Turing Machines and Turing CompletenessIf you look at the set of things that are thinkable and computable, a Turing machine is special in that it can do anything in that set.But there are lots of other things that can do that too, which is why we have the term 'Turing completeness'.If you have a system that isn't Turing complete, it can only perform a subset [of all possible computations/thoughts]. For example, if relativity is outside that subset, then relativity is unthinkable to that machine.