I must remind you that our credulity is not to be measured by the truth of the things we believe. When men believed that the earth was flat, they were not credulous: they were using their common sense, and, if asked to prove that the earth was flat, would have said simply, "Look at it." Those who refuse to believe that it is round are exercising a wholesome skepticism.
George Bernard Shaw (1856–1950), Anglo-Irish playwright, critic. (1916). Androcles and the Lion, preface, The Bodley Head Bernard Shaw: Collected Plays with their Prefaces, vol. 4, ed. Dan H. Laurence (1972).