Thought

Following a practice characteristic of medieval Arab, and later Jewish, Neoplatonists, in the best known of all his philosophical works, the Book ofDefinitions, Isaac Israeli proposes a reading of philosophy that combines Platonic and Aristotelian themes. The starting point is represented by the four philosophical questions introduced by Aristotle in his Posterior Analytics to define things: whether, what, which, and why; i. e., existence, quiddity, quality, and quantity. Philosophy - Israeli explains - is not included in a genus from which its definition could be composed: having no answer to the question ‘‘what,’’ we are only in the condition to describe philosophy through its name, property and effect. The result is that philosophy is respectively the love of wisdom, the assimilation to the works of the Creator (i. e., to acquire the true knowledge of things and to do what corresponds to the truth) and man’s knowledge of himself (by knowing himself in both his spirituality and corporeality, man knows the macrocosm in its spiritual and corporeal substances).

Yet apart from this aspect, which represents only a general introduction to Israeli’s work, what actually characterizes his thought? There follows the definitions of the substances that are arranged between God (or God’s

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Perfection) and the imperfect lower world according to less and less pure ranks. In Israeli’s hierarchically ordered universe - later reproposed with the same structure and the same terms in the Fountain of Life by Avicebron, who undoubtedly knew Israeli’s work - God creates ex nihilo two simple substances, matter and form; and if primary matter is described as the substratum of diversity or as the truly first genus, the first form is what, imprinting itself on this matter, establishes the nature of the intellect. From the intellect, which Israeli defines as the totality of forms, emanates the world of souls (the rational soul, the animal soul, and the vegetative soul); and so, in descending order, the world of the spheres and the sublunary world, with the four elements and their compounds. The reason for the differences between the various substances is that the light originating in the supernal world gradually diminishes, as it passes downward through the degrees of the emanation. In short, the further this light is from its source, the more it darkens and thickens, but without disappearing (if this were not so, the substantial unity and continuity of the universe would be compromised); and the more the substances are imperfect. As it is not difficult to see, what changes is not only the quality of the light, and consequently the nature of the substances, but also the manner in which the cosmological process occurs. The distinction is, succinctly, between

•  Creatio ex nihilo, or innovation: the action with which God makes existent the first two simple substances from the nonexistent

•  Emanation, which concerns the hypostases in the spiritual world (every substance flows from ‘‘the splendor and the brilliance’’ of the one that comes before)

•  Natural causality: the passing of corporeal substances from privation to existence.

The theological motive behind this threefold distinction is quite obvious: introducing the concept of creation into the framework of an emanationist metaphysics, and the necessary procession that it implies, Isaac Israeli preserves God’s Power, Will, and Wisdom.

(an excerpt). In: Isaac Israeli. A Neoplatonic philosopher ofthe early tenth century. Oxford University Press, London, pp 3-145 Muckle JT (1937-1938) Isaac Israeli, Liber de definicionibus. AHDLMA 12:299-340

Secondary Sources

Monographs

Altmann A, Stern SM (1958) Isaac Israeli. A Neoplatonic philosopher of the early tenth century. Oxford University Press, London Guttmann J (1911) Die philosophischen Lehren des Isaak ben Salomon Israeli. Aschendorffsche Verlagsbuchhandlung, Miinster Collections

Altmann A (ed) (1981) Creation and emanation in Isaac Israeli: a reappraisal. In: Essays in Jewish intellectual history. University Press of New England, Hanover, pp 17-34 Pessin S (2003) Jewish Neoplatonism: being above being and divine emanation in Solomon ibn Gabirol and Isaac Israeli. In: Frank DH, Leaman O (eds) The Cambridge companion to medieval Jewish philosophy. Cambridge University Press, Cambridge, pp 91-110

Wolfson HA (1973a) Isaac Israeli on the internal senses. In: Twersky I, Williams GH (eds) Studies in the history of philosophy and religion, vol 1. Harvard University Press, Cambridge, pp 315-343 Wolfson HA (1973b) The meaning of ex nihilo in Isaac Israeli. In: Twersky I, Williams GH (eds) Studies in the history of philosophy and religion, vol 1. Harvard University Press, Cambridge, pp 222-233 Journal Articles

Muckle JT (1933) Isaac Israeli’s definition of truth. AHDLMA 8:5-8 Stern SM (1956-1957) Isaac Israeli and Moses Ibn Ezra. J Jewish Stud 7:83-89

Stern SM (1961) Ibn Hasday’s Neoplatonist: a Neoplatonic treatise and its influence on Isaac Israeli and the longer version of the theology of Aristotle. Oriens 13-14:58-120