No reason justifies disbelief.

[fredd bear]

Some things are known through logic. Then you can hold them up to the real world and see if they're compatible. But it may be that no certainty is possible.

How could one learn anything about the existence of a god through logic alone?  You'd have to define god first, which would require that you know something about him.

 Logic 101 : Logic is not used as a general way or arriving at truth.   Contrary to Mr Spock, logic dictates nothing , it implies, or suggests .

 All formal logical argument begins with IF A-----------

An inference  (logical conclusion) may be declared as true IF AND ONLY IF the premise is also true. I.E. IF A is true--then a truth claim may be inferred (concluded), but not otherwise 

The claim that "some things are known through logic" is technically correct, but disingenuous. It, gives the false impression that logic is commonly used to arrive at a truth .