[evanb]

I of course agree with most of what you say. The thing that impresses me about this whole ruliad business is that it seems to operationalize computational version Tegmark's mathematical universe hypothesis: all sets of mathematical axioms plus their computable consequences equally well have the secret fire of existence, our SU(3) x SU(2) x U(1) world is not the only realized one.

But it's also slightly different; in Tegmark's description of the MUH there's not a meaningful connection between the universe that realizes (let's say) Euclid's axioms and our universe. They're just separate places in the Platonic realm; they way we learn about Euclidean geometry is by computing, using some little Turing-complete region to simulate geometry. If I understand correctly, the ruliad says no, it is possible, in principle, to navigate through the hell of a mess and actually find the place in the hypergraph, not disconnected from the place that describes our lived experience, that is Euclidean geometry. It's sort of the ultimate reading of the Copernican principle: the laws we see around us are not particularly special and aren't privileged over other laws.

I find that to be a pretty beautiful philosophical idea while also thinking it's not a very practical one for doing actual science. If it contains representations all possible consistent axioms, well, how would you ever make a prediction about an actual experiment nearby? In the framework of relativistic QFTs we can make a bunch of different models and test them, settle on one, and use it to make predictions. Or find that actually it was just a low-energy EFT all along, falsifying our model. But the ruliad can never be falsified; the claim is that every possible universe is in there. How do I use it to make predictions about physics beyond the standard model? Or even just SM physics? Unclear.