The Coming of the Quantum Cats can - given different social conditions - develop completely different character traits (timid or assertive, benevolent or predatory, etc.) The title refers to the famous thought-experiment known as "Schrödinger's Cat", where the outcome of a real-world event depends on a quantum event. By some interpretations, the real-world object, in this case a cat, must be in two states simultaneously until it is observed. However, the story is more closely related to the many-worlds interpretation of quantum mechanics where all possible outcomes of an event occur, each in its own parallel universe. The same concept was treated, somewhat more pessimistically, in
Introduction to quantum mechanics its twin had revealed. In trying to show that quantum mechanics was not a complete theory, Einstein started with the theory's prediction that two or more particles that have interacted in the past can appear strongly correlated when their various properties are later measured. He sought to explain this seeming interaction in a classical way, through their common past, and preferably not by some "spooky action at a distance." The argument is worked out in a famous paper, Einstein, Podolsky, and Rosen (1935; abbreviated EPR), setting out what is now called the [[EPR paradox]]. Assuming what is now usually called