I'm not particularly worried about truth.
An odd thing for a person who revels in the pursuit of knowledge, I suppose. But my early training taught me to question everything, and while in most people I think this usually leads to a quest for pure facts, in me it produced a rather blasé attitude toward the truth. If everything could be wrong, why commit to one thing and call it a fact? The idea that absence of proof is not proof of absence allows us to consider the possibility of almost anything.
I also don't particularly worry about belief. I don't believe in much, but I do love to think things, which is almost like believing. Take, for example, this photograph of a herd of unicorns on the hill across from my house:
Of course, I know they're probably horses, and I could always hike over there and prove that they are horses. But I really enjoy thinking that they are unicorns. If you pinned me down (I'd give you a good fight, but I'm out of practice so you might try it) I'd probably admit that I don't actually believe in unicorns. But should silly little things like truth and belief get in the way of my enjoyment?
That's one of the things I love most about writing fiction – and reading it, for that matter. I can wholeheartedly believe in something I know isn't true.
What do you believe in, or pretend to believe in, or wish you could believe in, even though you know (or assume) it isn't true?