Kitāb al-Nafs al-mansūb li Isḥāq ibn Ḥunayn, published by Dr. Aḥmad Fu'ād al-Ahwāni along with the Talkhīṣ Kitāb al-Nafs of Ibn Rushd (Imprimerie Misr S.A.E., Cairo, 1950), appears to be the earliest extant Arabic commentary of the De Anima of Aristotle. The edition is based on the only known manuscript, in the Escorial Library of Madrid. Though the opening words of the text clearly indicate that it is the translation of Aristotle's De Anima, it is in fact a commentary and not a translation. Hartwig Derenbourg, the cataloguer of the Escorial Library, was misled by the opening words of the manuscript and has, therefore, ascribed it to Isḥāq ibn Ḥunayn. Casiri, an earlier cataloguer, was equally wrong when he ascribes the work to Ibn Rushd. Terms and expressions clearly demonstrate that the work is either a maiden attempt of Isḥāq, or done by somebody who preceded him and was not associated with his school. Terms such as
(form),
(matter),
(the final cause) and
(the common sense), and the like which occur in the work were represented by Isḥāq and his school by expressions such as
, and
respectively. It is, therefore, difficult to accept the ascription of the work to Isḥāq ibn Ḥunayn.