Relation of Two Meanings of Quiddity (" What Makes a thing to Be What it is" and " What Is Said in Answer to What is it") in the Philosophy of Ibn Sina

Quiddity has two well-known definitions: “what makes a thing to be what it is” “or being and “what is said in answer to what is it?” Or the concept of a whole thing. Mulla Sadra is the first philosopher who has specified the meaning and purport of each. This view is compatible with the principality and unity of being as the most important foundation of Sadrian system and even an acompanying element of it. At the same time given these two principle have not been the subject of discussion by the philosophers before Sadra and in particular Ibn Sina even if these two afore-mentioned meaning can be deduced from some passages of Shykh because of the foundamental differences of Avicennian and Sadrian systems the relation of them is not the same in these two philosophical systems.In Ibn Sina’s philosophy quiddity is nothing except what a thing is by what it is which is definitely the same truth and essence of a thing and distinct from being. If what makes a thing by what it is or the quiddity of a thing is unknown the answer to it is by what it is and answer or the same as what is answered in answer to what it is, is a concept which it denotes completely in contrast to what is found in Mulla Sadra’s philosophy have a relation of significant and signifcation and in a way it can be said that are to degrees or stations of one thing. With this interpretation other commentaries which Sadra and his followers from transcendental have is not infered from some passages of shykh.