Graziano Toto

TITLE: Aristotle on Identity

SUPERVISED BY: Dr Luca Castagnoli

Aristotle has devoted no specific writing to the concept of identity and the passages that deal with this notion are not central in his corpus. These probably are the reasons why there has not been any attempt in the scholarship to reconstruct an Aristotelian theory of identity from the evidence of his texts. More precisely, up to now the Aristotelian conception of identity has been studied in connection with several specific issues, but not as a whole. In fact, on the one hand the attention has been focused on a law of identity that Aristotle formulated in Top. VII 1, 152b25-29 and that now we call Principle of Indiscernibility of Identicals and on the problem of its possible restriction (Fait 2008, Matthews 1982, White 1971, etc.); on the other hand, there has been some emphasis on the function that identity has within the Aristotelian theory of predicables (Gobbo 2000), but it has not been highlighted that both the investigations of Topics and the resolution of the paralogisms that involve the notion of identity (Sophistical Refutations) constitute an application of the same set of assumptions. Moreover, the problem of identity through time has been considered in isolation from Aristotle’s investigation of identity in the logical works.

The focus of my research project will be a handful of passages in which Aristotle contrasts two things that are the same (or different) in some respect, but different (or the same) in another one. It is within one of these discussions (Sophistical Refutations 24 179a37-39) that Aristotle formulates an important restriction to his law of identity. The analysis of all the cases of opposition between identity and difference, both in their synchronic and in their diachronic declension, will be fundamental for our understanding of this law. Furthermore, it will show that, on the one hand, Aristotle’s refutation of the sophistical arguments fits consistently in the wider context of his theory of predication, in which the notion of identity plays a key role; on the other hand, that identity is an important theoretical tool used to account for change in the physical world.