Among philosophers, figures like Sheikh Ishrāq, Allamah Ḥillī, and their followers believed in the principality of quiddity (māhiyyah) and naturally considered existence to be a secondary intelligible. However, with the emergence of transcendent philosophy and the endorsement of the principality of existence, it was expected that proponents of this perspective would not categorize existence as a secondary intelligible. Nevertheless, we observe that Mullā Ṣadrā and his followers in transcendent philosophy still consider existence as a secondary intelligible. The aim of this research is to answer whether these two perspectives are conflicting and contradicting each other or not. In case of a contradiction, how does Mullā Ṣadrā reconcile and justify his statements. Naturally, our method in this research is descriptive and analytical. Based on Mullā Ṣadrā's statements and making a final conclusion of his viewpoint, we could say that, firstly, there is no doubt that he endorses the principality of existence and concurrently consider existence as a secondary intelligible. Secondly, from the perspective of the writers, based on the fact that Mullā Ṣadrā not only acknowledges the attribution of the secondary philosophical intelligibles to be external, but also considers their occurrence as external, there is essentially no fallacy or contradiction remaining. Hence, there is no need to reject any one of Mullā Ṣadrā's ideas.