217. Oriental Branch of Arabian Philosophers Proper. Alfarabi. Avicenna. -- The motazilite^{1} AN-NAZZAM (about 835) is set down as the first Arabian philosopher. He studied Alexander of Aphrodisias and espoused the latter's defence of human freedom. A little later, ALKINDI (fl. about 873), a contemporary of Scotus Eriugena, wrote, collected and translated an extensive philosophical literature, especially in the domain of logic. His writings are to be had only in recently published Latin versions, made by Gerard of Cremona and John Avendeath (226, II.). He probably recast an original Arabic version of the Theology of Aristotle. Another philosopher of the school of Bagdad, better known to the scholastics, is ALFARABI (fl. 950), the greatest Arabian philosopher prior to Avicenna. He not only translated but interpreted and extensively annotated the Grecian philosophers, and has left many important treatises on the various branches of philosophy. Among those on logic, which testify to his profound knowledge of Aristotle, are his commentary on the Posterior Analytics, a treatise De Ortu Scientiarum, and another De Intellectu et Intelligibili often quoted in the Middle Ages. The germ of pantheism is contained in his metaphysics, which embodies the Neo-Platonic theory of Divine Emanation and issues in mystic tendencies. Alfarabi is credited by Carra de Vaux with the honour of propounding clearly the theory of the active intellect (intellectus agens) as a pure form, separate from matter. The same author describes him as "a really powerful and singular personage . . . more fascinating than Avicenna, more impetuous and daring in his intellectual flights, more agile in his retorts. His thought usually attains to the elevation of the lyric; his logic is keen, clever and bold; and he gives expression to a flow of profound speculation in language that has the rare merit of simplicity and conciseness."^{2}

Alfarabi's successor, IBN-SINA or AVICENNA (980-1036), while also a theologian and a physician, must be regarded as one of the greatest of the Arabian philosophers.^{3} Though his life was one of many vicissitudes, he is said to have written over a hundred distinct works. He is, among all the Arabians, one of the most faithful interpreters of Aristotle. Starting with the system of Alfarabi, he freed it from many Neo-Platonic theories in order to bring it nearer to genuine peripateticism.

Among his general treatises on philosophy, we may mention the Chifâ, called by the scholastics Sufficientiae (logic, mathematics, physics and metaphysics: the Metaphysica Avicennae, published at Venice in 1499, appears to be a portion of the Chifâ); the Nadjât, an abridgment of the former; the Book of Theorems; the Guide to Wisdom; the Philosophy of Aroudi; the Philosophy of Alâ. His special treatises deal with a variety of subjects; and he has also left numerous works on mysticism and on science (especially medicine and astronomy).

His logic, which is clear and concise, is a running commentary on Aristotle, emphasizing definition and inference. Logic is not itself philosophy but a means or instrument for attaining to philosophy. Avicenna's classification of the philosophical sciences was widely adopted by the scholastics of the thirteenth century and later. Physics, mathematics and theology, each having a pure and an applied part, constitute speculative philosophy; ethics, economics and politics constitute practical philosophy (see below, Gundissalinus).

To metaphysics Avicenna gives the place of honour in his philosophy: and the main problem that occupies him is that of the procession of Being, the generation of the manifold in the bosom of Unity. At the highest height of the metaphysical empyrean is enthroned the First Being, God, the Perfect intelligence, the Absolute Good. From this First Being proceeds the first caused being. From the latter's knowledge of the former there proceeds "an intelligence which is next in order below the first caused being, that namely of the sphere of Saturn. But the first caused being also knows itself as necessarily caused by the First Being, and from this knowledge flows a soul which is that of the limiting sphere; and from the same caused being knowing itself as possible in itself, there comes into existence a body which is that of the limiting sphere. The procession thus goes on according to the descending astronomical order of spheres. From the intelligence of Saturn, knowing God, proceeds the intelligence of the sphere of Jupiter; from the same intelligence, knowing itself, proceed the soul and the body of the sphere of Saturn. This mode of derivation continues down to the intellectus agens, where it stops; for, observes Avicenna, there is no need that it continue indefinitely."^{4}

This theory of the procession of the spheres is supplemented by a theory of their motion; and both together offer a synthetic or deductive explanation of the astronomical data of the Arabians. The circular motion of the spheres has its ultimate ground and cause in the finality exercised by God, the intelligent soul of each sphere seeking the Supreme Good, by the knowledge of which they are attracted. The active intellect, which is the last engendered of those pure intelligences, governs our earth: from it proceed, through the influence of the heavenly motions, all substantial forms destined to actuate sublunary matter. The active intellect, therefore, is no mere psychological factor in the genesis of knowledge, but a metaphysical principle from which human souls emerge in the emanations process in the same way as all other terrestrial forms. As for matter, it is not, as Alfarabi taught, an outflow of the soul, but an eternal element, co-existing with God, though affected with an absolute indifference to exist or not to exist.

His theory of causes, his Aristotelian solution of the Universals problem, and especially his thesis of the individuality of substances and of the three states of the essence (ante multitudinem, in multiplicitate, post multiplicitatem), give his other metaphysical doctrines a frankly Aristotelian spirit which won for them the attention of the Western scholastics.^{5}

In psychology Avicenna follows the main lines of Aristotle's teaching on the faculties of the soul. Though reducing their number, which the "brothers of purity" had excessively increased, he still allows himself to drift into exaggerated developments in detail. Thus in the speculative understanding (or passive intelligence, proper to each individual man) he admits five distinct states or stages, corresponding to successive actuations, -- in addition to the intervention of the intellectus agens, the separated form whose illumination is necessary for all intellectual activity whatever. These stages are: the material intelligence or absolute potentiality of knowledge; the possible intelligence, endowed with primary truths; the intelligence in act, or completely prepared to receive additional knowledge; the acquired intellect, in possession of this further knowledge; the holy spirit, or mystic intuition, reserved for favoured souls. Other faculties, like the cogitativa, are submitted to an interesting analysis. Pre-existence and metempsychosis are rejected. Abundant proofs are forthcoming for the spirituality and immortality of the soul. And this immortality is to be personal: another instance of the individualism by which Avicenna endeavours to counterbalance the pantheistic tendencies of his emanation theory. As with Alfarabi, so with Avicenna, philosophy leads up to mysticism, making way for numerous degrees of ecstasy and prophecy (Neo-Platonism).

{1} The " motazilites" were the first Arabian thinkers who attempted to "rationalize" the unquestioning, fatalistic beliefs of Mahometanism.

{2} op. cit., pp. 102 and 116.

{3} The "brothers of purity" who appeared about this time were encyclopedists and popularizers; they also formed a mystic sect. DIETERICI has published extracts from their writings.

{4} CARRA DR VAUX, op. cit., p. 247.

{5} Logic, Venice edit., 1508, fol. 12, V.A.