What is speciesism, and is it wrong to put humans first?

The objection

“Of course humans matter more than animals. We’re more intelligent, we use language and we make plans for the future. Favouring our own species is natural loyalty, the same instinct that makes us care more for family than for strangers, and calling it ‘speciesism’ is an abuse of the word.”

The answer

Speciesism, a word Richard Ryder coined in a privately published pamphlet in 1970 and Peter Singer made famous in Animal Liberation (1975), means favouring the interests of members of your own species over the like interests of other animals because of the species they belong to [1].

The charge is narrower than it sounds. Singer doesn’t ask for humans and animals to be treated alike: a dog has no right to vote and neither does a young child, and equality in his sense “requires equal consideration”, which for different beings can mean different treatment [2]. What he rejects is discounting an individual’s interests because of the group they were born into, the move he sees in racism and sexism [1][2], and philosophers who have since worked on defining speciesism, such as Oscar Horta and Frauke Albersmeier (2020), keep it continuous with those forms of discrimination [3]. The comparison is about the shape of an argument and passes no judgement on anyone’s character.

Aren’t humans simply more intelligent than animals?

Most adult humans are, but intelligence can’t be what protects us, because some humans have less of it than many animals and we would never farm them. Jeremy Bentham noted in 1789 that a full-grown horse or dog is more rational than a month-old baby, and Singer adds that many animals are more self-aware and better able to plan ahead than people whose cognitive abilities are profoundly and permanently impaired [2]. Philosophers call this the argument from species overlap [5], or more traditionally the argument from marginal cases [2], and it works against any capacity you care to name, because none is shared by every human and some of those said to mark out persons, such as self-awareness, may be shared by several other species [1]. It applies with force to pigs. A 2015 review noted that relatively little is known about the psychology of pigs, but concluded that what is known suggests they are cognitively complex and share many traits with animals we consider intelligent [4].

Doesn’t being human count for something in itself?

Some respected philosophers say it does, but two of the most prominent versions of the claim rest on intuition or loyalty that they don’t go on to justify [1]. Bernard Williams (2006) argued that loyalty to our own kind is an ethical concept we already use. Shelly Kagan (2016) thinks a separate view, “modal personism”, on which it matters morally whether a being could have been a person, deserves “careful further investigation”, but of the plain speciesist view that human suffering counts for more he admits he has “offered no argument” beyond intuition [1]. The philosopher Jeroen Hopster (2019) replies that self-serving intuitions deserve suspicion, and that a racist could argue in just the same way that it matters whose group a pain belongs to [1].

Hopster himself thinks a different case holds more promise: the knowledge and culture humans have built up over generations arguably make most human lives, though not every one, richer than the lives of other animals, a claim he says still needs substantiating [1]. That case rests on what a life contains, so the species overlap applies to it too, and Hopster adds that it would take “further argument” to get from richer lives to human interests counting for more than the like interests of animals. How far the two can be compared, he writes, is “still far from resolved” [1].

Chappell and Meissner (2025) weigh two more objections. One treats what is normal for each species as a baseline, which would explain why curing a disabled person seems more urgent than enhancing a healthy pig. The other answers the argument from species overlap directly: society may give severely cognitively disabled people rights beyond what their moral status strictly requires, and it wouldn’t obviously follow that we wrong animals by withholding the same, so Singer’s claim that such animals deserve as strong a right to life as comparable humans may need more defending [2]. They conclude that neither objection is a defence of factory farming, because Singer’s case against mistreating animals needs only the premise that the suffering of any innocent sentient being is seriously bad [2].

Isn’t putting your own species first like putting your family first?

Only up to a point, because partiality explains why you would save your own child first but gives you no right to harm someone else’s, and almost everyone who shares your species is a stranger to you. Some ethicists do model our ties to fellow humans on family ties, and others dispute the comparison [1]. The Utilitarianism.net guide notes that the case against speciesism sits comfortably with special duties to friends and family, though those duties don’t stretch to strangers who merely share a category with you [2].

Does rejecting speciesism mean a mouse matters as much as a person?

Rejecting speciesism doesn’t make a mouse’s life worth as much as a person’s, and Singer says so himself. He accepts that killing a self-aware adult who plans for the future and has close relationships can be worse than killing a mouse, and the Utilitarianism.net guide says his principle is compatible with saving a human child before a few chickens [2]. What Singer rules out is drawing the line exactly at the species boundary and counting the same pain differently according to who feels it, so a pig’s suffering counts as much as the like suffering of a dog or a person, as far as the two can be compared [2]. The line he draws instead is at sentience, the capacity to feel pain or pleasure [2].