>>> But then the "appropriate limits" are part of your theory.
That's certainly true. I'm not active in that field, but a couple of examples of appropriate limits are where classical mechanics is an appropriate limit of both quantum mechanics and special relativity. It only says that if your theory profoundly disagrees with existing observation, try again. At an even simpler level, the approximately parabolic arc of a stone thrown in the air is an appropriate limit of Newton's mechanics.
But the hope is to create a theory where some other limit can also be found -- such a limit might be an unexpected new particle, astronomical observation, etc.
That's certainly true. I'm not active in that field, but a couple of examples of appropriate limits are where classical mechanics is an appropriate limit of both quantum mechanics and special relativity. It only says that if your theory profoundly disagrees with existing observation, try again. At an even simpler level, the approximately parabolic arc of a stone thrown in the air is an appropriate limit of Newton's mechanics.
But the hope is to create a theory where some other limit can also be found -- such a limit might be an unexpected new particle, astronomical observation, etc.