But having the cat’s information in two places—inside and outside the black hole—violates another rule of quantum theory: quantum information can’t be copied. Not only is quantum information never destroyed, it can never be cloned. This is counterintuitive. I can copy information onto a hard drive. I can lose, or destroy, that drive. But my file consists of classical bits, which record classical information. Quantum information, however, is different from classical, and this raises the ante in the conflict between general relativity and quantum theory.
