In the case of the bent stick, would you be willing to finish the sentence "I observed that..." such that this sentence cannot come up false on the basis of a new theory?

"I observed that my image of the stick shows the stick as bent." It is not a statement of objective reality, but a statement of appearances to me, in my direct experience, that a new theory must not contradict. The new theory is allowed to say that my image of the stick does not accurately describe the stick, but it may not say that I didn't observe the image.

I believe, more strongly than most in this community, that it is essentially impossible to draw a clear line between observation and theory. But the important issue is deciding what theories are worth paying attention to, not figuring what observations to attend to.

This seems to me to entail a rejection of Egan's law, but I should qualify that. It doesn't reject the rule of thumb that a good theory preserves the phenomena (though it may overturn them too). As a heuristic about choosing between theoretical explanations, this is quite sensible.

But the thing I'm objecting to is the a priori claim that a true theory preserves observations. This originally came up in the context of an argument about free will in MWI. Egan's law was there used as an argument for the claim that MWI is compatible with free will, and I'm objecting to the validity of any such argument (note that I'm not claiming that MWI and free will are incompatibile, just that this isn't a good argument for their compatibility). In short, if theories may well overturn observations (since they cannot be entirely extricated from theory), then nothing prevents a true theory from overturning something like free will. It may have simply appeared to us that we have free will, in the way it merely appeared to me that the stick was bent.

In short, if Egan's law is 'All other things being equal, prefer the theory which preserves the phenomena' then fine. But then Egan's law can't be used to argue that a given theory actually does preserve a given phenomenon.

Can't speak for anyone else, but yeah, in the context under discussion I'd agree with this. Somehow knowing what's really happening, as opposed to what I experience and infer, is not a normal event.

Hmm, I didn't expect anyone to bite this bullet. I think I'm happy with this conclusion insofar as it gets us a rejection of Egan's law as an argument that theory A preserves phenonmenon X, where X isn't a mere appearance (not that you thought otherwise).

The next step (if my karma can withstand it) on my part would be to argue that 'appearing to be blue' is logically posterior to 'being blue', such that if we arrived at a theory that said that 'being blue' was simply nonsense, we would have to throw out 'appearing to be blue' along with it. In other words, the dependence of 'appearance' style sentences on straightforward fact-stating sentences means that appearances are no less susceptible to attack. The idea would be to show that there's no possible 'normal' that's in principle immune to attack by a theory, even if there is a battery of everyday observations that aren't likely to be attacked.