Philosopher Steven Hales has written an article disproving the myth, “You Can’t Prove a Negative.”
Abstract: It is widely believed that you can’t prove a negative. Some people even think that it is a law of logic—you can’t prove that Santa Claus, unicorns, the Loch Ness Monster, God, pink elephants, WMD in Iraq and Bigfoot don’t exist. This widespread belief is flatly, 100% wrong. In this little essay, I show precisely how one can prove a negative, to the same extent that one can prove anything at all.