Sean Carroll

It's not the three-dimensional space in which we live.

So you're allowed to think of wave functions as living in, as functions of configuration space.

And some people take that super-duper seriously, and they talk that way.

Configuration space is very big.

You know, Avogadro's number, which is the number chemists and physicists throw around for

the approximate number of particles in a macroscopic thing, really just like a gram of something, not a big thing, but a pretty big thing compared to an atom.

What is it?

Six times 10 to the 23, a big, big number.

So six times that is the size of the number of dimensions of configuration space.

for Avogadro's number of particles.

So configuration space is a giant thing.

And the fact that this is one of the steps, one of the stops at which people get off the bus about realism of the quantum wave function, because people feel a deep-seated need to think that things live in space.

This is one of Einstein's points of view.

Like, I'm very pro-Einstein.

I think that he had a lot of good ideas about quantum mechanics.

But one of the things that I think I would disagree with him, if we could conjure up his spirit here,

is that he really was devoted to things having locations in space.

And I think this is exactly what quantum mechanics says doesn't happen.

The closest you can do is to say that wave functions have values as a function of configuration space for many, many particles, okay?

And that's weird enough.