A non-believer is generally a person who does not believe in God. It may also mean a person who doesn't believe in the God of your chosen religion. My personal belief is that a person cannot be a real believer unless they follow God, and the philosophy and way of life inevitably flows from that.
People can believe or not believe in lots of things, but a non-believer in this context doesn't believe in a god/gods. There can't be any half-measures. If there were the subject wouldn't be a non-believer - he'd be a 'don't know'.
Non-belief does not preclude the possibility that what one does not believe might nevertheless exist. It is at the point of believing that one no longer qualifies as a non-believer. Regarding any specific issue one is either a believer or a non-believer. There is no fence to sit on.
For me I'm a non-believer for the simple reason : there is no testable proof . Billions of prayer are offered up every day and have been for millennia , with the same result ,when objectively tested they fail !
Old Geezer That's true but by using some of your five senses you can discover the truth. Whereas none of your senses can prove a God exists. The reverse is the case . Of course it depends on what you define as proof. A theist sees proof everywhere . If something/anything exists that in itself proves to a theist God also exists. There is no answer to that
illogicality as you can't prove or disprove something that is only imaginary in the first place.