In his al-Zura’ Dawani analyzes the issue of causality. Concerning the cause effect relation, he speaks as if the Existence of effect in his philosophy is both the Existence of inhering Existence and copulative Existence. Hence, he has created a confusion of meanings here. When criticizing Dawani's philosophy regarding causality, Mulla Sadra deals with the part of his interpretations which is in conformity with inhering Existence and keeps silent about the part which is in conformity with copulative Existence and in which he has referred to the issue of causality as tasha'un. He himself propounded the ontological dependence of the effect on the cause by posing the theory of "indigence possibility and ontological indigence". In his view, the Existence of effect is the same as relation to and dependence on the cause. However, the identity of the Existence of cause and relation to cause had also been propounded in Peripatetic Philosophy, but the difference was that Peripatetics saw the dependence of effect on cause in the effect's quiddity, while the followers of the Transcendent Philosophy saw it in its Existence. Moreover, in Peripatetic Philosophy, we can allow some independence from the cause for the effect, while in the Transcendent Philosophy the effect depends on the cause in every respect, and the relation between them is of the type of illuminative (ishraqiyyah) relation. In this paper, through an analysis of the views of jalal ad-Din Dawani and Mulla Sadra concerning causality, the writer tries to show that both of them are of the same idea concerning the gnostic theory of the individual unity of being. This theory has not been coherently stated in Dawani's interpretations; however, it has been completely elaborated in those of Mulla Sadra.