First Part of Spinoza’s Ethica: Concerning God
III. God is Substance. Substance is God.
1. God possesses infinite attributes (Def. VI).
2. Substance possesses infinite attributes (Prop. VIII-X).
3. God is a substance (Def. VI).
4. There is only one substance (Argument II).
5. God and substance are identical (Prop XI).
Corollary: God exists necessarily (Prop. XI).
There is a subordinate step that Spinoza does not state specifically:
4a. There is only one set of infinite attributes.
If we accept Def. VI. of God and the the preceding two arguments as well as the idea that there is only one set of infinite attributes there are no logical faults in this third argument. We do not even need to try to understand what is an infinite attribute or an infinite and eternal essence. This a pure equivalence of stipulative definitions of the form "If a=b and b=c then a=c" where "a," "b," and "c" can stand for pretty much anything.
But arguments I and II are not valid. Therefore argument III and particularly the corollary that God exists necessarily is also invalid. [ Next ]