Abstract

Although the issue of the principiality of existence is introduced as one of the innovative and most fundamental issues of Sadrian philosophy, it seems to suffer from certain ambiguities. The effects of such ambiguities are sometimes so great that they cause problems in clearly interperting some of the other principles and positions adopted by this school of philosophy.To explain this issue, we should first see whether Mulla Sadra has presented a clear and accurate definition for the concept of principiality, so that in the light of which we could understand the quiddity's being mentally-posited. We should also inquire if external quiddity, alongside with mental quiddity - whose existence he assumes necessary in his discussion of mental existence - has any realization, and explore its relation to the principial existence. On the other hand, one might ask how we could consider something which possesses external realization in some way, although through a kind of union with existence as being mentally-posited.By clarifying the relation between principial existence and the external quiddity, the meanings of the principiality of existence and quiddity's being mentally-posited can be re-evaluated. Undoubtedly, the best way for doing this is to resort to Mulla Sadra's own words to prove that this ambiguity is in fact rooted in his own words. Ultimately, one might conclude that the main source of this ambiguity is his confusion of conceptual or mental quiddity with the external quiddity.