Speciesism () is a term used in philosophy and animal ethics for the treatment of individuals according to their species membership. The term has several definitions. Some writers define it as discrimination or unjustified treatment based on species membership, while others define it more broadly as prioritizing some species over others, regardless of whether that prioritization is justified. Richard D. Ryder, who coined the term, defined it as "a prejudice or attitude of bias in favour of the interests of members of one's own species and against those of members of other species".
The concept is used by philosophers, psychologists, sociologists and animal rights advocates to analyse differences in how humans treat non-human animals. Writers on the subject have applied it to practices including factory farming, animal slaughter, blood sports, the use of animals for fur and leather, animal testing, and the treatment of animals classified as feral or invasive. Some authors also connect speciesism with the refusal to assist animals suffering in the wild when their suffering results from natural processes.
The term first appeared in 1970 in a pamphlet by Ryder protesting against animal experimentation. It was later popularized by Peter Singer in Animal Liberation (1975). Other writers associated with the concept include Oscar Horta, Steven M. Wise, Gary L. Francione, Melanie Joy, David Nibert, Steven Best, and Ingrid Newkirk. The concept has also been criticized or rejected by writers including Carl Cohen, Nel Noddings, Bernard Williams, Peter Staudenmaier, Christopher Grau, Douglas Maclean, Roger Scruton, Thomas Wells, and Robert Nozick.
History
Preceding ideas
Early perspectives on animal sensation and kinship Buffon, a French naturalist, writing in Histoire Naturelle in 1753, questioned whether it could be doubted that animals "whose organization is similar to ours, must experience similar sensations", and that "those sensations must be proportioned to the activity and perfection of their senses". Despite this, he also maintained that there was a gap between humans and other animals.
In the poem "Poème sur le désastre de Lisbonne", Voltaire described a kinship between sentient beings, humans and animals alike, writing: "All sentient things, born by the same stern law, / Suffer like me, and like me also die."
Jeremy Bentham Jeremy Bentham has been described as an early Western philosopher to argue for animals' equal consideration within a secular moral framework. He argued that species membership is morally irrelevant and that any being capable of suffering has intrinsic value. In his 1789 book An Introduction to the Principles of Morals and Legislation, he wrote:
The day may come, when the rest of the animal creation may acquire those rights which never could have been withheld from them but by the hand of tyranny. ... [T]he question is not, Can they reason? nor, Can they talk? but, Can they suffer?
Bentham also supported animal welfare laws. At the same time, he accepted the killing and use of animals, provided that what he regarded as unnecessary cruelty was avoided.
Lewis Gompertz
In his 1824 work Moral Inquiries on the Situation of Man and of Brutes, English writer and early animal rights advocate Lewis Gompertz argued for egalitarianism and extended it to nonhuman animals. He stated that humans and animals have similar feelings and sensations, and that experiences such as hunger, desire, fear and anger affect both in similar ways. Gompertz also pointed to shared physiological characteristics between humans and animals, which he took to suggest similar capacities for sensation. He criticized human use of animals, drawing attention to what he saw as disregard for their feelings, needs and desires.
Charles Darwin English naturalist Charles Darwin, writing in his notebook in 1838, observed that humans tend to regard themselves as masterpieces produced by a deity, but recorded his own view that it was "truer to consider him created from animals". In his 1871 book The Descent of Man, Darwin argued:
There is no fundamental difference between man and the higher mammals in their mental faculties ... [t]he difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind. We have seen that the senses and intuitions, the various emotions and faculties, such as love, memory, attention, curiosity, imitation, reason, etc., of which man boasts, may be found in an incipient, or even sometimes in a well-developed condition, in the lower animals.
Lewis H. Morgan In 1843 Lewis H. Morgan published "Mind or Instinct: An Inquiry Concerning the Manifestation of Mind by the Lower Orders of Animals" in The Knickerbocker. Using anecdotes such as dogs returning to surgeons, beavers building dams, ants storing grain and marmots posting lookouts, Morgan argued that animals display memory, foresight and reasoning. He rejected appeals to "instinct" as an explanation, suggesting that humans and other species share a common mental principle differing only in degree. He also questioned claims of human moral superiority and criticized practices such as hunting for sport and killing animals for food. He developed these arguments in 1857 in an unpublished paper, "Animal Psychology", read to the Pundit Club in Rochester, New York. The paper again rejected instinct and attributed animal behaviour to perception, memory, reflection, volition and reason. Morgan also speculated that animals might possess moral capacities and immortal souls, and he placed species on a "scale of gradation" of intelligence while remaining a creationist. Although little noticed at the time, the essay has been described in later scholarship as an unusually early critique of instinct within American comparative psychology.
Arthur Schopenhauer
German philosopher Arthur Schopenhauer criticized anthropocentrism as, in his view, a fundamental defect of Christianity and Judaism. He argued that these religions contributed to the suffering of sentient beings by separating humans from other animals and encouraging their treatment as mere things. By contrast, Schopenhauer praised Brahmanism and Buddhism for their emphasis on kinship between humans and other animals and for their teaching about a connection between them through metempsychosis.
Secular and utilitarian animal advocacy
According to historian Chien-Hui Li, some secularist thinkers in the late 19th and early 20th centuries argued for animals on utilitarian grounds and on the basis of evolutionary kinship. They linked these views to a broader critique of Christian doctrines about suffering and social order, and sought a morality independent of religious authority. Some initially supported vivisection for human benefit but later questioned its necessity. Figures such as G. W. Foote argued for broader utility, focusing on long-term moral principles rather than immediate gains. Drawing on evolutionary theories, these writers described common origins and similarities between humans and animals and argued that morality should extend to animals as beings capable of experiencing pain and pleasure. They rejected the idea of a theological gulf separating humans from animals and used contemporary scientific theories to support various proposals for animal rights and welfare.
British writer and animal rights advocate Henry S. Salt, in his 1892 book Animals' Rights, argued that for humans to do justice to other animals they must look beyond the conception of a "great gulf" between them, claiming instead that people should recognize the "common bond of humanity that unites all living beings in one universal brotherhood".
Edward Payson Evans, an American scholar and animal rights advocate, criticized anthropocentric psychology and ethics in his 1897 work Evolutional Ethics and Animal Psychology. He argued that such views treat humans as fundamentally different from other sentient beings, and denied that this distinction removes all moral obligations toward animals. Evans held that Darwin's theory of evolution implies moral duties not only toward enslaved humans but also toward nonhuman animals. He asserted that beyond kind treatment, animals need enforceable rights to protect them from cruelty. Evans contended that recognizing kinship between humans and other sentient beings would make it impossible, in his view, to mistreat them.
An 1898 article in The Zoophilist, titled "Anthropocentric Ethics", argued that some early civilizations before Christianity regarded tenderness and mercy toward sentient beings as a moral requirement. It discussed Zarathustra, Buddha and early Greek philosophers who practiced vegetarianism as examples of this outlook. The article claimed that this understanding of human-animal kinship persisted into early Christianity but was challenged by figures such as Origen, who saw animals as mere automata for human use. It concluded that the relationship between animal psychology and evolutionary ethics was gaining scientific and moral attention.
In 1895, American zoologist, philosopher and animal rights advocate J. Howard Moore described vegetarianism as the ethical result of recognizing the evolutionary kinship of all creatures, connecting his position with Darwin's insights. He criticized what he called the "pre-Darwinian delusion" that nonhuman animals were created for human use. In his 1899 book Better-World Philosophy, Moore argued that human ethics were still anthropocentric, having developed to include various human groups but not animals. He proposed "zoocentricism" as a further development, extending ethical concern to the entire sentient universe. In his 1906 book The Universal Kinship, Moore criticized what he described as a "provincialist" attitude leading to animal mistreatment, comparing it to denying ethical relations among human groups. He rejected what he saw as a human-centred perspective and urged consideration of the standpoint of animal victims. Moore concluded that the Golden Rule should apply to all sentient beings, advocating equal ethical consideration for animals and humans:
[D]o as you would be done by, and not to the dark man and the white woman alone, but to the sorrel horse and the gray squirrel as well; not to creatures of your own anatomy only, but to all creatures.
Coining of the term
The term speciesism, and the argument that it is a prejudice, first appeared in 1970 in a privately printed pamphlet written by British psychologist Richard D. Ryder. Ryder was a member of a group of academics in Oxford, England, the nascent animal rights community, now known as the Oxford Group. One of the group's activities was distributing pamphlets about areas of concern; the pamphlet titled "Speciesism" was written to protest against animal experimentation. Supporters of the term intended it to draw a categorical and rhetorical connection with racism and sexism.
Ryder stated in the pamphlet that "[s]ince Darwin, scientists have agreed that there is no 'magical' essential difference between humans and other animals, biologically-speaking. Why then do we make an almost total distinction morally? If all organisms are on one physical continuum, then we should also be on the same moral continuum." He wrote that, at that time in the United Kingdom, 5,000,000 animals were being used each year in experiments, and that attempting to gain benefits for one's own species through the mistreatment of others was "just 'speciesism' and as such it is a selfish emotional argument rather than a reasoned one".
Ryder used the term again in an essay, "Experiments on Animals", in Animals, Men and Morals (1971), a collection of essays on animal rights edited by philosophy graduate students Stanley and Roslind Godlovitch and John Harris, who were also members of the Oxford Group. Ryder wrote:Ryder (1971), p. 81