Adam Brown

So...

This duality idea where you have two different descriptions of the same thing is not – the ADS-CFT was not the first such example in physics.

It's a common trope in physics that you can have two different descriptions of the same thing, some of which are more useful in one scenario, some of which are more useful in the other scenario, but which are both exactly correct.

And there are non-gravitational examples in physics that go back a long way.

You may then ask, you know, which one is right and which one is not right.

Yeah.

Is it actually a CFT that has this weird alternative description as a gravitational theory, or is the gravitational theory correct and the other one's not correct?

I think this is more of a philosophical question.

My answer would be is if the isomorphism was just an approximation, like it was really one thing and you were just pretending it was the other thing and that approximation worked in some region of validity and not others, then I would say that the

that one was right and the other one was just an alternative fanciful description.

That is not our understanding of ADS-CFT as we understand it today.

Our understanding is that this is a precise isomorphism.

It's not an analogy, it's not a metaphor, it is not an approximation that is valid in some domain and not another.

It really is the case that these two theories are exactly equivalent to each other.

And if that's correct, then as a matter of philosophy, I would say those are both equally real.

So it's not the case that one is more real than the other.

They're perfect simulations of each other.

Yeah.

Are you an ADS dreaming you're a CFT or a CFT dreaming you're an ADS?

I think these are just two completely different, inequivalent descriptions of the same identical physics.