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LOGIC (Heb. חָכְמַת הַדִּבּוּר or מְלֶאכֶת הַהִגַּיוֹן), the study of the principles governing correct reasoning and demonstration. The term logic, according to Maimonides, is used in three senses: to refer to the rational faculty, the intelligible in the mind, and the verbal expression of this mental content. In its second sense, logic is also called inner speech, and in its third, outer speech. Since logic is concerned with verbal formulation as well as mental content, grammar often forms a part of logical writings. Shem Tov ibn *Falaquera, for example, prefaces his Reshit Ḥokhmah with an account of the origin of language, its nature, and its parts. As Maimonides had done in the introduction to the Guide of the Perplexed, Falaquera classifies terms into distinct terms, synonyms, and homonyms, a classification which was very important in the medieval philosophic exegesis of the Bible.

The two mental acts which are basic to logic are conception and judgment. The former is involved in the apprehension of the essence of things, the latter, in deciding whether propositions are true or false.

Maimonides does not consider logic a part of philosophy proper as the Stoics did, but follows the Peripatetics in viewing it as the instrument and auxiliary of all the other sciences.

Although some of the methods of biblical exegesis and legal interpretation (middot) employed by the rabbis of the talmudic period rest upon the rules of logic (see *Hermeneutics), it is doubtful that the rabbis had a formal knowledge of the subject. However, beginning with Saadiah, who refers to Aristotle's categories, proving that they are not applicable to God (Emunot ve-De'ot, 2:8), Jewish thinkers have been acquainted with the Organon – the title traditionally given to the body of Aristotle's logical treatises which formed the basis of logic – as propounded by the logicians of Islam. During the Islamic period, few works on logic were written by Jews. While Isaac *Israeli and Joseph ibn *Ẓaddik appear to have written works on logic, the first extant work on logic written by a Jew is Maimonides' Maqāla fi-Ṣināʿat al-Manṭiq (ed. by M. Turker (1961); Arabic text in Hebrew characters published by I. Efros in: paajr, 34 (1966), 9–42 (Hebrew section); translated by the same into English under the title Maimonides' Treatise on Logic, in: paajr, 8 (1937/38), 34–65). It was only when the setting of Jewish philosophy shifted to Christian countries and Arabic ceased to be the language of the Jews that logical works were translated into Hebrew and a greater number of Hebrew works on logic were written by Jews.

In the Maqāla fi-Ṣināʿat al-Manṭiq Maimonides offers concise exposition of the 175 most important logical, physical, metaphysical, and ethical terms used in the discussion of logical theory. The popularity of this treatise is attested by the fact that it was translated into Hebrew three times, under the title Millot ha-Higgayon or Shemot ha-Higgayon: once in a florid style by *Ahitub, a physician in Palermo in the 13th century; again, by Joseph ben Joshua ibn Vivas (of Lorca) in the 14th century; and by Moses b. Samuel ibn *Tibbon (all three translations appear in: paajr, 8 (1937/38), 23–129). This last translation was by far the most popular and has gone through many editions. Maimonides' work served not only as a handbook of logic, but, until comparatively recent times, also as an introduction to general philosophy. Of the commentaries written on it, those of Mordecai b. Eliezer *Comtino and Moses *Mendelssohn may be singled out.

While there is little information on the logical authorities used by the Jews up until the middle of the 12th century, it is known that by this time al-Fārābī was the acknowledged authority on logic. Maimonides, in a famous letter to Samuel ibn Tibbon, the Hebrew translator of his Guide, advises him to study logic only from the works of al-Fārābī, and, as M. Tucker has shown, Maimonides in his Maqāla fi-Ṣināʿat al-Manṭiq relied heavily on four works by al-Fārābī. During the first half of the 13th century, *Averroes too came to be regarded as an authority on logic, soon superseding al-Fārābī. Thus, Judah ben Samuel ibn *Abbas, in his Ya'ir Nativ, suggested that in order to learn the principles of logic, a student should read the works of al-Fārābī or Averroes.

While it appears that there were no translations into Hebrew of any of the books comprising the Organon, all the commentaries of al-Fārābī and Averroes were translated and annotated. Jacob b. Machir translated Averroes' Epitome of the Organon, and Jacob *Anatoli, Averroes' middle commentaries, which he completed in 1232. *Kalonymus b. Kalonymus and Moses b. Samuel ibn Tibbon were among some of the others who undertook to translate the logical writings of al-Fārābī and Averroes. Anatoli's translation of the middle commentaries was utilized by Joseph *Kaspi in his compendium of logic, entitled Ẓeror ha-Kesef.

The Jews were also familiar with the logical writings of Avicenna. Their knowledge of Avicenna's writings did not come from translations of Avicennian works, but rather through the logical portions of al-*Ghazālī's "Intentions of the Philosophers" (Maqāṣid al-Falāsifa). In addition to the Islamic tradition, a work by a Christian scholar, Peter of Spain's SummulaeLogicales, was also popular, as the four or five Hebrew translations or extracts of it, which are still extant, testify.

These translations are of great importance because in many instances the original Arabic texts of the commentaries are no longer extant. Moreover, many of these texts were translated from the Hebrew into Latin by Jews who served as the intermediaries between the logicians of Islam and the scholastics. *Levi b. Gershom wrote supercommentaries on the middle commentaries and epitomes of Averroes, as well as an independent work on logic entitled Ha-Hekkesh ha-Yashar ("The Correct Syllogism"), which drew upon itself the attention of gentile scholars and was translated into Latin under the title Liber Syllogismi Recti. In the 15th century, *Judah b. Jehiel Messer Leon wrote a supercommentary on Averroes' middle commentaries which shows the influence of the scholastic Walter Burleigh.


L. Jacobs, Studies in Talmudic Logic and Methodology (1961), 3–50; A. Hyman, in: Actes du quatrième congrès international de philosophie médiévale (1969), 99–110; I. Husik, Judah Messer Leon's Commentary on the "Vetus Logica" (1906); Steinschneider, Uebersetzungen, 43–168; Waxman, Literature, 1 (19602), 319–20; 2 (19602), 213.

[Jacob Haberman]

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