PhDs in physics (thermodynamics of ecosystems), moral philosophy (animal rights) and economics (altruistic motivation and incentives for blood donation), co-founder of EA Belgium, environmental footprint analyst at Ecolife
Stijn Bruers 🔸
Karma: 1,023
Ok, let me exaggerate a bit. Assume when state S=(X,Y,Z)=(87455.668741, −258.142567, −11024.441253), you are indifferent with nonexistence. Now consider state S’=(87455.668741, −258.142567, −11024.441153). You can confidently say that S’ gives you a positive welfare? If yes: close your eyes and write down, for the given X and Y of state S, a value of Z that gives you a positive welfare lower than S’. I bet your brains are too small to do this exercise. Now consider a nematode with much smaller brains....
Perhaps we should run a survey, ask people if they have a neutral range. Can they give values of X, Y and Z such that if they would experience X, Y and Z units of some welfare determining components, they would be indifferent between that experience and non-existence, whereas if they had X+dX, Y and Z units, they would state a positive welfare and X-dX, Y and Z units would correspond with a negative welfare. I’m personally very skeptical that most people’s neutral ranges are zero. You claim to have a zero neutral range?
I guess you’re suggesting that the neutral range is not well-defined? When experiences are composed of positive and negative parts without correct weighting, the neutral range could be larger than when experiences are more dominated by either positive or negative parts? I’m open to such a possibility.
Well, I’ll probably move to teaching at high school. It got me thinking...
I also feel the increased competition with AI. I underestimated how important it became to learn to use state of the art AI https://80000hours.org/2025/04/to-understand-ai-you-should-use-it-heres-how-to-get-started/
I implicitly assumed the welfare range includes zero.
About the intransitivity argument: The comparison of the X seconds of breeze and the lecture is a coarse-grained comparison, i.e. in a coarse-grained frame. Also comparing X+1 seconds of breeze with the lecture is in a coarse-grained frame. But comparing X with X+1 seconds of breeze is fine-grained. So the comparisons assume different frames, as with reference frames in special relativity and welfare frames in utilitarian ethics.
Thanks for the reference. I quickly read that paper, and at the very end the authors seem to defend what I interpret as an account of incommensurability (the part about context-sensitivity). Perhaps I misunderstand that paper, but anyway, I’m not yet convinced that incommensurability of welfare is impossible, in particular because of the analogy with special relativity, where time is really (mathematically) incommensurable: the notion of ‘now’ depends on the reference frame.
I can relate to that. In the past 2 years, I applied for almost 50 positions at 30 EA-aligned organizations, with no success. (Yet, I have 3 PhD’s, am president and co-founder of EA Belgium) Especially the remote jobs are extremely competitive.
yes, this was a fruitful discussion; thanks! I summarized my arguments here: https://forum.effectivealtruism.org/posts/udcCBBwGnCneLRjkH/should-we-consider-the-welfare-of-small-soil-animals-on-the
Should we consider the welfare of small soil animals? On the special relativity of welfare
Yes, I think newborns can compare their welfare with non-existence, to a small degree, but I’m uncertain about it. That is why I think it is so difficult to estimate whether my newborn sons have a positive or negative welfare. I tend to believe that my first son had a negative welfare the first few weeks and positive now, and my second son (who is a month old and lying next to me now) has an average positive welfare these days. But it could easily be indeterminate. For a nematode I’m much more confident that it is indeterminate. A question I would ask is: would the most empathic veterinarians prefer to euthanize a nematode, like they prefers to euthanize a dog when that dog has a negative welfare? I doubt it. Would the most empathic total utilitarians prefer to breed more nematodes, like they prefer the existence of more individuals with positive welfare? I doubt it. Would those people believe that a nematode happens to have exactly 0 welfare? I doubt it. So a nematode’s welfare is not clearly negative, not clearly positive, and not clearly zero. Then what is it? It’s incommensurable with 0.
I wrote some ideas about that neutral range here:
Yes, if a nematode’s neutral range was smaller or zero, I would say that there is an objective fact of the matter whether the nematode has positive or negative welfare. just like when speed of light is infinite, there is an absolute reference frame, and every space-time event is either in the future, the present or the past of this space time-event I call “now!” That’s Newtonian physics.
Your case would be like assigning a probability of 0 to the possibility that the speed of light is finite. Note that the fact that welfare is continuous, is irrelevant: also time in special relativity is continuous.
The crucial issue is that a nematode may not be able to compare its welfare with non-existence. Even for me it may be hard to compare welfare with non-existence, i.e. imagining a level of welfare at which I would be indifferent with non-existence. I believe there is not always a straightforward answer, even under hedonism, when one’s welfare is at a similar level as non-existence. Just as in special relativity there is not always a straightforward answer when a space-time event happens now. Still, in special relativity, time is a continuous variable that can in principle be measured with infinite accuracy (i.e. clocks could in principle be infinitely well-calibrated in the theory of special relativity). So the notion of time makes perfect sense in special relativity, but the notion of “now” does not. Similarly: the notion of welfare makes perfect sense in hedonism, but the notion of zero welfare does not.
Yes, we are missing quantitative estimates for determining zero welfare of nematodes and insects. Like we do not know the speed of light. All I can say is that in the special relativity analogy, a nematode has a “lower speed of light” than an insect. And sure, I consider it likely that even insects have a welfare range that is smaller than the neutral range. This neutral range is the range of welfare levels that are incommensurable with zero, or the range of welfare levels for which there always is a valid welfare frame such that the welfare is zero. If the welfare range is smaller than the neutral range, it is always impossible to objectively/absolutely determine whether a welfare is positive or negative: there is always a valid welfare frame for which the welfare is positive, and another equally valid welfare frame for which the welfare is negative. This is all compatible with hedonism. I guess you assume in your hedonic theory, the speed of light is infinite, which means there is one absolute welfare frame (as in Newtonian physics there is one absolute reference frame). The more I think about it, the more skeptical I am about that assumption of an absolute welfare frame.
I still prefer the special relativity analogy, because its mathematical structure is similar to what I have in mind about welfare of nematodes. Your alcohol temperature analogy seems to be misleading, because it speaks about over- and underestimations and being well calibrated, but that is not the issue. The clocks of observers in special relativity are all well-calibrated, no clock overestimates time. And yet there is this weird kind of intransitivity in special relativity, where space-time events X and Y happen simultaneously (at time 0), space-time event Z is in the future of Y, and yet events X and Z also happen simultaneously (at time 0, but according to another reference frame). Same goes for nematode welfare: nematode in state X (non-existence) and Y have the same welfare (equal to 0), the nematode in state Z is strictly happier than in Y, and yet there is a welfare frame according to which states X and Z are equally good (welfare 0).
I believe (farmed) insects have a wider welfare range than nematodes, which means it is less likely that all their positive and negative experiences are incommensurable with non-existence. An insect can be so miserable that its welfare is negative according to all welfare frames, in which case it is objectively/absolutely true that that insect has a negative welfare. A nematode cannot reach such intense levels of misery.
To make the analogy with the scale more accurate: suppose mass could also be negative (because welfare can be negative), and most of all: suppose Newton’s law would use the measured mass, as measured on that scale. The latter would be a bit like quantum mechanics, as if the feather is in a superposition of different masses, and doing a quantum measurement with that scale gives its mass that enters Newton’s law. Then the question whether the mass of the feather is positive or negative, is ill-defined when the feather is in a superposition of both positive and negative masses.
A better physics analogy is Einstein’s theory of special relativity. Suppose you and I have super accurate clocks. I determine that “now!” corresponds with time zero. Relative to my “now!”, there are events in the past and future. But suppose you also determined your “now!” as time zero on your clock. And suppose the space-time event that corresponds with you saying “now!” lies outside the lightcone of my “now!” space-time event. The question is: is your “now!” in the future or the past of my “now!”? When the speed of light is finite, this question is always ill-defined, even if we had infinitely accurate clocks. You can always pick a reference frame according to which your “now!” exactly corresponds with time zero on my clock (yes, with infinite precision; what a coincidence!). And pick another reference frame according to which your “now!” is in the future of my “now!”. In the analogy, the time of your “now!” on my clock, corresponds with the welfare of the nematode relative to non-existence. My “now!” corresponds with zero welfare of non-existence, your “now!” corresponds with the welfare of the nematode. If your “now!” is in the future (past) of my “now!”, that corresponds with a positive (negative) welfare of the nematode. The different reference frames in special relativity correspond with different ‘welfare frames’ of the nematode. So even if a nematode could measure physical forces with infinite precision, and would be sensitive to the pain of the slightest increase in a physical force, it would still be impossible to say whether the nematode has a positive or negative welfare. I can compare my welfare with non-existence to a high degree, but not infinitely accurately. In the special relativity analogy, this corresponds with a space-time with a very high lightspeed. But for the nematode, the comparison with non-existence is much more difficult, which would correspond with a space-time with a very low speed of light. If the speed of light is extremely low, or say zero, almost all your space-time events are outside my lightcone, which means you can pick any moment along your timeline and I can pick a reference frame according to which that moment is in the future of my “now!”. With the nematode: pick any full description of its experiences, the physical forces that it feels and so on, and I can pick a welfare frame according to which that nematode has a positive welfare, and you picked a welfare frame according to which that same nematode, with the very same experiences, has a negative welfare. There is no objective way to determine which of our welfare frames is the correct one. If a nematode’s welfare range is very small, it is likely that all its experiences that it could possibly have always lead to a welfare level that is incommensurable with zero, even if the nematode could measure its own welfare with infinite precision.
As for the TAI: the point is that I can give another equally reasonable/valid definition of a TAI as the one of Metaculus, and there is no objective way to determine which of our definitions is the correct one. This intrinsic indeterminacy of the definition results in the incommensurability of the timelines. I can always pick a definition according to which the arrival of TAI is after 2039, even if according to Metaculus’ definition of TAI, the arrival is exactly in 2039 and we can measure that arrival date with infinite precision. The different definitions of TAI correspond with the different reference frames in special relativity, and the different welfare frames of the nematode.
I expect if someone’s welfare range is very small, it is more likely that its welfare is incomparable to (incommensurable with, on par with, neither better nor worse nor equal to) non-existence. When I look at my welfare, I try to imagine the average welfare W I would have over a period of say a month, that would make me indifferent between living that month versus non-existence. That welfare level W corresponds to 0 (by definition of zero welfare). Now imagine that same month, but with a tiny bit of extra happiness, for example the taste of one extra piece of chocolate. The welfare is W+dW (with W=0 and dW small). However, I think I would still be indifferent between living that month (with the extra chocolate) and non-existence. Hence, W+dW is also 0. In other words, my indifference curve is rather an indifference band. I believe I have such small indifference bands when it comes to comparing my welfare with non-existence. Now, the width of my indifference band is easily larger than your estimated welfare range of a nematode. You see where this is heading? If the nematode would have an equally wide indifference band as me when it comes to comparing its actual welfare with non-existence (and I have no reason to believe it is otherwise), and if its welfare range is smaller than this indifference band, then all its welfare levels are incomparable with non-existence, or indifferent from 0.
The analogy with TAI timelines: there are many ways to define TAI, based on the set of capacities of the AI. Suppose I say that a TAI needs to have capacities S, and I believe those capacities are reached by the year 2030. Now you may have another definition of TAI, with another set of capacities S’. That will correspond with another timeline, say 2035. The crucial problem is: there is no objective way to determine which definition of TAI is the correct one. So there is no objective way to uniquely determine the timeline. There is rather a range of timelines.
The crucial consideration is not about the welfare range, but about the welfare sign: whether a nematode’s welfare is positive or negative. According to your reasoning, (animal) agriculture is very good if nematode’s welfare is slightly negative and very bad if it is slightly positive, even if the welfare range is small. Some people believe the welfare sign is negative, others say it is positive, I expect most people believe it is around zero. There does not seem to be any consensus about the welfare sign. And we have no clue how we can possibly answer this question, what research method we could possibly use to determine the welfare sign. This is even more difficult than determining whether a nematode is sentient. I don’t expect a solution the next decades. Therefore, I would say the welfare sign of a nematode is indeterminate: the question whether the welfare is positive or negative is ill defined. According to one reference frame, it is negative, according to another equally valid reference frame, it is positive. There is no objective, unique, absolute sign of a nematode’s welfare. As in Einstein’s special relativity, the moment ‘now’ for another observer (like the welfare ‘zero’ for another sentient being) is ill defined and depends on your frame of reference (e.g. whether you move towards or away from that observer). So in a sense it is meaningless to say a nematode’s welfare is negative. This implies that we can basically neglect effects that change the size of the nematode population. Saying that animal agriculture is good or bad because it decreases the size of the nematode population, becomes meaningless.
A small remark: your welfare range estimate has three significant digits, which I find very weird given the large uncertainty range. Instead of writing 6.68*10^-6, which gives a false impression of accuracy, I would rather write ‘around 10^-5’. (I hate it when my students give overly exact estimates with many digits.)
Also: I tend to believe that, as with the welfare sign, a nematode’s welfare range is not exact and has no unique, objective, absolute value. There is a range of valid values for the nematode’s welfare range. The intensity of welfare experiences of a nematode and a human are intrinsically incomparable. Like asking the question whether ‘i’ (the square root of minus 1) is larger or smaller than 1: that is mathematically meaningless, because there are different, equally valid metrics one could use.
The crucial consideration is whether those small invertebrates have a positive or negative welfare significantly different from zero. My best guess is that for those animals, their average welfare is incommensurable with zero, where zero represents the welfare in the state of non-existence. That means a nematode with welfare X can be considered equally good as a non-existing nematode, and increasing that nematode’s welfare to X+dX can still be considered equally good as non-existence. In this case, we can neglect population-changing effects on soil nematodes. The effects of agriculture on nematodes are such population-changing effects (agriculture decreases the population sizes of small soil invertebrates), and hence can be neglected.
I haven’t yet read the direct economic benefit studies: can you briefly say what are those extra jobs? I don’t see why plant-based food production would be more labor intensive. And what types of jobs are those? High or low-skilled jobs?
My arguments why meat offsetting is impermissible (and hence personal veganism is a moral duty): https://stijnbruers.wordpress.com/2019/08/22/carbon-offsetting-versus-meat-offsetting/
I’d like to see a few more surveys on moral weights, with larger samples of both animal welfare experts and lay people, than this small one (n=100) I conducted in Belgium https://brill.com/view/journals/jaae/7/1/article-p91_6.xml
You raised a good point. Yes, I guess I agree that when there is only a positive experience and no negative, the welfare is definitely positive, even if the positive experience is very small. But thinks get tricky when there are both positive and negative experiences, as is the case for almost all sentient beings, and probably also for nematodes if they are sentient. The more welfare is composed of positive and negative parts, the more difficult it becomes to compare it with a zero welfare level. Might have to do with information processing capacity. Adding up many positives and negatives is more difficult that considering a single positive or negative value. Evaluating mixed experiences (with both positive and negative parts) might require a more coarse-grained approach. The level of coarse-graining might relate to the neutral range: the more coarse-graining is used, the wider the neutral range.