is a classic thought experiment in quantum physics. Simon's description is almost completely accurate, but it fails in that the life or death of the cat is left up to the cat's choice of "to eat or not to eat" the poison fish. The woman he approaches spots this flaw, in fact. In a properly constructed experiment, all choice is left out of it, and the release of a poison gas which kills the cat if it is released is left to totally random chance, as by a geiger counter receiving a certain number of clicks from a mildly radioactive material also in the box. The state of the cat is also not, as suggested by Simon, left to the observer's choice, but left to the observer to discover, which is not the same thing at all. The key issue here is that the cat is in what is called an "indeterminate state", neither alive nor dead (or both at once, if you prefer) until the observer accesses the box in some fashion to determine the fate of the cat. It is the action of observation which seals the fate of the cat. It seems very counterintuitive, but there are many experiments on the microscopic scale which demonstrate the validity of the concept. In real life, such situations are impossible to create on a "macro" scale, which is why we never experience such things, and it seems to run against common sense.