Ayman Shihadeh

Avicenna's Corporeal Form and Proof of Prime Matter in Twelfth-Century Critical Philosophy: Abū l-Barakāt, al-Masʿūdī and al-Rāzī

This article explores a previously unknown twelfth-century debate surrounding Avicenna’s theory of matter, in particular his views that, being deprived of actuality, prime matter is non-corporeal, and that body is invested with corporeity by a substantial form impressed into matter known as corporeal form. Avicenna’s main proof of prime matter from body’s susceptibility to division was targeted earlier in the century by Abū l-Barakāt al-Baghdādī and Sharaf al-Dīn al-Masʿūdī, but was later reinterpreted and developed by Fakhr al-Dīn al-Rāzī, who brought this particular debate to a close. The problem, however, persisted as a puzzle that exercised later Arabic philosophers.

THE ARGUMENT FROM IGNORANCE AND ITS CRITICS IN MEDIEVAL ARABIC THOUGHT

The earliest debate on the argument from ignorance emerged in Islamic rational theology around the fourth/tenth century, approximately seven centuries before John Locke identified it as a distinct type of argument. The most influential defences of the epistemological principle that ‘that for which there is no evidence must be negated’ are encountered in Muʿtazilī sources, particularly ʿAbd al-Jabbār and al-Malāḥimī who argue that without this principle scepticism will follow. The principle was defended on different grounds by some earlier Ashʿarīs, but was then rejected by al-Juwaynī, and was eventually classed as a fallacy by Fakhr al-Dīn al-Rāzī whose Nihāyat al-ʿuqūl contains the most definitive and comprehensive refutation of classical kalām epistemology and the first ever defence of Aristotelian logic in a kalām summa. According to the eighth/fourteenth-century historian Ibn Khaldūn, this debate provided the main impetus for the philosophical turn that Ashʿarism took during the sixth/twelfth century.