I do not pretend to be able to prove that there is no God. 

I equally cannot prove that Satan is a fiction. 

The Christian god may exist; 

so may the gods of Olympus, 

or of ancient Egypt, 

or of Babylon. 

But no one of these hypotheses is more probable than any other:

 they lie outside the region of even probable knowledge, 

and therefore there is no reason to consider any of them.