Authorities. In addition to Munk's Mélanges and
Frank's La Cabbale, etc. (Paris, 1843), Max Doctor's Die
Philosophie des Josef (ben) Zaddik (Münster, 5895), Baeumker's
edition of Avicebrol's Fons Vitae (Münster, 1892), and
Guttmann's Die Scholastik des XIII Jahrh. in ihren Beziehungen sum
Judentum (Breslau, 1902) may be mentioned as authorities on the
history of Jewish philosophy.
The Jews, before their contact with Arabian civilization, developed a
system of mystic philosophy based upon the cabalistic Sephiroth, or
mystic numbers. It was, however, after they had come in contact with
the Arabians in the East and in the Moorish kingdom, that Greek
learning passed from the mosque to the synagogue, and the systems of
philosophy were developed which influenced the course of Christian
thought during the thirteenth century.
Avicebrol (1020-1070) was born at Malaga. His real name was
Salomon ben Gabirol, the name Avicebrol being the Latinized form of
what was supposed to be an Arabian name. Indeed, it was only in recent
times that the nationality of this philosopher was determined with
certainty. His principal work, Fons Vitae, was probably composed
in Arabic; Munk found a Hebrew copy of the work, and quite recently the
Latin translation, made about the beginning of the twelfth century, has
been published. 
Avicebrol's philosophy is a blending of Jewish religious doctrines with
the doctrines of the Neo-Platonists. The importance attached to
contemplation, and to a striving towards union with the divine, the
doctrine of the preëxistence of the soul, of knowledge by means of
reminiscence, of the eternity of matter, -- all these are evident
signs of Neo-Platonic influence.
The most characteristic of Avicebrol's tenets is the doctrine ascribed
to him by Albertus Magnus  and St. Thomas,  that all things finite,
whether corporeal or incorporeal, are composed of matter and form; that
matter is, consequently, the substratum of all finite
 Summa Totius Theologiae, I, 4, 22.
 Quaestio Disputata De Anima, Art. 6.
 Cf.Fons Vitae, V, 21.
González calls attention to the similarity existing between
Avicebrol's doctrine of universal matter and the doctrines of Duns
Scotus regarding materia primo-prima. Indeed, all the first
Franciscan masters maintained that matter is coextensive with finite
 Op. cit., II, 486.
Moses Maimanides (1135-1204), who was born at Cordova in 1135
and died at Cairo in 1204, was the greatest of the Jewish
Aristotelians. His philosophical treatise, entitled Guide of the
Doubting, is an exposition of Aristotelian philosophy combined with
Jewish religious teaching: "Intentio hujus libri," he says, "est docere
sapientiam legis secundum veritatem et ex fundamentis." 
 Preface to Guide.
Moses departs from the teaching of Aristotle whenever he considers that
Jewish dogma is opposed to Peripatetic philosophy. He maintains, for
instance, that the world is not eternal, except in the sense that it
proceeds by natural necessity from its cause which is eternal. He is
willing, however, to grant that the eternity of the world is possible,
although he does not agree with the Aristotelians who hold that it is
necessary. In treating of the immortality of the soul, he cites
passages from the Bible, quotes the opinions of the Greek and Arabian
commentators, distinguishes between the soul that is born with us, and
the intellect which is acquired, and ends by asserting that only the
souls of the just are immortal.  This doctrine of acquired immortality
became one of the most distinctive doctrines of the Jewish school.
 Guide, etc., trans. by Munk, Vol. II, 205.
Historical Position. Although less original than Avicebrol,
Maimonides was destined to exercise a more profound influence on
succeeding generations of philosophers. To him may be traced the
scientific movement which manifested itself among the Jews of the
thirteenth and the two following centuries, and he is commonly regarded
as the one who, of all the Jewish thinkers, contributed most to the
system of Spinoza.
Anonymous Works. There were three works of doubtful authorship,
which, on being translated from Arabic into Latin, became for the
schoolmen common sources of information concerning Arabian, Jewish, and
even Greek philosophy: (1) The Secretum Secretorum, a scientific
miscellany, attributed to Aristotle; (2) Theologia Aristotelis,
or De Secretiori AEgyptiorum Philosophia, which was sometimes
attributed to Aristotle, but which is in reality a collection of
excerpts from the Enneades of Plotinus; (3) Liber de
Causis, which, under various titles, was ascribed to Aristotle, to
St. Augustine, to Avempace, and to Gilbert de la Porrée.
Albertus Magnus and St. Thomas decided against its Aristotelian
authorship, the former ascribing it to a certain Jew named David, the
latter judging it to be an Arabian compilation of a work by
The preponderance of evidence is in favor of St. Thomas' opinion.
 Cf. Bardenhewer, Die pseudo-aristotelische Schrift
über das reine Gute (Freiburg im B., 1882), p. 41.