The Antispeciesist Revolution

By David Pearce

When is it ethically acceptable to harm another sentient being? On some fairly modest assumptions, to harm or kill someone simply on the grounds they belong to a different gender, sexual orientation or ethnic group is unjustified. Such distinctions are real but ethically irrelevant. On the other hand, species membership is normally reckoned an ethically relevant criterion. Fundamental to our conceptual scheme is the pre-Darwinian distinction between “humans” and “animals”.


In law, nonhuman animals share with inanimate objects the status of property. As property, nonhuman animals can be bought, sold, killed or otherwise harmed as humans see fit. In consequence, humans treat nonhuman animals in ways that would earn a life-time prison sentence without parole if our victims were human. From an evolutionary perspective, this contrast in status isn’t surprising. In our ancestral environment of adaptation, the capacity to hunt, kill and exploit sentient beings of other species was fitness-enhancing(2). Our moral intuitions have been shaped accordingly. Yet can we ethically justify such behaviour today?

Naively, one reason for disregarding the interests of nonhumans is the dimmer-switch model of consciousness. Humans matter more than nonhuman animals because (most) humans are more intelligent. Intuitively, more intelligent beings are more conscious than less intelligent beings; consciousness is the touchstone of moral status.

The problem with the dimmer-switch model is that it’s empirically unsupported among vertebrates with central nervous systems, and probably in cephalopods such as the octopus as well. Microelectrode studies of the brains of awake human subjects suggest that the most intense forms of experience, for example agony, terror and orgasmic bliss, are mediated by the limbic system, not the prefrontal cortex. Our core emotions are evolutionarily ancient and strongly conserved. Humans share the anatomical and molecular substrates of our core emotions with the nonhuman animals whom we factory-farm and kill. By contrast, distinctively human cognitive capacities such as generative syntax, or the ability to do higher mathematics, are either phenomenologically subtle or impenetrable to introspection. To be sure, genetic and epigenetic differences exist between, say, a pig and a human being that explain our adult behavioural differences, e.g. the allele of the FOXP2(1) gene implicated in the human capacity for recursive syntax. Such mutations have little to do with raw sentience(1).

So what is the alternative to traditional anthropocentric ethics? Antispeciesism is not the claim that “All Animals Are Equal”, or that all species are of equal value, or that a human or a pig is equivalent to a mosquito. Rather the antispeciesist claims that, other things being equal, equally strong interests should count equally. Experiences that are subjectively negative or positive in hedonic tone to the same degree must count for the same. And conscious beings of equivalent sentience often have equally strong interests, which (other things being equal) we must care for and respect equally – though other animals who may be less sentient can also have important interests as well. A pig, for example, is of comparable sentience to a prelinguistic human toddler. As it happens, a pig is of comparable (or superior) intelligence to a toddler as well(5). However, such cognitive prowess is ethically incidental. If ethical status is a function of sentience, then to factory-farm and slaughter a pig is as ethically abhorrent as to factory-farm and slaughter a human baby. To exploit one and nurture the other expresses an irrational but genetically adaptive prejudice.

On the face of it, this antispeciesist claim isn’t just wrong-headed; it’s absurd. Philosopher Jonathan Haidt speaks of “moral dumbfounding”(6), where we just know something is wrong but can’t articulate precisely why. Haidt offers the example of consensual incest between an adult brother and sister who use birth control. For evolutionary reasons, we “just know” such an incestuous relationship is immoral. In the case of any comparisons of pigs with human infants and toddlers, we “just know” at some deep level that any alleged equivalence in status is unfounded. After all, if there were no ethically relevant distinction between a pig and a toddler, or between a battery-farmed chicken and a human infant, then the daily behaviour of ordinary meat-eating humans would be sociopathic – which sounds crazy. In fact, unless the psychiatrists’ bible, Diagnostic and Statistical Manual of Mental Disorders, is modified explicitly to exclude behaviour towards nonhumans, most of us do risk satisfying its diagnostic criteria for the disorder. Even so, humans often conceive of ourselves as animal lovers. Despite the horrors of factory-farming, and in general of slaughterhouses where all farmed animals perish, most consumers of meat and animal products are clearly not sociopaths in the normal usage of the term; most factory-farm managers are not wantonly cruel; and the majority of slaughterhouse workers are not sadists who delight in suffering. Serial killers of nonhuman animals are just ordinary men doing a distasteful job – “obeying orders” – on pain of losing their livelihoods.

Should we expect anything different? Political theorist Hannah Arendt spoke famously of the “banality of evil”(7). If twenty-first century humans are collectively doing something posthuman superintelligence will reckon monstrous, a crime against sentience akin to the [human] Holocaust or Atlantic slave trade, then it’s easy to assume our moral intuitions would disclose this to us. Our intuitions don’t disclose anything of the kind; so we sleep easy. But both natural selection and the historical record offer powerful reasons for doubting the trustworthiness of our naive moral intuitions. So the possibility that human civilisation might be founded upon some monstrous evil should be taken seriously – even if the possibility seems transparently absurd at the time.

One possible speciesist response is to raise the question of “potential”. Even if a pig is as sentient as a human toddler, there is a fundamental distinction between human toddlers and pigs. Only a toddler has the potential to mature into a rational adult human being.

The problem with this response is that it contradicts our treatment of humans who lack “potential”. Thus we recognise that a toddler with a progressive disorder who will never live to celebrate his third birthday deserves at least as much love, care and respect as his normally developing peers – not to be packed off to a factory-farm on the grounds it’s a shame to let good food go to waste. We recognise a similar duty of care for mentally handicapped adult humans and cognitively frail old people. For sure, historical exceptions exist to this perceived duty of care for vulnerable humans, e.g. the Nazi “euthanasia” program, with its eugenicist conception of “life unworthy of life”. But by common consent, we value young children and cognitively challenged adults for who they are, not simply for who they may – or may not – one day become. On occasion, there may controversially be instrumental reasons for allocating more care and resources to a potential genius or exceptionally gifted child than to a normal human. Yet disproportionate intraspecies resource allocation may be justified, not because high IQ humans are more sentient, but because of the anticipated benefits to society as a whole.

Practical Implications.
1. Invitrotarianism.

The greatest source of severe, chronic and readily avoidable suffering in the world today is man-made: animal agriculture, most notably factory farming. Humans currently slaughter over fifty billion sentient beings each year. One implication of an antispeciesist ethic is that factory farms should be shut and their surviving victims rehabilitated.

In common with most ethical revolutions in history, the prospect of humanity switching to a cruelty-free diet first strikes most practically-minded folk as utopian dreaming. “Realists” certainly have plenty of hard evidence to bolster their case. As English essayist William Hazlitt observed, “The least pain in our little finger gives us more concern and uneasiness than the destruction of millions of our fellow-beings.” Without the aid of twenty-first century technology, the mass slaughter and abuse of our fellow animals might continue indefinitely. Yet tissue science technology promises to allow consumers to become moral agents without the slightest hint of personal inconvenience. Lab-grown in vitro meat produced in cell culture rather than a live animal has long been a staple of science fiction. But global veganism – or its ethical invitrotarian equivalent – is no longer a futuristic fantasy. Rapid advances in tissue engineering mean that in vitro meat will shortly be developed and commercialised. Today’s experimental cultured mincemeat can be supplanted by mass-manufactured gourmet steaks for the consumer market. Perhaps critically for its rapid public acceptance, in vitro meat does not need to be genetically modified – thereby spiking the guns of techno-luddites who might otherwise worry about “FrankenBurgers”. Indeed, cultured meat products will be more “natural” in some ways than their antibiotic-laced counterparts derived from farmed animals.

Momentum for commercialisation is growing. Non-profit research organisations like New Harvest(8), working to develop alternatives to conventionally-produced meat, have been joined by hard-headed businessmen. Visionary entrepreneur and Stanford academic Peter Thiel(9) has just funnelled $350,000 into Modern Meadow, a start-up that aims to combine 3D printing with in vitro meat cultivation. Within the next decade or so, gourmet steaks could be printed out from biological materials. In principle, the technology should be scalable. While work on in vitro meat continues, rapid advances are being made in the development of so-called plant meats. Beyond Meat(10), for example, has already brought to market the first plant-based meat with a texture almost identical to chicken flesh.

Tragically, billions of nonhuman animals will atrociously suffer and die this century at human hands before the dietary transition is complete. Humans are not obligate carnivores; eating meat and animal products is a lifestyle choice. “But I like the taste!” is not a morally compelling argument. Vegans and animal advocates ask whether we are ethically entitled to wait on a technological fix. The antispeciesist answer is clear: no.

2. Compassionate Biology.
If and when humans stop systematically harming other sentient beings, will our ethical duties to members of other species have been discharged? Not if the same ethical considerations as apply to members of other human races or age-groups apply also to members of other species of equivalent sentience. Thus if famine breaks out in sub-Saharan Africa and young human children are starving, then we recognise we have a duty to send aid; or better still, to take proactive to measures to ensure famines do not arise in the first instance, i.e. to provide not just food aid but family planning. So why not assist, say, starving free-living elephants? Until recently, no comparable interventions were feasible for members of other species. The technical challenges were insurmountable. Not least, the absence of cross-species fertility control technologies would have often made bad problems worse. Yet thanks to the exponential growth of computer power, every cubic metre of the planet will shortly be computationally accessible to micro-management, surveillance and control. Harnessed to biotechnology, nanotechnology and robotics, such tools confer unprecedented power over Nature. With unbridled power comes complicity. Ethically speaking, how many of the traditional cruelties of the living world do we wish to perpetuate? Orthodox conservation biologists argue we should not “interfere”: humans can’t “police” Nature. Antispeciesists disagree. Advocates of compassionate biology argue that humans and nonhumans alike should not be parasitised, starved, disembowelled, asphyxiated, or eaten alive.

As always, bioconservatives insist such miseries are “natural”; status quo bias runs deep. “”Custom will reconcile people to any atrocity””, observed George Bernard Shaw. Snuff movies in the guise of Nature documentaries are quite popular on Youtube, a counterpoint to the Disneyfied wildlife shows aired on mainstream TV. Moreover even sympathetic critics of compassionate biology might respond that helping free-living members of other species is prohibitively expensive. An adequate welfare safety-net scarcely exists for humans in many parts of the world. So how can we contemplate its extension to nonhumans – even just to large-brained, long-lived vertebrates in our Nature reserves? Provision of comprehensive healthcare for all free-living elephants(11), for example, might cost between two or three billion dollars annually. Compassionate stewardship of the living world would be technically daunting too, entailing ecosystem management, cross-species fertility control via immunocontraception, veterinary care, emergency famine-relief, GPS tracking and monitoring, and ultimately phasing out or genetically “reprogramming”(12) carnivorous predators. The notional bill could approach the world’s 1.7 trillion-dollar annual arms budget. But irrespective of cost or timescale, if we are to be consistently non-speciesist, then decisions about resource allocation should be based not on species membership, but directly or indirectly on sentience. An elephant, for example, is at least as sentient as a human toddler – and may well be as sentient if not sapient as adult humans. If it is ethically obligatory to help sick or starving children, then it’s ethically obligatory to help sick or starving elephants – not just via crisis interventions but via long-term healthcare support.

A traditional conservation biologist might respond that elephants helped by humans are no longer truly wild. Yet on such a criterion, clothes-wearing humans or beneficiaries of food aid and family planning aren’t “wild” humans either. Why should this matter? “Free-living” and “wild” are conceptually distinct. To assume that the civilising process should be confined to our own species is mere speciesist prejudice. Humans, transhumans and posthumans must choose what forms of sentience we want to preserve and create on Earth and beyond. Humans already massively intervene in Nature, whether though habitat destruction, captive breeding programs for big cats, “rewilding”, etc. So the question is not whether humans should “interfere”, but rather what ethical principles should govern our interventions(13).

Speciesism and Superintelligence.
Why should transhumanists care about the suffering of nonhuman animals? This is not a “feel-good” issue. One reason we should care cuts to the heart of the future of life in the universe. Transhumanists differ over whether our posthuman successors will most likely be nonbiological artificial superintelligence; or cyborgs who effectively merge with our hyperintelligent machines; or our own recursively self-improving biological descendents who modify their own genetic source code and bootstrap their way to full-spectrum superintelligence(14). Regardless of the dominant lifeform of the posthuman era, biological humans have a vested interest in the behaviour of intellectually advanced beings towards cognitively humble creatures – if we survive at all. Compared to posthuman superintelligence, archaic humans may be no smarter than pigs or chickens – or perhaps worms. This does not augur well for Homo sapiens. Western-educated humans tend to view Jains as faintly ridiculous for practising ahimsa, or harmlessness, sweeping the ground in front of them to avoid inadvertently treading on insects. How quixotic! Yet the fate of sentient but cognitively humble lifeforms in relation to vastly superior intelligence is precisely the issue at stake as we confront the prospect of posthuman superintelligence. How can we ensure a Jain-like concern for comparatively simple-minded creatures such as ourselves? Why should superintelligences care any more than humans about the well-being of their intellectual inferiors? Might distinctively human-friendly superintelligence turn out to be as intellectually-incoherent as, say, Aryan-friendly superintelligence? If human primitives are to prove worthy of conservation, how can we implement technologies of impartial friendliness towards other sentients? And if posthumans do care, how do we know that a truly benevolent superintelligence wouldn’t turn Darwinian life into utilitronium with a communal hug?

Viewed in such a light, biological humanity’s prospects in a future world of superintelligence might seem dire. However, this worry expresses a one-dimensional conception of general intelligence. No doubt the nature of mature superintelligence is humanly unknowable. But presumably full-spectrum(15) superintelligence entails, at the very least, a capacity to investigate, understand and manipulate both the formal and the subjective properties of mind. Modern science aspires to an idealised “view from nowhere”(16), an impartial, God-like understanding of the natural universe, stripped of any bias in perspective and expressed in the language of mathematical physics. By the same token, a God-like superintelligence must also be endowed with the capacity impartially to grasp all possible first-person perspectives – not a partial and primitive Machiavellian cunning of the kind adaptive on the African savannah, but an unimaginably radical expansion of our own fitfully growing circle of empathy.

What such superhuman perspective-taking ability might entail is unclear. We are familiar with people who display abnormally advanced forms of “mind-blind”(17), autistic intelligence in higher mathematics and theoretical physics. Less well known are hyper-empathisers who display unusually sophisticated social intelligence. Perhaps the most advanced naturally occurring hyper-empathisers exhibit mirror-touch synaesthesia(18). A mirror-touch synaesthete cannot be unfriendly towards you because she feels your pain and pleasure as if it were her own. In principle, such unusual perspective-taking capacity could be generalised and extended with reciprocal neuroscanning technology and telemetry into a kind of naturalised telepathy, both between and within species. Interpersonal and cross-species mind-reading could in theory break down hitherto invincible barriers of ignorance between different skull-bound subjects of experience, thereby eroding the anthropocentric, ethnocentric and egocentric bias that has plagued life on Earth to date. Today, the intelligence-testing community tends to treat facility at empathetic understanding as if it were a mere personality variable, or at best some sort of second-rate cognition for people who can’t do IQ tests. But “mind-reading” can be a highly sophisticated, cognitively demanding ability. Compare, say, the sixth-order intentionality manifested by Shakespeare. In Othello, for example, Shakespeare intends his audience believe that Iago intends that Othello imagines that Desdemona is in love with Cassio and that Cassio reciprocates Desdemona’s amorous feelings(19). Thus we shouldn’t conceive superintelligence as akin to God imagined by someone with autistic spectrum disorder. Rather full-spectrum superintelligence entails a God’s-eye capacity to understand the rich multi-faceted first-person perspectives of diverse lifeforms whose mind-spaces humans would find incomprehensibly alien.

An obvious objection arises. Just because ultra-intelligent posthumans may be capable of displaying empathetic superintelligence, how do we know such intelligence will be exercised? The short answer is that we don’t: by analogy, today’s mirror-touch synaesthetes might one day neurosurgically opt to become mind-blind. But then equally we don’t know whether posthumans will renounce their advanced logico-mathematical prowess in favour of the functional equivalent of wireheading. If they do so, then they won’t be superintelligent. The existence of diverse first-person perspectives is a fundamental feature of the natural world, as fundamental as the second law of thermodynamics or the Higgs boson. To be ignorant of fundamental features of the world is to be an idiot savant: a super-Watson(20) perhaps, but not a superintelligence(21).

High-Tech Jainism?
Jules Renard once remarked, “I don’t know if God exists, but it would be better for His reputation if He didn’t.” God’s conspicuous absence from the natural world needn’t deter us from asking what an omniscient, omnipotent, all-merciful deity would want humans to do with our imminent God-like powers. For we’re on the brink of a momentous evolutionary transition in the history of life on Earth. Physicist Freeman Dyson predicts we’ll soon “be writing genomes as fluently as Blake and Byron wrote verses”(22). The ethical risks and opportunities for apprentice deities are huge.

On the one hand, Karl Popper warns, “Those who promise us paradise on earth never produced anything but a hell”(23). Twentieth-century history bears out such pessimism. Yet for billions of sentient beings from less powerful species, existing life on Earth is hell. They end their miserable lives on our dinner plates: “for the animals it is an eternal Treblinka”, writes Jewish Nobel laureate Isaac Bashevis Singer(24).

In a more utopian vein, some utterly sublime scenarios are technically feasible later this century and beyond. It’s not clear whether experience below Sidgwick’s(25) “hedonic zero” has any long-term future. Thanks to molecular neuroscience, mastery of the brain’s reward circuitry could make everyday life wonderful beyond the bounds of normal human experience. There is no technical reason why the pitiless Darwinian struggle of the past half billion years can’t be replaced by an earthly paradise for all creatures great and small. Genetic engineering could allow “the lion to lie down with the lamb.” Enhancement technologies could transform killer apes into saintly smart angels. Biotechnology could abolish suffering throughout the living world. Artificial intelligence could secure the well-being of all sentience in our forward light-cone. Our quasi-immortal descendants may be animated by gradients of intelligent bliss orders of magnitude richer than anything physiologically feasible today.

Such fantastical-sounding scenarios may never come to pass. Yet if so, this won’t be because the technical challenges prove too daunting, but because intelligent agents choose to forgo the molecular keys to paradise for something else. Critically, the substrates of bliss don’t need to be species-specific or rationed. Transhumanists believe the well-being of all sentience(26) is the bedrock of any civilisation worthy of the name.


1. How modest? A venerable tradition in philosophical meta-ethics is anti-realism. The meta-ethical anti-realist proposes that claims such as it’s wrong to rape women, kill Jews, torture babies (etc) lack truth value – or are simply false. (cf. JL Mackie, Ethics: Inventing Right and Wrong, Viking Press, 1977.) Here I shall assume that, for reasons we simply don’t understand, the pain-pleasure axis discloses the world’s inbuilt metric of (dis)value. Meta-ethical anti-realists may instead wish to interpret this critique of speciesism merely as casting doubt on its internal coherence rather than a substantive claim that a non-speciesist ethic is objectively true.

2. Extreme violence towards members of other tribes and races can be fitness-enhancing too. See, e.g. Richard Wrangham & Dale Peterson, Demonic Males: Apes and the Origins of Human Violence, Houghton Mifflin, 1997.

3. Fisher SE, Scharff C (2009). “FOXP2 as a molecular window into speech and language”. Trends Genet. 25 (4): 166–77. doi:10.1016/j.tig.2009.03.002. PMID 19304338.

4. Interpersonal and interspecies comparisons of sentience are of course fraught with problems. Comparative studies of how hard a human or nonhuman animal will work to avoid or obtain a particular stimulus give one crude behavioural indication. Yet we can go right down to the genetic and molecular level, e.g. interspecies comparisons of SCN9A genotype. (cf. We know that in humans the SCN9A gene modulates pain-sensitivity. Some alleles of SCN9A give rise to hypoalgesia, others alleles to hyperalgesia. Nonsense mutations yield congenital insensitivity to pain. So we could systematically compare the SCN9A gene and its homologues in nonhuman animals. Neocortical chauvinists will still be sceptical of non-mammalian sentience, pointing to the extensive role of cortical processing in higher vertebrates. But recall how neuroscanning techniques reveal that during orgasm, for example, much of the neocortex effectively shuts down. Intensity of experience is scarcely diminished.

5. Held S, Mendl M, Devereux C, and Byrne RW. 2001. “Studies in social cognition: from primates to pigs”. Animal Welfare 10:S209-17.

6. Jonathan Haidt, The Righteous Mind: Why Good People Are Divided by Politics and Religion, Pantheon Books, 2012.

7. Hannah Arendt, Eichmann in Jerusalem: A Report on the Banality of Evil, Viking Press, 1963.


9. “PayPal Founder Backs Synthetic Meat Printing Company”, Wired, August 16 2012.

10. Beyond Meat:



13. The scholarly literature on the problem of wild animal suffering is still sparse. But perhaps see Arne Naess, “Should We Try To Relieve Clear Cases of Suffering in Nature?”, published in The Selected Works of Arne Naess, Springer, 2005; Oscar Horta, “The Ethics of the Ecology of Fear against the Nonspeciesist Paradigm: A Shift in the Aims of Intervention in Nature”, Between the Species, Issue X, August 2010. ; Brian Tomasik, “The Importance of Wild-Animal Suffering”, ; and the first print-published plea for phasing out carnivorism in Nature, Jeff McMahan’s “The Meat Eaters”, The New York Times. September 19, 2010.

14. Singularity Hypotheses, A Scientific and Philosophical Assessment, Eden, A.H.; Moor, J.H.; Søraker, J.H.; Steinhart, E. (Eds) Spinger 2013.

15. David Pearce, The Biointelligence Explosion. (preprint), 2012.

16. Thomas Nagel, The View From Nowhere , OUP, 1989.

17. Simon Baron-Cohen (2009). “Autism: the empathizing–systemizing (E-S) theory” (PDF). Ann N Y Acad Sci 1156: 68–80. doi:10.1111/j.1749-6632.2009.04467.x. PMID 19338503.

18. Banissy, M. J. & Ward, J. (2007). Mirror-touch synesthesia is linked with empathy. Nature Neurosci. doi: 10.1038/nn1926.

19. see “The Social Brain Hypothesis and its Relevance To Cognitive Psychology by R.I.M. Dunbar, published in Evolution and the Social Mind: Evolutionary Psychology and Social Cognition, Forgas, J.P; Haselton, M. G.; von Hippel, W. (Eds) Psychology Press 2007.

20. Stephen Baker. Final Jeopardy: Man vs. Machine and the Quest to Know Everything. Houghton Mifflin Harcourt. 2011.

21. Orthogonality or convergence? For an alternative to the convergence thesis, see Nick Bostrom, “The Superintelligent Will: Motivation and Instrumental Rationality in Advanced Artificial Agents”, 2012,; and Eliezer Yudkowsky, Carl Shulman, Anna Salamon, Rolf Nelson, Steven Kaas, Steve Rayhawk, Zack Davis, and Tom McCabe. “Reducing Long-Term Catastrophic Risks from Artificial Intelligence”, 2010.

22. Freeman Dyson, “When Science & Poetry Were Friends”, New York Review of Books, August 13, 2009.

23. As quoted in Jon Winokur, In Passing: Condolences and Complaints on Death, Dying, and Related Disappointments, Sasquatch Books, 2005.

24. Isaac Bashevis Singer, The Letter Writer, 1964.

25. Henry Sidgwick, The Methods of Ethics. London, 1874, 7th ed. 1907.

26. The Transhumanist Declaration (1998, 2009).    

U.S. plan to give some higher consciousness species personhood rights: Personhood Beyond the Human Conference

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