> A theory that purports to describe how the universe actually functions, can’t have places where the theory says “and now the universe bluescreens”. A theory

> A theory that purports to describe how the universe actually functions, can’t have places where the theory says “and now the universe bluescreens”. A theory that provides useful predictions in some conditions and doesn't provide useful predictions in other conditions is a useful theory if you can determine which conditions are which. My lay understanding is general relativity provides useful predictions as long as mass isn't too dense (black hole) and as long as nothing breaks the speed limit; which is pretty general for everyday use, even if it doesn't cover the whole universe.