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June 04, 2010



Yes it's true, we do not need to eat 'meat' animal flesh. I'm not in the least bit religious, I just know it's wrong to think that nonhuman animals are ours to enslave, use & do what we wish to them. The only way to a truly peaceful world is to become Vegan & nothing less.


I agree with most his points, I'm a vegitarian myself plan to become vagan in the near future.
However if a large reason to not kill animals has to do wtih the potenial good in their lives wouldn't eggs be even worse to eat because they have their whole lives ahead of them?


Shauna, eggs that are eaten by consumers have not been fertilized. This means that they will not hatch into birds.

Alex Pozdnyakov

Submitted to philosophy bites blog on 6.12.2010

I have continued to be an "examined" meat eater even after studying Peter Singer, but Jeff McMahan made me think, for the first time in my life, that being a vegetarian might be manageable. However, his motivation for becoming a vegetarian failed to move me.

I admired Mr. McMahan’s presentation of the vegetarian discipline because it gives an out to societies/circumstances where eating meat is essential to survival. Mongolia is one example of such an insecure habitat I know.

My objections to vegetarianism have always been practical, rather than ethical. Too much mastication, too complicated to balance a diet etc. I recognize that these can be easily overcome with proper motivation.

Alas, I am not convinced that "not robbing animals of happy experiences" is a sound motivation for becoming vegetarian. My impression is that animals in the wild, much like many humans in the world, do not live lives full of happy experiences (even on balance). Instead, they struggle to survive against fairly even odds. Farm animals would not even be alive unless they were intended for food - their alternative happiness would be nil or no higher than wild ones'. And we don't eat our pets, whose happiness is actually important to us. So, once you start comparing the happiness of food animals to your happiness from enjoying their meat, then at best, its not a clear cut win for either side. Perversely, the wealthier the person, the more pleasure he/she may extract from eating meat at the better steakhouses.

I find it difficult to think ethically about nutrition, which I stoically see as being, at its core, a means of survival rather than an epicurean object. Ethical calculus based solely on happiness is a privilege of the secure. For the rest, security is a value in itself and leads to a very different ethical calculus - the kind that is sometimes condescendingly called vulgar or base - but is very real and legitimate nevertheless.

I appreciate that Mr. McMahan's view encompasses various ethical conditions. I also agree that rich educated people should not need to eat meat, especially factory farmed/processed type. They can make do with adzuki and quinoa. However, Mr. McMahan is basically asking us to treat cattle as pets, and, while I sympathize, I am unmoved.


McMahan seems to suggest that the moral responsibilities for children are not fundamentally different to those for livestock as, in both cases, we are dealing with sentient beings. This is an erroneous view. Parents are responsible for looking after children until they can fend for themselves as adults. If an animal is brought into existence to be eaten, the farmer’s moral responsibility is no more than to ensure that it is well treated before slaughter. The permission to kill such an animal follows from the fact that its raison d’etre is to be eaten. It wouldn’t exist otherwise.

Gavin B

I can think of a better reason to become a vegetarian and that is: the earth is creaking at the seams trying to support our current population & we should consume food that doesn't need exorbitant amounts of fuel/water to raise. Water & energy shortages are going to get worse in the forseeable future. We can easily support earth's existing population on a plant-based diet because it takes less fuel to cultivate them as food (compared to meat). Thus, we turn the problem from a moral issue into a survival issue for the human species.


Stephen, assuming we ensured good treatment to them while alive, would it be ok to bring children or a race of humans into existence in order to kill them later? How exactly does bringing a being into existence for the purpose of killing justify the killing?


Radim, the killing of humans is of a different order. Different moral status. The point I was making was in reference to McMahan’s statement that he was not clear why bringing an animal into existence in order to be able to eat it gives you permission to kill it later on. Perhaps he meant to ask what gives you permission to bring a farm animal into existence into the first place, as the sole purpose of a farm animal’s existence is to be slaughtered for food. One could argue, however, that rearing an animal for food at least gives it some life that it would not otherwise have had. The key moral issue is how animals are raised and slaughtered, not whether it is right to kill animals at all.

Roger Morris

This is, I believe, a mis-application of moral philosophy, counter-physiological and just plain silly. McMahan's initial premise, that the moral harm done to a sentient animal (by cutting short it's life and depriving it of pleasurable life experiences) outweighs the benefits to humans of eating animal products, is flawed and exactly where this particular argument for vegetarianism falls down. McMahan seems to imply that the only benefit for humans when eating animal products is pleasure only. This too is flawed.

If one wants to argue this on evolutionary grounds, there is ample evidence that humans have evolved as obligate omnivores, in the same manner as chimps and gorillas. Some evidence of this is:

1. Dentition consistent with being an obligate omnivore.

2. A gastro-intestinal set up like an obligate omnivore. Not the short gut of a pure carnivore and not the long, multi-stomached GI system of an obligate herbivore.

3. The commonly seen nutritional deficiencies that result from a vegetarian diet that is not artificially supplemented - B12 deficiency, iron deficiency, protein deficiency.

This is strong evidence that humans are physiologically set up as obligate omnivores. Couple this with the fact that humans may have evolved as hunters and gatherers - that is HUNTERS and gatherers - with the evolutionary advantages that this omnivorous diet conferred and there really is no argument - HUMANS ARE MEANT TO CONSUME ANIMAL PRODUCTS.

In a Darwinian worldview, is it even coherent to question the morality of eating animals? It seems to me to be a situation of trying to "have your lentils, and eat them to". Either, as per Darwinian physicalism, humans have evolved as omnivores and objective morality is illusory, or not. If the former is the case, then as obligate omnivores we should continue to consume animal products,without guilt, in exactly the same manner as we evolved to - a characteristic that gave us an evolutionary edge over other animals.

That said:

1. Do Westerners eat too much animal products? It seems so. But the logical response is not to throw the baby out with the bathwater, but to consume animal products in physiological moderation, as part of a balanced diet.

2. Should animals intended for consumption be treated humanely and compassionately? Of course, as sentinent and feeling beings, the most certainly should, at all times and in all ways.

3. Should animals intended for consumption be killed as cleanly, quickly and painlessly as possible? Of course - catch them by surprise and kill them quickly.

4. Should we get all bound up with worry and self-loathing about how eating animal products deprives them of a happy and fulfilling life? This is a naive anthropomorphization - it is almost impossible to conceive life as another species, what constitutes a 'happy life' for livestock, and whether the concept of having a happy and fulfilling life even registers in their psyches as a priority.

One wonders whether McMahan vexes so much over the concept of depriving a fellow human being of a potentially long, fruitful and fulfilling life, this particular human being having the misfortune of combining the disabilites of being as-yet-unborn, defencelss and (unfortunately)unwanted by it's parents?


Roger, what we eat is determined primarily by cultural and environmental factors. We are not “meant” to consume any particular product. Modern-day western societies have little in common with hunter-gathered communities, including the kind of food eaten. Social Darwinian and biological justifications for meat-eating are specious. For most people, meat eating is a choice, not a necessity; some cultures eat a lot of it, others don’t. More than a quarter of all Hindus are vegetarian, for example. So how can we justify the practice of meat-eating? Well, from a human perspective, the interests of humans outweigh those of non-human animals, and no doubt vice versa. Animal protein - unlike most choices of vegetarian protein - provides the full range of amino acids, which we require for building new proteins in the body. Add to this the fact that meat can be rather tasty! For those who like meat, this is justification in itself. The ethicality of the matter, however, depends on your cultural context and cannot be determined in any absolute way.

Roger Morris

Stephen, I beg to differ. As humans, we are physiologically designed to be obligate omnivores, not exclusive herbivores. This is evidenced by the design features I suggested above, not the least the fact that a strict vegan diet (unsupplemented with artificial vitamins and minerals) quickly leads to nutrient deficiencies, particularly in pregnant women and growing children.

Vegetarianism and veganism are certainly lifestyle choices open to free humans, but are lifestyle choices that are made IN SPITE OF our natural physiological needs.

I restate my concern that much of the moral transference in this discussion is simply over-zealous, and possibly misplaced, anthropomorphism and highlights the problem of other minds, particularly those of other species.



P.S. I have expanded my response and posted it here:


Roger, your comments about "other minds" and about how humans are "meant" to eat animals seem to me very problematic.

To start with the second point, when you argue that humans are justified in eating animals because there's a Darwinian explanation of how humans have evolved to be meat-eaters, this is totally beside the point when we're thinking about the issue from a moral perspective. Regardless of whether or not humans were "meant" to eat animals from a Darwinian perspective, the question of whether it's morally justified is totally different, and giving an answer to the question of whether we were "meant" to eat animals doesn't take us any farther in answering the question of whether we ought to do so. It could well be that certain activities and aptitudes are favored by Darwinian processes and yet are completely unjustifiable from the moral point of view. The fact that we can (attempt to) give a scientific explanation of why a certain trait or behavior evolved the way it did has absolutely no bearing on the question of whether the behavior is morally permissible and you're simply conflating the two questions.

Second, the question of "other minds". The fact that we can't experience reality in exactly the same way as other animals, and can't be sure exactly how other animals experience reality, does not mean that we can't have some justified beliefs about whether or not animals can suffer. Even if I can't experience the world exactly as my dog does, can I really doubt that the cry it makes when I step on its paw is a sign of pain? Maybe I can raise some abstract philosophical problem of other minds, but when it comes down to the particular case of stepping on my dog's paws, does it really make sense to say that our cognitive capacities are so different that I can't judge whether or not my dog is suffering when it cries in response to my action?

Moreover, the problem of "other minds" is a byproduct of the Descartes's philosophy, in which a human being is a solipsistic mind trying to "infer" whether or not the coats he sees from his window are really humans or instead are automata. The problem of other minds is the problem of how we can "step outside" ourselves in order to experience other minds. From a phenomenological perspective, this characterization of how we experience other people as well as the world more generally seems highly dubious (except in certain very unusual circumstances), and it has been discarded a long time ago by philosophers like Edmund Husserl, Martin Heidegger, and Maurice Merleau-Ponty, who give much more plausible accounts of how our experience is directed to the world around us, rather than isolated from it.

Roger Morris

I understand what you are saying about the moral issues surrounding whether we should eat meat.

At the risk of laboring my point, we (as humans) are designed physiologically as obligate omnivores. So to raise the question of the morality of eating animal products, in the context of our obligate omnivorous status makes as much sense as questioning the morality of breathing air and producing CO2 when, clearly, we are physiologically designed to breath air.

The question should not be "Is it moral to eat other animals", rather it should be "Given we are physiologically designed to consume both animal and plant foods, how should we treat animals we intend to consume for food?".

It seems to me that the question of the morality of consuming animal products is a dilemma peculiar to comfortable, over-fed, excess-of-all-needs Western contemporary society. The small amount of animal products in the diet of 2/3s world cultures and historically past cultures is more of a factor of limited availability than moral conscience. It is only in chubby Western cultures, with the easy availability of artificial dietary supplements, that these questions are even entertained.

I maintain my position that voluntary veganism/vegetarianism is a lifestyle choice that is made in spite of physiological needs, often for dubious anthropomorphic justifications.

Thanks again for the interesting discussion.

Jeff McMahan

Nigel Warburton has written to invite me to contribute to the discussion of the issues raised in my interview and Roger, whose comments appear above, has written to me directly, so I’ll offer a few brief comments on the contributions that have appeared thus far.

First, I agree with Alex that the best reason to become a vegetarian isn’t that killing animals for food deprives them of good experiences that they might otherwise have had. The best reason not to eat meat is that when the demand for meat is as vast as it is in developed societies, it’s impossible to satisfy the demand in a cost-effective way without the use of factory farming or intensive rearing techniques, which cause unimaginable suffering to the literally billions of animals that are raised and killed in these ways. (I also agree with Gavin that it’s another good reason not to eat meat that concentrating on the production of plant-based foods would enable us to feed human populations more efficiently. I don’t agree, though, that focusing on this reason is to “turn the problem from a moral issue into a survival issue.” Whether some of us should sacrifice the pleasure we get from eating meat in order that poor people elsewhere can be more adequately fed is itself a moral issue.)

There are, therefore, a great many reasons not to eat meat and I don’t think the one on which I focused is the most important. When I gave the argument I did, I was responding to Nigel’s question about whether it could be permissible to eat meat if the animals to be eaten were raised in conditions of contentment and then killed painlessly. My response was that even if an animal has been treated well and even if it was caused to exist so that we could later eat it, when the time came to kill it the relevant question would be whether the harm we would do to it by killing it would outweigh the good that we might get from killing it. And I gave reasons for thinking that the answer is no. Those who think it’s permissible to kill and eat animals anyway have to explain how it can be morally permissible to cause harm for the sake of a lesser good, and for essentially selfish reasons.

Stephen suggests that we have moral responsibilities to human beings that we cause to exist but that in the case of animals the only responsibility is to be nice to them before we slaughter them. Here I agree with Radim. The presumption must be that if I cause a sensitive, sentient being to exist, I thereby cause it to be in a dependent and vulnerable position and that gives me responsibilities to it, no matter what species it’s a member of. Stephen makes the point that people have a higher moral status. I agree that those of us who are self-conscious and rational have a higher moral status than animals but what about those human beings who are not self-conscious and rational, such as fetuses, babies, the irreversibly demented, those who are congenitally severely cognitively impaired? Would it be permissible to cause human beings to exist in order to kill them provided we did it before they acquired psychological capacities higher than those of animals? If not, why is species membership relevant to moral status?

Roger claims that we are meant to eat meat. He refers to evolution but the properties we have as a result of natural selection aren’t ones that we’re “meant” or “intended” to have. They’re just ones that we have that can be explained by reference to natural selection. To this extent I agree with Stephen, and especially with Tom. I agree with Roger that a biologist looking at a representative human being would conclude that that individual has evolved to be an omnivore. But how is that relevant to morality? The theory of natural selection offers compelling explanations of a great many of the dispositions we have to act in ways that are wrong, such as the disposition many men have to commit rape. Presumably Roger doesn’t believe that because males have evolved to be disposed to inseminate women and thereby spread their genes as widely as possible, rape is natural and therefore permissible. To paraphrase Dr. Johnson, most of what’s best in human action involves resisting the impulses of our nature.

Suppose we take Roger’s terms “meant” and “designed” literally. Only purpose agents can mean thing or design things. So suppose some being designed me and meant for me to eat meat. Given that I would have to harm and kill innocent beings in order to fulfill that being’s purpose, I would defy that being unless it could offer me a compelling justification for harming and killing other beings in pursuit of my own interests. The challenge for meat eaters is to find that justification. If they can’t, they should become vegetarians.


Jeff, my point was that humans in general, regardless of their cognitive powers, have a higher moral status than animals. I would counter the argument from marginal cases with the argument from species normality and with the point that all humans have the ‘potential’ for developing a rational capacity and hence have moral agency and moral rights, even if this capacity is subsequently lost or diminished. It is not species membership that is of moral relevance here, for our morality is based on our purely human experience, contingent as it is. We are of moral import due to our fundamentally human capacities, which only we have, primarily the reflective nature of our consciousness. As a result, it would not be permissible to cause human beings to exist in order to kill them, unless, that is, the underlying conditions of existence morph into something entirely different. The moral status of animals places them beyond and above comparison in this regard, which, I would argue, justifies our right to use them for our purposes, as long as they are treated well.


If I wanted to counter the argument from marginal cases, I would not resort to the argument from species normality, which is logically so shaky as to have an air of desperation about it. Have a look at what the person who coined the name says:

Better to go the route of Bonnie Steinbock ("Speciesism and the Idea of Equality") or of Elizabeth Anderson ("Animal Rights and the Values of Nonhuman Life"). But note the reply to Anderson by Daniel Dombrowski ("Is the Argument from Marginal Cases Obtuse?"):

See also Jeff McMahan's own essay "'Our Fellow Creatures'":

Roger Morris

The science says:

“Humans are omnivorous, capable of consuming plant, animal, and inorganic material.[1] Varying with available food sources in regions of habitation, and also varying with cultural and religious norms, human groups have adopted a range of diets, from purely vegetarian to primarily carnivorous.

In some cases, dietary restrictions in humans can lead to deficiency diseases; however, stable human groups have adapted to many dietary patterns through both genetic specialization and cultural conventions to utilize nutritionally balanced food sources.[2]”

1. Haenel H (1989). “Phylogenesis and nutrition”. Nahrung 33 (9): 867–87. PMID 2697806.
2. American Dietetic, Association; Dietitians Of, Canada (2003). “Vegetarian Diets”. Journal of the American Dietetic Association 103 (6): 748–765. doi:10.1053/jada.2003.50142. PMID 12778049. online copy available

The closest primate to humans, the bonobo/chimpanzee, is mainly frugivorous, but supplements its diet with leaves and meat from small vertebrates, such as flying squirrels and duikers,[1] and invertebrates.[2] In some instances, Bonobos have been shown to consume lower-order primates.[3][4]

1. Ihobe H (April 1992). “Observations on the meat-eating behavior of wild bonobos (Pan paniscus) at Wamba, Republic of Zaire”. Primates 33 (2): 247–250. doi:10.1007/BF02382754.
2. Rafert, J. and E.O. Vineberg (1997). “Bonobo Nutrition – relation of captive diet to wild diet,” Bonobo Husbandry Manual, American Association of Zoos and Aquariums
3. Surbeck M, Fowler A, Deimel C, Hohmann G (2008). “Evidence for the consumption of arboreal, diurnal primates by bonobos (Pan paniscus)”. American Journal of Primatology 71 (2): 171–4. doi:10.1002/ajp.20634. PMID 19058132.
4. Surbeck M, Hohmann G (14 October 2008). “Primate hunting by bonobos at LuiKotale, Salonga National Park”. Current Biology 18 (19): R906–7. doi:10.1016/j.cub.2008.08.040. PMID 18957233.

Roger Morris

Interestingly, I am one of a small percentage of modern humans who are fortunate (or maybe not) enough to be characterised by a congenital absence of all four wisdom teeth/3rd molars (hypodontia).

Anthropologically, the 3rd molars (which erupted relatively late in development) functioned as "back up" dentition for early humans whose earlier dentition had been worn down by a diet high in tough/fibrous plant foods.

My dentist tells me that my congenital lack of wisdom teeth is an evolutionary improvement through natural selection. As I am obviously one who is more highly evolved and genetically more suited to a softer omnivorous diet, maybe we omnivores will inherit the earth as vegetarians die out from their dental abscess and bad breath (who would want to breed with someone like that?)


Jim Vaughan

Wow, what a heated debate! I am a lapsed veggie, who stopped because I started feeling unwell on a veggie diet. So, my ethics had to adapt! This is my justification: Our relationship with animals is a symbiosis. Humanely farmed animals are housed, fed, protected, healed when sick and die well compared to wild animals. The price is to be killed for meat. We should therefore eat only ethically treated animals, and support humane farming methods. Factory farming is obscene! We have a responsibility to provide the highest quality of life possible, but as long as it is above that of similar animals in the wild, we are behaving ethically. However, it is still more ethical to avoid eating meat altogether!


Stephen states that: "If an animal is brought into existence to be eaten, the farmer’s moral responsibility is no more than to ensure that it is well treated before slaughter. The permission to kill such an animal follows from the fact that its raison d’etre is to be eaten. It wouldn’t exist otherwise." A major flaw with this argument is that the farmer does not truly bring the animal into existence. In order to do that, the farmer would have to create the animal from scratch, including creating the atoms and cells that are necessary for the animal to begin existence. Rather, the animal is part of a chain of life that goes back to its most distant ancestors. The fact that the particular sperm cell and particular egg cell may never have united without intervention by the farmer in no way lessens the degree to which the animal is part of a continuing chain of life. Because the farmer does not create the life of the animal, the farmer disrespects that life with the cruelty of slaughter.


There is nothing inhumane about killing animals for consumption. Would the lion stop killing other animals because it's wrong? No! It's in his nature, as it is in ours. Our teeth are designed for us to be omnivores (that mean both meat and plants). One argument is that the way we kill cows, chickens, pigs etc. in inhumane ways. Have you ever watched a lion kill its prey? It bites its throat off, tears it to shreds, while it's still alive. Tell me that's not cruel. Eating meat is in our nature.


The suffering that goes on behind the scenes in the mostly intense farming methods in which pigs are kept in metal pens without being able to turn round and have interaction with other animals, chickens and turkeys de beaked and de feathered in hot chambers whilst still aware of pain and calves sent abroad to be turned into veal is enough of a reason to not eat meat. I don't think that sentiment comes into it, sentiment comes into the advertising of 'happy meals' and laughing children consuming mass produced chickens and other animals which have suffered miserable lives to the beats of soul music in campaigns. Meat is not necessary to live a healthy life, even Bill Clinton was put on an almost vegan diet devoid of meat, dairy and eggs as this diet can help to prevent heart disease. Many philosophers like Plato, Herodutus "Why cause suffering to these innocent orders of being and why take the life...why cut flesh yet dripping from innocent blood" and Cicero were vegetarian. Cicero said "Nothing cruel is useful or expedient". I myself have seen such cruelty on the animal rights organisation PETA's website that I cannot bear to eat this flesh any more.

Victoria Colewood

I think that most animals reared for meat are kept in cramped unnatural conditions where they are forced to bear young and have them taken away for the meat market, or sometimes if they are lucky calves killed straight away rather than been trucked away for the veal market. Many cancers and heart disease are caused by eating processed meat so rather than being a key to good health, reducing consumption of meat would ensure a longer life and reduce the NHS bill. Many animals are reared abroad and the widespread need for cheap meat has meant that many animals live lives that are not worth being born into. Turkeys and chickens also are mostly reared in cramped surroundings and often not killed humanely. Nutrition wise there are many books which guide vegetarians into having a wide ranging and nutritious tasty diet. Many 'meat' substitutes are readily available aand so much meat is thrown away either by buying too much and disposing of or huge supermarket chains throwing lots away rather than reducing and selling. It is also a contributing factor to famine and poverty, land that could be used for growing crops, or rainforest which should be protection and heritage for the local people and wildlife is being destroyed at an unsustainable rate every year.


John, did you even read the above discussion? You could've at least skimmed it to see whether your point was addressed. Of course it's inhumane for a human being to act like a lion, that's what the word "inhumane" refers to, a non human act. Human beings are capable of rational discussion, morality, and compassion, which the lion appears not to be (as far as I know). Is this not a "natural" trait? Appeals to naturalism always seem ludicrous to me, and can lead to many slippery slopes. Like mentioned above, presumably it's in human nature to be predatory, rapacious and act in self interest, does that mean that we should govern society by these premises? I'm inclined to say no. Whether it's "natural" to eat animals is not on the table, what's up for discussion is whether it's right or necessary. We know that for dietary purposes it's not necessary, a vegetarian or vegan diet is more than sufficient to sustain a human being, we also know that large-scale meat production is highly wasteful, since the amount of protein you have to feed an animal is on an unbalanced ratio to what you get. Is this sustainable? Factory farming clearly isn't, and it also seems slightly immoral to me when large portions of the world are starving to waste such large quantities of protein because people "like the taste" of beef. For me, it's morally "okay" to inflict pain if the reason is sufficient enough, because one likes the taste of meat is not a sufficient reason for me.


This episode is getting on a bit now and I'm sure the recent episode with Gary Francione has corrected the balance some but the nutritional myths put forth by the presenters and comments above are long outdated now.

I also hope Jeff has seen fit to walk the talk consistently and become vegan now as it's the logical conclusion of what he was getting at.

After all cows farmed for their milk and hens farmed for their eggs all get killed once they start becoming unproductive, free range or not. 50% of egg hatchlings get killed at birth too in many gruesome ways for being born a "worthless" male just as with calves in the dairy industry.

All this is to use only Jeff's criteria of death being the ultimate issue and says nothing of use, exploitation and property status issues. There were some gaping holes in Jeff's knowledge at this time certainly.

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