That's is what he means by good: one with enough competence in the field to do actually useful work. If you manage to do useful work in physics, that work could

That's is what he means by good: one with enough competence in the field to do actually useful work. If you manage to do useful work in physics, that work could translate into a Nobel Prize just as easily as any other useful work. A bad theoretical physicist is one who only understands enough to sound smart to their friends. AKA, a crank.