"This system, although it clashes with those ideas of ours that the end can be no other than good, is probably more sustainable than that of Leibniz, Pope, etc., that everything is good. I would not dare however to go on to say that the universe which exists is the worst of possible universes, thereby substituting pessimism for optimism. Who can know the limits of possibility?"
January 1, 1970
https://en.wikiquote.org/wiki/Philosophical_pessimism