Ciechi e non vedenti. Inserti persiani nella letteratura filosofica araba su affermazione e negazione

In the logical section of Abū Ḥāmid al-Ġazālī’s (d. 1111) The Intentions of the Philosophers [Maqāṣid al-falāsifa, MF], an Arabic text which depends on Avicenna’s (Ibn Sīnā, d. 1037) Persian summa titled Book of Science for ʿAlāʾ al-Dawla [Dānešnāme-ye ʿAlāʾī, DN], an interesting insert in Persian is preserved. The insertion serves to exemplify some conceptual problems concerning the affirmative or negative value of a predicate (and a proposition), through recourse to a language different from Arabic. Persian, in particular, can add the negation to both the predicate and the copula, thus allowing one to distinguish with precision between affirmative clauses with a negative predicate, and simply negative clauses. The discussion, which uses as key examples the attributes of ‘blind’ and ‘non-seeing’, also considers more complex case studies, such as the negation applied to an existentially void subject. Altogether, al-Ġazālī’s discussion offers highly interesting historical and methodological insights, by providing a further, linguistic confirmation of the derivation of the MF from the Persian DN, on the one hand, and by allowing to assess in vivo, on the other hand, the complex theoretical reflection on how natural languages can be an obstacle, or conversely a support, for the development of a supralinguistic logic.