Erwin Schrödinger, the Nobel prize-winning physicist who bent our minds with his quantum mechanics theories, is being celebrated today with a Google Doodle. He's perhaps best known for his "Schrödinger's Cat" thought experiment involving a feline that's both alive and dead until its box is opened. Though it had nothing to do with his famous wave equations describing the energy levels of atoms, he used the metaphor to criticize an interpretation of quantum mechanics that was becoming popular at the time. It helped prove that a quantum system could exist in two states at once until measured, and he took pains to point out it was reductio ad absurdum and unrelated to cat murder. The creatures have enough to worry about, after all.