My husband and I are locked, and he believes in aliens. Our son is currently into outter space stuff. So you can see where this is going. Help. That's what I want to do to my husband, give him the fish-eater smackdown. ;D
Believes in? Or is accepting of the possibility to a probable extent?
I'd ask "Where is the basis for this belief?". If the answer is not dangerous, then I'd leave it alone. How can one argue with such beliefs? If the answer is dangerous (in violation of known truths revealed), then I'd offer correction and leave it alone. One gets no where by arguing.
Of course, if someone did truly believe in such things, it would be a handy excuse. "Who ate all the cookies?!". "Aliens, they came and left in peace".
If that person believed, and there was no direct evidence to the contrary, how could that not be acceptable?
I don't suggest lying. That is just an example of the psychological effects. People believe in things like this because of curiosity and awe, not because of something meaningful. Even if there are aliens, we have to do the same things anyway and it is a sign of time and comfort for speculation.