Sean Carroll

That's good for traditional measures of scientific simplicity.

The fewer postulates, the fewer axioms you have for your theory, the better.

It's bad for the philosophical task of connecting the formalism to reality, right?

Because whatever it is saying is, you know, I just trust the equations.

They're telling me what happens.

And as long as I interpret who I am in the equations correctly, I'm going to fit the data.

But that interpretation of who you are in the wave function is a highly non-trivial thing.

That requires a little bit of work.

So, Everettian quantum mechanics is much more philosophical heavy lifting than Copenhagen or really any other version of quantum mechanics.

Well, it's—sorry, I shouldn't say that.

There's different philosophical heavy lifting in Copenhagen.

You have to disbelieve in reality until you actually measure something, which is even arguably a heavier lift.

But it's a different kind of heavy lift, philosophically speaking.

Okay, so that's the minimal introduction to Everettian quantum mechanics, but that's not where I want to dwell here.

I want to talk about sort of good old textbook quantum mechanics because I've been saying something over and over again, and maybe it's been bugging you or maybe it hasn't, but it's certainly something you should think about.

Okay.

I said that the wave function of, let's say, go back to a single electron, don't worry about entanglement or observers or anything like that.

Again, textbook, simple, undergraduate, first semester, quantum mechanics.

I said that the wave function assigns a number, a complex number as it happens, to every possible measurement outcome.

But then what I spoke of was measuring the position of the electron.