this one's interesting and true I suppose. if I believe that I can fly of my own volition because i want to be able to fly then i'm only believing in that because i desire it to be true. belief is when you believe it to be true for the truth of it, not because you want that reality to be true. i suppose if you believe something to be true strictly because you want it to be could lead to insanity or one-sided vision? if i believe in aliens from other planets and i want them to exist then i may see something in the sky and my opinion or belief would get stronger because that affirms my beliefs. if i was looking for the truth i would look at all possibilities. rationality i suppose?