Many ancient believers of god used cognition to 'think' their way from belief to atheism. What initially seems a silly question to reason over, can actually destroy a whole theology.
Here is a question made famous by 'Saint' Thomas Aquinas, believers in a almighty god with unlimited ability, please have a think about this....
The OMNIPOTENCE PARADOX:
"Could an omnipotent being create a stone so heavy that even he could not lift it?"