'The Fundamental Truth of Christian Philosophy': The Identity of Existence and Essence in God

'The Fundamental Truth of Christian Philosophy': The Identity of Existence and Essence in God

Part One: The Text

From the young St. Thomas' book, On Being and Essence, ch. 4:

[Argument for the Real Distinction, in Angels, between Essence and Existence.] Although substances of this kind [i.e., 'separate substances', or angels] are form alone and are without matter, they are nevertheless not in every way simple, and they are not pure act; rather, they have an admixture of potency, and this can be seen as follows. Whatever is not in the concept of the essence or the quiddity comes from beyond the essence and makes a composition with the essence, because no essence can be understood without the things that are its parts. But every essence or quiddity can be understood without understanding anything about its existence: I can understand what a man is or what a phoenix is and nevertheless not know whether either has existence in reality. Therefore, it is clear that existence is something other than the essence or quiddity...


[Argument for the Possibility of Only One Being Whose Essence and Existence are Identical.] ... [U]nless perhaps there is something whose quiddity is its very own existence, and this thing must be one and primary. For, there can be no plurification of something except by the addition of some difference, as the nature of a genus is multiplied in its species; or as, since the form is received in diverse matters, the nature of the species is multiplied in diverse individuals; or again as when one thing is absolute and another is received in something else, as if there were a certain separate heat that was other than unseparated heat by reason of its own separation. But if we posit a thing that is existence only, such that it is subsisting existence itself, this existence will not receive the addition of a difference, for, if there were added a difference, there would be not only existence but existence and also beyond this some form; much less would such a thing receive the addition of matter, for then the thing would be not subsisting existence but material existence. Hence, it remains that a thing that is its own existence cannot be other than one, and so in every other thing, the thing's existence is one thing, and its essence or quiddity or nature or form is another. In the intelligences, therefore, there is existence beyond the form, and so we say that an intelligence is form and existence.

[Argument for a Being Whose Essence and Existence are Identical, i.e., God.]  Everything that pertains to a thing, however, either is caused by the principles of its own nature, as risibility in man, or else comes from some extrinsic principle, as light in the air from the influence of the sun. Now, it cannot be that existence itself is caused by the very form or quiddity of the thing (I mean as by an efficient cause), because then the thing would be its own efficient cause, and the thing would produce itself in existence, which is impossible. Therefore, everything the existence of which is other than its own nature has existence from another. And since everything that is through another is reduced to that which is through itself as to a first cause, there is something that is the cause of existing in all things in that this thing is existence only. Otherwise, we would have to go to infinity in causes, for everything that is not existence alone has a cause of its existence, as said above. It is clear, therefore, that the intelligences are form and existence and have existence from the first being, which is existence alone, and this is the first cause, which is God.

(See Part Two)