Samuel Ibn Tibbon, the translator of the " Guide of the Perplexed," expresses himself in terms little flattering concerning Israeli's worth as a philosopher.29 He is a mere physician, Maimonides says, and his treatises on the Elements, and on Definitions consist of windy imaginings and empty talk. We need not be quite as severe in our judgment, but the fact remains that Israeli is little more than a compiler and, what is more to the purpose, he takes no attitude in his philosophical writings to Judaism as a theological doctrine or to the Bible as its source. The main problem, therefore, of Jewish philosophy is not touched upon in Israeli's works, and no wonder Maimonides had no use for them. For the purely scientific questions treated by Israeli could in Maimonides's day be studied to much better advantage in the works of the great Arabian Aristotehans, Al Farabi and Avicenna, compared to whom Israeli was mediocre. We are not to judge him, however, from Maimonides's point of view. In his own day and generation he was surpassed by none as a physician; and Saadia alone far outstrips him as a Jewish writer, and perhaps also David Al Mukam- mas, of whom we shall speak later. Whatever may be said of the intrinsic value of the content of his philosophical work, none can take away from him the merit of having been the first Jew, so far as we know, to devote himself to philosophical and scientific discussions, though not with the avowed aim of serving Judaism. The rest was bound to come later as a result of the impulse first given by him.
The two works of Israeli which come in consideration for our purpose are those mentioned by Maimonides in his letter to Samuel Ibn Tibbon spoken of above, namely, the "Book of the Elements," 30 and the "Book of Definitions." 31 Like all scientific and philosophic works by Jews between the ninth and thirteenth centuries with few exceptions, these were written in Arabic. Unfortunately, with the exception of a fragment recently discovered of the "Book of Definitions," the originals are lost, and we owe our knowledge of their contents to Hebrew and Latin translations, which are extant and have been published.32 We see from these that Israeli was a compiler from various sources, and that he had a special predilection for Galen and Hippocrates, with whose writings he shows great familiarity. He makes use besides of Aristotelian notions, and is influenced by the Neo-Platonic treatise, known as the "Liber de Causis," and derived from
