Ontological Explanation of " Predication" in Mulla Sadra and Allameh Tabatabaei's points of view

This paper intends to find an answer to the problematic description of the difference between Mulla Sadra and Allameh Tabatabaei’s views on the ontological explanation of “predication” and also، tries to find the origin of this difference. Since subject and predicate are different degrees of one existence in Mulla Sadra’s philosophical structure، the reality of predication is the union of two things with one existence; moreover، the sufficient condition for a valid predication is a kind of causal relation between subject and predicate. But in Allameh’s philosophical structure، the in-itself existence of the subject differs with the predicate’s one; so، they are not unitary existence. But the “existence for something-else” of predicate is united in “existence foritself” of subject and makes a relationship between them through copulative existence.