On interpersonal utility comparisons, I agree with basically all of your points in your doc and I’m skeptical that all interpersonal comparisons are possible, but it seems pretty likely to me that some interpersonal comparisons are possible in theory, and reasonably likely that many comparisons with artificial sentience would be in practice.
The obvious case is two completely identical brains: as long as we grant intrapersonal comparisons, then we should get interpersonal comparisons between identical brains. Of course, this is not a very interesting case, and it’s too rare to be useful on its own (except maybe for two artificial sentiences that are built identically), but we can possibly extend it by asking whether there’s a sequence of changes from experience E1 in brain B1 to experience E2 in brain B2 that let us rank E1 and E2. For example, if B1 and B2 only differ in the fact that some of B2′s pain-causing neurons (assuming that makes sense) are less sensitive or removed (or B1′s pain-mitigating neurons are more sensitive or removed), and B1 and B2 receive the same input signals that cause pain, then it seems likely to me that B1′s painful experience E1 is more intense than B2′s E2. Unfortunately, it’s not clear to me that there should be any cardinally quantitative fact of the matter about how much more intense, which makes utilitarianism more arbitrary (since individual normalization seems wrong, but it’s not clear what else to do), and it makes things harder if we have both intensity-increasing and intensity-decreasing changes, since there may be no way to determine whether together they increase or decrease the intensity overall.
We can get useful comparisons if there exists a sequence of changes that turn E1 in B1 into E2 in B2 such that:
each change has the same direction of impact on the intensity, i.e. all intensity increasing (or preserving) or all intensity decreasing (or preserving), or
each change has a cardinally quantifiable effect on intensity and they can be aggregated (including intrapersonal changes just to the experience, and not the brain structure or function), or
a mix of 1 and 2, such the impacts of the unquantifiable changes all have the same direction as the net impact of the quantifiable changes (assuming “net impact” makes sense).
EDIT: You can replace “intensity” with the actual signed value, so we can turn goods into bads and vice versa.
EDIT2: Also, I could imagine unquantifiable changes with opposite direction that should “cancel out” because they’re basically structurally opposites, but may not necessarily be combined into a single value-preserving change, because non-value-preserving changes have to happen between them. There could be other cases of comparability I’m missing, too.
I think 1 is probably almost never going to hold across members of different animal species, and possibly never across two members of the same species. There are just so many differences between brains that it just seems unlikely that they could all be lined up in the same direction.
I could buy that 2 (or 3) holds across individuals within certain taxons, but I don’t see a clear way to establish it. Between human-like brains, maybe we can imagine just asking the individual to quantify the change in each step before and after, but it’s not clear to me their answers would be valid, as you suggest. Also, 2 and 3 become really doubtful across brains generating valence in very structurally different ways, and I think between extant invertebrates and extant vertebrates, because all the common ancestors of any extant vertebrate and any extant invertebrate were very probably not conscious*.
On the other hand, we could imagine making a digital copy of a human’s brain, and then applying a sequence of changes designed to increase the intensity of its experiences (like 2 or 3 with large quantifiable impacts). Not all artificial sentience need be designed this way or comparable, but if enough of them are or could be, this could support Shulman and Bostrom’s points.
Another awkward issue for individual normalization is the possibility of asymmetric welfare ranges and differences in how asymmetric they are, e.g. maybe my worst suffering is 20x as intense as my peak pleasure, but your worst suffering is 40x as intense as your peak pleasure. This would mean that we can’t match the max, min and 0 across every brain. Still, if we didn’t think interpersonal comparisons were really possible in the first place, this shouldn’t bother us too much: we probably have to normalize somehow if we want to say anything about interpersonal tradeoffs, and we may as well normalize by dividing by the difference between the max and min. If individuals’ maxes and mins don’t line up, so be it. We could also consider multiple normalizations (normalize by the difference between the max and 0 on one view, and the difference between 0 and the min on another) and deal with them like moral uncertainty.
* C. elegans and bivalves, in my view very unlikely to be conscious (barring panpsychism), are more closely related to cephalopods and arthropods than any vertebrate is, and the Ambulacraria, closer to vertebrates than cephalopods and arthropods are, also contains species that seem unlikely to be conscious. Even some chordates, like tunicates, the sister taxon to vertebrates, are pretty plausibly not conscious.
Also, separately, I can imagine functionalist definitions of intensity, like Welfare Footprint Project’s, that allow at least ordinal interpersonal comparisons. At some intensity of pain (its affective component/suffering/negative valence), which they define as disabling, the pain doesn’t leave the individual’s attention (it’s “continually distressing”), presumably even if they try to direct their attention elsewhere. And then excruciating pain leads to risky or seemingly irrational behaviour, plausibly due to extreme temporal discounting. It’s not clear there should be anything further than excruciating that we can use to compare across minds, though, but maybe just higher and higher discount rates?
We could define pleasure intensities symmetrically, based on attention and induced temporal discounting.
On the other hand, maybe some beings only have all-or-nothing pain experiences, i.e. their pain always meets the definition of excruciating whenever they’re in pain, and this could happen in very simple minds, because they don’t weigh different interests smoothly, whether simultaneous interests, or current and future interests or different future interests. Maybe we wouldn’t think such minds are sentient at all, though.
Thanks for this Michael. I don’t have a proper reply to it right now, because it raises so many complicated issues that I haven’t thought through yet (though briefly, I don’t actually think same brain guarantees same pain when embedded in different bodies/environments). But your right that differences in trade-offs between best pleasure and worst pain probably sink the naive normalization strategy I was suggesting. I’d need to know more maths than I do to have a sense of whether it is fixable. Someone suggested to me that some of the ideas in this book (which I haven’t read yet) would help: https://philpapers.org/rec/MACMU-3
On interpersonal utility comparisons, I agree with basically all of your points in your doc and I’m skeptical that all interpersonal comparisons are possible, but it seems pretty likely to me that some interpersonal comparisons are possible in theory, and reasonably likely that many comparisons with artificial sentience would be in practice.
The obvious case is two completely identical brains: as long as we grant intrapersonal comparisons, then we should get interpersonal comparisons between identical brains. Of course, this is not a very interesting case, and it’s too rare to be useful on its own (except maybe for two artificial sentiences that are built identically), but we can possibly extend it by asking whether there’s a sequence of changes from experience E1 in brain B1 to experience E2 in brain B2 that let us rank E1 and E2. For example, if B1 and B2 only differ in the fact that some of B2′s pain-causing neurons (assuming that makes sense) are less sensitive or removed (or B1′s pain-mitigating neurons are more sensitive or removed), and B1 and B2 receive the same input signals that cause pain, then it seems likely to me that B1′s painful experience E1 is more intense than B2′s E2. Unfortunately, it’s not clear to me that there should be any cardinally quantitative fact of the matter about how much more intense, which makes utilitarianism more arbitrary (since individual normalization seems wrong, but it’s not clear what else to do), and it makes things harder if we have both intensity-increasing and intensity-decreasing changes, since there may be no way to determine whether together they increase or decrease the intensity overall.
We can get useful comparisons if there exists a sequence of changes that turn E1 in B1 into E2 in B2 such that:
each change has the same direction of impact on the intensity, i.e. all intensity increasing (or preserving) or all intensity decreasing (or preserving), or
each change has a cardinally quantifiable effect on intensity and they can be aggregated (including intrapersonal changes just to the experience, and not the brain structure or function), or
a mix of 1 and 2, such the impacts of the unquantifiable changes all have the same direction as the net impact of the quantifiable changes (assuming “net impact” makes sense).
EDIT: You can replace “intensity” with the actual signed value, so we can turn goods into bads and vice versa.
EDIT2: Also, I could imagine unquantifiable changes with opposite direction that should “cancel out” because they’re basically structurally opposites, but may not necessarily be combined into a single value-preserving change, because non-value-preserving changes have to happen between them. There could be other cases of comparability I’m missing, too.
I think 1 is probably almost never going to hold across members of different animal species, and possibly never across two members of the same species. There are just so many differences between brains that it just seems unlikely that they could all be lined up in the same direction.
I could buy that 2 (or 3) holds across individuals within certain taxons, but I don’t see a clear way to establish it. Between human-like brains, maybe we can imagine just asking the individual to quantify the change in each step before and after, but it’s not clear to me their answers would be valid, as you suggest. Also, 2 and 3 become really doubtful across brains generating valence in very structurally different ways, and I think between extant invertebrates and extant vertebrates, because all the common ancestors of any extant vertebrate and any extant invertebrate were very probably not conscious*.
On the other hand, we could imagine making a digital copy of a human’s brain, and then applying a sequence of changes designed to increase the intensity of its experiences (like 2 or 3 with large quantifiable impacts). Not all artificial sentience need be designed this way or comparable, but if enough of them are or could be, this could support Shulman and Bostrom’s points.
Another awkward issue for individual normalization is the possibility of asymmetric welfare ranges and differences in how asymmetric they are, e.g. maybe my worst suffering is 20x as intense as my peak pleasure, but your worst suffering is 40x as intense as your peak pleasure. This would mean that we can’t match the max, min and 0 across every brain. Still, if we didn’t think interpersonal comparisons were really possible in the first place, this shouldn’t bother us too much: we probably have to normalize somehow if we want to say anything about interpersonal tradeoffs, and we may as well normalize by dividing by the difference between the max and min. If individuals’ maxes and mins don’t line up, so be it. We could also consider multiple normalizations (normalize by the difference between the max and 0 on one view, and the difference between 0 and the min on another) and deal with them like moral uncertainty.
* C. elegans and bivalves, in my view very unlikely to be conscious (barring panpsychism), are more closely related to cephalopods and arthropods than any vertebrate is, and the Ambulacraria, closer to vertebrates than cephalopods and arthropods are, also contains species that seem unlikely to be conscious. Even some chordates, like tunicates, the sister taxon to vertebrates, are pretty plausibly not conscious.
Also, separately, I can imagine functionalist definitions of intensity, like Welfare Footprint Project’s, that allow at least ordinal interpersonal comparisons. At some intensity of pain (its affective component/suffering/negative valence), which they define as disabling, the pain doesn’t leave the individual’s attention (it’s “continually distressing”), presumably even if they try to direct their attention elsewhere. And then excruciating pain leads to risky or seemingly irrational behaviour, plausibly due to extreme temporal discounting. It’s not clear there should be anything further than excruciating that we can use to compare across minds, though, but maybe just higher and higher discount rates?
We could define pleasure intensities symmetrically, based on attention and induced temporal discounting.
On the other hand, maybe some beings only have all-or-nothing pain experiences, i.e. their pain always meets the definition of excruciating whenever they’re in pain, and this could happen in very simple minds, because they don’t weigh different interests smoothly, whether simultaneous interests, or current and future interests or different future interests. Maybe we wouldn’t think such minds are sentient at all, though.
https://reducing-suffering.org/is-brain-size-morally-relevant/#Reductio_against_equality_Binary_utility_function
Thanks for this Michael. I don’t have a proper reply to it right now, because it raises so many complicated issues that I haven’t thought through yet (though briefly, I don’t actually think same brain guarantees same pain when embedded in different bodies/environments). But your right that differences in trade-offs between best pleasure and worst pain probably sink the naive normalization strategy I was suggesting. I’d need to know more maths than I do to have a sense of whether it is fixable. Someone suggested to me that some of the ideas in this book (which I haven’t read yet) would help: https://philpapers.org/rec/MACMU-3