• Question: Will we ever have a theory of everything? If so, when? What will all the scientists do after that?

    Asked by eigenvector to Arttu, Ceri, James_M, Monica, Philip on 19 Jun 2011.
    • Photo: James M Monk

      James M Monk answered on 19 Jun 2011:

      I suspect not – for one thing the energy scales where it would apply seem to be extremely high – so high that I cannot imagine it being feasible to test such a theory. The theory may also turn out to be impossible to solve.

      People often reference Gödel’s incompleteness theorem in response to this. This is a mathematical principle that says there can be some self-consistent theories for which it is not possible to prove whether they are right or wrong. It is possible that any theory of everything would be like that.

    • Photo: Arttu Rajantie

      Arttu Rajantie answered on 19 Jun 2011:

      I don’t think we will ever have a final theory, which would describe exactly everything in the universe, and even if we did, I am not sure how we would know that. Therefore physicists would still continue to try and find flaws in the theory and phenomena it cannot explain.

      Even if we were all convinced that the theory really is the exact description of nature, there would still be a lot to do, because just knowing the theory does not necessarily mean you understand what it predicts. Even now, we have a theory of strong nuclear forces called quantum chromodynamics. The theory has been around for decades, and we are pretty sure it is correct, but we still don’t understand why quarks are permanenty confined into protons and neutrons, even though we can see it happening when we solve the theory numerically with supercomputers. (An American foundation has promised $1000000 to whoever solves that problem first, so you can be sure people are trying!)

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