We require new predictions not because the theory is newer than some other theory it could share predictions, but because the predictions must come before the experimental results. If we allow theories theories to rely on the results of already known experiments, we run into two problems:
Overfitting. If the theory only needs to match existing results it can be constructed a way that matches all these results—instead of trying to match the underlying rules that generated these results.
We may argue ourselves into believing our theory made predictions that match our results, regardless of whether the theory naturally makes these predictions.
Now, if the new theory is a strictly simpler versions of an old one—as in “we don’t even need X” simpler—then these two problems are nonissue:
If the more complicated theory did not overfit, the simpler version is as good as guaranteed to not overfit either.
We don’t need to guess what our new theory would predict if we didn’t know the results—the old theory already did those predictions before knowing the results, and it should be straightforward to show it wasn’t using the part we removed.
We require new predictions not because the theory is newer than some other theory it could share predictions, but because the predictions must come before the experimental results. If we allow theories theories to rely on the results of already known experiments, we run into two problems:
Overfitting. If the theory only needs to match existing results it can be constructed a way that matches all these results—instead of trying to match the underlying rules that generated these results.
We may argue ourselves into believing our theory made predictions that match our results, regardless of whether the theory naturally makes these predictions.
Now, if the new theory is a strictly simpler versions of an old one—as in “we don’t even need X” simpler—then these two problems are nonissue:
If the more complicated theory did not overfit, the simpler version is as good as guaranteed to not overfit either.
We don’t need to guess what our new theory would predict if we didn’t know the results—the old theory already did those predictions before knowing the results, and it should be straightforward to show it wasn’t using the part we removed.
So… I will allow it.