Abstract

The issue of existence - quiddity difference is one of the important issues that were put forward for the first time in Islamic philosophy without having any background in Greek philosophy. Aristotle's metaphysics which is the main source of the first philosophy contains only synonymous and verbal meaning ofexistence. The issue of existence - quiddity difference has no room in Aristotle's works. This issue was proposed first by Farabi and then was completed by Ibn sina. In Islamic philosophy when it is proved that existence in the mind is neither identical with quiddity nor a part of it but differs with it and is excess of it, that is, when it is proved that existence occurs on quiddity, this question arises that how is their relation in the outside? Whether existence occurs on quiddity or existence and quiddity are identical in the external world? To this question the Islamic philosophers answer that existence and quiddity are identical in the outside and it isimpossible that they differ from each other in the external world. The importance of this issue is that it finally led to the origination of the doctrine of the principality of existence which is known as the culmination of Islamic philosophy. The main goal of this article is study this issue and its impact upon the origination of the doctrine of the principiality of existence.