In the 2010s, moral philosopher Jeff McMahan wrote a series of very good articles about predation, arguing that humans should bioengineer predation out of animals if we have the technological means and scientific knowledge to do so without inadvertently causing ecological catastrophes. I find his arguments to be very persuasive, and will reproduce them here with a little bit of commentary. Feel free to read his beautifully written piece for the New York Times, and his more detailed journal article “The Moral Problem of Predation”.
Conditional Structure: A Rant
Before discussing anything I want to state and restate something about what the argument is and is not doing. The thesis has a conditional structure: if we can do X, we should do X. This is obvious, but it seems to not sink into people’s heads for some reason. In a follow-up to his first piece in the New York Times, McMahan notes:
Earlier I noted that by far the most common objection to my article was that I ignored the likely consequences of the elimination or even the mere reduction of predation. If you have the patience, review the first 152 comments on my article. You will find this objection stated in 28 of them — that is, in one of every 5.4, or nearly 20 percent. Given that I explicitly stated and addressed that objection, and later reverted to it six times, it seems clear that many, and probably most, of the readers of the article gave it only a cursory glance before pouncing on their keyboards to give me a good roasting.
If you read the top-rated comments to this follow-up article in turn, you will see many that acknowledge this and swiftly proceed to just do it again, and justify doing it again by calling McMahan a troll, or say that he’s thin-skinned, or imply he’s a simpleton for not understanding that morality is subjective, that life isn’t fair, that suffering isn’t real, or whatever other arbitrary, illogical, and irrelevant dictum they chose to toss at him. Personally, it seems to me many of these people have actually read McMahan’s article, but that something in their minds just makes them refuse to follow the argument. I don’t think in general that one should expect New York Times readers to be able to follow an argument, but I point to this because it illustrates a general tendency that manifests in basically all public discussions about the ethical treatment of animals. Though I am a meat-eater, it seems plain to me that carnism makes people systematically stupid.
That being said, I do think it is interesting to speculate about reasons that could emerge about why it is systematically impossible to eliminate predation. The great Darwinian, William Hamilton (who discovered the concept of inclusive fitness) became worried towards the end of his life about the dysgenic effects of modern medicine. Gert Korthof has a very nice write-up about this, and summarized the argument as follows (I have edited the quote for formatting reasons):
Hamilton worries that modern medicine eliminates natural selection and our genome will steadily accumulate more and more deleterious mutations. He fears that our scientific and technological abilities to diagnose and repair these mutations will be insufficient, now and in the near future. The accumulation of mutations has accelerated since humans have partly eliminated natural selection by medical practice. Medical intervention amounts to phenotypic curing (spectacles, phenylalanine-free diets for PKU) of every defect in the germ line. He does not believe that future technologies will improve to the point that we will be able to correct all deleterious mutations and can keep our genome healthy. Hamilton is more pessimistic than scientists like Steve Jones and John Maynard Smith who think we can repair the known deleterious mutations by engineering the germ line or soma. There are hundreds known single gene disorders, but many more unknown genes that affect disease. Hamilton estimates there are 100.00 genes in the human genome. Most mutations are bad. The majority of genes will accumulate bad mutations. This happens at a rate of perhaps one mutation per genome per individual per generation ('Kondrashov threshold', [from Hamilton’s Narrow Roads of Gene Land] p. 464), but the rate could be an order of magnitude above or below the Kondrashov threshold, so between 0.1 and 10.
"If humans turn out to be near the Kondrashov limit —that is, if on average every gamete has one bad mutation created during the lifetime of its producer— it is obviously not going to be nearly enough to test a baby for the subset of the few hundreds or so of well-characterized genetic defects... There are certainly tens of thousands more possible mutations that the baby could have that have not been characterized well enough..." ( [from Hamilton’s Narrow Roads of Gene Land] p. 465).
Correcting those is an impossible task just like Maxwell's Demon. This is a depressing future. We are unable to prevent the degradation of the human genome.
I offer this idea just an object of speculation for now, and will return to it in later posts.
Even if we could currently prove that the total elimination of predation is in principle impossible, that would not render McMahan’s predation thesis moot. It would still provide a guiding moral principle that would justify a minimization variant of the predation thesis, namely that we have reasons to minimize the amount of wild animal predation insofar as we are able to do so without causing mass ecological harm. There is no plausibility to the notion that every possible degree of reduction in predation will cause ecological collapse and immense harm. Humans intervene into the “natural world”, intentional and unintentionally, in myriad ways that both do not cause ecological collapse and are more ecological consequential than an epsilon amount of predation reduction.
Let’s now turn to the predation argument.
The Problem of Evil and Animals
The wolfe also shall dwell with the lambe… and the lyon shall eate straw like the oxe
(Isaiah 11:6-7, 1611 KJV)
There is a wealth of moving writing about the horror of natural suffering. In the Dialogues Concerning Natural Religion, David Hume writes through his character Philo “Observe too… the curious artifices of Nature in order to embitter the life of every living being. The stronger prey upon the weaker and keep them in perpetual terror and anxiety. The weaker too, in their turn, often prey upon the stronger, and vex and molest them without relaxation.” In his autobiography, Charles Darwin bemoaned “for what advantage can there be in the sufferings of millions of the lower animals throughout almost endless time?”
This sentiment may be sharpened into a variant of the Problem of Evil. McMahan quotes John Stuart Mill’s Three Essays on Religion:
… if there are any marks at all of special design in creation, one of the things most evidently designed is that a large proportion of all animals should pass their existence in tormenting and devouring other animals. They have been lavishly fitted out with the instruments necessary for that purpose; their strongest instincts impel them to it, and many of them seem to have been constructed incapable of supporting themselves by any other food. If a tenth part of the pains which have been expended in finding benevolent adaptions in all nature, had been employed in collecting evidence to blacken the character of the Creator, what scope for comment would not have been found in the entire existence of the lower animals, divided, with scarcely an exception, into devourers and devoured, and a prey to a thousand ills from which they are denied the faculties necessary for protecting themselves! If we are not obliged to believe the animal creation to be the work of a demon, it is because we need not suppose it to have been made by a Being of infinite power.
In my view, the ordinary version of the Problem of Evil alone supplies an overwhelming reason to reject basically all religions. The extension of the problem to animals supplies yet another gauntlet of difficult questions, as animals are typically assumed in Western religions to have neither free will nor souls, so their suffering is not adequately explained by most theodicies.
The Problem of Evil has consequences beyond religious matters. The problem is of the form “X would not be created by a sufficiently ethical and powerful being”. This also implies that we are not allowed to do certain things when we are sufficiently powerful. For those of us interested in questions concerning humanity’s deep future, we can usefully recontextualize the Problem of Evil to ask what our ethical obligations would consist of under different levels of technological development.
The Predation Argument
In The Moral Problem of Predation, McMahan states the predation argument thus:
The case in favor of intervening against predation is quite simple. It is that predation causes vast suffering among its innumerable victims, and to deprive those victims of the good experiences they might have had were they not killed. Suffering is intrinsically bad for those who experience it and there seems always to be a reason, though not necessarily a decisive one, to prevent it—a reason that applies to any moral agent who is capable of preventing it. (If suffering can be deserved, deserved suffering might constitute an exception, as its intrinsic badness for the victim might be outweighed by its impersonal goodness.) There seems, indeed, to be a universally applicable reason not only to prevent the painful deaths of potential prey that exist now, but also to terminate the cycle in which new predators continuously replace the old, thereby ensuring an inexhaustible supply of sentient beings that can avoid suffering and death themselves only by inflicting suffering and death on others. The elimination of predation could therefore make the difference between an indefinitely extended future in which millions of animals die prematurely and in agony every day and an alternative future in which different animals would live longer and die in ways other than in terror and agony in the jaws of a predator.
Let’s look at the objections now, and McMahan’s arguments against them. The most common objection was already discussed above in my rant, so I’ll skip that one. I will also skip the genre of objection that says “suffering isn’t real”, “suffering is good”, “animals don’t feel pain”, “suffering exists for humans subjectively, but it doesn’t exist in Nature”, etc. McMahan does address arguments of this type, but I think I cannot fit a non-confusing account of his metaphysics of suffering into this post. For now, I’m operating on the following assumptions: humans suffer, suffering is bad in itself (suffering can be instrumentally useful, like when you feel pain that warns you of danger to your body, but when considered non-instrumentally suffering is bad), the main thing that is bad about suffering is the experience itself, many animals feel pain, and many animals can suffer. Peter Singer and other animal ethicists supply very good arguments for all of these points, but again it’s best for now to take these as givens. I also just think all of these assertions are believable at face-value. If I were to go to your house and start caning your dog:
your dog would suffer from the caning
your dog might coincidentally learn something useful from the caning but the suffering from the caning would be bad in itself
it’d be bad of me to be damaging your property and hurting something for no reason, but the main thing that’d be bad about the situation is that your dog is suffering
your dog would be actually feeling pain
And so on.
Objection 1: “Playing God”
One common objection is that tampering with animals in this way is “playing God”. To eliminate predation we’ll be doing extensive germ-line editing, restructuring every biome, choosing explicitly and exhaustively which lifeforms to keep, which to edit, and which to end. The “playing God” objection (if coming from a religious person) is about impiety or (if coming from a nonreligious person) about hubris. McMahan gives four counter-arguments in his New York Times piece:
One is that it singles out deliberate, morally-motivated action for special condemnation, while implicitly sanctioning morally neutral action that foreseeably has the same effects as long as those effects are not intended. One plays God, for example, if one administers a lethal injection to a patient at her own request in order to end her agony, but not if one gives her a largely ineffective analgesic only to mitigate the agony, though knowing that it will kill her as a side effect. But it is hard to believe that any self-respecting deity would be impressed by the distinction. If the first act encroaches on divine prerogatives, the second does as well.
The second counter-argument is that there is no God, so there is no authority of his to usurp. If in place of God, you argue that eliminating predation is going “against Nature”, McMahan says:
This slogan also has a long history of deployment in crusades to ensure that human cultures remain primitive. And like the appeal to the sovereignty of a deity, it too presupposes an indefensible metaphysics. Nature is not a purposive agent, much less a wise one. There is no reason to suppose that a species has special sanctity simply because it arose in the natural process of evolution.
The fourth counter-argument is that you should be skeptical in general about deploying the phrase “playing God” because it has in the past been thoughtlessly used to justify nonsense (very notably in the history of medicine and public health).
Objection 2: “Not Our Business”
Another objection is while we may have a duty to not harm animals, we do not have a duty to stop animals from harming each other. McMahan argues:
There is an element of truth in this view, which is that our moral reason to prevent harm for which we would not be responsible is weaker than our reason not to cause harm. Our primary duty with respect to animals is therefore to stop tormenting and killing them as a means of satisfying our desire to taste certain flavors or to decorate our bodies in certain ways. But if suffering is bad for animals when we cause it, it is also bad for them when other animals cause it. That suffering is bad for those who experience it is not a human prejudice; nor is an effort to prevent wild animals from suffering a moralistic attempt to police the behavior of other animals. Even if we are not morally required to prevent suffering among animals in the wild for which we are not responsible, we do have a moral reason to prevent it, just as we have a general moral reason to prevent suffering among human beings that is independent both of the cause of the suffering and of our relation to the victims. The main constraint on the permissibility of acting on our reason to prevent suffering is that our action should not cause bad effects that would be worse than those we could prevent.
McMahan is making a distinction here between having a moral duty to do something and having a moral reason to do something. This sort of distinction was made prominent by Derek Parfit in Reasons and Persons, and typically the distinction amounts to saying that you have a moral duty to do something when you have a moral reason to do something that overrides all the other reasons, and you have a moral reason to do something, basically, when there is a rational argument to do something that has some sort of “impersonal” character. It is possible to have conflicting moral reasons, and maybe something like Utilitarianism will help you figure out where your aggregated moral reasons vector ultimately points (i.e. what your moral duty is). Of course, you may have doubts about which theory to choose for this purpose, or even whether there could in principle be such a theory, but we can hopefully contain those doubts to the discussion of moral duty such that they do not leak over to the more generic discussion of moral reasons. For example, it seems fair to say that there is a moral reason to not inflict pain on someone randomly and purposelessly. There are many different ways to supply impersonal justification of this point which are not dependent on solving the question of how moral reasons balance out with each other and other reasons.
To step away from the abstract, I do think in any case that you should not buy the “not our business” argument. This may be idiosyncratic, but I don’t think there is an important ethical difference between causing a harm to happen and merely allowing that harm to happen. I think many of us recognize that there is moral value in rectifying harms that we had no part in causing. If you have the unique ability to ameliorate a harm, at little to no cost to yourself, and just choose forever to not do it because you believe that there is nothing bad about merely allowing harms to happen… surely this is just very shabby.
Objection 3: “The Impersonal Value of Species”
This objection I find the most interesting and cruxy. The legal philosopher Ronald Dworkin argued:
…we tend to treat distinct animal species (though not individual animals) as sacred. We think it very important, and worth a considerable economic expense, to protect endangered species from destruction… Few people believe the world would be worse if there had always been fewer species of birds, and few would think it important to engineer new bird species if that were possible. What we believe important is not that there be any particular number of species but that a species that now exists not be extinguished by us.
There is value to the species that does not reduce to the sum of the values of the individual animals constituting said species. In other words, a species has impersonal value. This does seem to capture a lot of the unease I personally feel about extensively bioengineering animals. Let’s say there were 10^15 (stressed, fearful) animals on Earth prior to predation removal, and we get 10^15 (chilling) animals after predation removal. It does still seem that some value is lost in abolishing the tiger, even if we replaced them with the same number of well-fed post-tigers.
McMahan supplies two counter-arguments. The first is that it would be surprising that there was distinct moral value on the species-level, as species do not individuate from each other as particular animals individuate from each other:
What, after all, are species? According to Darwin, they “are merely artificial combinations made for convenience.” They are collections of individuals distinguished by biologists that shade into one another over time and sometimes blur together even among contemporaneous individuals, as in the case of ring species. There are no universally agreed criteria for their individuation.
In practice, the most commonly invoked criterion is the capacity for interbreeding, yet this is well known to be imperfect and to entail intransitivities of classification when applied to ring species. Nor has it ever been satisfactorily explained why a special sort of value should inhere in a collection of individuals simply by virtue of their ability to produce fertile offspring. If it is good, as I think it is, that animal life should continue, then it is instrumentally good that some animals can breed with one another. But I can see no reason to suppose that donkeys, as a group, have a special impersonal value that mules lack.
The second counter-argument is that even if impersonal species value exists, it is not clear that these values are nonfungible:
Even if animal species did have impersonal value, it would not follow that they were irreplaceable. Since animals first appeared on earth, an indefinite number of species have become extinct while an indefinite number of new species have arisen. If the appearance of new species cannot make up for the extinction of others, and if the earth could not simultaneously sustain all the species that have ever existed, it seems that it would have been better if the earliest species had never become extinct, with the consequence that the later ones would never have existed. But few of us, with our high regard for our own species, are likely to embrace that implication.
All of this is persuasive to me. What matters ethically in the “animal world” is the well-being of a big set of individual animals, not the maintenance of a particular set of species. It seems to me that it is mainly just scope insensitivity that prevents us from intuitively feeling the big set of individuals view.
Practical Upshot
I enjoy philosophy for its own sake. If you find philosophy not so interesting, but do find the wild animal suffering angle of McMahan’s work interesting, I’d recommend reading Animal Charity Evaluator’s resources on wild animal suffering mitigation.
Maybe this argument has been knocked down on the internet already, but still I'll ask: would eliminating predation not result in too much leisure and "pleasure", to the point where (most?) animals would not enjoy it? And automatically psychologically adapt to the new conditions so that they don't actually feel "better"? Humans do this. Do animals?