Mock dialogue of the Theist/Atheist discussion here.

[Mystic]

Your argument was this:

Atheists use their reason to accept all sorts of reasonable arguments for other things.
They don't accept it for God, it must be because those arguments don't work in the case of God (ie. they aren't reasonable)

This is incorrect.

The other existential claims I accept I do so based on demonstrable and falsifiable evidence, reasoned argument and valid/sound logic.

The arguments for existence of a god does not meet the above criteria. 

If the existence of a god met the criteria that I use for other claims, I would accept the claim.

I can't refute what you said. However I think you misunderstood by "they", I meant the arguments. Basically the arguments that are use to argue for God are not reasonable. To infer that due Atheists accepting reason in other places means they would accept it if it proved God...by analogy one can say if all reasons to dismiss things like FSM or invisible dragon can be used to dismiss God....they should all dismiss God by the same reasons.

So it seems neither of us accept this line of reasoning.