I’m often asked to explain the principle of Heisenberg’s Uncertainty Principle and the associated paradox of Schrödinger’s Cat. (this is a lie). Anyhow, a while back it came up in a pub conversation (don’t ask) and I was put on the spot. This, ladies and gents, is quantum mechanics in a nutshell – and the way I’ve interpreted it since I was at school:
Imagine you’re walking along the road and you spot a hottie walking towards you. You really hope she’s checking you out (replace “she” with “he” if you like). Here’s the paradox: if you look at her, she will definitely look away, and you won’t know if she’s checking you out or not. Therefore she will only check you out if you don’t know that she’s doing it. As soon as you make the measurement, she’ll be looking the other way. Although at least this will mean you can ogle to your heart’s content.
This is the observer principle, closely related to the Uncertainty Principle, a basic principle of quantum mechanics, – that every measurement you make affects the result of the quantity being measured. The measurement here is whether the fit bird is looking at you; you make the measurement by looking; as soon as you make that measurement, the value itself is affected. If you hadn’t looked, then she might have been eyeing you up, but if you look at her, she’ll look away.
This is similar to Schrödinger’s Cat – that is, she’s in a superpositional state of both checking you out AND not checking you out, as long as you don’t look at her, in the same way that the cat is both alive and dead until you open the box.
As for me – my hunch is that I don’t need quantum mechanics to tell me that hot girls don’t give me the time of day, so I give them a good ogle and move on, as they stare at their toes, consoling myself that according to the laws of physics, she wouldn’t be looking at me even if I was Jude Law.