The article was intended primarily to stimulate careful reflection about potential conflicts among values that most of us recognize and endorse, such as the reduction of suffering and the preservation of species. My claim was that if we faced a choice between the elimination of predatory species (though perhaps I ought to have focused, less provocatively, on the reduction of predation though reductions in the number of predators and perhaps certain selective extinctions) and a great reduction in the suffering of animals, the importance of reducing suffering ought to trump the value of preserving species. But my argument was explicitly conditional: the claim that the reduction of suffering has priority over the preservation of species has practical significance only if the reduction or eliminate of predation could be brought about without causing harm as a side effect that, together with loss of impersonal value through the extinction of species, would outweigh the good of reducing suffering. (For more on this, see the response I posted to comments on my article in the New York Times website, The Stone.)

“Closet Puritan” and Gerardo Camilo are skeptical that my argument could ever be of practical significance. Mark Reid and David Olivier, by contrast, suggest that my argument has immediate practical significance and that it would be desirable to begin to eliminate predators right away. I don’t have the empirical knowledge necessary to judge which of them is right. But I don’t think the points made by “Closet Puritan” and Camilo are decisive. “Closet Puritan” suggests that if we tried to prevent mass starvation among herbivores whose numbers were no longer controlled by predators, we would have to control their reproduction, perhaps by germ-line genetic manipulation. But our efforts would soon be thwarted by mutations that would give a reproductive advantage to animals that would have escaped the limits we had imposed. Camilo explains the notion of an evolutionarily stable strategy and argues that a region without predators would be “ripe for a predatory strategy to invade.” But it seems that if we had the ability to eliminate predators without disaster in the first place, we would also have the ability to maintain a stable environment without predation. This might involve further genetic intervention to prevent the proliferation of animals with a newly evolved capacity for higher fertility, or efforts to prevent the introduction or evolution of new predators in the region, or interventions to increase the food supply (as we always ought to do to prevent human famine) for an expanded population of herbivores. Evolutionarily stable strategies are relative to environments; thus, to the extent that we can control an environment, we can determine what strategies will be evolutionarily stable and which will not. Perhaps this is all fanciful, but I see no a priori reason to suppose that it must be. And I agree with Maria Comninou that it would be a terrible mistake to suppose that it’s somehow presumptuous to use our intelligence and our moral capacities to try to make our world better. If it could be better but we don’t act to make it so, no one else will do it for us.

Camilo makes two further points. He asserts, as if it were a truism, that morality “resides in the evolved brain.” Some of the greatest philosophers in history have devoted years of thought to trying to determine whether something of this sort is true. Many have concluded that it’s not. Here are a couple of questions for those who think it is. Do numbers reside only in the brain? If so, does that mean that before brains evolved, it was never true that there were two things in any region of space?

Camilo also observes that “what you may perceive as barbarism, I perceive as the beauty of nature in all its splendor.” First, animals can’t be barbaric, any more than they can be civilized. Second, even though I don’t think morality is just something produced by our brains, I do think that some instances of beauty are perspectival. A person may derive some aesthetic gratification from the spectacle of a lion stalking and killing a zebra. But we should ask ourselves why one wouldn’t have the same reaction to the spectacle of a lion stalking and killing a human child. Mightn’t the fact that the latter event would not be beautiful suggest that the alleged beauty of the former is an illusion?

Pat Duffy reveals what I think is a similarly insufficient sensitivity to the suffering of animals. After recounting with approval an instance in which a forest fire in Yellowstone was allowed to burn, leading to a renewal of certain types of vegetation and a consequent reinvigoration of the elk population, Duffy observes that “human value systems should not be applied to systems that are the result of complex interactions…” But doesn’t the judgment that it was good to allow the forest to burn derive from a human value system? It’s certainly an evaluative judgment, one that I suspect derives from a mistaken value system, which sees the growth of “fresh browse” that enables more elk to exist as an important good, but apparently attributes no significance to the fact that forest fires cause many thousands of animals to be burned to death. If there had been human beings in the forest, even only a tiny fraction of the number of animals that were there, no one would have objected to the application of a human value system to the situation and no human value system would have judged it permissible to allow those people to burn to death so that some fresh browse would become available to the elk.

Chris Desopoulos revives a form of argument found in traditional theodicy: namely, the idea that the existence of certain evils is justified by their being necessary for certain forms of good. Suffering, for example, is necessary for the exercise of the virtue of compassion; if, therefore, it’s important for there to be compassion, there has to be some suffering. I think it would be a mistake to dismiss this form of argument altogether. Shelly Kagan, a philosopher at Yale, has written a paper – still unpublished to the best of my knowledge – that considers what dimensions of human well-being might remain in a utopia from which all evils, or all bad things, had been eliminated. Such a utopia might well strike us as rather tame, shallow, and insipid. But even if it’s true that we require a certain degree of adversity for our well-being, it doesn’t follow that other, simpler animals do. And even if the elimination of all sources of suffering would result in an impoverished world, it doesn’t follow that the elimination of any particular source of suffering would be bad. We would have to eliminate most sources of suffering before any threat of impoverishment would arise. The point here is rather similar to one often made in discussions of the badness of death. Some claim that if we were immortal, life would cease to be worth living, as it would become endlessly repetitive. But even if that were true, it wouldn’t count against increases in longevity that would stop short of the point at which life would become intolerably boring.

The views articulated by Torbjörn Tännsjö, David Benatar, and Oscar Horta present striking and interesting contrasts. David believes that the presence of any degree of suffering within a life makes it the case that it would have been better had the life never begun. Torbjörn seems to think that even factory farmed animals in general have lives worth living and that it’s better that more of them exist than fewer. Oscar occupies a middle position according to which most factory farmed animals and most animals in the wild have lives in which the intrinsically bad elements outweigh the intrinsically good. All three of these positions are at odds with common sense views. My own view is closest to Oscar’s but the relevant issues are largely though not entirely empirical (a lot also depends on the proper analysis of well-being) and I simply don’t have the expertise necessary to advance a view with any confidence. I will say, however, that I’m unpersuaded by Torbjörn’s reason for rejecting vegetarianism. His argument presupposes principles that are wholly impersonal in character. It presupposes, in particular, that the death of an existing individual is no worse than the failure of a new individual of the same kind to come into existence – indeed that a death is normally less bad than a failure to come into existence since the latter normally involves a greater loss of impersonal value. I find this impossible to believe. (There is some further discussion of this and certain related issues in an article I published a few years ago in Daedalus.)

I think that Ingmar Persson’s position is correct up to a point. He’s certainly right to advise caution in taking major steps, such as driving a species to extinction, that would be irreversible. Even if it’s true, for example, that the reduction over time in the number of Siberian tigers to just a few hundred has significantly reduced the amount of suffering by other types of animal in the large areas that were once its habitat, it might still be important both for instrumental reasons and because it’s intrinsically valuable that there be Siberian tigers in the world to preserve some members of the species for the indefinite future. The same might true even of dreadfully dangerous microbes such as HIV, which might someday prove to be of instrumental value. But Ingmar’s cautionary principles don’t, as he acknowledges, support a wholesale prohibition of intervention in the natural world. Rather, he recommends a piecemeal approach as opposed to large scale intervention. But what counts as piecemeal will vary with our capacities. What would count as dangerous large-scale intervention now might count as gradualist and piecemeal in a future in which our knowledge had greatly expanded and our methods of intervention had been enhanced.

Paula Casal, in her two comments, makes various interesting and important points. I don’t have many quarrels with what she says. I suspect, however, that she attributes greater intrinsic significance to the preservation of individual species than I do. When she says that “extinction is bad” and contrasts that with predation not being bad “in itself,” I think she has in mind the impersonal badness of the extinction of a species rather than the instrumental badness. And impersonal badness isn’t bad for any individual. I do accept that there are impersonal values and I think that Lori Gruen is right that the continued existence of a group of animals of a certain sort can be an instance of something with impersonal value, even if the criteria for distinguishing the group from others are lacking in moral significance. But I do question how much weight such an impersonal value can have when it conflicts with the reduction of suffering.

I have nothing to add to the interesting discussions of Kant. I’m glad to know of the passage Mark Reid cites, though I agree with Brian Leiter that it leaves it open for Kant to approve of “agonizing physical experiments” on animals if they were for an end other than mere speculation and the end couldn’t be achieved in any other way. I also agree with Victor Tadros’s judgments about the views he describes as abhorrent. If Kantian theory were to entail those views, that would be sufficient for me to rule out Kantianism as a viable moral theory.

Thanks again to everyone for joining in this discussion.

One issue concerns hedonic states and another concerns intrinsic. Many believe that humans and nonhumans are fundamentally different in their distribution of hedonic experiences. Some believe that humans house a hedonic range that dips low into pain and misery and that soars high into pleasure and happiness, while nonhumans have capacities for suffering that are nearly as deep as humans but not the capacities for pleasure and happiness that humans have. Some believe the reverse of this, and some believe that humans and nonhumans are similar in their hedonic range.

Set against hedonics, the issue of intrinsic value evokes the question of whether and under what conditions humans and nonhumans have lives that are worth living? Both issues effect how this question is answered. For instance, a conscious life’s intrinsic value can, it would seem, be trumped by hedonic states at least under certain conditions. If someone believes that nonhumans are largely capable of suffering, then the intrinsic value of the conscious life would have to be large in order for that life to be worth living. If someone believes that deep, complex conscious human and nonhuman life has huge intrinsic value and that humans and nonhumans have capacities for hedonic states that are similar and roughly equally capable of positive and negative states, then one would believe that the Schopenhauerian gloom is silly and instead that there is no need to move from the premise that Jeff’s thesis (in some form) is valid to the nihilism of all conscious life. Jeff’s thesis brings the aim, it seems to me, to improve the lot of experiences for conscious life, not remove the whole lot of conscious life.

Animals – this is a very general term, most commentators are using the term to mean vertebrates, and especially mammals. Should you not be more concerned with your terminology? I am seeing very little mention of the vast majority of animals, the invertebrates and especially insects (except for the ants, which was a great comment). I am very fond of most insect predators, since otherwise we would have much larger populations of herbivorous insects, including those who eat our crops and fruits and stored products, and those who transmit plant diseases.

As well, the fact that most of us die (excluding some clone lineages that seem to be almost immortal) means that the issues are how we die and what we do with our lives. Ile Royale was an interesting situation. Before the moose crossed over Lake Superior the island managed just fine with trees and small animals. Moose caused huge devastation as their populations increased without predators, and then they experienced a massive starvation one winter because they had eaten all the accessible food. Is mass starvation over a long period of time a desirable death? And consider the scavengers. There was very little nourishment for them in the moose carcasses. It took years for the vegetation to recover and the moose populations to also recover. Since wolves arrived the moose and wolf populations have been fairly stable (all populations fluctuate) and the vegetation has not been seriously overgrazed. This is true i many situations, predators are a stabilizing influence on herbivore and omnivore populations.

Another situation – in North America we have acted as God re forest fires, to the detriment of the forests. When we let the Yellowstone fire burn, instead of allowing mass destruction we found that the habitat went back to what it originally had been (a mix of forest and open areas) and the elk population, which had been unhealthy and in decline, was invigorated as fresh browse became available.

The point of this is that human value systems should not be applied to systems that are the result of complex interactions that we do not fully understand. We have many examples of situations where our interference has resulted in unintended consequences.

I understand the joy of thought experiments, but they should not be considered to have much relevance to the living world around us, which is a system that we do belong to, even though many pretend we are no longer a part of it.

And as an aside, our digestive system is omnivorous. Historically human populations have tended to be more vegetarian or carnivorous depending on what was available (think Inuit for a people that historically had little choice). Bears, which are also omnivores, have also done this, polar bears are the most carnivorous and pandas are the most vegetarian.

For the overwhelming majority of animal species, the reproductive strategies which maximize inclusive fitness very commonly entail that many more animals are born than those who survive (this is so because they follow what is called an “r-selection” strategy for reproduction). The reason for this is, of course, that the chances that an animal who has just come into existence has of reaching sexual maturity and procreating can be extremely low. This happens in particular in the case of invertebrates, who may lay hundreds, if not several thousands eggs, but also in the case of reptiles, amphibians, fish and other vertebrates. It also happens that these animals are, by far, the ones that exist in the highest numbers in nature.

This means that the majority of the sentient animals that come to existence die very soon after they start to be sentient. Many of them die from starvation. Others are eaten alive by predators or parasites. This means that most of these animals in almost all certainty experience more suffering than positive wellbeing in their lives. In other words, we have very strong reasons to claim that their lives are not worth living. It would be better for the overwhelming majority of the animals that come to existence not to have existed.

As I mentioned in a previous comment, this point is explained in Yew-Kwang Ng’s “Towards welfare biology: Evolutionary economics of animal consciousness and suffering”, Biology and Philosophy 10, 255–285.

So, if we consider the good of individuals, the conclusion is striking, but also very clear: disvalue in nature tremendously outweighs the value in it. This follows if we assume an egalitarian, a sufficientarian, a utilitarian, or a maximin conception of the good, among others. Or if we assume any other view according to which an outcome in which some individuals gets some benefits but some others get harmed cannot be good (as some who hold deontological or virtue ethics approaches may assume).

Now, this may conclusion may be opposed if we think that there are other values in nature of a completely different sort. For instance, if we think that the mere existence of different species is good in itself (Ingmar Persson’s view seems to be this). However, even conceding that such value does exist –something I, for one, would not do–, would be so high to outweigh the huge disvalue I’ve just pointed at? That doesn’t seem plausible to me, and one argument I’d use to support this claim is that we would never accept it, I think, if those suffering the disvalue were humans.

McMahan’s ideas could also be practically implemented by using birth control on both predators and their prey.

Many find predators to be magnificent animals; might their killing ways be an important part of this value, something we would lose by replacing them with non-violent, look alikes.

In my view his conclusion is not heretical enough. We have reason to desire the extinction not just of predators, but of all conscious animals. (This includes both predatory and non-predatory humans.) While it is true that predators cause unspeakable suffering to those they hunt, it is sadly true that suffering is so deeply entrenched in the structure of conscious life that the extinction of predators would not eliminate or even significantly reduce it.

Professor McMahan shows some recognition of this when he considers the Malthusian catastrophe that would result if herbivorous populations were left unchecked by predators. However the problem extends well beyond that. Even if herbivores’ population growth could be controlled in some painless way – such as contraceptives in the water sources – massive quantities of suffering would still persist. Injury and disease would continue. Some of this would be in younger animals, but more often it would be in ageing animals, which would be a more common phenomenon in the absence of predators. Billions of animals would experience years of suffering as well as painful and protracted deaths. And unlike some (that is, the more privileged) humans, who can seek relief from medical science, almost all wild animals have no such refuge. Their broken bones are not set, and their pain and suffering are not treated.

These horrors, like those of predation, are hidden from those who take a panoramic view rather than a focused one. Yet they are no less real or terrible, and it would certainly be better if it never existed. While we can imagine some utopia in which conscious beings exist without suffering, pinning our hopes on the realization of such a world is a bet that is guaranteed to lose. Extinction, by contrast, is very likely. It may take a long time, but it will come. There is good reason to think that its arrival will not be a bad thing.

That we have a reason to desire the extinction of all sentient life does not mean that we should take up the sword. There are many good reasons, that I shall not enumerate here, not to engage in “speciescide”.

A reference that should be noted: Steve Sapontzis, Morals, Reason, and Animals, 1987, chapter 13, “Saving the Rabbit from the Fox”. A French translation can be found online on the website of the Cahiers antispécistes. In France, several antispeciesist activists took up the predation question back in 1996, and the entire issue #14 of the Cahiers antispécistes is dedicated to the problem.

Concerning the “we have no right to meddle with nature” argument. As noted by Stephen Webb, our control of the “natural” world is increasing. It’s like having a baby thrust into your hands; you didn’t choose it, but you have it. We are the stewards of the planet, whether we like it or not; our responsibility is to be benevolent stewards. One quote I like a lot:

Frodo: I wish the Ring had never come to me. I wish none of this had happened.

Gandalf: So do all who live to see such times, but that is not for them to decide. All we have to decide is what to do with the time that is given to us.

Another important reference, in my mind, is Daniel Botkin, Discordant Harmonies. It shows how so many of our conceptions about nature being “balanced” are simply false. The picture we have, for instance, of a kind of harmonious relation between prey and predators, the latter being necessary for the stability of the population of the former, are very much overdone. It may be true in some cases, but there is no reason to believe it always is, or even that it often is. The simple fact that the predators themselves, such as wolves or tigers, have no predators of their own (nor do elephants, etc.), without having a “population explosion” problem, shows that there is no general law in the matter.

“Predation” is a catch-all term that covers many many different situations. It’s like the word “disease”. Some diseases are much worse than others, and some are much easier to cure than others. Recognizing that predation is an evil does not imply that we must be able to cure all predation. There is no reason for it to be all or nothing matter. It is nonetheless important to recognize that it is an evil. I don’t know the cure for AIDS any more than Fred Phelps does, but the fact that I see AIDS as an evil, and that he sees it as a blessing and is impervious to the suffering of the victims, does make a lot of difference between us, and makes a lot of difference concerning what we will do or not do to alleviate, and perhaps some day remedy, the problem.

Like Mark Reid, I believe that the issue of predation is not just for the far-off future. We cannot abolish all predation now, but there are many choices of ours that can be affected if we keep in mind the suffering of prey animals.

I do think, however, that the issue implies hard thinking about many questions. Not only factual questions, but also philosphical ones. Is death necessarily a great harm? I actually don’t think so, and I think that the forms of predation that cause great suffering are more urgent to address than those that “only” cause death. That is, of course, debatable. Also, the fact must be kept in mind that predation may oblige many animals to live in a permanent state of terror.

Furthermore, as I said, the issue is a key one. The animal movement can be seen as a reactionary attempt to “return to nature’s laws”, or as a progressive one, an attempt to better the world by casting away the age-old predatory logic. Our attitude towards the oldest and most cruel of “natural laws” will decide what way the movement goes.