Key Arguments

• Denying God as cause of essences would imply essences can be conceived without God, which contradicts that all things are in and conceived through God (Prop. XV)
• From Prop. XVI: given the divine nature, both essence and existence of things are inferred; hence God is the cause of all things as he is of himself
• Corollary: individual things are nothing but modifications of divine attributes expressed in a fixed and definite manner

Source Quotes

XXV. God is the efficient cause not only of the existence of things, but also of their essence. Proof.—If this be denied, then God is not the cause of the essence of things; and therefore the essence of things can (by Ax. iv.) be conceived without God.

God is the efficient cause not only of the existence of things, but also of their essence. Proof.—If this be denied, then God is not the cause of the essence of things; and therefore the essence of things can (by Ax. iv.) be conceived without God. This (by Prop. xv.) is absurd. Therefore, God is the cause of the essence of things.

This will be made still clearer by the following corollary. Corollary.—Individual things are nothing but modifications of the attributes of God, or modes by which the attributes of God are expressed in a fixed and definite manner. The proof appears from Prop. xv. and Def. v.

Key Concepts

• God is the efficient cause not only of the existence of things, but also of their essence.
• If this be denied, then God is not the cause of the essence of things; and therefore the essence of things can (by Ax. iv.) be conceived without God. This (by Prop. xv.) is absurd.
• Individual things are nothing but modifications of the attributes of God, or modes by which the attributes of God are expressed in a fixed and definite manner.

Context

Ethics I, PROPOSITION XXV with proof, note, and corollary (lines 304–435)