Effects on microorganisms are much larger than those on animals and plants under the assumptions of Rethink Priorities’ mainline welfare ranges? — EA Forum
1. It's true that we don't think you can take our methodology and extend it arbitrarily. We grant that it’s very difficult to draw a precise boundary. However, it's standard to develop a model for a purpose and be wary about its application in a novel context. Very roughly, we take those novel contexts to be ones where the probability of sentience is extremely low. We acknowledge that we don’t have a precise cutoff for “extremely low,” as establishing such a cutoff would be a difficult research project in its own right. There are unavoidable judgment calls in this work.
2. RP has done lots of work on animal sentience. It is not all the Moral Weight Project. It is not all connected and integrated. And some of our earliest MWP ideas are ones we later abandoned. What we stand behind now is really just what we published in the book. It is not fair to ask us to tell a coherent story about disconnected projects with different purposes, as well as all stages of the same project, given that different teams worked on these projects and the evolving understanding of people on a team for a given project.
3. We don't think that the assumptions of our "mainline welfare ranges" imply anything about the welfare ranges of plants, nematodes, and microorganisms, as the models simply aren't intended to be used the way you are using them. That's why we aren’t replying to you about the welfare ranges of plants, nematodes, and microorganisms. We would need to do an independent project to form opinions on your questions. Right now, we don’t have the funding for that project.
4. It's understandable that you're skeptical of our specific welfare range estimates. We, of course, are also skeptical of those precise numbers. That's why we've long encouraged people to focus on the order of magnitude estimates. We also disagree that they "are bound to be relatively close to 1." A few orders of magnitude lower than 1 is not close to 1, at least by one reasonable interpretation of "relatively close." Laura has already discussed this elsewhere.
For what it's worth, I think you're approaching the Moral Weight Project as something it is not. You are treating it as a general methodology where we can enter some information about the abilities of a system—whatever that system happens to be—and get out moral weights that we can use in expected value calculations for cause prioritization. But we did not try to produce a maximally general methodology. We tried to produce something useful for updating on the kinds of questions that decision-makers actually face: "Do layer hens matter so much more than carp that, despite the differences in population sizes, you should prioritize layers?" "Can we rule out insects entirely?" “If your job requires you to apply a discount rate to the welfare of some animals relative to others, what kinds of numbers should you consider?” "Is there a good reason for thinking that, even if humans don't literally have lexical priority over animals, they have that kind of priority for practical purposes?" And so on. I do think that the MWP is useful for shedding some light on these questions for some actors. Beyond that, we should be cautious with the outputs. And mostly, we should try to do better, as we only meant to issue the first word.
1. It's true that we don't think you can take our methodology and extend it arbitrarily. We grant that it’s very difficult to draw a precise boundary. However, it's standard to develop a model for a purpose and be wary about its application in a novel context. Very roughly, we take those novel contexts to be ones where the probability of sentience is extremely low. We acknowledge that we don’t have a precise cutoff for “extremely low,” as establishing such a cutoff would be a difficult research project in its own right. There are unavoidable judgment calls in this work.
I estimate effects on soil animals would still be much larger than those on the target beneficiaries for a welfare per animal-year of exactly 0 for animals with fewer neurons than those considered in your book, and "welfare range as a fraction of that of humans" = "number of neurons as a fraction of that of humans"^0.19, which explains very well the welfare ranges in Table 8.6 of your book (78.6 % of their variance for an exponent of 0.188). I calculate soil ants and termites have 2.91 and 1.16 times as many neurons as shrimp, so effects on them would still be relevant. I get the following increase in the welfare of soil ants and termites as a fraction of the increase in the welfare of the target beneficiaries for an exponent of 0.19 (the chicken welfare corporate campaigns would decrease animal welfare):
1. It's true that we don't think you can take our methodology and extend it arbitrarily. We grant that it’s very difficult to draw a precise boundary. However, it's standard to develop a model for a purpose and be wary about its application in a novel context. Very roughly, we take those novel contexts to be ones where the probability of sentience is extremely low.
Would you be able to provide a range for what is "extremely low", and briefly explain why the probability of sentience of black soldier flies (which are covered in the book) is not extremely low, but that of nematodes is extremely low? I do not know whether your "extremely low" means lower than 10^-10 or 1 %, but I guess the probability of sentience of nematodes may well be over 10 %. 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.
What we stand behind now is really just what we published in the book
Thanks for clarifying you only stand by what is in the book! I did not know this. Have you communicated this to organisations which have been using the estimates you had shared on EA Forum? I believe the community would find helpful a post where you share what you stand by, and which (expected) welfare ranges you recommend using for comparing welfare across species.
4. It's understandable that you're skeptical of our specific welfare range estimates. We, of course, are also skeptical of them. That's why we have long encouraged people to focus on the order of magnitude estimates.
For 10 of 11 species, my preferred welfare range is less than 10 % of the estimate RP shared on the EA Forum (see last table in my post), so I think the vast majority of these is more than 1 order of magnitude too high.
For what it's worth, I think you are approaching the Moral Weight Project as something it is not. You are treating it as a general methodology where we can enter some information about the abilities of a system—whatever that system happens to be—and get out moral weights that we can use in expected value calculations for cause prioritization.
I had understood from your past comment that the methodology is not supposed to apply to all biological systems (and I had already understood it was not supposed to apply to non-biological systems). However, I think it makes sense to trust the methodology less if you believe applying it to silkworms or nematodes produces results which are way less trustworthy than those for black soldier flies (which are covered in the book), as these do not seem that different from the former.
Quick note Vasco I don't think their book welfare ranges are substantially different from the ones posted on the forum, so practically I don't think it's a big deal for people applying them in CEAd
I retract that Vasco, you are correct - I had a quick glance at pigs and chickens and thought they were about the same, for those smaller animals they are indeed far higher. Perhaps it stems from these sentience numbers in the book being higher for Shrimps and Soldier flies than in the forum posts? Â
Thanks, Nick. Here are the estimates from the book.
The mean for:
Pigs is 85.4 % (= 0.44/0.515) of the estimate in RP's post.
Chickens is 1.20 (= 0.40/0.332) times the estimate in RP's post.
Carp is 2.70 (= 0.24/0.089) times the estimate in RP's post.
Octopuses is 1.27 (= 0.27/0.213) times the estimate in RP's post.
Shrimp is 2.58 (= 0.08/0.031) times the estimate in RP's post.
Black soldier flies (BSF) is 5.62 (= 0.073/0.013) times the estimate in RP's post.
There were significant updates for carp, shrimp, and BSF. @vicky_cox, @Neil_Dullaghan🔹 , and @Vince Mak 🔸, you may want to consider the welfare ranges from Bob's book instead of those from RP's post, and stop using the value from RP's post respecting silkworms to model the benefits of interventions targeting farmed arthropods. Bob said "What we [RP] stand behind now is really just what we published in the book", and this does not have estimates for the welfare range of larvae.
The higher values for shrimp and BSF also make me think one would obtain larger welfare ranges applying the book's methodology to less complex organisms (although I know it is not supposed to be extended).
I am not sure whether RP stands by the book's means or medians. Could you clarify this, Bob? In any case, they do not differ much.
Hello. Could you clarify what would be extending my conclusions? I have analysed microorganisms, including bacteria, in the post, and took the same conclusion.
I speculate soil microorganisms have a negative welfare per organism-year, as is my best guess for soil nematodes, and therefore recommend decreasing their population. I expect the density of microorganisms to correlate with net primary production, and this to be lower for agricultural land than the counterfactual land use. So I recommend increasing agricultural land to increase the welfare of soil microorganisms.
Effects on microorganisms are much larger than those on animals and plants under the assumptions of Rethink Priorities’ mainline welfare ranges?
Under the assumptions of Rethink Priorities’ (RP’s) mainline welfare ranges, it seems clear that effects on microorganisms are much larger than those on nematodes, and that these are much larger than those on humans, farmed animals, and plants.
My understanding is that Bob Fischer, who led RP’s moral weight project, thinks the methodology used to calculate RP’s mainline welfare ranges does not apply to silkworms, or organisms similarly or less complex than these, like microorganisms and nematodes. I wonder whether RP balked at estimates friendly to plants, nematodes, and microorganisms. They gathered lots of information about proxies for welfare for those organisms, but did not present it, estimate their welfare range, or arguably sufficiently explain how to interpret the mainline welfare ranges they presented for more complex organisms considering the estimation method is less applicable to less complex organisms.
I think the welfare ranges of plants, nematodes, and microorganisms are much smaller than implied by the assumptions of RP’s mainline welfare ranges. However, I still expect effects on microorganisms to be much larger than those on nematodes, and these to be much larger than those on humans, farmed animals, and plants.
I recommend being highly sceptical of RP’s mainline welfare ranges, which I believe are bound to be relatively close to 1. At the same time, I recommend being even more sceptical of non-systematic approaches to estimate welfare ranges. I think these are at higher risk of being disconnected from empirical evidence, and lacking transparency, thus being harder to improve upon.
For organisms with neurons, I suggest using welfare ranges equal to the geometric mean between the number of neurons as a fraction of that of humans, and RP’s mainline welfare ranges. This ensures the welfare range is not solely determined by structural properties, but that these moderate the effect of behavioural proxies on it. My preferred welfare ranges are in the last table below.
I speculate soil microorganisms have a negative welfare per organism-year, as is my best guess for soil nematodes, and therefore recommend decreasing their population. I expect the density of microorganisms to correlate with net primary production, and this to be lower for agricultural land than the counterfactual land use. So I recommend increasing agricultural land to increase the welfare of soil microorganisms. Nonetheless, I guess this is only 50 % likely to be beneficial, as I guess the probability of microorganisms having a negative welfare per organism-year is roughly 50 %, although below this.
My top recommendation is decreasing the uncertainty about the welfare in QALY/organism-year of soil microorganisms and nematodes. In particular, it is crucial to know whether they have positive or negative lives. Nevertheless, I am not aware of any opportunities one can support now to make progress on that in a sufficiently targeted way which I consider more cost-effective than funding HIPF.
Introduction
I estimated effects on soil nematodes, mites, and springtails are much larger than those on target beneficiaries. So I decided to investigate the effects on microorganisms too. Here are my calculations.
I suppose 230 billion farmed shrimp as computed by RP for 2020. I have not considered animals besides nematodes, and farmed shrimp. I think effects on nematodes account for the vast majority of the effects on animals, and shrimp are the farmed animals existing in greater numbers, thus providing good context about farmed animals.
Welfare range
RP estimated their mainline welfare ranges based on 9 models giving a weight of 1/9 to each. They also calculated the welfare range conditional on sentience of plants, nematodes, protists, and prokaryotes for 2 of those 9 models, the cubic, and pleasure-and-pain-centric models. The sheet I just linked is no longer public, but here is a copy from July 2. I assume the welfare range conditional on sentience is 0 for all the other 7 models to get lower bounds for RP’s mainline welfare ranges of plants, nematodes, protists, and prokaryotes. In addition, I speculate the probability of sentience of plants, protists, and prokaryotes is 6.8 % that of nematodes, which I set to RP’s estimate of 6.8 %. This implies the ratio between the probability of sentience of plants/protists/prokaryotes and nematodes equals the ratio between the probability of sentience of nematodes and humans, who I assume are certain to be sentient. RP does not present a probability of sentience for shrimp, as I commented on February 12, so I supposed it to be equal to that of crayfish of 45.3 %.
The results are below. “E” stands for “*10^”. As I expected, farmed shrimp and nematodes have the 1st and 2nd highest lower bound for RP’s mainline welfare, and that of protists is higher than that of prokaryotes. The lower bounds for RP’s mainline welfare ranges of plants, nematodes, and microorganisms are relatively close to 1. This is because RP’s welfare ranges conditional on sentience of plants, nematodes, and prokaryotes for the cubic and pleasure-and-pain-centric models are relatively close to 1, and each of these models has a significant weight of 1/9.
Organisms
Probability of sentience
Welfare range conditional on sentience for the cubic model
Welfare range conditional on sentience for the pleasure-and-pain-centric model
Lower bound for RP's mainline welfare range conditional on sentience
Lower bound for RP's mainline welfare range
Plants
0.462%
1.33E-04
0.0556
0.00619
2.86E-05
Farmed shrimp
45.3%
0.0147
0.296
0.0345
0.0156
Nematodes
6.80%
0.0456
0.389
0.0483
0.00328
Protists
0.462%
0.00984
0.130
0.0155
7.18E-05
Archaea
0.462%
7.75E-04
0.0741
0.00832
3.85E-05
Bacteria
0.462%
7.75E-04
0.0741
0.00832
3.85E-05
Maximum annual welfare gain
I calculate the lower bound for the maximum annual welfare gain multiplying the population by the lower bound for RP’s mainline welfare range. I estimate that lower bound as a fraction of the maximum annual welfare gain for humans assuming this equals the human population in 2024 of 8.16 billion, as the welfare range of humans is 1 by definition.
The results are below. Under the assumptions of RP’s mainline welfare ranges, it seems clear that effects on microorganisms are much larger than those on nematodes (as I had commented), and that these are much larger than those on humans, farmed animals, and plants.
Organisms
Lower bound for the maximum annual welfare gain
Lower bound for the maximum annual welfare gain as a fraction of the maximum annual welfare gain for humans
Plants
2.86E+08
3.51%
Farmed shrimp
3.60E+09
44.1%
Nematodes
3.28E+18
4.02E+08
Protists
1.44E+23
1.76E+13
Archaea
3.85E+24
4.71E+14
Bacteria
3.85E+25
4.71E+15
My understanding is that Bob Fischer, who led RP’s moral weight project, thinks the methodology used to calculate RP’s mainline welfare ranges does not apply to silkworms, or organisms similarly or less complex than these, like microorganisms and nematodes. Laura Duffy, who wrote the report describing the estimation of RP’s mainline welfare ranges, said that, “When Bob was selecting the species, he was thinking of adult insects as the edge cases for the model (bees, BSF [black soldier flies]). He included juveniles [silkworms] to see what the model implies, not because he really thought the model should be extended to them”. I wonder whether RP balked at estimates friendly to plants, nematodes, and microorganisms. They gathered lots of information about proxies for welfare for those organisms, but did not present it, estimate their welfare range, or arguably sufficiently explain how to interpret the mainline welfare ranges they presented for more complex organisms considering the estimation method is less applicable to less complex organisms. I encouraged Bob Fischer and Laura Duffy to present information about proxies for welfare for nematodes on June 12, and asked for clarifications about RP’s welfare ranges conditional on sentience for the cubic and pleasure-and-pain-centric models on July 2, as I noted the very high values for plants, nematodes, and microorganisms, but they have not replied.
I think the welfare ranges of plants, nematodes, and microorganisms are much smaller than implied by the assumptions of RP’s mainline welfare ranges. However, I still expect effects on:
Microorganisms to be much larger than those on nematodes:
I guess the welfare range per unit mass decreases with mass, and bacteria individually have a way smaller mass than nematodes, so I think bacteria have a way larger welfare range per unit mass.
Bacteria collectively have 3.50 k (= 70/0.02) times as much carbon as nematodes.
Nematodes to be much larger than those on humans, farmed animals, and plants:
Nematodes individually have a way smaller mass than humans, farmed animals, and plants, so I think nematodes have a way larger welfare range per unit mass.
Nematodes collectively have 33.3 % (= 0.02/0.06), 20.0 % (= 0.02/0.1), and 0.00444 % (= 0.02/450) times as much carbon as humans, farmed animals, and plants, which I guess is enough for the above effect to dominate.
My recommendations
I recommend being highly sceptical of RP’s mainline welfare ranges, which I believe are bound to be relatively close to 1. A single behavioural proxy likely to be absent, meaning 12.5 % (= (0 + 0.25)/2) likely to be present, implies a welfare range conditional on sentience, and the rate of subjective experience of humans under the pleasure-and-pain-centric model of at least 0.00339 (= 0.125/37) regardless of the simplicity of the organism. The sheet I just linked has meanwhile been made private, but the model considers 37 equally important hedonic proxies whose effect is not moderated by structural properties like the number of neurons.
At the same time, I recommend being even more sceptical of non-systematic approaches to estimate welfare ranges. I think these are at higher risk of being disconnected from empirical evidence, and lacking transparency, thus being harder to improve upon.
For organisms with neurons, I suggest using welfare ranges equal to the geometric mean between the number of neurons as a fraction of that of humans, and RP’s mainline welfare ranges. This ensures the welfare range is not solely determined by structural properties, but that these moderate the effect of behavioural proxies on it. My preferred welfare ranges are below. I used the number of neurons from RP’s neuron count model. This sheet has meanwhile been made private, but there are similar values here.
Animal
Number of neurons
Number of neurons as a fraction of that of humans
RP's mainline welfare range
My preferred welfare range
My preferred welfare range as a fraction of RP's mainline welfare range
Human
8.60E+10
100%
1.00
1.00
100%
Pig
4.30E+08
0.500%
0.515
0.0507
9.85%
Chicken
2.20E+08
0.256%
0.332
0.0291
8.78%
Octopus
5.00E+08
0.581%
0.213
0.0352
16.5%
Carp
1.30E+07
0.0151%
0.0890
0.00367
4.12%
Bee
9.00E+05
0.00105%
0.0710
8.62E-04
1.21%
Salmon
1.30E+07
0.0151%
0.0560
0.00291
5.20%
Crayfish
8.00E+04
9.30E-07
0.0380
1.88E-04
0.495%
Shrimp
8.00E+04
9.30E-07
0.0310
1.70E-04
0.548%
Crab
1.00E+05
1.16E-06
0.0230
1.64E-04
0.711%
Black soldier fly
3.50E+05
4.07E-06
0.0130
2.30E-04
1.77%
Silkworm
8.60E+05
0.00100%
0.00200
1.41E-04
7.07%
I speculate soil microorganisms have a negative welfare per organism-year, as is my best guess for soil nematodes, and therefore recommend decreasing their population. I expect the density of microorganisms to correlate with net primary production, and this to be lower for agricultural land than the counterfactual land use. So I recommend increasing agricultural land to increase the welfare of soil microorganisms. Nonetheless, I guess this is only 50 % likely to be beneficial, as I guess the probability of microorganisms having a negative welfare per organism-year is roughly 50 %, although below this. Relatedly, Brian Tomasik has a post about the welfare of bacteria and plants.
I estimated the cost-effectiveness of funding HIPF from CEARCH accounting for humans, and soil nematodes, mites, and springtails to be 16.5 times the past cost-effectiveness of SWP’s HSI. Nonetheless, I think funding HIPF is way more cost-effective than this due to decreasing the population of microorganisms via increasing agricultural land. As a result, I recommend funding HIPF instead of SWP, or other organisations I had recommended targeting invertebrates.
My top recommendation is decreasing the uncertainty about the welfare in QALY/organism-year of soil microorganisms and nematodes. In particular, it is crucial to know whether they have positive or negative lives. Nevertheless, I am not aware of any opportunities one can support now to make progress on that in a sufficiently targeted way which I consider more cost-effective than funding HIPF. I asked people from the Animal Welfare Fund (AWF), RP, Wild Animal Initiative (WAI), and Welfare Footprint Institute (WFI) about this 2 months ago in the context of soil nematodes, mites, and springtails. Only Cynthia Schuck‑Paim from WFI replied, saying Wladimir Alonso from WFI is working on a project related to assessing differences in hedonic capacity, which I guess relates to this post.
This post presents the executive summary from Giving What We Can’s impact evaluation for 2025. At the end of this post we share links to more information, including the full report and...
I used AI to fix transcription errors, rerrarange the ideas, and suggest tweaks to the title and some sentences.
Three of the most exciting projects to come out of EA in recent years are, in a vague sense, CEA spinouts:
* Kairos is directly a spinout of CEA and now handles most support for university AI safety groups. Basically everyone I've found who knows them is really excited about what they do
* NEST is an opinionated ideas-fi...
Hi Vasco,
Several quick clarifications.
1. It's true that we don't think you can take our methodology and extend it arbitrarily. We grant that it’s very difficult to draw a precise boundary. However, it's standard to develop a model for a purpose and be wary about its application in a novel context. Very roughly, we take those novel contexts to be ones where the probability of sentience is extremely low. We acknowledge that we don’t have a precise cutoff for “extremely low,” as establishing such a cutoff would be a difficult research project in its own right. There are unavoidable judgment calls in this work.
2. RP has done lots of work on animal sentience. It is not all the Moral Weight Project. It is not all connected and integrated. And some of our earliest MWP ideas are ones we later abandoned. What we stand behind now is really just what we published in the book. It is not fair to ask us to tell a coherent story about disconnected projects with different purposes, as well as all stages of the same project, given that different teams worked on these projects and the evolving understanding of people on a team for a given project.
3. We don't think that the assumptions of our "mainline welfare ranges" imply anything about the welfare ranges of plants, nematodes, and microorganisms, as the models simply aren't intended to be used the way you are using them. That's why we aren’t replying to you about the welfare ranges of plants, nematodes, and microorganisms. We would need to do an independent project to form opinions on your questions. Right now, we don’t have the funding for that project.
4. It's understandable that you're skeptical of our specific welfare range estimates. We, of course, are also skeptical of those precise numbers. That's why we've long encouraged people to focus on the order of magnitude estimates. We also disagree that they "are bound to be relatively close to 1." A few orders of magnitude lower than 1 is not close to 1, at least by one reasonable interpretation of "relatively close." Laura has already discussed this elsewhere.
For what it's worth, I think you're approaching the Moral Weight Project as something it is not. You are treating it as a general methodology where we can enter some information about the abilities of a system—whatever that system happens to be—and get out moral weights that we can use in expected value calculations for cause prioritization. But we did not try to produce a maximally general methodology. We tried to produce something useful for updating on the kinds of questions that decision-makers actually face: "Do layer hens matter so much more than carp that, despite the differences in population sizes, you should prioritize layers?" "Can we rule out insects entirely?" “If your job requires you to apply a discount rate to the welfare of some animals relative to others, what kinds of numbers should you consider?” "Is there a good reason for thinking that, even if humans don't literally have lexical priority over animals, they have that kind of priority for practical purposes?" And so on. I do think that the MWP is useful for shedding some light on these questions for some actors. Beyond that, we should be cautious with the outputs. And mostly, we should try to do better, as we only meant to issue the first word.
I estimate effects on soil animals would still be much larger than those on the target beneficiaries for a welfare per animal-year of exactly 0 for animals with fewer neurons than those considered in your book, and "welfare range as a fraction of that of humans" = "number of neurons as a fraction of that of humans"^0.19, which explains very well the welfare ranges in Table 8.6 of your book (78.6 % of their variance for an exponent of 0.188). I calculate soil ants and termites have 2.91 and 1.16 times as many neurons as shrimp, so effects on them would still be relevant. I get the following increase in the welfare of soil ants and termites as a fraction of the increase in the welfare of the target beneficiaries for an exponent of 0.19 (the chicken welfare corporate campaigns would decrease animal welfare):
Thanks, Bob.
Would you be able to provide a range for what is "extremely low", and briefly explain why the probability of sentience of black soldier flies (which are covered in the book) is not extremely low, but that of nematodes is extremely low? I do not know whether your "extremely low" means lower than 10^-10 or 1 %, but I guess the probability of sentience of nematodes may well be over 10 %. From Andrews (2024):
Thanks for clarifying you only stand by what is in the book! I did not know this. Have you communicated this to organisations which have been using the estimates you had shared on EA Forum? I believe the community would find helpful a post where you share what you stand by, and which (expected) welfare ranges you recommend using for comparing welfare across species.
For 10 of 11 species, my preferred welfare range is less than 10 % of the estimate RP shared on the EA Forum (see last table in my post), so I think the vast majority of these is more than 1 order of magnitude too high.
I had understood from your past comment that the methodology is not supposed to apply to all biological systems (and I had already understood it was not supposed to apply to non-biological systems). However, I think it makes sense to trust the methodology less if you believe applying it to silkworms or nematodes produces results which are way less trustworthy than those for black soldier flies (which are covered in the book), as these do not seem that different from the former.
Quick note Vasco
I don't think their book welfare ranges are substantially different from the ones posted on the forum, so practically I don't think it's a big deal for people applying them in CEAdI retract that Vasco, you are correct - I had a quick glance at pigs and chickens and thought they were about the same, for those smaller animals they are indeed far higher. Perhaps it stems from these sentience numbers in the book being higher for Shrimps and Soldier flies than in the forum posts?
Â
Thanks, Nick. Here are the estimates from the book.
The mean for:
There were significant updates for carp, shrimp, and BSF. @vicky_cox, @Neil_Dullaghan🔹 , and @Vince Mak 🔸, you may want to consider the welfare ranges from Bob's book instead of those from RP's post, and stop using the value from RP's post respecting silkworms to model the benefits of interventions targeting farmed arthropods. Bob said "What we [RP] stand behind now is really just what we published in the book", and this does not have estimates for the welfare range of larvae.
The higher values for shrimp and BSF also make me think one would obtain larger welfare ranges applying the book's methodology to less complex organisms (although I know it is not supposed to be extended).
I am not sure whether RP stands by the book's means or medians. Could you clarify this, Bob? In any case, they do not differ much.