Debate with Puritan Lad

I am having a debate with Puritan Lad on his blog. I am frustrated by his lack of ability to see the flaw of his proof.

Premise 1: If the human mind can obtain meaningful knowledge, the God exist, since God is the precondition for meaningful knowledge.

Premise 2: The human mind can obtain meaningful knowledge.

Conclusion: God exists.

The following will be my last attempt to get him to understand the flaw.

Premise 1: If the human can shit, Zeus exist, since Zeus is the precondition for shitting.

Premise 2: The human can shit.

Conclusion: Zeus exists.