alt Hacker News>GR and QFT are incompatible
I did physics at uni and kind of dropped out when it got too hard.
I've long guessed the incompatibility is because the maths is just too hard for human brains, though I'm probably biased there, and we'll get a breakthrough when AI can handle much more complex maths than us. Probably not so long till we find out on that one.
I once tried to write a simplified explanation for why a spin-2 quantum theory naturally results in something like general relativity and totally failed - man that stuff's hard.
The math is hard, but I don't think that's the problem. Hard math eventually succumbs.
I think that even if AI were to find a good unification of GR and QM, we wouldn't be able to test it. We might accept it without additional confirmation if it were sufficiently natural-feeling (the way we accepted Newtonian gravity long before we could measure G), but there's no guarantee that we'd ever be able to meaningfully test it.
We could get lucky -- such a theory might point at a solution to some of the few loose threads we get out of existing collider and cosmological measurements -- but we might not. We could be stuck wishing we had a galaxy-sized collider.