Many human beings cause a lot of harm to non-human animals. They hunt them for food and sport, and they poison animals like rats and moles. Scientists inflict injuries and diseases on animals to carry out experiments. And they raise animals in factory farms, ensuring lifetimes of pain.
English philosopher Jeremy Bentham (1748-1832) argues that when it comes to causing pain, there is no justification for treating non-human animals any worse than we treat humans. He thereby rejects any attempts to ignore or rationalize away the moral significance of animals’ pain and suffering.
This essay explores Bentham’s argument.
1. The Suffering of Non-Human Animals and Humans
Bentham argues that it is not easier to justify inflicting suffering on sentient non-human animals than it is to justify inflicting suffering on humans. If you try to think of some reason that inflicting pain on humans is somehow worse than inflicting pain on non-human animals, he claims that “no reason can be given,” meaning that no good reason can be given.
One often given reason is that humans are more rational than other animals. Another is that humans use language, while other animals don’t. Bentham replies by providing counterexamples. He notes that “a full grown horse or dog is beyond comparison a more rational, as well as a more conversable animal, than an infant of a day, or a week, or even a month old.”
Moreover, Bentham argues that when it comes to suffering, both rationality and language are irrelevant. “Suppose the case were otherwise,” he says, and human infants were more rational than adult horses or dogs. That would have no relevance to justifying the infliction of pain, because when asking whether it is morally acceptable to cause pain to someone (human or non-human), “the question is not, Can they reason? nor, Can they talk? but, Can they suffer?”
According to Bentham, difference in species, like difference in skin color, is not morally relevant. What matters is whether the individual can suffer. As he puts it, “the French have already discovered that the blackness of the skin is no reason why a human being should be abandoned without redress to the caprice of a tormenter.” The same is true of “the number of legs,” and of any other difference between humans and non-human animals.
To deny this is to defend “speciesism” – the view that mere membership in the human species by itself is relevant to how we should treat someone. But, as Bentham’s argument about skin color suggests, bare prejudice for one’s species might not be any more defensible than bare prejudice for one’s race. Speciesism may be no better than racism.
Bentham’s views about suffering come from his ethical theory, utilitarianism. Bentham accepts a kind of utilitarianism known as hedonistic utilitarianism, which says pleasure is the only thing that is good and pain is the only thing that is bad. According to utilitarians like Bentham, we should do whatever causes the greatest balance of pleasure over pain for all sentient creatures.
For Bentham, it is bad to cause suffering in itself. Suffering is only justified if it is outweighed by greater pleasure than the suffering brings about. For example, it might be good for a dentist to cause you to suffer through a dental procedure if this will cure your toothache.
According to Bentham, it is bad to cause unjustified suffering no matter how rational or talkative the sufferer is. A dog, a horse, and a human can all suffer, so according to Bentham’s utilitarianism, the suffering of a dog or a horse matters just as much as the suffering of a human.
Bentham’s utilitarianism was as radical in his day as it is today. It led Bentham to oppose slavery and sexism at a time when race-based slavery was legal in England and women in England were denied equal status to men. For instance, married women’s property largely belonged to their husbands.
This shows how a moral theory starting from very simple premises like “pleasure is good” and “pain is bad” can lead to conclusions that strike many people as radical, both in the past the present.
One way to object to Bentham would be to say that utilitarianism is not the right account of morality. Maybe morality is not about pleasure and pain, but about something else, like mutual agreements we make with other humans so that we can stay safe. Maybe non-human animals are excluded from this agreement, so we can do whatever we want to them. This view is known as contractarianism.
But, as Bentham points out, human infants are no better at making contracts than non-human animals. We don’t think we can do whatever we want to human infants, so maybe it is mistaken to think that morality is based on mutual agreements.
Another objection attacks Bentham for not going far enough. Bentham thinks that it’s wrong to cause pain to non-human animals, but that painlessly killing them for food is fine, because “we are the better for it, and they are never the worse.”
Someone might argue that although death itself is painless, it prevents non-human animals from experiencing pleasure in the future – pleasure that would exceed the pleasure we get from eating them. So, the objector says that Bentham should oppose killing non-human animals, not just oppose inflicting suffering on them.
Many philosophers, utilitarian or not, agree with Bentham that any creature that can suffer is a creature who deserves moral consideration. If Bentham is right, then many of our present practices are deeply immoral.
Bentham’s argument presents us with a challenge. Either we accept Bentham’s main conclusion, which is that when it comes to suffering, all who can suffer deserve equal consideration; or, we identify some difference between all humans and all other animals that explains why it is okay to inflict suffering on them but not on each other. That difference, however, has not been easy to find.
 For information on these uses of animals, see, e.g., the Humane Society International’s “Trophy Hunting,” “About Animal Testing,” and “Factory Farming,” and the Humane League’s “Factory Farming: What it is and Why it’s a Problem.”
 See Jeremy Bentham’s An Introduction to the Principles of Morals and Legislation Chapter XVII §1.IV, note 1. All subsequent quotes from Bentham are from this same note.
 See Shane Gronholz’s Consequentialism and Utilitarianism and Dale Miller’s John Stuart Mill on the Good Life: Higher-Quality Pleasure.
 See David Antonini’s Social Contract Theory and my “Nasty, Brutish, and Short”: Thomas Hobbes on Life in the State of Nature.
 For a prominent Utilitarian defense of non-human animals see Peter Singer’s Practical Ethics. For a prominent non-Utilitarian defense of non-human animals see Christine Korsgaard’s Fellow Creatures and Tom Regan’s Empty Cages.
The Moral Status of Animals by Jason Wyckoff
Speciesism by Dan Lowe
Theories of Moral Considerability by Jonathan Spelman
Aristotle’s Defense of Slavery by Dan Lowe
Consequentialism and Utilitarianism by Shane Gronholz
Mill’s Proof of the Principle of Utility by Dale E. Miller
John Stuart Mill on the Good Life: Higher-Quality Pleasure by Dale E. Miller
(Im)partiality by Shane Gronholz
Social Contract Theory by David Antonini
Aristotle’s Defense of Slavery by Dan Lowe
Is Death Bad? Epicurus and Lucretius on the Fear of Death by Frederik Kaufman