When my information changes, I alter my conclusions. What do you do, sir?
— John Maynard Keynes
Reply to a criticism during the Great Depression of having changed his position on monetary policy, as quoted in A Treatise of Melancholie (1940) by Timothie Bright, page 24. (Later books have altered this quotation to, "When the facts change, I change my mind. What do you do, sir?")