The question therefore becomes; which assumptions do we make? Personally, I attempt to be parsimonious in my assumptions as this leaves the smallest possible window for error, reduces dissonance, and eliminates redundancy. Within this framework, and relating back to your OP, the lack of evidence excises the claim. No evidence for the claim of god provides all that is necessary to not believe in god.
-Raithere
No evidence for the claim that God is not is thus all that is necessary to believe in God?
-Raithere
No evidence for the claim that God is not is thus all that is necessary to believe in God?