Metaphysics or first philosophy, as the general knowledge or as the foundation of all knowledge, discusses the quiddity and existence and their issues. The main job of all knowledge is question and answer of special quiddities and special existences. The issues of any systematic philosophy reach to existence and quiddity. Hence Islamic philosophy in its recent period has raised the question of which of these two is original (asil) and which is credible (eatebari). Two theories of the originality of quiddity and the originality of existence were raised to this question. Each of these two theories that is accepted in a philosophy has a different face to a philosophy that accepted rival theory. No difference has been as effective as this difference in the separation of philosophies. The fame of theory of originality of existence in the recent period and denying the originality of quiddity while establishing it has made it not an independent interpretation of originality of quiddity in famous and popular books. In this article, we try to interpret the theory of originality of quiddity and the compatibility between the two theories and the same time preferring over the theory of originality of existence from the language of Fayyaz Lahiji.