Question: do you believe that there is a theory of everything in physics?

Ian Stephenson answered on 25 Jun 2014:

Probably not in any meaningful sense.

One of the problems is what would it look like, and what would you do with it if I told you? There’s always be other ways of looking at things which are easier and/or more useful.

The biggest problem I see is it almost certainly wouldn’t be predictive. It’s really easy to build systems on a computer, where you can’t figure out whats going to happen. If you write a program on a computer the only way to figure out what its going to do is run it. Maybe you can figure out whats going to happen by examining that program with a more complex program/computer, but how would you figure out what THAT program/computer is going to d0 – you’d need a bigger one.

If you could build a theory of everything I suspect the only way you could use it to predict whats going to happen would be to build a simulator and run the simulation. But then you need a simulator bigger than the universe!