I Tawt I Taw A Puddy Tat - Or Did I?

"One can even set up quite ridiculous cases. A cat is penned up in a steel chamber, along with the following device (which must be secured against direct interference by the cat): in a Geiger counter there is a tiny bit of radioactive substance, so small, that perhaps in the course of the hour one of the atoms decays, but also, with equal probability, perhaps none; if it happens, the counter tube discharges and through a relay releases a hammer which shatters a small flask of hydrocyanic acid. If one has left this entire system to itself for an hour, one would say that the cat still lives if meanwhile no atom has decayed. The psi-function of the entire system would express this by having in it the living and dead cat (pardon the expression) mixed or smeared out in equal parts.
It is typical of these cases that an indeterminacy originally restricted to the atomic domain becomes transformed into macroscopic indeterminacy, which can then be resolved by direct observation. That prevents us from so naively accepting as valid a "blurred model" for representing reality. In itself it would not embody anything unclear or contradictory. There is a difference between a shaky or out-of-focus photograph and a snapshot of clouds and fog banks."

These are the words of Erwin Schrödinger, Austrian scientist/theoretical physicist, who, in a sheer flash of brilliance, came up with one of my (and my feline-loving friend Jessa's) favorite theories! For those of you who just skimmed, Schrödinger claimed that if he built the device described, then the cat would have an equal chance of living or dying. That's the "magic" of quantum mechanics, you see.

Although no Hugh Everett, Schrödinger's theory may have set the whole ball rolling. Why not, I suppose, have the cat's chances at living or dying expressed simultaneously? Can it be done? In our universe, if the cat has died, could it be alive in another? What is the true reality here?

For those of you who know Neils Bohr's Copenhagen observation: dis-proved! According to Bohr, the cat would remain both dead and alive until the box is opened and it is observed. That was the way of the Copenhagen observation: particles could be in several places at once until they were observed; during observation, they'd be as still and unipresent as lambs. Sure.

The multiversal element wasn't brought in until 1957, when personal hero Hugh Everett suggested it (he said that once the cat was observed, the two elements split the box-and the observer-from each other in a decoherent universal state, with no interaction). The multiversal theory has been expounded on since then, but Schrödinger's cat will, to me, be one of the commanding factors in multiversal physics.

This information is largely from a ThinkTV report that I memorized from a few months ago. Praise PBS!