A conceptualist argument for God is a form of transcendental argument that claims propositions, which must exist, require a mind that also must exist. It has been used by various philosophers including Alvin Plantinga. The argument was criticised by Quentin Smith who argued it was not rationally compelling. 
"How could there be truths totally independent of minds or persons?... How could the things that are in fact true or false—propositions, let’s say—exist in serene and majestic independence of persons and their means of apprehension? How could there be propositions no one has ever so much as grasped or thought of?"
- "Concepts existed before us. Concepts require a mind. That mind is God. "
- All propositions are cause by an existent mind (conceptualism).
- Propositions, which are statements that are either true or false, exist in every possible world (actualism).
- Therefore, at least one mind exists in every possible world.
- Some possible worlds contain no non-divine minds.
- Therefore, God is the only mind that exists in every possible world.
- God exists.
The premises, particularly that of conceptualism, are difficult to establish and may be fundamentally beyond potential human knowledge. The argument depends on them and lead to a highly uncertain conclusion.
"I don't think it is a good argument because I agree with the Neutralist on this. I don't see any reason to think that the truth of 2+2=4 commits you to the reality of 2+2 or 4."
Proof by logic
- Main Article: Proof by logic
This argument defines God into existence. This is not a reliable way to establish if an a posteriori statement is true.