The Schroedinger’s Cat thought experiment was created because Austrian Physicist Erwin Schroedinger along with the supporters of the EPR (Einstein Podolsky Rosen) paper did not agree with the Copenhagen Interpretation of Quantum Mechanics on how quantum mechanics describes the macroscopic world. The EPR paper argued against the completeness of quantum mechanics, much like Schroedinger did, by stating that without interfering with a system, the value of physical quantity can be predicted with confidence. Schroedinger’s argument was different from the EPR supporter’s, but they both pursued the purpose of proving the Copenhagen Interpretation and its leader, Physicist Neils Bohr, wrong [6] [16].

It should be noted that Schroedinger's Cat is a thought experiment and not an actual experiment. A thought experiment is an experiment that someone imagines using previously researched information to exemplify the hypothesis. An actual experiment is when the actual experiment is carried out in reality [17]. No cat has been harmed.

In the Schroedinger's Cat thought experiment, a cat was placed in a lead box containing a radioactive substance that was connected to a Geiger counter. If the Geiger counter detects radioactive decay from the substance, a hammer breaks a vial filled with hydrocyanic acid. This experiment is, of course, protected from direct interference from the cat, which would break everything inside at the first opportunity. This would disrupt the course of the experiment [7].

There are three possible outcomes from this experiment: it is observed and the cat is alive, it is observed and the cat is dead, and it is not observed and the cat is both alive and dead.

In the first outcome, the cat has a 50 percent chance of being alive if it is observed. Until the cat is observed, or measured, the cat is not real according to wave-function collapse, a concept of the Copenhagen Interpretation which introduced the role of the observer in the event [7]. The second outcome is when the cat has a 50% chance of being dead if it is observed by virtue of wave-function collapse. The final outcome is when the cat is not observed. Because the cat is not observed, all possible paths can occur and superposition is evident [9] (Mouseover image to start animation).

Superposition is a principle showing the overlap of waves and states, something being in two states at once, an atom being decayed and not decayed, a cat being alive and dead, which is highly improbable. After all, the whole idea of Schroedinger's Cat was to show how improbable the Copenhagen Interpretation was, saying that the superposition of a cat being possible. This was meant to show how, in terms of wave function collapse of the Copenhagen Interpretation, how the cat would collapse into a definite state at the precise moment of it being measured [13].

That is the problem with applying a microscopic principle to the macroscopic world. That was Schroedinger's point!

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