I propose that there are four basic categories that all theoretical knowledge* eventually ends up in:

1) Wrong: These facts are shown to be straightforwardly incorrect.

2) Forgotten: We used to “know” these facts to be true, now we don’t remember them well enough to check.

3) Irrelevant: We might still think these facts are true, or maybe not, but no one cares enough to check.

4) Quaint: These facts were on to something that led somewhere, but reality turns out to be so vastly more complicated that the original ideas seem simpleminded, funny, or even cute.


*By this I technically mean all a posteriori propositional knowledge, though it may turn out to be true in a broader sense. I suppose, however, that the best I can hope for in the long run is that this proposal is true in a “quaint” sense.