"Not a day goes by without our using the word optimism, coined by Voltaire against Leibniz, who had demonstrated (in spite of the Ecclesiastes and with the approval of the Church) that we live in the best of possible worlds. Voltaire, very reasonably, denied that exorbitant opinion... Leibniz could have replied that a world which has given us Voltaire has some right to be considered the best."
January 1, 1970
https://en.wikiquote.org/wiki/Voltaire