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 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.