Thursday, March 26, 2009

Science: Bell's inequality the most profound fact ever discovered?

In response to this post ("Quantum theory: Finally facing up to its threat to special relativity"), friend Malcolm Chisholm writes to say:
I have been wondering when you would blog about Bell's inequality.

Bell's Inequality has its foundation in traditional logic (stuff developed by the scholastic guys of the Middle Ages). It states the following

The number of objects which have parameter A but not parameter B plus the number of objects which have parameter B but not parameter C is greater than or equal to the number of objects which have parameter A but not parameter C.

So for instance, if you have a class of students, then

The number of girls who are not blond plus the number of blond students who are under six feet tall must be greater or equal to the number of girls who are under six feet tall.

This will always be true. It is amazing. You can do it for all kind of populations that possess 3 attributes in the macroscopic world that we inhabit. And yet it can be applied to the domain of quantum entanglement to prove that everything in the universe is utterly connected at a very fundamental level. It really is the most profound fact ever discovered in science

Here is a link for
more (and it's Canadian!).
Well, he knows how I will love that!

If Bell's inequality is indeed the most profound fact ever discovered in science, it is interesting (at least to me), that Bell started out wanting to disprove it. He was a follower of Einstein and shared the Einsteinian suspicion of quantum physics.

I read his book and toward the end he finally concedes defeat, in the nicest possible way. I recall it as somewhat touching.

Here's more about Irish physicist John Bell, pictured above. Here are his collected works, Foundations of Quantum Mechanics.