Here’s why you should be. I’ve taught existentialism in the context of literature for a number of years. I’ve looked for its “roots” in places as different (and old) as Dostoevsky and Ortega y Gasset. And in the course of doing some research on the ontological argument for a talk on Descartes I’m giving tomorrow, look at what I found:
According to Mulla Sadra, “existence precedes the essence and is thus principal since something has to exist first and then have an essence.” (emphasis mine)
It is notable that for Mulla Sadra this was a question that specifically applied to God and God’s position in the universe, especially in the context of reconciling God’s position in the Qur’an verses cosmological philosophies of Islam’s Golden Era.
( Mulla Sadra was an Islamic philosopher from around 1600 AD, just a tad before Dosteoevsky…)