"The only certainty is that nothing is certain. (Fuller version: This series of instances entangles unforeseeing mortality, so that among these things but one thing is in the least certain—that nothing certain exists, and that nothing is more pitiable, or more presnmptuous, than man! In Latin: Quae singula inprovidam mortalitatem involvunt, solum ut inter ista vel certu(m) sit nihil esse certi nec quicquam miserius homine aut superbius. Some sources have "certu", others "certum".)"