I think that neither of your examples is correctly using the reversal test. IMO, two different versions of the reversal test are useful: the marginal reversal test, and the counterfactual reversal test.
Marginal version: “So you don’t think that increasing your body temperature a small amount is good—do you think decreasing it a small amount would be good? If not, can you explain why your current state is optimal?”
Counterfactual version: “So you don’t think that increasing your body temperature by 50 degrees would be good? Would you still think that if your body temperature had always been 50 degrees higher, and we were talking about decreasing it 50 degrees?”
I think in both cases the reversal tester correctly loses the argument. I also think that they both do a good job of helping to decide where to find the interesting bits of argument.
“helping to decide where to find the interesting bits” is exactly where this technique shines, and I don’t think it’s overrated (at least in my circles).
Note that even in the “yes, this is the right level, for X reasons”, there’s still a bunch of value in identifying the forces at equilibrium that make this the right level. You can then ask “do you want to change some of THOSE values”?
When you say that the reversal tester loses the argument, do you mean that one could easily refute the rhetoric of the question posed, as in, homeostasis being the optimal condition, or one can counter that with a flaw in the rhetoric, as in, there is an implicit assumption there in the question of some sort that defeats the main intention of the question itself. If it is the second one, I am genuinely curious as to how that can be countered.
I think the marginal version is indeed a good way of dissecting arguments (and I thought I did use that version)
The counterfactual version is a bit more icky. I’m not saying it can never be used, but if we take this example I feel like if “I” always had a brain that ran smoothly even though it was 50 degrees higher that wouldn’t really be “me”.
Maybe it’s just a failure of imagination on my part, but in most cases I feel like I’m supposed to speak for a creature that I can’t really speak for.
I think the main difference between the marginal reversal test and how I read your post is just the magnitude of the change. For the marginal reversal test to make sense, I think the change needs to be small relative to “typical” values of the parameter. So, changing life spans by months rather than years, or changing body temperature by single degrees.
And yeah, I think that the counterfactual reversal test is much more of a heuristic than a careful argument, but it does seem useful as a way of disentangling disagreements, especially with sufficiently thoughtful interlocutors.
I think that neither of your examples is correctly using the reversal test. IMO, two different versions of the reversal test are useful: the marginal reversal test, and the counterfactual reversal test.
Marginal version: “So you don’t think that increasing your body temperature a small amount is good—do you think decreasing it a small amount would be good? If not, can you explain why your current state is optimal?”
Counterfactual version: “So you don’t think that increasing your body temperature by 50 degrees would be good? Would you still think that if your body temperature had always been 50 degrees higher, and we were talking about decreasing it 50 degrees?”
I think in both cases the reversal tester correctly loses the argument. I also think that they both do a good job of helping to decide where to find the interesting bits of argument.
“helping to decide where to find the interesting bits” is exactly where this technique shines, and I don’t think it’s overrated (at least in my circles).
Note that even in the “yes, this is the right level, for X reasons”, there’s still a bunch of value in identifying the forces at equilibrium that make this the right level. You can then ask “do you want to change some of THOSE values”?
When you say that the reversal tester loses the argument, do you mean that one could easily refute the rhetoric of the question posed, as in, homeostasis being the optimal condition, or one can counter that with a flaw in the rhetoric, as in, there is an implicit assumption there in the question of some sort that defeats the main intention of the question itself. If it is the second one, I am genuinely curious as to how that can be countered.
I meant the first thing, sorry for lack of clarity
I think the marginal version is indeed a good way of dissecting arguments (and I thought I did use that version)
The counterfactual version is a bit more icky. I’m not saying it can never be used, but if we take this example I feel like if “I” always had a brain that ran smoothly even though it was 50 degrees higher that wouldn’t really be “me”.
Maybe it’s just a failure of imagination on my part, but in most cases I feel like I’m supposed to speak for a creature that I can’t really speak for.
I think the main difference between the marginal reversal test and how I read your post is just the magnitude of the change. For the marginal reversal test to make sense, I think the change needs to be small relative to “typical” values of the parameter. So, changing life spans by months rather than years, or changing body temperature by single degrees.
And yeah, I think that the counterfactual reversal test is much more of a heuristic than a careful argument, but it does seem useful as a way of disentangling disagreements, especially with sufficiently thoughtful interlocutors.