1934–1996 · American astronomer and science communicator
Carl Sagan spent the last years of his life arguing, in The Demon-Haunted World and on television, that wanting something to be true is not evidence that it is — so a slogan that says exactly that in eight words is going to end up with his name on it. He is the patron saint of a certain kind of hopeful scepticism, and hopeful sceptics need a motto. The irony is that his own version is better and is fully sourced to a page number, and almost nobody quotes it.