Consequences of an ultimate model [of physics]
Even if one knows an ultimate model for the universe, there will inevitably be irreducible difficulty in working out all its consequences. Indeed, questions like "does there exist a way to transmit information faster than light?" may boil down to issues analogous to whether it is possible to construct a configuration that has a certain property in, say, the rule 110 cellular automaton. And while some such questions may be answered by fairly straightforward computational or mathematical means, there will be no upper bound on the amount of effort that it could take to answer any particular question.