How Much Do Wild Animals Suffer? A Foundational Result on the Question is Wrong.

NOTE: I would like to clarify that the post below and the published paper show that a result from 1995 does not hold, but they do NOT make the case for the 1995 model being correct. There are many reasons the models in both papers are likely to be deeply flawed: path dependency, dynamic ecosystems, philosophical problems with the definition of suffering and enjoyment, and so on. The primary point here is to treat the 1995 result and other work on wild animal suffering with caution.

In 1995, Yew-Kwang Ng wrote a groundbreaking paper, "Towards welfare biology: Evolutionary economics of animal consciousness and suffering" that explored the novel question of the wellbeing of wild animals as distinct from the conservation of species. As perceptive as it was innovative, the paper proposed a number of axioms about evolution and consciousness to study which animals are sentient, what their experiences are, and what might be done about it.

Among the many results in the paper was the Buddhist Premise, which stated that under reasonable conditions, suffering should exceed enjoyment for the average wild animal. The finding matches the intuitions of many people who have thought about the issue and concluded that nature is "red in tooth and claw" in Alfred, Lord Tennyson's phrase. As it turns out, though, this "evolutionary economics" argument is wrong. This week, Ng and I published a new paper showing that the original "Buddhist Premise" does not hold: under the model in the paper, the balance of suffering and enjoyment can go either way.

The mistake in the original paper may appear technical, but it is suggestive of an aspect of wild animal suffering that prevailing intuitions in the space may miss. Our paper basically points out a math mistake in the proof that total suffering exceeds total enjoyment in nature based on a set of assumptions about the evolutionary benefits of consciousness and affective states. Ng's original paper offered an intuitive argument in addition to the mathematical one, though. Most wild animals have far more offspring than can survive to maturity, so the experience of an average animal is to be born and then nearly immediately suffer a horrible death. Based on this, Ng speculated that the Buddhist Premise should hold before offering a proof of it based on the axioms.

But the intuitive argument misses a potential evolutionary pressure the math picks up. Because the costs (e.g. resource usage) of suffering depend on the probability of experiencing suffering, when the probability of suffering increases, the severity of suffering should decrease. In other words, if the probability of being born and then immediately dying is sufficiently high, then increasing the amount of suffering is less advantageous for genetic reproduction.

Note well: suffering may very well dominate enjoyment in nature. We cannot arrive at a conclusion on that. Our point is that it does not necessarily dominate.

For me, the paper leads me to suspect that the view that suffering predominates in nature may be anchored on an incorrect result. Few people explicitly give the technical argument from the 1995 paper in conversations about wild-animal wellbeing, so it might seem to not be that influential. If you look at writings on wild-animal wellbeing, though, you find that many academic and lay research cite Ng (1995) and often cite multiple sources that all cite Ng (1995) for the claim that suffering should dominate enjoyment in nature. Many more people than realize it may have been influenced by this result. Our new paper does not show that enjoyment predominates, but it does give reason to pause and reflect on work to date.


  1. (Allowing myself to post this comment in a few different places)

    Thanks for engaging with this important subject, Zach. A better understanding of the lives of non-humans in nature is very important.  

    I must say that I think there is a problem with underspecified terms and tacit assumptions in the article. Though to be fair, this is very common in all of EA.

    The issue lies in what it means to say things like “more suffering than happiness” as well as what follows from this and (seemingly) similar claims. For example, talking about “whether suffering or enjoyment is more common” (p. 3) sounds rather descriptive, whereas saying that, or whether, “suffering predominates” (ibid.) will often have evaluative and/or moral connotations. The same is true of a term like welfare: it often has an evaluative/axiological meaning as opposed to a purely descriptive one (see e.g. sec. 1.1.1 here:

    Indeed, the question as to “whether suffering predominates” can mean at least three very different things, and the article seems, as far as I can tell, to implicitly refer to all of them at the same time (especially in the introductory and concluding sections). At any rate, there appears to be a lack of clarity about it.

    For one, it may refer to a purely descriptive statement: there is a greater quantity of happiness than suffering, by some given measure. (And this, in turn, implies further questions concerning how one indeed measures happiness and suffering, in particular how one measures them against each other, and whether they are even commensurable, not just evaluatively but also in purely descriptive terms, cf. and

    Second, it may mean something along evaluative lines such as “there is more positive value than negative value” in the existing happiness and suffering respectively. And this is a very different claim in that one can claim there is far more happiness than suffering in the world, by some given measure, yet still maintain that the disvalue of the suffering is far greater than the value of the happiness. Indeed, quite a number of philosophers and traditions in the East (cf. and the West (including Epicurus and Schopenhauer) have defended views according to which the disvalue of suffering dominates that of happiness entirely; for recent defenses of such views, see Gloor: and Wolf:

    Third, one can think there is far more happiness than suffering in the world, even in evaluative terms, yet still think the suffering carries much greater moral/deontic significance; asymmetries of this kind have in fact been defended by quite a few prominent philosophers, including W. D Ross, cf. sec. 2.5 here:

    Beyond that, there are also issues concerning intra and inter-personal trade-offs: even if most lives in nature contain far more happiness than suffering (by some assumed measure), this would not mean that the happiness of some beings can ever outweigh the suffering of others, either in evaluative terms or deontic terms. Many ethicists accept intra-personal trade-offs while rejecting inter-personal ones (for instance Richard Ryder and Stevan Harnad, and to some extent Jamie Mayerfeld).


  2. The perhaps most important question to ponder deeply, in my view, is whether we think any amount of happiness can morally outweigh the very worst of suffering. I have argued in the negative:
    And so have philosophers Jamie Mayerfeld, Joseph Mendola, Ingemar Hedenius, and Ragnar Ohlsson, among others.

    Just thought this was worth pointing out. Notions of “net negative” and “net positive” lives — as pertaining both to single individuals and (especially) to groups — require serious unpacking in terms of their meaning and assumed evaluative and moral implications.

  3. Thanks for those very thoughtful and well-referenced comments, Magnus V. These are things I've been thinking for a long time (i.e., that happiness should not be considered to "outweigh" suffering in any meaningful way) but have not been able to express anywhere near as well.
    And to Zach, I am looking forward to reading your paper, though I share Magnus V's concerns.

  4. Thanks for this, Magnus. These are all very good points, and I will keep this in mind in future discussions. Our claim is decidedly the first type, a descriptive claim (although some, especially economists, have tried to say that this claim is actually normative even if it appears descriptive).

    Regarding the second and third sorts of claims, while the paper does not address it, I find the asymmetry in the second claim untenable, though I'm aware there's disagreement. The third claim to me seems like it must be balanced by the deontological arguments for non-interference/autonomy, which seem to weigh against any practical implications of heightened deontological emphasis on suffering relative to pleasure. I'm admittedly not as well-versed in this set of questions as you are, though, and this is something I would like to give more thought to at some point.

    1. Thanks for your reply, Zach. Before I reply, I should say I regret that my message failed to convey my admiration and gratitude for your activism and dedication over the years. But you should know: I find it truly inspiring!  

      “Our claim is decidedly the first type, a descriptive claim”

      First, I believe the use of a word like “goodness” will usually be read as evaluative by philosophers, and it may be good to highlight the distance there may be to purely descriptive claims. Second, even if one makes a descriptive claim, there are still crucial and highly non-trivial assumptions that I think would need to be defended. Two stand out: 1) that happiness and suffering are cardinal quantities, and 2), even if they are, that happiness and suffering are commensurable.

      On the latter, neuroscience lends some support to the skepticism of many philosophers. Two relevant quotes here:

      >The distinction between good and bad (pleasant and unpleasant) emotions is well established in psychology and familiar to nearly everyone. Although laypersons typically regard these as opposites, there is some evidence that the two are somewhat independent […]

      >Recent results from the neurosciences demonstrate that pleasure and pain are not two symmetrical poles of a single scale of experience but in fact two different types of experiences altogether, with dramatically different contributions to well-being.

      “Regarding the second and third sorts of claims, while the paper does not address it, I find the asymmetry in the second claim untenable, though I'm aware there's disagreement.”

      I am curious as to 1) what you find untenable, and 2) why you find it untenable and what your strongest objections are.
      In relation to 1), it should be noted that one can defend a wide variety of value asymmetries between happiness and suffering, and they can have very different structures, and be “weaker” or “stronger” (cf. For example, while Gloor’s view cited above places no intrinsic value on happiness (beyond its absence), Wolf’s view, also cited above, does. There are also asymmetries with different structures, such as those defended by Mayerfeld and Mathison, which hold the disvalue of suffering to, in a sense, increase faster than the value of happiness as intensity increases, cf. Mayerfeld’s Suffering and Moral Responsibility (recommendable book; Mayerfeld’s asymmetry is both evaluative and moral),,


    2. For some extremely brief arguments for a value asymmetry: if one adopts a purely welfarist account of value, and if one insists that there is a symmetry between happiness and suffering, then it would follow that our practice of animal exploitation — all the beings boiled alive, the testicles cut off without anesthesia, the beings skinned alive, etc. — could have net positive value if only people gained enough enjoyment from it. I suspect most animal activists, you included, would find this difficult to accept.
      Or to take an example on a smaller scale: if we accept the same assumptions, it follows that a gang rape could have net positive value if only the rapists derive a sufficient amount of enjoyment from it. (This example is due to Richard Ryder:
      It also follows that the value of reliving the suffering for someone who is in extreme pain (torture, say) is no greater than, say, raising the happiness of someone who is asleep to “corresponding” heights of happiness. I believe most people would reject this.

      As mentioned, I am keen on hearing the strongest objections against value asymmetries of this kind.

      It should also be noted that many objections against asymmetries between happiness and suffering relate to death, and worries that such asymmetries may permit death. Yet death can be considered a separate issue, something one can consider a bad in itself. After all, classical utilitarianism also has counter-intuitive implications when it comes to death: it can, in theory, allow us to kill beings to replace them with happier beings, and it can allow us, in theory, to kill a very unhappy person with a self-declared very negative quality of life who nonetheless wants to live on (assuming he lives in complete isolation). Many people’s intuitions will have us take consent into account beyond pure hedonic well-being, and perhaps consider death an intrinsic bad. That these intuitions conflict with all pure utilitarian views (which is one reason, I believe, so many academics reject utilitarianism these days; Mayerfeld and Wolf both endorse pluralist accounts of value and ethics).

  5. "when the probability of suffering increases, the severity of suffering should decrease."
    Appealing idea, how do you integrate the will to survive? If experiences of suffering are important to elicit cognition/behavior that increase the probability of survival, individuals most capable of suffering would, on average, tend to be more likely of dealing with harsh environments than individuals less capable of suffering. Such processes might possibly indicate a positive association of probability of suffering with severity of suffering?


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