Peter Singer’s Equality for Animals (Will Lead to Environmental Destruction)?

(Ethics / Moral Philosophy)

Jarren Nylund
6 min readJan 11, 2022


IMAGE: Australian utilitarian philosopher Peter Singer petting a sheep. © Derek Goodwin.

Peter Singer is an Australian utilitarian philosopher who is well-known for his work in bioethics and for creating some of the foundational ideas behind the animal advocacy movement (Duignan, n.d.). A chapter of Singer’s (2011, p. 48) book, Practical Ethics, argues for the principle of equality to be applied to non-human animals in the same way that it has been applied to humans. And that not doing so, is speciesism, where one is unfairly discriminating on the basis of species. He does this by arguing that a distinction of sentience should be used to define the boundary of moral concern. However, in this essay, I will argue that doing so creates an only slightly less problematic ethical viewpoint than speciesism. I will do this by refuting a core premise of his argument, as well as demonstrating the arbitrary nature of the distinction of sentience, and proposing that it can lead to the justification of environmental destruction.

IMAGE: The cover of the third edition of Peter Singer’s (2011) Practical Ethics. © Cambridge University Press.

In the chapter titled “Equality for Animals?” of Practical Ethics, Singer (2011, p. 48) argues a utilitarian case for extending the principle of equality, as it applies to humans, to other non-human animals. He does this by following in the footsteps of one of the founders of utilitarianism, Jeremy Bentham (1780), who wrote:

“The day may come when the rest of the animal creation may acquire those rights which never could have been withholden from them but by the hand of tyranny…The question is not, Can they reason? nor Can they talk? but, Can they suffer?” (p. 307).

Singer (2011, p. 50) accepts the premise of Bentham’s utilitarian argument, where he believes that it is a being’s capacity for suffering which grants it worthy of equal consideration. He then argues that a capacity for suffering and pleasure is required for a being to have self-interest and be worthy of moral concern. The construct he uses to define the limit of a capacity for suffering and pleasure is sentience, and he argues that defining the limit by any other characteristic, such as rationality or intelligence, would be arbitrary and indefensible. Here, Singer presents a case for the idea of speciesism as being similar to the idea of racism. But, where racism is having more concern for members of your own race, speciesism is having more concern for members of your own species, where the suffering of animals is not of equal concern to the suffering of humans.

In placing the sole emphasis of moral concern on the sentience of beings, Singer (2011, p. 50) is making a case for sentientism, but I am going to assert that sentientism is only a matter of degree less problematic than the speciesism and racism that Singer argues against. Singer argues that racists violate the principle of equality by placing more concern on members of their own race, and that speciesists violate the principle of equality by placing more concern on members of their own species. But, sentientism similarly violates the principle of equality by placing more concern on beings depending on their level of sentience. He tries to justify this discrimination by arguing that sentience is a prerequisite for having interests at all, and that without it there is nothing to be taken into account. However, Thomas Wells (2016), argues that this is a false assertion, as other forms of non-sentient life clearly have an interest in their survival, growth, and reproduction. Wells also makes the point that it is possible to reach similar conclusions to Singer through the path of virtue ethics, instead of the utilitarian path that Singer takes. This is where one is concerned with one’s moral character, sentiment, and the kind of person that one should try to be, rather than what kinds of actions one ought to take (like in other ethical theories such as utilitarianism and deontology).

IMAGE: “Plants have electrical and chemical signaling systems, may possess memory, and exhibit brainy behavior in the absence of brains” (Pollan, 2013). © Construction by Stephen Doyle / Photograph by Grant Cornett.

It may also be the case that seemingly non-sentient entities have a kind of sentience that is so unlike our own that we simply don’t recognize it. Recent scientific studies suggest that plants are much more intelligent than we have previously given them credit for, demonstrating evidence that plants are able to sense things in their environment and communicate with one another (Pollan, 2013). Ultimately, because it is impossible to know with any certainty what consciousness is like for another entity, it is using a measure that is at best, a guesstimation. Using sentience as a construct creates an only slightly less discriminatory measure, where the traits of a healthy human adult are considered to be the ideal, and where the moral worth of a being is considered less the further away a being is from that ideal. These points create a problem for Singer’s argument because it establishes a far less clear boundary of moral concern, and where the line is drawn becomes as arbitrary as the other boundaries he argues against. Wherever this murky line is drawn, on one side, there are sentient entities with graduating levels of intrinsic value (i.e., the value that entities have in themselves), and on the other, there are entities with graduating levels of instrumental value (i.e., they are only valued in how they serve the desires of sentient life). And where any entity falls on this spectrum is being determined by humans, and based on a large degree of ignorance in their conscious experience.

IMAGE: The cover of Tom Regan‘s (1983) The Case for Animal Rights. © The University of California Press.

Tom Regan (1983, p. 181) has presented an alternative case for the ethical consideration of animals through an animal rights framework, which extends Immanuel Kant’s deontological arguments for intrinsic values to encompass animals. This is where animals, like humans, are considered “ends in themselves” and therefore ought not to be exploited. Regan (1981, p. 27) also proposed the idea that if we were able to create an environment that is better for sentient beings, then the utilitarian ethical perspective would require that the natural environment be replaced. Therefore, he concluded that a utilitarian ethic is unacceptable. Although this is a highly theoretical example, it does illustrate the point that sentientism creates an ethical viewpoint that places no value in things such as plants and ecosystems beyond their use-value to sentient life, and one that can allow for the justification of environmental destruction.

In this essay, I have argued that using sentience as a boundary for moral concern — as is done in sentientism — is problematic. This was achieved through rejecting Singer’s (2011, p. 50) core foundational premise that sentience is needed for a being to have interests, as well as presenting the case that sentience is just as arbitrary as the other boundaries of moral concern which Singer rejects, and that sentientist ethical values can lead to a justification for environmental destruction. In conclusion, it would seem as though the sentientist ethical system, which places no intrinsic value in non-sentient life, is almost as flawed as speciesism itself.


Bentham, J. (1780). An introduction to the principles of morals and legislation. London: T. Payne and Sons.

Duignan, B. (n.d.). Peter Singer: Australian philosopher. Britannica. Retrieved from

Pollan, M. (2013, December). The intelligent plant: Scientists debate a new way of understanding plants. The New Yorker. Retrieved from

Regan, T. (1981). The nature and possibility of an environmental ethic. Environmental Ethics, 3, 19–34. doi:10.5840/enviroethics19813131

Regan, T. (1983). The case for animal rights. Berkley: The University of California Press.

Singer, P. (2011). Practical ethics. New York: Cambridge University Press.

Wells, T. (2016, October). The incoherence of Peter Singer’s utilitarian argument for vegetarianism. ABC Religion & Ethics. Retrieved from



Jarren Nylund

🧠 Psychological Science Student, UQ ✏️ Designer, Design Good Design Studio 🌏 Climate Reality Leader 💁‍♂️ Pronouns: he/him 🔗