence is due to its form. A thing free from matter would be all that it is at once. It would not be liable to change of any kind, whether progress or retrogression. All the objects of our experience in the sublunar world are not of this kind. They realize themselves gradually, and are never at any given moment all that they are capable of becoming. This is due to their matter. On the other hand, pure matter is actually nothing. It is just capacity for being anything, and the moment it is anything it is affected with form.
It is clear from this account that matter and form are the bases of sublunar life and existence. No change, no motion without matter and form. For motion is presupposed in all kinds of change. If then all processes of life and death and change of all kinds presuppose ​matter and form, the latter cannot themselves be liable to genesis and decay and change, for that would mean that matter is composed of matter and form, which is absurd. We thus see how Aristotle is led to believe in the eternity of matter and motion, in other words, the eternity of the world processes as we know them.
Motion is the realization of the potential qua potential. This is an Aristotelian definition and applies not merely to motion in the strict sense, i. e., movement in place, or motion of translation, but embraces all kinds of change. Take as an example the warming of the air in a cold room. The process of heating the room is a kind of motion; the air passes from a state of being cold to a state of being warm. In its original state as cold it is potentially warm, i. e., it is actually not warm, but has the capacity of becoming warm. At the end of the process it is actually warm. Hence the process itself is the actualization of the potential. That which is potential cannot make itself actual, for to make itself actual it must be actual, which is contrary to the hypothesis of its being potential. Potentiality and actuality are contradictory states and cannot exist side by side in the same thing at the same time in the same relation. There must therefore be an external agent, itself actual, to actualize a potential. Thus, in the above illustration, a cold room cannot make itself warm. There must be some agency itself actually warm to cause the air in the room to pass from cold to warm. This is true also of motion in place, that a thing cannot move itself and must be moved by something else. But that something else if itself in motion must again be moved by something else. This process would lead us to infinity. In order that a given thing shall be in motion, it would be necessary for an infinite number of things to be in motion. This is impossible, because there cannot be an infinite number of things all here and now. It is a contradiction in terms. Hence if anything is to move at all, there must be at the end of the finite chain a link which while causing the next link to move, is itself unmoved. Hence the motion existing in the world must be due ultimately to the existence of an unmoved mover. If this being causes motion without being itself in motion it does not act upon the bodies it moves as one body acts upon another, for a body can move another body only by being itself in motion. The manner in which the unmoved mover moves the world is rather to be ​conceived on the analogy of a loved object moving the loving object without itself being moved. The person in love strives to approach and unite with the object of his love without the latter necessarily being moved in turn. This is the way in which Aristotle conceives of the cause of the world's motion. There is no room here for the creation of the world. Matter is eternal, motion is eternal, and there is an eternal mind for the love of which all motions have been going on eternally.
The unmoved mover, or God, is thus not body, for no body can move another body without being itself in motion at the same time. Besides, all body is finite, i. e., it has a finite magnitude. A body of infinite magnitude is an impossibility, as the very essence of body is that it must be bounded by surfaces. A finite body cannot have an infinite power, as Aristotle proves, though we need not at present go into the details of his proof. But a being which causes eternal motion in the world must have an infinite power to do this. Hence another proof that God is not corporeal.
If God is not subject to motion, he is not subject to change of any kind, for change involves motion. As matter is at the basis of all change God is without matter, hence he is pure form, i. e., pure actuality without the least potentiality. This means that he is what he is wholly all the time; he has no capacities of being what he is at any time not. But if he is not corporeal, the nature of his actuality or activity must be Thought, pure thinking. And the content of his thought cannot vary from topic to topic, for this would be change, which is foreign to him. He must be eternally thinking the same thought; and the highest thought it must be. But the highest thought is himself; hence God is pure thought thinking himself, thought thinking thought.
The universe is in the shape of a sphere with the earth stationary in the centre and the heavens revolving around it exactly as appears to us. The element earth is the heaviest, hence its place is below or, which is the same thing, in the centre. This is its natural place; and its natural motion when away from the centre is in a straight line toward the centre. Water is the next heaviest element and its natural place is just above earth; hence the water in the world occupies a position spherical in shape round about the earth, i. e., it forms a ​hollow sphere concentric with the earth. Next comes the hollow sphere of air concentric with the other two. Its natural motion when away from its place in the direction of the earth is in a straight line toward the circumference of the world, not however going beyond the sphere of the lightest element of all, namely, fire. This has its natural place outside of the other elements, also in the form of a hollow sphere concentric with the other three. Its natural motion is in a straight line away from the centre of the world and in the direction of the circumference. Our earth, water, air and fire are not really the elements in their purity. Each one has in it also mixtures of the other three elements, the one which gives it the name predominating.
All minerals, plants and animals are formed from these four elements by various combinations, all together forming the sublunar world, or the world of generation and decay. No individual thing in this world is permanent. All are subject to change and to ultimate destruction, though the destruction of one thing is the genesis of another. There is no annihilation.
The causes of the various combinations of the elements and the generation and destruction of mineral, plant and animal resulting therefrom, are the motions of the heavenly bodies. These are made of a purer substance than that of the four elements, the ether. This is proven by the fact that the heavenly bodies are not subject to change or destruction. They are all permanent and the only change visible in them is change of place. But even their motions are different from those of the four elements. The latter are in a straight line toward the centre or away from it, whereas the heavenly bodies move in a circle eternally around the centre. This is another proof that they are not composed of the same material as sublunar bodies.
The heavens consist of transparent spheres, and the stars as well as the planets are set in them and remain fixed. The motions of the heavenly bodies are due to the revolutions of the spheres in which they are set. These spheres are hollow and concentric. The outer-most sphere forming the outer limit of the universe (the world is finite according to Aristotle) is studded with the fixed stars and moves from east to west, making a complete revolution in twenty-four hours. This motion is transmitted to the other spheres which carry ​the planets. Since, however, we notice in the sun, moon and the other planetary bodies motions in the contrary direction in addition to that from east to west, there must be other spheres having the motions apparent to us in the positions of the planets borne by them. Thus a given body like the sun or moon is set in more than one sphere, each of which has its own proper motion, and the star's apparent motion is the resultant of the several motions of its spheres. Without entering into further details concerning these motions, it will be sufficient for us to know that Aristotle counted in all fifty-five spheres. First came the sphere of the fixed stars, then in order the spheres of Saturn, Jupiter, Mars, Mercury, Venus, Sun, Moon.
God himself sets the outer sphere in motion, or rather is the eternal cause of its motion, as the object of its desire; and in the same way each of the other motions has also its proper mover, likewise a pure form or spirit, which moves its sphere in the same incorporeal and unmoved manner as God.
Thus we have in the supra-lunar world pure forms without matter in God and the spirits of the spheres, whereas in the sublunar world matter and form are inseparable. Neither is found separately without the other.
In man's soul, however, or rather in his intellect we find a form which combines in itself the peculiarities of sublunar as well as celestial forms. When in contact with the human body it partakes of the nature of other sublunar forms exhibiting its activity through matter and being inseparable from it. But it is not destroyed with the death of the body. It continues as a separate form after death.
The soul, Aristotle defines as the first entelechy of the body. The term entelechy which sounds outlandish to us may be replaced by the word realization or actualization and is very close in meaning to the Aristotelian use of the word form. The soul then, according to Aristotle, is the realization or actualization or form of the body. The body takes the place of matter in the human composite. It has the composition and the structure which give it the capacity for performing the functions of a human being, as in any other composite, say an axe, the steel is the matter which has the potentiality or capacity of being made into a cutting instrument. Its cutting function is the form of the axe—we might almost say the soul of the axe, if ​it were not for the circumstance that it cannot do its own cutting; it must be wielded by someone else.
So far then the human soul forms an inseparable unit with the body which it informs. As we do not think of the cutting function of an axe existing apart from the axe, so neither can we conceive of sensation, emotion or memory as existing without a body. In so far as the soul is this it is a material form like the rest, and ceases with the dissolution of the body. But the soul is more than this. It is also a thinking faculty. As such it is not in its essence dependent upon the body or any corporeal organ. It comes from without, having existed before the body, and it will continue to exist after the body is no more. That it is different from the sensitive soul is proven by the fact that the latter is inherent in the physical organ through which it acts, being the form of the body, as we have seen. And hence when an unusually violent stimulus, say a very bright light or a very loud sound, impinges upon the sense organ, the faculty of sight or hearing is injured to such an extent that it cannot thereafter perceive an ordinary sight or sound. But in the rational faculty this is not the case. The more intense the thought occupying the thinking soul, the more capable it becomes of thinking lesser thoughts. To be sure, the reason seems to weaken in old age, but this is due to the weakening of the body with which the soul is connected during life; the soul itself is just as active as ever.
We must, however, distinguish between two aspects of the rational soul, to one of which alone the above statements apply. Thought differs from sensation in that the latter perceives the particular form of the individual thing, whereas the former apprehends the essential nature of the object, that which constitutes it a member of a certain class. The sense of sight perceives a given individual man; thought or reason understands what it is to be a member of the human species. Reason therefore deals with pure form. In man we observe the reason gradually developing from a potential to an actual state. The objects of the sense with the help of the faculties of sensation, memory and imagination act upon the potential intellect of the child, which without them would forever remain a mere capacity without ever being realized. This aspect of the reason then in man, namely, the passive aspect which receives ideas, grows and dies with the body. ​But there is another aspect of the reason, the active reason which has nothing to do with the body, though it is in some manner resident in it during the life of the latter. This it is which enables the passive intellect to become realized. For the external objects as such are insufficient to endow the rational capacity of the individual with actual ideas, any more than a surface can endow the sense of sight with the sensation of color when there is no light. It is the active intellect which develops the human capacity for thinking and makes it active thought. This alone, the active intellect, is the immortal part of man.
This very imperfect sketch of Aristotle's mode of approach to the ever-living problems of God, the universe and man shows us the wide diversity of his method from that with which the Jews of Biblical and Rabbinic tradition were identified. Greek philosophy must have seemed a revelation to them, and we do not wonder that they became such enthusiastic followers of the Stagirite, feeling as they must have done that his method as well as his results were calculated to enrich their intellectual and spiritual life. Hence the current belief of an original Jewish philosophy borrowed or stolen by the Greeks, and still betraying its traces in the Bible and Talmud was more than welcome to the enlightened spirits of the time. And they worked this unhistorical belief to its breaking point in their Biblical exegesis.
Aristotle, however, was not their only master, though they did not know it. Plotinus in Aristotelian disguise contributed not a little to their conception of God and his relation to the universe. The so-called "Theology of Aristotle" is a Plotinian work, and its Pantheistic point of view is in reality foreign to Aristotle's dualism. But the middle ages were not aware of the origin of this treatise, and so they attributed it to the Stagirite philosopher and proceeded to harmonize it with the rest of his system as they knew it.
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 rehgious 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.
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 Mutakalhmun 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.
The practical part of philosophy, ethics, the Mutakallimun among the Arabians discussed in connection with the justice of God. In opposition to the Jabariya and the Ashariya who advocated a fatalistic determinism denying man's ability to determine his own actions, some going so far as to say that right and wrong, good and evil, are entirely relative to God's will, the Mu'tazila insisted that man is free, that good and evil are absolute and that God is just because justice is inherently right, injustice inherently wrong. Hence reward and punishment would be unjust if man had not the freedom to will and to act. The Karaites Joseph Al Basir and Jeshua ben Judah discuss the problem of the nature of good and evil and vindicate their absolute character. God desires the good because it is good, and it is not true that a thing is good because God has commanded it. Freedom of man is a corollary of the goodness of God. The Rabbanites take it ​for granted that good is good inherently, and God desires and commands it because it is identical with his wisdom and his will. Freedom of man does follow as a corollary from the justice of God and it is also taught in the Bible and the Talmud. The very fact of the existence of a divine law and commandments shows that man has freedom. And those passages in Scripture which seem to suggest that God sometimes interferes with man's freedom are explained away by interpretations ad hoc. Our own consciousness of power to determine our acts also is a strong argument in favor of freedom. Nevertheless the subject is felt to have its difficulties and the arguments against free will taken from the causal sequences of natural events and the influence of heredity, environment and motive on the individual will are not ignored. Judah Halevi as well as Abraham Ibn Daud discuss these arguments in detail. But freedom comes out triumphant. It is even sought to reconcile the antinomy of freedom vs. God's foreknowledge. God knows beforehand from all eternity how a given man will act at a given moment, but his knowledge is merely a mirror of man's actual decision and not the determining cause thereof. This is Judah Halevi's view. Abraham Ibn Daud with better insight realizes that the contingent, which has no cause, and the free act, which is undetermined, are as such unpredictable. He therefore sacrifices God's knowledge of the contingent and the free so as to save man's freedom. It is no defect, he argues, not to be able to predict what is in the nature of the case unpredictable. Maimonides cannot admit any ignorance in God, and takes refuge in the transcendent character of God's knowledge. What is unpredictable for us is not necessarily so for God. As he is the cause of everything, he must know everything. Gersonides who, as we have seen, is unwilling to admit Maimonides's agnosticism and transcendentalism, solves the problem in the same way as Ibn Daud. God knows events in so far as they are determined, he does not know them in so far as they are contingent. There is still another possibility and that is that God knows in advance every man's acts because no act is absolutely free. And there is an advocate of this opinion also. Hasdai Crescas frankly adopts the determinist position on the basis of God's knowledge, which cannot be denied, as well as of reason and experience, which recognizes the determining character of temperament and motive. But reward and punishment are natural and ​necessary consequences, and are no more unjust than is the burning of the finger when put into the fire.
In respect to the details of ethical doctrine and the classification of the virtues, we find at first the Platonic virtues and their relation to the parts of the soul, in Saadia, Pseudo-Bahya, Joseph Ibn Zaddik and even Abraham Ibn Daud. In combination with this Platonic basis expression is given also to the Aristotelian doctrine of the mean. Maimonides, as in other things, so here also, adopts the Aristotelian views almost in their entirety, both in the definition of virtue, in the division of practical and intellectual virtues, and the list of the virtues and vices in connection with the doctrine of the mean. As is to be expected, the ultimate sanction of ethics is theistic and Biblical, and the ceremonial laws also are brought into relation with ethical motives. In this rationalization of the ceremonial prescriptions of Scripture Maimonides, as in other things, surpasses all his predecessors in his boldness, scientific method and completeness. He goes so far as to suggest that the institution of sacrifice has no inherent value, but was in the nature of a concession to the crude notions of the people who, in agreement with their environment, imagined that God's favor is obtained by the slaughter of animals.
Among the peculiar phenomena of religion, and in particular of Judaism, the one that occupies a fundamental position is the revelation of God's will to man and his announcement of the future through prophetic visions. Dreams and divination had already been investigated by Aristotle and explained psychologically. The Arabs made use of this suggestion and endeavored to bring the phenomenon of prophecy under the same head. The Jewish philosophers, with the exception of Judah Halevi and Hasdai Crescas, followed suit. The suggestion that prophecy is a psychological phenomenon related to true dreams is found as early as Isaac Israeli. Judah Halevi mentions it with protest. Abraham Ibn Daud adopts it, and Maimonides gives it its final form in Jewish rationalistic philosophy. Levi ben Gerson discusses the finer details of the process, origin and nature of prophetic visions. In short the generally accepted view is that the Active Intellect is the chief agent in communicating true visions of future events to those worthy of the gift. And to become worthy a combination of innate and acquired powers is necessary together with ​the grace of God. The faculties chiefly concerned are reason and imagination. Moral excellence is also an indispensable prerequisite in aiding the development of the theoretical powers.
Proceeding to the more dogmatic elements of Judaism, Maimonides was the first to reduce the 613 commandments of Rabbinic Judaism to thirteen articles of faith. Hasdai Crescas criticised Maimonides's principle of selection as well as the list of dogmas, which he reduced to six. And Joseph Albo went still further and laid down three fundamental dogmas from which the rest are derived. They are the existence of God, revelation of the Torah and future reward and punishment.
The law of Moses is unanimously accepted as divinely revealed. And in opposition to the claims of Christianity and Mohammedanism an endeavor is made to prove by reason as well as the explicit statement of Scripture that a divine law once given is not subject to repeal. The laws are divided into two classes, rational and traditional; the former comprising those that the reason approves on purely rational and ethical grounds, while the latter consist of such ceremonial laws as without specific commandment would not be dictated by man's own reason. And in many of these commandments no reason is assigned. Nevertheless an endeavor is made to rationalize these also. Bahya introduced another distinction, viz., the "duties of the heart," as he calls them, in contradistinction to the "duties of the limbs." He lays stress on intention and motive as distinguished from the mere external observance of a duty or commandment.
Finally, some consideration is given in the works of the majority of the writers to eschatological matters, such as the destiny of the soul after death, the nature of future reward and punishment, the resurrection of the body and the Messianic period, and its relation to the other world. This brief sketch will suffice as an introduction to the detailed treatment of the individual philosophers in the following chapters.