Distinction between Existence and Essence According to Ibn Sina and Suhravardi

In the history of Islamic Philosophy Ibn Sina and Farabi are known to be originator of the distinction between existence and quiddity. In the philosophy of these two philosophers the distinction of existence and quiddity is used as a proof for the existence of God who is the end of the first philosophy. According to Ibn Sina positively this distinction is based on essential possibility and necessity by something else and this is also is based on a division of existent into necessary and possible being. It is here that the discussion about occurance of existence to quiddity is propounded. Shayh by anticipating what later his predecessors including Ibn Rushed have propounded sometimes has considered this occurrence in view of conception the opposite of essential in the chapter of Isagogue and sometimes has also regarded the connection between existence and quiddity of the kind of relation. But in view of instance (in outside) has considered existence and quiddity as a unified thing.The distinction between existence and quiddity is not propounded in illuminist philosophy in relation to the distinction between necessary and possible being and effective in proving the existence of the Most High. Suhravardi by his own explicit assertion considers the prepatetic philosophers as holding to a distinction between external existence and essence and for this reason has objected to them. But what he has in mind of existence, unlike what prepatetic philosophers have in view, is the concept of existence not the truth of existence.