The objection that eating animals is natural
The appeal to nature in the debate over eating animals
One of the most common objections to veganism is the claim that eating animals is right because it’s natural. People often point out that, in nature, animals eat one another, and that humans sit at the top of the food chain: “it’s fine, because it’s the natural order of things.” It’s also common to point to our canine teeth: “look, they’re designed for tearing meat, which proves that eating meat is natural for human beings and therefore right.”
Defenders of veganism, for their part, usually respond to this objection by trying to show that eating meat may be natural for other animals, such as lions, but that it isn’t natural for human beings. They tend to point out, for example, that humans are unable to tear or digest raw meat, and that eating meat is linked to a range of health problems in people. They conclude, therefore, that we shouldn’t eat meat because doing so wouldn’t be natural for human beings.
Although the two sides of this debate hold opposite positions on whether eating meat is right or wrong, they share a common assumption: that knowing whether a behavior is natural is relevant to knowing whether it’s right or wrong. And it’s precisely that assumption which, if we look into it closely, we’ll find to be deeply problematic1. Noticing this point matters, because the appeal to nature shows up in debates about many ethical questions: people simply assume that if a behavior is natural, that makes it justifiable, and that if it isn’t natural, it’s wrong. In this article, we’ll look at the problems with this presupposition.
The ambiguity in the definition of natural behavior
To assess whether a behavior’s being natural is or isn’t relevant to whether it’s justified, we first need to understand what people mean when they say a behavior is natural. And here we already run into a first problem, because people mean many different things by that claim. Below, we’ll look at five different senses of the statement “this is natural,” and examine whether any of them is relevant to knowing whether a behavior is justified.
“But humans are omnivores”
Sometimes, what people mean when they say that eating meat is natural for humans is that the human body is able to survive on meat. In this sense, someone defending the consumption of animals points out that, biologically, humans are omnivores, which means that their bodies can survive on a plant-based diet just as well as on an animal-based one.
But, obviously, the fact that a behavior is possible doesn’t imply that it’s justifiable. If it did, then every possible act would be justifiable, and it wouldn’t even make sense to investigate which acts are justifiable. For example, it’s also possible for humans to eat human flesh, but that doesn’t make it right to kill humans for that purpose. In the same way, the mere fact that humans can kill animals of other species and eat their flesh doesn’t make such an act justifiable.
“But it’s our instinct”
At other times, what someone means by “that behavior is natural” is that it’s an instinctive behavior, one we’re genetically inclined toward. In that same sense, those who claim that eating meat isn’t natural for human beings point out that human babies usually make friends with nonhuman animals rather than prey on them.
This does seem to show that humans have no instinctive inclination to kill and eat other animals. But suppose we all did have an instinctive inclination to kill animals and eat their flesh. The question is: does the fact that a behavior comes from an instinctive inclination make it justifiable?
Imagine, for example, that humans had an instinctive inclination to take advantage of the most vulnerable. Certainly, if that tendency existed, it might have the appearance of being right, since human genetics would incline people to think, in a biased way, that it is (and might even incline them to try to rationalize that tendency by searching for a justification for it).
However, an act’s seeming right is very different from an act’s being right. If merely feeling instinctively inclined to do something justified doing it, then it would make no sense to ask, “do I actually have a justification for doing what I feel inclined to do?” But if that question does make sense and it’s one of the central questions driving reflection on any ethical matter, then the fact that a behavior is instinctive doesn’t have the power to justify it.
“But animals eat one another”
Often, what people mean when they say that an act is natural is that animals do it too. For example, eating animals is frequently defended on the basis of the claim that, in nature, animals eat one another.
There are at least two problems with this defense of eating animals. The first is that there are also animals that don’t eat other animals. We can find an endless variety of behaviors among animals in nature. So if that justified a behavior, then almost any behavior could be justified, since one can almost always find some animal that does it too. It’s therefore, at the very least, suspicious for someone to defend eating animals in this way. They would have to explain why they choose to copy the behavior of the animals that do exactly what they want to do, rather than that of the animals that don’t. If they can’t find a justification for that selectivity, their attitude is biased.
The second and greater problem is this. Suppose every animal in nature ate other animals. Why would the fact that an act is also carried out by an animal make that act justified? After all, there are animals in nature that also steal, kill, and perform sexual acts against the victim’s will. But that doesn’t imply that it’s right for us to do the same. We humans possess a rational capacity that allows us, among other things, to reflect on whether or not there’s a justification for our decisions. It’s therefore, to say the least, strange to base those decisions on the behavior of animals that lack such a capacity.
And, incidentally, the appeal to what animals do shows up almost exclusively as an attempt to justify eating meat. Animals in nature don’t use cell phones, cars, computers, the internet, or hospitals, for example, yet no one refuses to use those things just because animals don’t. This shows that the appeal to what animals do isn’t really sincere: it’s merely a rationalization of the desire to eat meat.
“But humans are at the top of the food chain”
Often, when someone says “eating meat is natural,” what they mean is that humans are at the top of the food chain. It’s pointed out, for example, that in nature the more powerful animals kill and eat the less powerful ones, and that it’s therefore right for humans to kill the other animals who are at their mercy. It’s part of the natural order of things.
However, there’s nothing that forces humans to kill animals in order to eat. In fact, there are many humans who choose not to consume animals. So this is no different from saying that we’re justified in doing something simply because we have the power to do it. But we’ve already seen the problems with that position: the fact that something is possible doesn’t mean there’s a justification for doing it.
One might object that, in the natural order of things, the more powerful kill and eat the less powerful. That is, on this view, eating animals is right because that’s just how things are. However, this position has even more problems than the previous one. Consider:
First, it makes a leap from what is to what ought to be. That is, it observes “things are this way in the world” and concludes “therefore it’s fine that they are this way.” But one doesn’t necessarily follow from the other: the mere fact that something is the way it is doesn’t show that it’s good, right, just, or even acceptable.
Second, we would never regard such a position as correct if the roles were reversed. Imagine, for example, that there were a species more powerful than humans, and that its members killed and ate humans without any need to do so (they could feed on plants alone). If we were the victims, we would consider what they do unjust. But if so, then the defense that humans are justified in consuming animals because they’re at the top of the food chain is biased: its proponents defend it only because they know they won’t be among those harmed by the practice in question.
“But what’s natural is what’s right”
Finally, at other times what someone means by “that act is natural” is simply that the act in question is right. But if that’s the meaning of the term, then the claim “eating meat is right because it’s natural” is empty, since it would amount to simply saying “eating meat is right because it’s right,” without giving any reason for it.
This holds for any other appeal to nature: if someone says that “natural = right,” and then says “act x is right because it’s natural,” they’re merely asserting, redundantly, “x is right because it’s right,” without giving any reason to think that it actually is.
Conclusion: what we can learn from all this
As we’ve seen, however the term “natural” is defined, the fact that a behavior is natural doesn’t make it justifiable. Why, then, is the appeal to nature so present in discussions of various ethical questions? Simple: because people aren’t in the habit of examining the assumptions they start from when they think. We’ve seen that, once we carry out that examination, the problems with the appeal to nature become very clear. So clear that, once we’ve examined the assumption, we’re left wondering, “how could we ever have held a belief as baseless as this?”
That being so, it’s not only problematic to try to justify eating animals by appealing to nature: it’s equally problematic to argue that eating animals is wrong because it isn’t natural. What’s wrong with eating animals is that it’s an unjust practice, one that violates the principles of equal consideration2 and impartiality3. For example, anyone who approves of eating animals does so only because they know they’ll be the beneficiary and not the victim. That alone already makes the attitude unjust, because it violates the principle of impartiality. That’s what’s wrong with eating animals and with animal exploitation as a whole, and it has nothing to do with whether or not eating animals is natural.
In their rush to challenge the objections raised by those who defend eating animals, animal advocates often focus on challenging the factual claim without questioning the normative assumption the objection starts from. For example, if someone says “eating meat is right because it’s natural,” they aren’t only claiming that eating meat is natural (a factual claim): they’re also assuming that if an act is natural, it’s right (a normative assumption). However, because that assumption remains implicit, animal advocates rush to challenge the factual claim, forgetting that the normative assumption is already problematic in itself (and if so, we don’t need to evaluate the factual claim to see that the argument is unsound, because even if the factual claim were true, the argument would still be a bad one). The problem is this: perhaps those who oppose eating meat don’t question that assumption not because they fail to notice it, but because they too accept it (and that’s why they go to such lengths to try to show that eating meat isn’t natural).
This shows how important it is not only to examine this particular assumption, but to examine the assumptions we hold in general when we think through various questions. For example, if we examined beliefs such as the belief that nonhuman animals should be given less consideration, the belief that animals in nature are only seriously harmed by human practices4, the belief that we aren’t morally responsible for natural harms5, or even the belief that concern for animals and environmentalism are complementary worldviews6, we would be just as surprised at how fragile they are.
References
Cunha, L. C. (2025) A ética e a situação dos animais selvagens: uma análise da questão dos danos naturais, Florianópolis: Senciência e Ética [accessed on 21 July 20266].
Dorado, D. (2015) El conflicto entre la ética animal y la ética ambiental: bibliografía analítica, doctoral dissertation, Getafe: Universidad Carlos III de Madrid [accessed on 21 July 2026].
Animal Ethics (2020) Introduction to wild animal suffering, Oakland: Animal Ethics [accessed on 21 July 2026].
Mill, J. S. (1904 [1874]) “On nature,” Lancaster Philosophy Department [accessed on 21 July 2026].
Rachels, J. & Rachels, S. (2012 [1986]) The elements of moral philosophy, 7th ed., New York: McGraw-Hill.
Rowlands, M. (2009 [1998]) Animal rights: Moral theory and practice, 2nd ed., New York: Palgrave Macmillan.
Singer, P. (2011 [1979]) Practical ethics, 3rd ed., Cambridge: Cambridge University Press.
Notes
1 For a detailed critique of the appeal to nature, see Mill (1904) and Rachels & Rachels (2012 [1986], pp. 44–48, 54–58).
2 The best-known formulation of this principle is found in Singer (2011 [1979], pp. 20–24). In essence, the principle holds that there is no justification for being biased in how we weigh the harms and benefits that fall on those affected by our decisions.
3 For an application of this principle to our decisions affecting animals, see Rowlands (2009 [1998], pp. 118–175). In essence, the principle states that a decision is just if it is the one that would be endorsed by rational agents who did not know what position they would occupy among those affected by it.
4 For a detailed account of how natural processes harm animals in the wild, see Animal Ethics (2020) and Cunha (2025).
5 For a discussion of this question, see Cunha (2025, pp. 55–62).
6 On the opposition between environmentalism and concern for animals, see Dorado (2015).