Actually your semantics here are causing problems, and you have set up an illogical double-standard. If by calling someone a Christian you are saying that by definition they must believe in God, then by the same token when you call someone an Atheist they must never believe in God. In the real world, Atheists become Christians and Christians become Atheists. We all have these choices. This is a non-point. Again, evidence is only stuff. What we decide based on that evidence is what we believe. Evidence doesn't = empirical proof. What do you mean "informally logical"?