- Even outside of quantum computers, some of the theories that we've been talking about, what's your hope, what's most promising to test these theories? What are kind of experiments we can conduct, whether in simulation or in the physical world, that would validate or disprove or expand these theories? - Well, I think there's two parts of that question.

One is many worlds, and the other one is sort of emergent space time. For many worlds, there are experiments ongoing to test whether or not wave functions spontaneously collapse. And if they do, then that rules out many worlds, and that would be falsified. If there are hidden variables, there's a theorem that seems to indicate that the predictions will always be the same, as many worlds.

I'm a little skeptical of this theorem. I'm not completely, I haven't internalized it. I haven't made it in part of my intuitive view of the world yet. So there might be loopholes to that theorem. I'm not sure about that. Part of me thinks that there should be different experimental predictions if there are hidden variables, but I'm not sure.

But otherwise, it's just quantum mechanics all the way down. And so there's this cottage industry in science journalism of writing breathless articles that say, quantum mechanics shown to be more astonishing than ever before thought, and really, it's the same quantum mechanics we've been doing since 1926. Whereas with the emergent space time stuff, we know a lot less about what the theory is.

It's in a very primitive state. We don't even really have a safely written down, respectable, honest theory yet. So there could very well be experimental predictions we just don't know about yet. That is one of the things that we're trying to figure out. - But for emergent space time, you need really big stuff, right?

- Well, or really fast stuff, or really energetic stuff. We don't know. That's the thing. So there could be violations of the speed of light if you have emergent space time. Not going faster than the speed of light, but the speed of light could be different for light of different wavelengths, right?

That would be a dramatic violation of physics as we know it, but it could be possible. Or not, I mean, it's not an absolute prediction. That's the problem. The theories are just not well-developed enough yet to say. (silence) (silence) (silence) (silence) (silence) (silence) (silence)