Sean Carroll

So there's absolutely physics behind these facts, these statements.

They're not made up.

You can find explanations in, for example, my first volume of the Biggest Ideas in the Universe book, Space, Time, and Motion.

I do not say that space and time switch roles inside a black hole.

That's not something that I say.

People say that.

I disagree with them.

Time is time.

Space is space.

What switches roles are the coordinates that we use to describe space and time, but who cares about that?

You don't have to choose coordinates that switch roles.

So I wouldn't ever say that.

But

I would say that the Big Bang is a singularity which is a moment in time in the past, and in black holes, in Schwarzschild black holes, in non-spinning black holes, when they spin and they have electric charge, things get more complicated.

But in the simplest Schwarzschild black hole, it's just a mathematical fact that the singularity is indeed in the future.

Schleyer says, do branches of the Everettian multiverse contain the full possibility space of evolution?

So I'm not sure by evolution whether you mean the evolution of the dynamical system called the universe or something like natural selection and Darwinian evolution.

But in either case, the answer is no, they don't.

The branches of the Everettian multiverse contain what is predicted by the Schrodinger equation, whatever that turns out to be.

There might be examples that just don't happen, right?