Sean Carroll

And if you've ever taken a chemistry class and you've learned about the orbitals of different electrons and atoms, really those are all just different solutions to Schrodinger's equation.

And it all fit the data very nicely, you know, because electrons could go from one energy level, one orbit to another one and emit certain amounts of light.

And we observed exactly those amounts of light in the spectrum of the various substances.

And so it's quantitatively super duper successful.

The problem is, of course, that when we

look at electrons, we don't see the wave function.

We see a dot.

We see the electron located at a point.

And this is all of the mystery of quantum mechanics.

The way that we explain what electrons or other things, everything is quantum.

The way that we explain what these things are is different than how they appear to us when we measure them.

So we teach our students something like that Copenhagen interpretation that I referred to that says that electrons behave in one way,

When you're not measuring them, that is to say they obey the Schrodinger equation and they settle into orbitals in atoms and so forth.

But then when you look at them, you need a whole other set of rules.

When you make a measurement, when you observe them, you see a dot.

You can't predict exactly where the dot's going to be.

What you can do is predict the probability of the dot being there.

And that measurement that you did radically changes the state of the electron.

We call that the collapse of the wave function.

Now, as I said in the intro, these ideas, these concepts that are playing a crucially important role here are not well-defined.