What would you do to increase the welfare of sentient soil animals and microorganisms if nothing else was sentient?

By Vasco Grilo🔸 @ 2025-12-20T09:35 (+17)

I think interventions may overwhelmingly change the welfare of soil animals and microorganisms in expectation. So I believe it is useful to imagine what to do if they were certain to be sentient, and all other potential beings, including humans, had a probability of sentience of exactly 0. These are not my actual views. I am only certain that I am sentient right now (not moments ago), and I would say even a Planck volume in deep space vacuum has a probability of sentience higher than 0. However, the hypothetical helps internalise dominant effects on soil animals and microorganisms. The goal would be increasing the welfare of these in the real world, so the views of others should be considered as they are in reality. The vast majority of people would still not care about the subjective experiences of soil animals and microorganisms.

One can increase the welfare of soil animals and microorganisms focussing on:

Increasing the welfare per organism-year, thus improving their lives.
Increasing the number of organisms with positive lives.
Decreasing the number of organisms with negative lives.
Building capacity for the above, such as by:
- Gathering or disseminating evidence that soil animals and microorganisms are more likely to be sentient than others assume (practically 0).
- Researching the conditions under which they have positive or negative lives.
- Finding which interventions cost-effectively change their population.
- Conducting other analyses which can increase funding for work on soil animals and microorganisms.

I think the focus should be on building capacity. For example, I recommend research informing how to increase the welfare of soil animals over pursuing whatever land use change interventions naively seem to achieve that the most cost-effectively. Nevertheless, such research will only be a good fit for a small fraction of people. In this post, I am asking about what you in particular would do in the hypothetical I described above.

I believe work planned with soil animals and microorganisms in mind will tend to be more cost-effective than that optimised around other target beneficiaries. Likewise, I would target (optimise for increasing the welfare of):

Humans in low and middle income countries (LMICs) instead of humans in high income countries (HICs) to increase the welfare of humans in LMICs.
Humans in HICs instead of humans in LMICs to increase the welfare of humans in HICs.
Shrimps instead of chickens to increase the welfare of shrimps.
Chickens instead of shrimps to increase the welfare of chickens.
Dogs instead of chickens to increase the welfare of dogs.
Chickens instead of dogs to increase the welfare of chickens.
AI systems instead of shrimps to increase the welfare of AI systems.
Shrimps instead of AI systems to increase the welfare of shrimps.

Aditya_Karanam @ 2025-12-20T16:43 (+5)

Conduct research to map the source of harms and pleasures that they go through, alongside the weight of their interests. Basically their life history.
Identify interventions to reduce the harms that they go through in a cost effective way.
If they are r strategists and intrinsically are prone to high juvenile mortality, identifying fertility management measures to decrease the harms that they go through.

Vasco Grilo🔸 @ 2025-12-20T21:31 (+2)

Thanks for the good points, Aditya! I wonder how one would increase the funding and researchers available for such research.

Henry Howard🔸 @ 2025-12-20T10:27 (+4)

Can you give some examples of what research you could do to improve our understanding about either 1. whether soil microbes are sentient, or 2. whether their average life experience is net positive or negative?

These both seem completely unanswerable. with a billion dollars and no other interests I wouldn't know where to begin answering these questions.

Vasco Grilo🔸 @ 2025-12-20T11:39 (+7)

Thanks for the comment, Henry!

On 1, Rethink Priorities (RP) could extend their welfare range table to cover soil ants, termites, springtails, mites, nematodes, and some microorganisms. I would also like to see much more work informing interspecies comparisons of expected hedonistic welfare. RP's research agenda about interspecies welfare comparisons has some question about that. There could also be more research related to @Wladimir J. Alonso's and @cynthiaschuck's post on whether primitive sentient organisms feel extreme pain. "This discussion is part of a broader manuscript in progress, focusing on interspecific comparisons of affective capacities—a critical question for advancing animal welfare science and estimating the Welfare Footprint of animal-sourced products".

On 2, it would be helpful to have detailed descriptions of the life-fates of soil animals and microorganisms. Ideally, there would be a quantitative break-down of how organisms of a given species in certain conditions spend their time. For example, how much time they spend eating, drinking, mating, being eaten, being crushed, sleeping, and having certain diseases. I know about a private project proposal to investigate the life-fates of springtails, mites, or nematodes.

I know about 2 project proposals for researching the welfare of soil animals. They are not public, but one will most likely start next year. I hope there will be more related projects. People are welcome to fill this very short form if they are interested in funding research informing how to increase the welfare of soil animals.

Henry Howard🔸 @ 2025-12-23T14:43 (+6)

None of that suggested work seems very clarifying

The welfare ranges are extremely broad for the animals they do cover, and that's with questionable assumptions. I don't see how extending these to microbes would clarify anything.

Doing "more research" on the day-to-day experience of nematodes and how they respond to noxious stimuli or calculating their neural energy consumption as a proxy for their ability to suffer also doesn't seem clarifying. Imagine you knew all this information about nematodes. Still the fundamental question will remain how their "suffering" or "joy" compares to ours and how morally important it is. A lot of animal ethics is driven by our ability to relate to animals ("I can relate somewhat to a chicken and I wouldn't want to be a chicken in a cage") but this falls apart by the time we get to nematodes, so you have to rely solely on your numbers, which will be extremely uncertain.

I remain very puzzled how you ever see us getting low enough error bars on the joy/suffering of microscopic worms that we could make decision based on it.

Vasco Grilo🔸 @ 2025-12-23T15:39 (+4)

Thanks for the pushback, Henry!

The welfare ranges are extremely broad for the animals they do cover, and that's with questionable assumptions. I don't see how extending these to microbes would clarify anything.

I have come to believe this is a very fair objection. I believe you have acknowledged the uncertainty in RP's welfare ranges much better than me in the past. At the same time, RP extending their welfare range table to soil animals and microorganisms (which does not involve calculating welfare ranges; it would just be a literature review) would help decrease the uncertainty about their (expected hedonistic) welfare.

Imagine you knew all this information about nematodes. Still the fundamental question will remain how their "suffering" or "joy" compares to ours and how morally important it is.

Great point. I would currently prioritise decreasing the uncertainty about how the welfare of soil animals and microorganisms compares with that of humans over investigating ways of increasing their welfare. I asked RP 2 days ago about whether they "have any plans for projects decreasing the uncertainty of interspecies comparisons of expected hedonistic welfare".

I remain very puzzled how you ever see us getting low enough error bars on the joy/suffering of microscopic worms that we could make decision based on it.

I do not know about any intervention which robustly increases welfare, and I am not confident this will ever change. However, I do not think people should give up on increasing welfare before much more effort is put into decreasing the uncertainty about interspecies comparisons of expected hedonistic welfare.