Schrödinger’s Uncertain Cat

William Blake said: “What is now proved was once only imagined.” Take Schrödinger’s Cat for instance.

It’s a nice cat. It lives in a box. Also sharing its box is a Geiger counter and a small amount of radioactive material. If the radioactive material decays by even as little as one atom, then a sprung hammer will be released, smashing into a vial of prussic acid, therefore killing the cat.

It’s okay. It’s not a real cat. It’s a hypothetical cat. Mr Schrödinger imagined it. He probably never had a real cat, and if he did, I’m sure he fed it on Whiskas and stroked it every day. As they say in the movies, “No animals were hurt in the making of this production.”

The thing is, you can’t know if the cat is alive or dead until you open the box, because you can’t know if the atom has decayed or not. Mr Schrödinger merely posited the cat as a way of highlighting the weird contradictions inherent in the world of Quantum Mechanics; that is, on the small scale of atoms and subatomic particles.

Is the cat alive or dead? Only the cat knows. And if you look, who is to say that your looking didn’t contribute to the result? Perhaps the cat is alive and dead at the same time.

Such are some of the theories being bandied about by Physicists, not so much about cats as about subatomic particles, which can apparently exist in two places at the same time, among a host of other strange qualities.

Is light made up of waves or particles? Actually it is both. It depends how you view it. With some devices it appears as waves, with others as particles. So it can be either a wave or a particles, or it can be both, or it can be neither, and nobody is really sure. In other words, the one constant in our universe, light – which always travels at the same speed, no matter where you go – is also paradoxical, meaning that it appears to be two contradictory things at the same time.

The same may be true of subatomic particles. If you fire a subatomic particle at a metal plate with two slits in it, the particle will pass through both slits at the same time.

It’s as if I threw a tennis ball at a wall with two windows and it broke both windows at precisely the same moment. It didn’t bounce. It must have turned into two balls, or spread itself out like a wave so that it could pass through both windows at the same time. But when it appears on the other side of the wall, it’s just one ball again.

This, of course, is a paradox. If you look at it in one way it appears as a particle. If you look at it another way, it appears as a wave. The very act of observing alters what is observed. The observer affects the observed. By looking at something we change it. This is known as Heisenberg’s Uncertainty Principle, and should be a lesson to anyone who ever believes they know the answer to anything.

Nothing is certain. A belief is just another way of viewing the world. By looking at the world through one particular belief system, you are affecting the world in some way. You are helping to confirm your belief, regardless of whether your belief is true or not.

Erwin Schrödinger won the Nobel prize for physics in 1933 for something we now know as Schrödinger’s Equation. It has nothing to do with cats. In later life he said he wished he’d never met that damned cat.