Earlier quoted context omitted.
> So far as I can tell, there is no such authority for facts. Huh? You just described it: reality is the authority. > I think this situation is simpler if these all count as separate facts. No, they are different theoretical descriptions of the facts. The facts are the particular experimental apparatus Michelson and Morley used and the particular numbers they recorded when they made their measurements. > Do "the fact…
> reality is the authority Suppose you have two theories, and you run an experiment whose results produce two assertions, each couched in the language of their respective theories, (I'd call these assertions facts). You say that reality is the authority on whether the two assertions represent the same underlying fact or different underlying facts, but it's not like there's some oracle that I can consult in the matter…
I wouldn't. An experiment will produce one set of "assertions", about what was done and what happened. Those are facts.
Different theories might add different "assertions" on top of that, but that doesn't change what was done and what happened in the experiment, and the theoretical "assertions" aren't facts. They're theories.
> So you've got a bunch of mirrors and a pattern of light, and then later in the day you have the same pattern of light. That's not facts, that's just phenomena.
No, they're facts. What you are calling "phenomena" are facts. At least, I call them facts.
> a fact is some correspondence between a model (which lives in a theory) and some phenomenon (which lives in reality).
No, I would not call that a fact. The phenomenon is the fact. The correspondence is a successful test of the model.
To go all the way back to what I quoted from you to start this subthread: the question you asked was "which facts to use?" And my answer was "the ones that are confirmed by experiments". Now that I see what you meant by "facts", I think the way you should have phrased your question is simply "which theoretical models to use?" And the answer is still "the ones that are confirmed by experiments", but with the added note that "confirmed by experiments" means "confirmed as correctly describing the facts".