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?
“Because of the increase in life longevity, America can now assume that at any given time three, and perhaps four, former presidents will still be alive, even when the current president is occupying the White House.”
“Always speak the truth, think before you speak, and write it down afterwards.”