Author: Dan Lowe
Category: Ethics
Word Count: 994

Human beings use non-human animals in a variety of ways: for scientific experimentation, clothing, and food. These uses typically harm animals, and causing harm is often wrong. So what is it about animals, if anything, that might justify harming them in these ways?

One answer is that we are justified in using animals in these ways simply because they are animals. This is the idea of speciesism: the claim that how a being should be treated is determined (partly or completely) by its species-membership.[1] Speciesism typically involves prioritizing the interests of one’s own species over other species’ interests: because animals are not of our species, we may treat them in ways we would never treat human beings.

Most people seem to accept speciesism. However, some philosophers argue that speciesism reflects a biased prejudice for our own group, similar to racism and sexism. This essay explains different versions of speciesism and the objections they face.[2]

Adam naming the animals
Adam naming the animals

1. Species Membership In Itself

What is it to be a member of a given species, like homo sapiens? It involves membership in a biological group; if one’s DNA is configured in a certain way, then that makes someone a member of the human species.[3]

This raises an objection to speciesism: How one’s DNA is configured is just a fact about the order of molecules in our cells, and that seems morally irrelevant. If you found out that your DNA happened to have an unusual structure (but didn’t affect your health or abilities in any way), that wouldn’t seem to change your moral status.

This objection reveals why some philosophers have argued that speciesism is similar to racism or sexism.[4] Racists say that one race is superior to another; but what race one belongs to (like one’s gender) does not make a difference to one’s moral status. Likewise, the speciesist attaches moral significance to a feature that is, in itself, morally irrelevant.

2. Distinctively Human Capacities

One might respond to this objection by noting that human beings have very different mental capacities from animals: humans have sophisticated language, the capacity for complex thought, and the ability to live according to moral ideals. Perhaps these capacities justify a preference for our own species.

In this case, having the typical mental or cognitive capacities of our species is what is fundamentally morally important, not our biology itself.[5]

This account, however, is vulnerable to the Argument from Species Overlap.[6] Babies and the severely mentally handicapped, for instance, may not have any of the three capacities listed above. Yet it would be profoundly wrong to use these human beings in the ways we use animals – e.g., harvesting the skin of babies as we harvest animals’ hides.

This version may also have parallels with racism and sexism. Racists and sexists have an arbitrary preference for their own race or sex. Likewise, we may look favorably on these capacities simply because they’re ours; as humans we value language, but if we were bats, we’d probably value echolocation instead.

3. Combining Capacities and Species-Membership

Perhaps these difficulties can be avoided through a combination of the previous views: a being’s moral status is determined by whether they are members of a species where the typical members have these important capacities.[7]

This version of speciesism does not depend on the idea that species membership itself gives moral status. And it doesn’t imply that babies or the severely mentally handicapped have inferior moral status; even if they lack these capacities, they are still members of a species in which the typical members do have them. So, this version of speciesism avoids the Argument from Species Overlap.

However, the view depends upon a dubious combination of ideas:

  • having certain capacities (e.g., rationality) matters for having another property (e.g., moral status);


  • some individuals can entirely lack those capacities, and still have that other property – just because typical members of that individual’s group (e.g., species) have those capacities.

To illustrate the problem, consider an analogy.[8] If a story has an engrossing plot and excellent character development, then it has the property of being a good story. Suppose that most of the Sherlock Holmes stories are like this – except “The Naval Treaty.” It would be wrong to say that, even though “The Naval Treaty” doesn’t have any of those qualities, it is still good because the typical members of the series do have those qualities.

Likewise, it would be wrong to say that a being has a moral status because the typical members of its species have certain characteristics. Being a member of a group does not mean that one has all, or even many, of the characteristics of other members of the group.[9]

This version of speciesism also has parallels with racism and sexism. Consider a racist who believes that most members of their race have certain special characteristics. Even if they were right about that, it wouldn’t justify treating all members of that race as special, even though this is how racists typically think. Likewise, appealing to the characteristics of typical members of a species doesn’t grant special moral status to all members of that species.[10]

4. Conclusion

If species-membership is irrelevant to the moral status of a being, then we should oppose speciesism just as we should oppose racism or sexism. But if species-membership doesn’t determine moral status, what does?

We have already considered one answer to that question – if the being has certain important capacities. The philosopher Jeremy Bentham famously remarked that animals already have the capacities which most matter for moral status: “The question is not, ‘Can they reason?’ nor ‘Can they talk?’ but, “Can they suffer?”[11] And yet we treat some animals, like puppies, very differently from others, like pigs – even though puppies and pigs are likely to have the same morally relevant capacities.[12]

What, if any, moral obligations do we have toward animals? It turns out that this question cannot be answered simply by the fact that humans and animals are of different species.


[1] The concept of speciesism was introduced to a wide audience by Peter Singer. He presents speciesism this way: “Speciesism … is a prejudice or attitude of bias toward the interests of members of one’s own species and against those of members of other species” (Animal Liberation, p. 7). The formulation used in this essay is different in two ways.

First, it is more neutral – it does not presuppose that speciesism is a form of prejudice or bias; this seems to suggest that speciesism is wrong or unjustified by definition, which would rule out the possibility that speciesism could be morally justified. Here I follow Jaquet (2019), who argues that the term’s function in debate requires that it be understood as purely descriptive.

Second, it is broader – it says that species-membership is relevant to moral status, but does not specify that it must involve preference for one’s own species. Singer is correct that this is how speciesism typically functions, but it is not an essential feature of the view; for example, speciesism can take the form of a species-based hierarchy which elevates different, non-human species above others (cats over cows, dogs over pigs, vertebrates over insects, for example). Such a hierarchy may be speciesist, but it need not involve prejudice in favor of one’s own species.

[2] Philosophers who advocate speciesism include Carl Cohen, Tibor Machan, and David Schmitdz; philosophers who contest it include Peter Singer, Tom Regan, and Lori Gruen.

[3] It is controversial whether species exist or how they exist: are species natural kinds or objective, natural categories, or are they are human-made categories that do not correspond to any deeper reality? In this way, the question of whether or how species exist is similar to the question of whether or how races exist. (For an overview of whether or how races exist, see The Ontology of Race by Abiral Chitrakar Phnuyal.) But if a speciesist is going to say that species-membership is morally significant, then this presumably requires them at least believing that species are more than created fictions.

[4] Peter Singer, Animal Liberation; Tom Regan, “The Case for Animal Rights.”

[5] An interesting implication of this view is that if members of other species, such as intelligent extraterrestrials, had those same capacities, they would also have the same moral status.

[6] This argument was formerly known as the “Argument from Marginal Cases”; see, for instance, Daniel Dombrowski, Babies and Beasts: The Argument from Marginal Cases. It is no longer called that since it risks being rude and disrespectful to call certain human beings “marginal.” The current name of this argument emphasizes that morally-relevant characteristics overlap, or are shared by, individuals of different species.

[7] Carl Cohen, “The Case for the Use of Animals in Biomedical Research”; David Schmidtz, “Are All Species Equal?”

[8] Nathan Nobis, “Carl Cohen’s ‘Kind’ Arguments For Animal Rights and Against Animal Rights”; and Jeff McMahan, The Ethics of Killing: Problems at the Margins of Life.

[9] The view also seems to imply, for instance, that human embryos and brain-dead individuals have full moral status, and thereby have all the same rights as fully-developed and typically-functioning human beings. So this view has implication for, at least, abortion and euthanasia. For introductions to those issues, see The Ethics of Abortion by Nathan Nobis and Euthanasia, or Mercy Killing by Nathan Nobis.

[10] Lori Gruen, Ethics and Animals: An Introduction, 53-55.

 [11] Jeremy Bentham, Introduction to the Principles of Morals and Legislation, Chapter 37, §1, IV, n. 1. Emphasis in original. See Daniel Weltman’s “Can They Suffer?”: Bentham on our Obligations to Animals.

[12] Alastair Norcross, “Puppies, Pigs, and People: Eating Meat and Marginal Cases.”


Bentham, Jeremy. Introduction to the Principles of Morals and Legislation. Clarendon Press, 1879.

Cohen, Carl. “The Case for the Use of Animals in Biomedical Research,” October 2, 1986, New England Journal of Medicine; 315:865-870

Dombrowski, Daniel. Babies and Beasts: The Argument from Marginal Cases. University of Illinois Press, 1997.

Gruen, Lori. Ethics and Animals: An Introduction. Cambridge University Press, 2011.

Jaquet, François. “Is Speciesism Wrong by Definition?” Journal of Agricultural and Environmental Ethics. 2019. https://doi.org/10.1007/s10806-019-09784-1

Machan, Tibor. Putting Humans First: Why We Are Nature’s Favorite. Rowman & Littlefield, 2004.

McMahan, Jeff. The Ethics of Killing: Problems at the Margins of Life. Oxford University Press, 2002.

Nobis, Nathan. “Carl Cohen’s ‘Kind’ Arguments For Animal Rights and Against Animal Rights.” Journal of Applied Philosophy, Vol. 21., No. 1, 2004.

Norcross, Alastair. “Puppies, Pigs, and People: Eating Meat and Marginal Cases” in The Ethical Life: Fundamental Readings in Ethics and Moral Problems, 2nd edition, ed. Russ Shafer-Landau. Oxford University Press, 2012.

Regan, Tom. “The Case for Animal Rights” in In Defense of Animals, ed. Peter Singer. Basil Blackwell, 1985.

Schmidtz, David. “Are All Species Equal?” in The Oxford Handbook of Animal Ethics, eds. R.G. Frey and Tom Beauchamp. Oxford University Press, 2011.

Singer, Peter. Animal Liberation. 1975. Updated Edition, HarperCollins Publishers, 2009.

Related Essays

The Moral Status of Animals by Jason Wyckoff

Theories of Moral Considerability: Who and What Matters Morally? by Jonathan Spelman

“Can They Suffer?”: Bentham on our Obligations to Animals by Daniel Weltman

Applied Ethics by Chelsea Haramia

The Ontology of Race by Abiral Chitrakar Phnuyal

The Ethics of Abortion by Nathan Nobis

Euthanasia, or Mercy Killing by Nathan Nobis

Principlism in Biomedical Ethics: Respect for Autonomy, Non-Maleficence, Beneficence, and Justice by G. M. Trujillo, Jr.

Revision History

This essay, posted 9/5/19, is a revised version of an essay originally posted 3/24/2014.

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Download this essay in PDF (link forthcoming).

About the Author

Dan Lowe is a lecturer in the department of philosophy at the University of Michigan. He works on moral and political philosophy, feminist philosophy, and their intersection with moral epistemology. https://sites.google.com/site/danlowe161

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