There may be fairies at the bottom of the garden. There is no evidence for it, but you can't prove that there aren't any, so shouldn't we be agnostic with respect to fairies?
“I don't want to think about how many people have thought or still think that I'm crazy.”
“Money is the root of all evil, and yet it is such a useful root that we cannot get on without it any more than we can without potatoes.”