The Original Schrödinger's Cat Revisited: Popular Reinterpretations

Schrödinger's Cat is commonly summarized as a cat that is “both alive and dead until observed.” This paper compares that familiar formulation with Schrödinger's original 1935 construction. The original passage contains a radioactive substance, the possibility that one atom decays or none does, the first atomic decay, a Geiger counter, relay, hammer, poison, and a cat inside a steel chamber. Schrödinger then states that the Psi-function of the entire system contains the living and dead cat “mixed or smeared in equal parts,” followed by a warning against naively accepting a “blurred model” as an image of reality. Several ideas commonly associated with the Cat therefore need to be distinguished: the physical state of the cat, the mathematical description of the system, the probabilities assigned to alternatives, and the information available to an outside observer. The popular Cat is a useful shorthand, but it is not identical to Schrödinger's original Cat.