The real work of scientists
[Karl Popper] realized that the real work of scientists is not to look for evidence that their theories are correct, but to look as hard as they can for evidence that their theories are false. The closest a scientist can ever come to proving that his or her theory is true is failing to find evidence that the theory is false. Popper used this same theory to argue that astrology, metaphysics, Marxist history, and Freudian psychoanalysis were not sciences because there is no way they could ever be falsified.
The Writer's Almanac on July 28th, 2013