h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

The experiment was that you had a small amount of a radioactive isotope in the box, which had a possibility of decaying., If it decays then it emits a neutron, which breaks a small vial of deadly poison, killing the cat. If you tried to kill the cat with some energy sensitive isotope (which seems a bit dubious anyway) then you'd have to wait till it starved for it to die.

Anyway, Schroedinger continued by saying that the cat existed, until you could observe it, as both a 50% chance of a dead cat, and a 50% chance of an alive cat. When you open the box and observe the cat the probablities resolve into either an alive or dead cat. He was trying to make a point about just how weird the quantum world is.

Here's an experiment that actually works, to show much the same thing:
If you pass a beam of light through two very narrow, parallel slits you get a pattern of bands, where the light from each slit overlaps and either builds up (to make bright bands) or cancels out (to make dark ones). Now, if you reduce the amount of light passing through, until you pass one photon (the quantum particle of light) through at a time you still get these bands!!! There is only one particle, so how do you still get the bands caused by the two beams of light interfering? It turns out that the photon 'splits' to form two 50% chances of a photon passing through each slit, and these chances interfere to form the patterns! What's more, you can't tell which slit the photon passes through, and if you set the experiment up so that you can observe which slit it goes through, the interferance patterns dissapear!

Why is it no one seems to be aware that the solution to all these quantum puzzles is to take an antirealist view. I.e "science does not tell us what nature is, instead it tells us what we can say about nature" and "the atom is not a thing, and "no phenomenon is a real phenomenon until it is an observed phenomenon". Attributed to Niels Bohr the father of modern quantum physics (exact wording not checked).

So only a realist has a problem with S's cat because she keeps persisting in wanting to know about something which has not yet been observed. An antirealist waits to see what state the cat is in when she observes it. Similarly for wave particle duality. People used to ask Bohr; is an electron a particle or a wave? He used to answer: "the problem with this question is the word "is" what do you mean by "is""?

So that's it folks; problem solved! (heh, heh.)

For further illumination of antirealism see the writings of The Good Bishop; George Berkeley 17th C(?) philosopher. He said "esse est percipi" (to be is to be percieved} and "there is no corporeal matter behind perceptions".