Some say there’s a default position in the great debate and there is; yours!
1) There can be no evidence for deity, therefore, Atheism isn’t based on evidence.
2) Logic doesn’t entail truth, therefore, Atheism isn’t proved by logic.
3) Logical conclusions are accepted and rejected outside of logic, therefore, reasonableness is the basis of Atheism.
4) Reasonableness entails to experience, intuition, risk, and utility, therefore, Atheism relies on the rational and irrational.
5) Since there is no evidence for God, then there can only be a sense about God, therefore, Atheists have a different sense about God than others.
Now for the chest-puffing Theist, re-read all of the above and change “Atheism” with “Theism” and “Atheist” with “Theist”.
For both balking currently, simply answer this:
There are two universes identical in every way, except one has a God and the other doesn’t. You find yourself in one of these universes. How do you tell which?
You might say that no universe can exist without God, but you’d realize you have no basis of fact for that even in theory. You might say that no universe requires a God at all in order for things to be just as they are, but you’d realize here too, there’s no basis of fact. Eventually you’d also realize that even if you discovered how universes come to be, it still wouldn’t settle the question. You realize you’re going to have to find another way to solve the problem.
Since both universes are identical, each has life, morality, logic, maths, sunrises, and cute little bunnies, you realize there’s no feature of reality that can help with the problem. You scratch you head, then you say …