ens a se (Latin ‘a being from itself’), a being that is completely independent and self-sufficient. Since every creature depends at least upon God for its existence, only God could be ens a se. In fact, only God is, and he must be. For if God depended on any other being, he would be dependent and hence not self-sufficient. To the extent that the ontological argument is plausible, it depends on conceiving of God as ens a se. In other words, God as ens a se is the greatest conceivable being. The idea of ens a se is very important in the Monologion and Proslogion of Anselm, in various works of Duns Scotus, and later Scholastic thought. Ens a se should be distinguished from ens ex se, according to Anselm in Monologion. Ens a se is from itself and not ‘out of itself.’ In other words, ens a se does not depend upon itself for its own existence, because it is supposed to be dependent on absolutely nothing. Further, if ens a se depended upon itself, it would cause itself to exist, and that is impossible, according to medieval and Scholastic philosophers, who took causality to be irreflexive. (It is also transitive and asymmetric.) Hence, the medieval idea of ens a se should not be confused with Spinoza’s idea of causa sui. Later Scholastics often coined abstract terms to designate the property or entity that makes something to be what it is, in analogy with forming, say, ‘rigidity’ from ‘rigid’. The Latin term ‘aseitas’ is formed from the prepositional phrase in ‘ens a se’ in this way; ‘aseitas’ is translated into English as ‘aseity’. A better-known example of forming an abstract noun from a concrete word is ‘haecceitas’ (thisness) from ‘haec’ (this). See also ANSELM, DIVINE ATTRIBUTES , DUNS SCOTUS , PHILOSOPHY OF RELIGIO. A.P.M.