Summary

  • I Fermi-estimated the scale of the welfare of various animal populations from the relative intensity of their experiences, moral weight, and population size.
  • Based on my results, I would be very surprised if the scale of the welfare of:
    • Wild animals ended up being smaller than that of farmed animals.
    • Farmed animals turned out to be smaller than that of humans.
An abstract oil painting of nematodes. Generated by OpenAI's DALL-E.

Introduction

If it is worth doing, it is worth doing with made-up statistics?

Methods

I Fermi-estimated the scale of the welfare of various animal populations from the absolute value of the expected total hedonistic utility (ETHU). I computed this from the product between:

  • Intensity of the mean experience as a fraction of that of the worst possible experience.
  • Mean moral weight.
  • Population size.

The data and calculations are here.

Intensity of experience

I defined the intensity of the mean experience as a fraction of that of the worst possible experience based on the types of pain defined by the Welfare Footprint Project (WFP) here (search for “definitions”). I assumed:

  • The following correspondence between the various types of pain (I encourage you to check this post from algekalipso, and this from Ren Springlea to get a sense of why I think the intensity can vary so much):
    • Excruciating pain, which I consider the worst possible experience, is 1 k times as bad as disabling pain.
    • Disabling pain is 100 times as bad as hurtful pain, which together with the above implies excruciating pain being 100 k times as bad as hurtful pain.
    • Hurtful pain is 10 times as bad as annoying pain, which together with the above implies excruciating pain being 1 M times as bad as annoying pain.
  • The intensity of the mean experience of:
    • Farmed animal populations is as high as that of broiler chickens in reformed scenarios. I assessed this from the time broilers experience each type of pain according to these data from WFP (search for “pain-tracks”), and supposing:
      • The rest of their time is neutral.
      • Their lifespan is 42 days, in agreement with section “Conventional and Reformed Scenarios” of Chapter 1 of Quantifying pain in broiler chickens by Cynthia Schuck-Paim and Wladimir Alonso.
    • Humans and other non-farmed animal populations is as high as 2/3 of that of hurtful pain. 2/3 (= 16/24) such that 1 day (24 h) of such intensity is equivalent to 16 h spent in hurtful pain plus 8 h in neutral sleeping.

Ideally, I would have used empirical data for the animal populations besides farmed chickens too. However, I do not think they are readily available, so I had to make some assumptions.

In general, I believe the sign of the mean experience is:

  • For farmed animal populations, negative, judging from the research of WFP on chickens.
  • For humans, positive (see here).
  • For other non-farmed animal populations, positive or negative (see this preprint from Heather Browning and Walter Weit).

Moral weight

I defined the mean moral weight from Rethink Priorities’ median estimates for mature individuals[1] provided here by Bob Fischer[2]. For the populations I studied with animals of different species, I used those of:

  • For wild mammals, pigs.
  • For farmed fish, salmon.
  • For wild fish, salmon.
  • For farmed insects, silkworms.
  • For wild terrestrial arthropods, silkworms.
  • For farmed crayfish, crabs and lobsters, mean between crayfish and crabs.
  • For farmed shrimps and prawns, shrimps.
  • For wild marine arthropods, silkworms.
  • For nematodes, silkworms multiplied by 0.1.

Population size

I defined the population size from:

  • For humans, these data from Our World in Data (OWID) (for 2021).
  • For wild mammals, the mean of the lower and upper bounds provided in section 3.1.5.2 of Carlier 2020.
  • For farmed chickens and pigs, these data from OWID (for 2014).
  • For farmed fish, the midpoint estimate of this analysis from Kelly Anthis and Jacy Anthis (for 2019).
  • For wild fish, the mean between the mean of the lower and upper bounds provided in section 3.1.5.5 of Carlier 2020, and the order of magnitude given in Table S1 of Barn-On 2018.
  • For farmed insects raised for food and feed, the mean of the lower and upper bounds provided here by Abraham Rowe (in the 2nd point of the section “Key Findings”).
  • For farmed crayfish, crabs and lobsters, and farmed shrimps and prawns, the ratio between the means of the lower and upper bounds for:
  • The number of individuals killed per year provided here by fishcount.org (for 2017).
  • The time in years farmed shrimps spend in grow-out ponds, developing from juvenile until market size, according to this Wikipedia page.
  • For wild terrestrial and marine arthropods, and nematodes, the orders of magnitude from Table S1 of Barn-On 2018.

Results

The results are presented in the table below by descending absolute value of ETHU as a fraction of that of humans, i.e. decreasing scale of welfare.

Population

Intensity of the mean experience as a fraction of that of the worst possible experience

Mean moral weight

Population size

Absolute value of ETHU

Absolute value of ETHU as a fraction of that of humans

Farmed insects raised for food and feed

1.96E-5

2.00E-3

8.65E10

3.38E3

0.0642

Farmed pigs

1.96E-5

5.15E-1

9.86E8

9.93E3

0.188

Humans

6.67E-6

1.00

7.91E9

5.27E4

1.00

Farmed crayfish, crabs and lobsters

1.96E-5

3.05E-2

1.57E11

9.38E4

1.78

Farmed fish

1.96E-5

5.60E-2

1.11E11

1.22E5

2.31

Farmed chickens

1.96E-5

3.32E-1

2.14E10

1.39E5

2.64

Farmed shrimps and prawns

1.96E-5

3.10E-2

9.87E11

5.98E5

11.3

Wild mammals

6.67E-6

5.15E-1

6.75E11

2.32E6

43.9

Wild fish

6.67E-6

5.60E-2

6.20E14

2.31E8

4.39 k

Wild terrestrial arthropods

6.67E-6

2.00E-3

1.00E18

1.33E10

253 k

Wild marine arthropods

6.67E-6

2.00E-3

1.00E20

1.33E12

25.3 M

Nematodes

6.67E-6

2.00E-4

1.00E21

3.91E12

74.2 M

Discussion

According to my results:

  • The intensity of the mean experience of farmed chickens, estimated from data for broilers in reformed scenarios, is 2.93 (= 19.6/6.67) times as high as that of humans. Intuitively, I would guess the ratio to be higher, but I believe I am biassed towards overweighting the time in disabling and excruciating pain. This is indeed super bad, but does not last for long.
  • Wild animal welfare dominates. Among the 12 populations I analysed, the 5 whose welfare has the largest scale respect wild animals, and the 7 lowest scale farmed animals and humans. This did not surprise me given the sheer numbers of wild animals.
  • The order of the scale of welfare among wild animals roughly matches what I estimated here based on the total number of neurons, with arthropods and nematodes being the major drivers. The welfare of nematodes has a greater scale here, but my guess for the moral weight of nematodes has quite low resilience.
  • Among the populations of farmed animals and humans, the welfare of insects raised for food and feed has the lowest scale. I actually expected it to be larger, but I think I was overestimating their population size.
  • There is a meat-eater problem. The combined importance of the 4 populations of farmed animals I analysed is 18.1 (= 1.78 + 2.31 + 2.64 + 11.3) times as large as that of humans. Consequently, a smaller human population will tend to increase welfare in the nearterm if we ignore the effects on wild animals. However, these dominate, and can be positive or negative, so I have no idea what is the overall nearterm effect of changing the size of the human population. For similar reasons, I think it is very hard to say whether GiveWell’s top charities are beneficial or harmful.

The specific ordering of the various animal populations by scale of welfare I got is not robust given the high uncertainty of my results. However, I would be very surprised if the scale of the welfare of:

  • Wild animals ended up being smaller than that of farmed animals.
  • Farmed animals turned out to be smaller than that of humans.

I would say any scope-sensitive ethic will lead to these conclusions, not just expectational total hedonistic utilitarianism.

  1. ^

     This post from Bob Fischer looks into the moral weight of juvenile insects.

  2. ^

     Bob Fischer shared the means here, but recommended using the medians.

39

New Comment
6 comments, sorted by Click to highlight new comments since: Today at 9:24 PM

Thanks for writing this!

You might be able to make some informed guesses or do some informative sensitivity analysis about net welfare in wild animals, given your pain intensity ratios. I think it's reasonable to assume that animals don't experience any goods as intensely good (as valuable per moment) as excruciating pain is intensely bad. Pleasures as intense as disabling pain may also be rare, but that could be an assumption to vary.

Based on your ratios and total utilitarian assumption, 1 second of excruciating pain outweighs 11.5 days of annoying pain or 1.15 days of hurtful pain, or 11.5 days of goods as intense as annoying pain or 1.15 days of goods as intense as hurtful pain, on average.

Just quickly Googling for the most populous groups I'm aware of, mites, springtails and nematodes live a few weeks at most and copepods up to around a year. There might be other similarly populous groups of aquatic arthropods I'm missing that you should include, but I think mites and springtails capture terrestrial arthropods by moral weight. I think those animals will dominate your calculations, the way you're doing them. And their deaths could involve intense pain and perhaps only a very small share live more than a week. However, it's not obvious these animals can experience very intense suffering at all, even conditional on their sentience, but this probability could be another sensitivity analysis parameter.

(FWIW, I'd be inclined to exclude nematodes, though. Including them feels like a mugging to me and possibly dominated by panpsychism.)

Ants may live up to a few years and are very populous, and I could imagine have relatively good lives on symmetric ethical views, as eusocial insects investing heavily in their young. But they're orders of magnitude less populous than mites and springtails.

Although this group seems likely to be outweighed in expectation, for wild vertebrates (or at least birds and mammals?), sepsis seems to be one of the worst natural ways to die, with 2 hours of excruciating pain and further time at lower intensities in farmed chickens (https://welfarefootprint.org/research-projects/cumulative-pain-and-wild-animal-welfare-assessments/ ). With your ratios, this is the equivalent of more than 200 years of annoying pain or 20 years of hurtful pain, much longer than the vast majority of wild vertebrates (by population and peehaps species) live. I don't know how common sepsis is, though. Finding out how common sepsis is in the most populous groups of vertebrates could have high value of information for wild vertebrate welfare.

Ah, welfare range estimates may already be supposed to capture the probability that an animal can experience intense suffering, like excruciating pain.

(FWIW, I'd be inclined to exclude nematodes, though. Including them feels like a mugging to me and possibly dominated by panpsychism.)

I included nematodes because they are still animals, and think seriously attempting to estimate (as opposed to guessing as I did) their moral weight would be quite valuable. From my results, the scale of welfare of an animal group tends to increase as the moral weight decreases (assuming the same intensity of the mean experience as a fraction of that of the worst possible experience). If the moral weight of nematodes turned out to be so small that the scale of their welfare was much smaller than that of wild arthropods, we would have some evidence, although very weak one, that the scale of the welfare of populations of beings less sophisticaded than nematodes[1] would also be smaller.

I suppose there is very little data relevant to assessing the moral weight of nematodes. However, it still seems worth for e.g. Rethink Priorities to do a very shallow analysis.

  1. ^

    From Table S1 of Bar-On 2017, bacteria (10^30), fungi (10^27), archaea (10^29), protists (10^27), and viruses (10^31). 

Thanks for the comments, Michael!

I definitely agree there are lots of potential improvements. In general, Rethink Priorities' Moral Weight Project made a great contribution towards quantifying the moral weight of different species, but it is worth having in mind there could be significant variation of the intensity of the mean experience (relative to the moral weight) across species and farming environments too.

Great post! Some points:

  • Insect farming is a relatively new and "rapidly growing" industry, which may help explain why the insect welfare scale was the lowest.
  • One piece of good news regarding the meat-eater problem is that humans seem to reduce wild invertebrate populations, and that there are many ethical arguments pointing to these invertebrates living net negative lives. There's some reason to believe that this dominates our (horrific) treatment of farmed animals.
     

Hi Ariel,

Great to know you liked the post!

Insect farming is a relatively new and "rapidly growing" industry, which may help explain why the insect welfare scale was the lowest.

Yes, nice point! In any case, the scale of the welfare of farmed insects being lower does not mean we should not try to mitigate it. One should also have tractability and neglectedness in mind, and these may well be higher earlier. So current efforts may well be especially cost-effective.

One piece of good news regarding the meat-eater problem is that humans seem to reduce wild invertebrate populations

I think net change in forest area is a major driver for the impact of humans on terrestrial arthropods. So, since humans have historically caused deforestation, and deforested areas have less terrestrial arthropods, I can see why humans have decreased the population of terrestrial arthropods. However, forest area is now increasing in many countries. From OWID:

So I think there is not a clear answer.

there are many ethical arguments pointing to these invertebrates living net negative lives

From reading Brian Tomasik's (great!) posts, I also got the impression wild animals have net negative lives. Meanwhile, I have become essentially agnostic. From here: