ALESSANDRO D'AFRODISIA. — Peripatetic philosopher of Caria and celebrated commentator on Aristotle. He lived at the end of the 2nd century A.D. and the beginning of the 3rd, under the emperor Septimius Severus. A disciple of Aristotle of Messina, he was the last great representative of the Aristotelian school at Athens.
The following works of certain attribution have come down to us: 1) the commentary on Books I–V of the Metaphysics (since the part concerning Books VI–XIV is by another later author, perhaps Michael of Ephesus); 2) the extensive exposition of Book I of the Prior Analytics; 3) the commentary on the Topics (the one attributed to the Sophistical Refutations appears to be by Michael of Ephesus); 4) the commentary on the De sensu; 5) the exposition of the books on the Meteorology; 6) a treatise in two books, De anima; 7) a treatise, De fato, dedicated to the emperors Septimius Severus and Caracalla (thus written between 198 and 211); 8) a treatise, De mixtione et augmento. His commentaries on the Categories, the De interpretatione, Book II of the Prior Analytics, the Posterior Analytics, the Physics, the De caelo, and the De generatione et corruptione have been lost, some of which were certainly known to the Arab Peripatetics. The purpose pursued by A. is to expound the doctrine of the philosopher of Stagira and to defend it against the objections of its opponents, especially the Stoics. For this reason he deserved to be called by the other Greek expositors «the commentator» par excellence, and was regarded as a «second Aristotle». The influence he exerted on the other commentators, both Greek and Arab, is remarkable, to such an extent that Averroes himself, who often combats him, does not deny that he «was one of the good expositors» of Aristotelian thought, and informs us that his contemporaries did not consider anyone a perfect philosopher «nisi qui est Alexandreus» (Averroes, De anima, III; comm. 14).
Insisting on the criticism Aristotle had made of Plato’s separate ideas, A. maintains that universal concepts would be nothing if they were not thought. This has led some to regard him as a nominalist. He does not, however, reject the Aristotelian theory of abstraction. According to him, this is accomplished through the action of the agent intellect, which is a separate substance in which are the ideas and forms of all things; indeed, he calls it outright «the first cause», that is, God. As he had heard from Aristotle of Messina, this intellect penetrates into them according to the mode and properties of each. Before existing in matter, forms exist in the agent intellect. Through abstraction, the human intellect contemplates pure forms, liberated from matter, by the light of the agent intellect that is joined to II. But what is the human intellect? With Aristotle he distinguishes a threefold intellect: the intellect that is a pure potency or disposition to understand, which he calls the natural intellect (φυσικός) or material intellect (ὁλικός), because of its resemblance to matter, which is in potency to become all things; the acquired intellect, already actualized by the idea and ready to understand and reason; and the agent intellect, which is the active cause through which the material intellect passes from potency to act. Whereas the natural or material intellect is a disposition or aptitude of the soul, which is the form of the body, to understand, and is therefore in us—as the acquired intellect likewise is in us—the agent intellect is instead outside us, and enters into us and operates from without. But since the soul, of which the material intellect is a capacity, is a form of the body and inseparable from it, it follows that when the body is corrupted, its form is also corrupted, and nothing remains of the material intellect and the acquired intellect, that is, of what corresponds to individual consciousness. Only the agent intellect is immortal and eternal. This interpretation of Aristotle’s thought was opposed by Themistius, Averroes, and St. Thomas, from very different standpoints. It was instead accepted by those who called themselves Alexandrists. It should be recalled, however, that G. Pico della Mirandola, in the first of the eight Conclusiones secundum Alexandrum Aphrodisium, and Agostino Steuco of Gubbio (Perenn. Philos., Basel 1542, I. IX, cols. 21–22), attempted to vindicate Aphrodisias against the accusation of having denied the immortality of the soul.
All the writings of Aphrodisias that still survive, already printed at Venice in Greek and in Latin translations at the end of the 15th century and in the first half of the 16th, have been printed in critical editions at Berlin in the Commentaria in Aristotelem graeca, I–III (the commentaries), and in the Supplementum aristotelicum (the minor writings and special dissertations), II.
BBL.: F. Fiorentino, Pietro Pomponazzi, Florence 1868, p. 103 ff.; F. Nourisson, Essai sur A. d'Aphrod., Paris 1870; A. Gercke, A. von Aphrod., in Pauly-Wissowa, Realencycl., I, col. 1454; E. Zeller, Philos. der Griech., III, Leipzig 1909, pp. 817–30; B. Nardi, Introduzione a Tommaso d'Aquino, trattato sull'unità dell'intelletto, Florence 1938, pp. 19–20, 40–42, 57, 134. Bruno Nardi