We didn’t do the welfare range calculations for plants, protists, nematodes, etc, because we don’t think the methodology is appropriate for organisms that lack a complex brain and/or nervous system. There are a lot of methodological complexities with even applying them to complex farmed animals like chickens, and if we were to try to do something similar for very simple organisms, we might take a quite different approach.
We don’t really put much stock in the probability of sentience estimates, which weren’t the focus of the project and are subject to much more uncertainty than the welfare range estimates themselves conditional on sentience (which themselves are highly uncertain). If you read the welfare range report’s footnotes, you’ll find that the 6.8% probability of sentience estimate for c elegans is driven substantially by my interpretation there that “probably not sentient” meant 10-35%, which was really just an off-the-cuff judgment. The other people whose views were included in that assessment gave under 1% or under 2% probabilities of sentience, and updating based on the proxies didn’t budge the priors much. On reflection, I think lower numbers are more appropriate than 6.8%, and I really would not anchor on that as “RP’s own lights”.
I think part of this stems from a misunderstanding about the spreadsheets that I mistakenly linked to in the welfare range report. The vast majority of the calculations in the spreadsheet you were working off of were from a very early draft of the project, before we had ironed out a methodology and which animals we thought the methodology could apply to. Since they were a first draft and lack the full context of decisions we made along the way, I really would not consider them as our official position. I am sorry for any confusion that may have caused with respect to our methodology, opinions, or the scope of the project. Here are updated tables containing the proxies: Public Welfare Range Data and Public sentience table (Though, please note that the sentience proxies do very little work at all in the sentience probability assessments, which, again, we don’t put that much stock in, particularly for simple animals)
On the 0.00027 welfare range being high: 1) this was just an example to illustrate that Nick isn’t correct about the structure of the model guaranteeing high numbers, not to show that it’s a suitable welfare range estimate for nematodes per se. We’re not claiming that it’s actually what we would arrive at if we did assess nematodes under a more appropriate framework. And 2) it’s only high if you think you can multiply very small numbers by very big numbers and then act on that, which is a separate point.
I think it’s fine if you or others have a different approach to weighing lean/likely no proxies, that was a judgment call. All of the code is public if you’d like the run it, and I created the ability for you to weigh likely/lean nos differently. That being said, they’re not creating very high estimates for many animals because there were relatively few “lean/likely no” judgments, we have many more models than just the pain/pleasure model that give lower welfare ranges, and we were quite conservative by assuming that all “Unknown” proxies were in fact absent. We’d love to have the chance to come up with new models using a more Bayesian framework, and in doing so, we might make different choices. But the point still holds that the models currently do not guarantee high welfare ranges.
Speaking personally (though I know some others on the team agree), I also reject approaches to meta-normative uncertainty that can easily lead you to be dominated by one fanatical theory. If you resolve meta-normative uncertainty by maximizing choiceworthiness, you’re equally susceptible to Pascal’s mugging. So, if (like me) you don’t want to go all-in on expected value maximization because of the Pascal’s mugging worry, you aren’t going to accept strategies for resolving meta-normative uncertainty that recreate that exact problem. In this case, then, the argument that we should still think that nematode welfare dominates our calculations even if we put a small credence on total hedonic utilitarianism doesn’t move me that much.
Overall, I encourage you and others on the EA Forum to not view our first version of the welfare range estimates as our final word on this. The book version, Weighing Animal Welfare, is more systematic, and we hope to improve on the methods in the future. But even still, I don’t think that the original version commits one to the view that very simple animals should dominate our calculations absent other highly controversial normative and meta-normative assumptions.
Could you clarify why your methodology is supposed to apply to silkworms, but not nematodes? I agree nematodes have a less complex brain and nervous system, but silkworms are also less complex than other animals, so I do not understand how you are deciding when your methodology is supposed to be applicable. Did you preregister the animals to which you thought your methods should apply to?
My understanding is that estimating RP’s mainline welfare ranges involved tens of judgement calls similar to the one you made to get the probability of sentience of nematodes. My broader point is that I do not know what majorly distinguishes nematodes from silkworms for you to think only the latter are reasonably covered by your methodology.
I had understood the estimates in the sheet which is no longer public were preliminary. However, it is still the case that the welfare range conditional on sentience under the pleasure-and-pain-centric model is proportional to the sum of the probabilities of the respective proxies being present? If so, for RP’s probability of sentience of nematodes of 6.8 %, a single behavioural proxy likely to be absent results in a welfare range of nematodes conditional on the rate of subjective experience of humans of at least 2.31*10^-4 (= 0.068*0.00339), which both me and Nick consider high.
The conversion from qualitative probabilistic descriptions to probabilities adds uncertainty, but I do not think it the driver of disagreement. In my mind, and I guess Nick’s, the major issue is that the effect of the presence of behaviours on the welfare range is not moderated by neural complexity. RP’s mainline welfare ranges consider “one-ninth weight to the possibility that an organism’s welfare range [conditional on sentience, and the rate of subjective experience of humans] is equal to the number of neurons it possesses relative to humans”. So an organism having 0 neurons only decreases its welfare range conditional on sentience, and the rate of subjective experience of humans by 1⁄9. I understand having no neurons at all would also lead to a lower probability of sentience, but I think it should directly imply a much larger decrease in the welfare range conditional on sentience.
What is your best guess for the probability of sentience of nematodes? It could be lower than 6.8 %, but still very far from Pascalianly low. I think reasonable approaches to deal with meta-normative uncertainty (about how to aggregate the recommendations of different moral theories) should not dismiss a 6.8 % or slightly lower chance of causing huge amounts of suffering.
In the book, “10 percent [weight is assined] to the equality model”, under which the welfare range conditional on sentience is 1. So the final welfare ranges conditional on sentience are at least 0.1 (= 0.1*1). Do you endorse the estimates presented in Table 8.6 of the book over RP’s mainline welfare ranges?
When Bob was selecting the species, he was thinking of adult insects as the edge cases for the model (bees, BSF). He included juveniles to see what the model implies, not because he really thought the model should be extended to them. You’ll notice that, in the book, the species list narrows considerably partly for this reason.
On the points related to sentience-conditioned welfare ranges, e.g. “So an organism having 0 neurons only decreases its welfare range conditional on sentience, and the rate of subjective experience of humans by 1⁄9. I understand having no neurons at all would also lead to a lower probability of sentience, but I think it should directly imply a much larger decrease in the welfare range conditional on sentience.” I think it’s a mistake to point to a hypothetical sentience-conditioned welfare range, which is an intermediate step in the calculations, for an animal that has zero neurons as indicative of an issue with the methodology overall for animals with complex brains.
Put straightforwardly, if an animal has zero neurons, it would have a welfare range of 0 overall, because I would give it a zero percent chance of being sentient, which affects all the models.
I also am not going to put a precise probability of sentience on nematodes, but I do think it’s much much closer to zero and crosses the threshold of being Pascal’s mugged.
I’m finding these discussions very draining and not productive at this point, so will not be engaging further in this debate.
I encourage you to disclaim in the post with RP’s mainline welfare ranges that Bob does not think the methodology used to produce them is applicable to silkworms. In practice, what does this mean? Would it be reasonable to neglect beings to which your methodology is not supposed to apply? Why is the methodology applicable to black soldier flies (BSFs), but not silkworms? I understand a methodology can be more or less applicable, but I still do not understand which concrete criteria you are using. I also think the applicability of the methodology should ideally be taken into account in the estimates such that these are more comparable.
I suggest people account for the lower applicability of your methodology to less complex organisms by using welfare ranges equal to the geometric mean between RP’s mainline welfare ranges, and the number of neurons as a fraction of that of humans. Does this seem reasonable?
I am not certain that neurons are required for an organism to have a non-constant welfare, so I think organisms without neurons have welfare ranges above 0. I guess you mean that organisms without neurons have a welfare range of roughly 0, but exactly how close to 0 matters. As I say in the post, “Rounding to 0 a probability of sentience, or welfare per animal-year close to 0 introduces an infinite amount of scope insensitivity. Regardless of the number of beings affected, the change in their welfare will be estimated to be exactly 0”.
Could you elaborate on why you seem to believe the probability of sentience of nematodes is Pascalianly low, and therefore arguably much lower than RP’s mainline estimate of 6.8 %? I feel like one can reasonably argue from this that the probability of sentience of silkworms is also Pascalianly low, and therefore not worry about improving the conditions of BSFs and mealworms, which RP estimates will be 417 billion in 2033.
Feel free to follow up later if you are finding this discussion draining, and not productive. I think it would be good for RP to write a post clarifying the extent to which the methodology used to produce RP’s mainline welfare ranges apply to the animals covered and not covered, and why.
If you read the welfare range report’s footnotes, you’ll find that the 6.8% probability of sentience estimate for c elegans is driven substantially by my interpretation there that “probably not sentient” meant 10-35%, which was really just an off-the-cuff judgment. The other people whose views were included in that assessment gave under 1% or under 2% probabilities of sentience, and updating based on the proxies didn’t budge the priors much. On reflection, I think lower numbers are more appropriate than 6.8%, and I really would not anchor on that as “RP’s own lights”.
I would say the probability of sentience of nematodes is higher than 6.8 %. From Andrews (2024):
Given the determinate development of their nervous systems, 30-some years ago it was taken as given that C. elegans are too simple to learn. However, once researchers turned to examine learning and memory in these tiny animals, they found an incredible amount of flexible behavior and sensitivity to experience. C. elegans have short-term and long-term memory, they can learn through habituation (Rankin et al., 1990), association (Wen et al., 1997), and imprinting (Remy & Hobert, 2005). They pass associative learning tasks using a variety of sensory modalities, including taste, smell, sensitivity to temperature, and sensitivity to oxygen (Ardiel & Rankin, 2010). They also integrate information from different sensory modalities, and respond differently to different levels of intoxicating substances, “support[ing] the view that worms can associate a physiological state with a specific experience” (Rankin, 2004, p. R618). There is also behavioral evidence that C. elegans engage in motivational trade-offs. These worms will flexibly choose to head through a noxious environment to gain access to a nutritious substance when hungry enough (Ghosh et al., 2016)—though Birch and colleagues are not convinced this behavior satisfies the marker of motivational trade-offs because it appears that one reflex is merely inhibiting another (Birch et al., 2021, p. 31).
C. elegans are a model organism for the study of nociceptors, and much of what we now know about the mechanisms of nociception comes from studies on this species (Smith & Lewin, 2009). Behavioral responses to noxious stimuli are modulated by opiates, as demonstrated by a study finding that administration of morphine has a dose-dependent effect on the latency of response to heat (Pryor et al., 2007). And, perhaps surprisingly, when the nerve ring that comprises the C. elegans brain was recently mapped, researchers found that different regions of the brain support different circuits that route sensory information to another location where they are integrated, leading to action (Brittin et al., 2021).
Even if we grant the author’s low confidence in nematodes’ having marker five (motivational trade-offs), current science provides ample confidence that nematodes have markers one (nociceptors), two (integrated brain regions), four (responsiveness to analgesics), and seven (sophisticated associative learning). Given high confidence that nematodes have even three of these markers, the report’s methodology [Birch et al. (2021)] would have us conclude that there is “substantial evidence” of sentience in nematodes.
Hi Vasco,
I just want to make a few points:
We didn’t do the welfare range calculations for plants, protists, nematodes, etc, because we don’t think the methodology is appropriate for organisms that lack a complex brain and/or nervous system. There are a lot of methodological complexities with even applying them to complex farmed animals like chickens, and if we were to try to do something similar for very simple organisms, we might take a quite different approach.
We don’t really put much stock in the probability of sentience estimates, which weren’t the focus of the project and are subject to much more uncertainty than the welfare range estimates themselves conditional on sentience (which themselves are highly uncertain). If you read the welfare range report’s footnotes, you’ll find that the 6.8% probability of sentience estimate for c elegans is driven substantially by my interpretation there that “probably not sentient” meant 10-35%, which was really just an off-the-cuff judgment. The other people whose views were included in that assessment gave under 1% or under 2% probabilities of sentience, and updating based on the proxies didn’t budge the priors much. On reflection, I think lower numbers are more appropriate than 6.8%, and I really would not anchor on that as “RP’s own lights”.
I think part of this stems from a misunderstanding about the spreadsheets that I mistakenly linked to in the welfare range report. The vast majority of the calculations in the spreadsheet you were working off of were from a very early draft of the project, before we had ironed out a methodology and which animals we thought the methodology could apply to. Since they were a first draft and lack the full context of decisions we made along the way, I really would not consider them as our official position. I am sorry for any confusion that may have caused with respect to our methodology, opinions, or the scope of the project. Here are updated tables containing the proxies: Public Welfare Range Data and Public sentience table (Though, please note that the sentience proxies do very little work at all in the sentience probability assessments, which, again, we don’t put that much stock in, particularly for simple animals)
On the 0.00027 welfare range being high: 1) this was just an example to illustrate that Nick isn’t correct about the structure of the model guaranteeing high numbers, not to show that it’s a suitable welfare range estimate for nematodes per se. We’re not claiming that it’s actually what we would arrive at if we did assess nematodes under a more appropriate framework. And 2) it’s only high if you think you can multiply very small numbers by very big numbers and then act on that, which is a separate point.
I think it’s fine if you or others have a different approach to weighing lean/likely no proxies, that was a judgment call. All of the code is public if you’d like the run it, and I created the ability for you to weigh likely/lean nos differently. That being said, they’re not creating very high estimates for many animals because there were relatively few “lean/likely no” judgments, we have many more models than just the pain/pleasure model that give lower welfare ranges, and we were quite conservative by assuming that all “Unknown” proxies were in fact absent. We’d love to have the chance to come up with new models using a more Bayesian framework, and in doing so, we might make different choices. But the point still holds that the models currently do not guarantee high welfare ranges.
Speaking personally (though I know some others on the team agree), I also reject approaches to meta-normative uncertainty that can easily lead you to be dominated by one fanatical theory. If you resolve meta-normative uncertainty by maximizing choiceworthiness, you’re equally susceptible to Pascal’s mugging. So, if (like me) you don’t want to go all-in on expected value maximization because of the Pascal’s mugging worry, you aren’t going to accept strategies for resolving meta-normative uncertainty that recreate that exact problem. In this case, then, the argument that we should still think that nematode welfare dominates our calculations even if we put a small credence on total hedonic utilitarianism doesn’t move me that much.
Overall, I encourage you and others on the EA Forum to not view our first version of the welfare range estimates as our final word on this. The book version, Weighing Animal Welfare, is more systematic, and we hope to improve on the methods in the future. But even still, I don’t think that the original version commits one to the view that very simple animals should dominate our calculations absent other highly controversial normative and meta-normative assumptions.
Thanks for sharing your thoughts, Laura!
Could you clarify why your methodology is supposed to apply to silkworms, but not nematodes? I agree nematodes have a less complex brain and nervous system, but silkworms are also less complex than other animals, so I do not understand how you are deciding when your methodology is supposed to be applicable. Did you preregister the animals to which you thought your methods should apply to?
My understanding is that estimating RP’s mainline welfare ranges involved tens of judgement calls similar to the one you made to get the probability of sentience of nematodes. My broader point is that I do not know what majorly distinguishes nematodes from silkworms for you to think only the latter are reasonably covered by your methodology.
I had understood the estimates in the sheet which is no longer public were preliminary. However, it is still the case that the welfare range conditional on sentience under the pleasure-and-pain-centric model is proportional to the sum of the probabilities of the respective proxies being present? If so, for RP’s probability of sentience of nematodes of 6.8 %, a single behavioural proxy likely to be absent results in a welfare range of nematodes conditional on the rate of subjective experience of humans of at least 2.31*10^-4 (= 0.068*0.00339), which both me and Nick consider high.
The conversion from qualitative probabilistic descriptions to probabilities adds uncertainty, but I do not think it the driver of disagreement. In my mind, and I guess Nick’s, the major issue is that the effect of the presence of behaviours on the welfare range is not moderated by neural complexity. RP’s mainline welfare ranges consider “one-ninth weight to the possibility that an organism’s welfare range [conditional on sentience, and the rate of subjective experience of humans] is equal to the number of neurons it possesses relative to humans”. So an organism having 0 neurons only decreases its welfare range conditional on sentience, and the rate of subjective experience of humans by 1⁄9. I understand having no neurons at all would also lead to a lower probability of sentience, but I think it should directly imply a much larger decrease in the welfare range conditional on sentience.
What is your best guess for the probability of sentience of nematodes? It could be lower than 6.8 %, but still very far from Pascalianly low. I think reasonable approaches to deal with meta-normative uncertainty (about how to aggregate the recommendations of different moral theories) should not dismiss a 6.8 % or slightly lower chance of causing huge amounts of suffering.
In the book, “10 percent [weight is assined] to the equality model”, under which the welfare range conditional on sentience is 1. So the final welfare ranges conditional on sentience are at least 0.1 (= 0.1*1). Do you endorse the estimates presented in Table 8.6 of the book over RP’s mainline welfare ranges?
Hi Vasco,
When Bob was selecting the species, he was thinking of adult insects as the edge cases for the model (bees, BSF). He included juveniles to see what the model implies, not because he really thought the model should be extended to them. You’ll notice that, in the book, the species list narrows considerably partly for this reason.
On the points related to sentience-conditioned welfare ranges, e.g. “So an organism having 0 neurons only decreases its welfare range conditional on sentience, and the rate of subjective experience of humans by 1⁄9. I understand having no neurons at all would also lead to a lower probability of sentience, but I think it should directly imply a much larger decrease in the welfare range conditional on sentience.”
I think it’s a mistake to point to a hypothetical sentience-conditioned welfare range, which is an intermediate step in the calculations, for an animal that has zero neurons as indicative of an issue with the methodology overall for animals with complex brains.
Put straightforwardly, if an animal has zero neurons, it would have a welfare range of 0 overall, because I would give it a zero percent chance of being sentient, which affects all the models.
I also am not going to put a precise probability of sentience on nematodes, but I do think it’s much much closer to zero and crosses the threshold of being Pascal’s mugged.
I’m finding these discussions very draining and not productive at this point, so will not be engaging further in this debate.
Thanks, Laura.
I encourage you to disclaim in the post with RP’s mainline welfare ranges that Bob does not think the methodology used to produce them is applicable to silkworms. In practice, what does this mean? Would it be reasonable to neglect beings to which your methodology is not supposed to apply? Why is the methodology applicable to black soldier flies (BSFs), but not silkworms? I understand a methodology can be more or less applicable, but I still do not understand which concrete criteria you are using. I also think the applicability of the methodology should ideally be taken into account in the estimates such that these are more comparable.
I suggest people account for the lower applicability of your methodology to less complex organisms by using welfare ranges equal to the geometric mean between RP’s mainline welfare ranges, and the number of neurons as a fraction of that of humans. Does this seem reasonable?
I am not certain that neurons are required for an organism to have a non-constant welfare, so I think organisms without neurons have welfare ranges above 0. I guess you mean that organisms without neurons have a welfare range of roughly 0, but exactly how close to 0 matters. As I say in the post, “Rounding to 0 a probability of sentience, or welfare per animal-year close to 0 introduces an infinite amount of scope insensitivity. Regardless of the number of beings affected, the change in their welfare will be estimated to be exactly 0”.
Could you elaborate on why you seem to believe the probability of sentience of nematodes is Pascalianly low, and therefore arguably much lower than RP’s mainline estimate of 6.8 %? I feel like one can reasonably argue from this that the probability of sentience of silkworms is also Pascalianly low, and therefore not worry about improving the conditions of BSFs and mealworms, which RP estimates will be 417 billion in 2033.
Feel free to follow up later if you are finding this discussion draining, and not productive. I think it would be good for RP to write a post clarifying the extent to which the methodology used to produce RP’s mainline welfare ranges apply to the animals covered and not covered, and why.
I would say the probability of sentience of nematodes is higher than 6.8 %. From Andrews (2024):