This happens to me every time someone asks me to explain what I believe. I say "uhhh..."
I try to ask people to be more specific (what do you believe about this particular topic)
If they don't, I just tell them I believe human rationality can come to an understanding of everything, and can at least attempt to account for the things it doesn't understand. I may be wrong, but it's so damn hard to start from nothing, even if you do know everything (which I don't).
Since Robert Pirsig put this very well, I’ll just copy down what he said. I don’t know if this story is based on reality or not, but either way, it’s true.