Scott Aaronson has formulated it in a similar way (quoted from here):
whenever it’s been possible to make definite progress on ancient philosophical problems, such progress has almost always involved a [kind of] “bait-and-switch.” In other words: one replaces an unanswerable philosophical riddle Q by a “merely” scientific or mathematical question Q′, which captures part of what people have wanted to know when they’ve asked Q. Then, with luck, one solves Q′.
Of course, even if Q′ is solved, centuries later philosophers might still be debating the exact relation between Q and Q′! And further exploration might lead to other scientific or mathematical questions — Q′′, Q′′′, and so on — which capture aspects of Q that Q′ left untouched. But from my perspective, this process of “breaking off” answerable parts of unanswerable riddles, then trying to answer those parts, is the closest thing to philosophical progress that there is.
…A good replacement question Q′ should satisfy two properties: (a) Q′ should capture some aspect of the original question Q — so that an answer to Q′ would be hard to ignore in any subsequent discussion of Q, [and] (b) Q′ should be precise enough that one can see what it would mean to make progress on Q′: what experiments one would need to do, what theorems one would need to prove, etc.
Thank you for the reference. I am not sure if Aaronson and I would agree. After all, depending on the situation, a philosopher of the kind I am talking about could claim that whatever progress has been made by answering the quesion Q’ also allows us to know the answer to the question Q (maybe because they are really the same question), or at least to get closer to it, instead of simply saying that Q does not have an answer.
I think Protagoras’ example of the question about whales being fish or not would make a good example of the former case.
Scott Aaronson has formulated it in a similar way (quoted from here):
Thank you for the reference. I am not sure if Aaronson and I would agree. After all, depending on the situation, a philosopher of the kind I am talking about could claim that whatever progress has been made by answering the quesion Q’ also allows us to know the answer to the question Q (maybe because they are really the same question), or at least to get closer to it, instead of simply saying that Q does not have an answer.
I think Protagoras’ example of the question about whales being fish or not would make a good example of the former case.