Home / A. Sentience and moral status / Part DIR
"It's normal for humans to be rational."
judging an individual by what other members of their species have isn't a reason; it's a change of subject. If the rule held, we'd have to say an anencephalic baby is intelligent because humans are intelligent. And the same rule, applied consistently, would condemn factory farming, which prevents every pig from living what's normal for a pig.
The most common way out of the argument from species overlap, cited in A1, A2, A7, A8 and A10
Short answer
Swapping the individual for the group doesn't work in any other context. We don't say an anencephalic baby is intelligent because the human species is intelligent. We don't admit someone to university by the species average, but by the person's ability. This collective criterion appears exactly once: when we need to justify what we do to animals.
And there's an interesting twist: if each species' norm defines what's owed to its members, then what's normal for a pig includes exploring, wallowing, living in a group and caring for piglets. Factory farming violates that norm every day.
For children
Imagine your class is really good at maths. Does that make you good at maths, even if you never learned? Of course not. Each person is the way they are, not the way their group is. When someone says "this baby counts because humans are intelligent", they're talking about the group, not the baby. What protects the baby is something else: they feel, like you and like animals.
"If the species norm decides, would you accept being judged by what's typical of your group rather than by who you are?"
Como pode aparecer
"Even without speaking, she's still a human being."
"Humans are rational by nature; animals aren't."
"One exception doesn't change the rule of the species."
"Are you comparing a sick person to a healthy animal?"
"Does a disabled person stop being a person?"
"Rationality is relevant at the level of the kind, not the individual." (Cohen)
"Each being's good is defined by its form of life."
"Human dignity doesn't depend on what each person can do."
The strongest version
"A baby or a person with a disability is still human, and humans are rational by nature."
Strongest version (steelman). It's known as the argument from kind, or from the species norm. Carl Cohen summed it up: the capacity for moral judgment "is not a test to be administered to human beings one by one", because "the issue is one of kind".
- P1The treatment owed to an individual is determined by the normal characteristics of their species, not by the capacities they themselves have.
- P2Rationality is the normal characteristic of the human species.
- P3No animal species has rationality as its norm.
- CEvery human, including those who aren't rational, has full status; no animal does.
There's a more philosophically refined variant, of Aristotelian inspiration, associated with Philippa Foot: what is good or bad for a living being depends on its form of life, not on an individual tally of capacities. That version is dealt with in (d), and there's a surprise there: it works better in favor of animals.
The argument is valid. Its soundness fails at P1, which swaps the individual for the group, and at P2, which depends on a sense of "normal" no one can fix without circularity.
Full answer
- a
Reconstruction and diagnosis
The argument makes a substitution: it attributes to the individual the properties of the group. In logic this has a name, the fallacy of division, and a simple test, proposed by Carlos Naconecy: swap "moral dignity" for "intelligence" and see what happens.
Formulation Does it sound acceptable? "This baby has dignity because the human species is rational" Many people accept it without a second thought "This baby is intelligent because the human species is intelligent" No one accepts it The only difference between the two sentences is the property attributed. If the second is a mistake, so is the first, unless it's explained why dignity would transfer from one individual to another and intelligence wouldn't. That explanation never comes.
There's also the question of what "normal" means. All three possible readings fail:
Sense of "normal" Problem Statistical (most members have it) Moral status would come to depend on demographic proportions, which change Teleological (it's the species' purpose) Species don't have purposes; that's a pre-Darwinian inheritance Ideal (the best specimen) Compares real individuals with an abstraction and calls the result a moral reason - b
Where the argument breaks
1. It's applied only once.
We use individual capacities to admit people to university, grant driving licenses, determine criminal responsibility and assess medical consent. As Naconecy notes, no one passes a student because the human species knows algebra. The collective norm appears only when we need to justify how animals are treated.
2. Judging the individual by the group is exactly what we condemn.
Stereotypes work this way: they attribute to a person the characteristics attributed to their group. When the group is racial, national or gendered, we recognize the error immediately.
3. Species don't have essences.
Evolutionary biology replaced typological thinking with population thinking: species are populations with variation, not ideal types with deviations. The "species norm" is a statistical average, not a property each individual carries.
4. The choice of norm is circular.
Why is the relevant norm rationality, and not sentience, which is also normal in the human species and many others? Because rationality produces the desired result. The norm is selected after the conclusion.
5. Applied consistently, the rule protects animals.
If what's owed to an individual depends on their species' pattern, then each animal is owed what's normal for its own: a sow builds a nest before farrowing, a hen scratches and perches, cattle graze and form stable social bonds. Cages, gestation crates and confinement systematically violate each species' norm. Taken seriously, the argument becomes an indictment.
6. And if a species appeared whose norm surpassed ours?
By the same criterion, its members would have higher status than us, even the least capable among them, and we'd be in the animals' position. Whoever rejects that consequence doesn't really believe the premise.
- c
Data and sources
Source What it offers Note Cohen, 1986, *NEJM* The capacity for moral judgment that distinguishes humans from animals "is not a test to be administered to human beings one by one"; "the issue is one of kind" The most cited formulation of the argument Naconecy, Ética e animais (2006), pp. 165-166 (in Portuguese) Proposes the substitution test ("would it be right to consider anencephalic babies intelligent because the human species is intelligent?") and notes that the criterion of kind isn't used, for example, for university admission Kaufman's (1998) citation appears in the same passage Horta, 2014, on species overlap Systematizes the replies to the argument, including the one from kind Journal of Applied Philosophy, 2014 Evolutionary biology, population thinking Species are populations with continuous variation, not types with deviations The consensus of biology since the modern synthesis; see the Stanford Encyclopedia of Philosophy entry "Species" Foot, Natural Goodness (2001) A living being's good is assessed by its form of life Used here as the strong version of the reply; Oxford University Press - d
The strongest counter-reply: the form of life
The most serious version doesn't speak of statistical averages. It says we judge living beings by their form of life: a three-legged dog is a dog with a disability, not a perfectly normal three-legged animal. This is Philippa Foot's neo-Aristotelian idea. Applied to morality, it would suggest we owe each being the respect due to its form of life, and that the human form of life, being rational, attracts a specific respect, even when an individual doesn't exercise that capacity.
There's also an emotional version, associated with Cora Diamond: our moral concepts arise from the idea of a "fellow", a fellow traveler, not from a tally of capacities. That's why we bury our dead and don't eat them, even when they have nothing more to lose.
- e
Why the counter-reply doesn't reach the conclusion
The form of life protects both sides.
If each being's good depends on its form of life, then preventing a sow from nesting or a hen from scratching is harm, by the same criterion. The reply buys protection for humans at the price of an indictment of industrial farming.
Explaining isn't justifying.
Cora Diamond explains why our moral concepts are as they are. That doesn't show they're right, and Diamond herself uses the idea of "fellow creature" to argue against eating animals, not for it.
It still doesn't answer the case of the individual.
What's owed to this being, who feels pain now, can't depend on what other members of its species can do.
The strong version isn't the one used in debate.
In practice, A11 appears as an emergency exit to keep babies in and animals out, not as a theory of each form of life's flourishing.
Sentience is also a form of life.
Suffering is part of the form of life of any sentient animal. If the form of life matters, their pain matters.
Reasoning errors
Logical
Is the form valid?
Fallacy of division
Begging the question
Selective application
Ambiguity
Epistemological
Does the evidence support it?
Species essentialism
Residual teleology
Moral
Is the criterion coherent?
Substituting the subject
Moral stereotyping
Biases
Psychological essentialism
Makes species seem an inner essence each individual carries, even without the capacity
Medin and Ortony, 1989; Gelman, 2003
Typological thinking
Treats the average as a real type and individuals as deviations
Contradicted by population biology
Stereotyping
Transfers group characteristics to the individual
A known mechanism in social psychology
Motivated reasoning
The collective criterion is adopted exactly where it saves the desired conclusion
General literature on motivated cognition
Extrapolations
The principle being tested is: "what holds for an individual is what's normal in their species".
If it applied to…Capacities, not just dignityTap to see
We'd have to say an anencephalic baby is intelligent, because the human species is intelligent. The group's property would pass to the individual in every case, not only when convenient
A test proposed by Naconecy; no one accepts the conclusion
If it applied to…Selection and responsibilityTap to see
Universities would admit by the species average and courts would judge by the group norm. If the kind decides, individual capacity stops mattering
We do the opposite in all these institutions
If it applied to…Human groupsTap to see
Each person would be judged by what's typical of their group, not by who they are. This is exactly the structure of a stereotype
We recognize the error at once when the group is racial, national or gendered
If it applied to…Farmed animalsTap to see
Each animal would be owed what's normal for its species: a nest for the sow, perches and dust baths for the hen, pasture and social bonds for cattle
Factory farming systematically violates that norm, which turns the argument into an indictment
If it applied to…A species more capable than oursTap to see
Its members would have higher status than us, even the least capable among them, and we'd be in the animals' position
Whoever rejects the conclusion is rejecting the premise
Contradictions
University, driving licenses, contracts, criminal responsibility and medical consent depend on what the person can do, not on the species average.
Judging a person by what's typical of their group is considered unfair in any other context.
The same person says "every dog is different" and "some people are much cleverer than others".
If the species norm defines what's owed, a pig's pattern of life should hold for pigs. No one who uses A11 defends this.
A human below the norm keeps full status; an animal above its species' norm, such as a dog who has learned hundreds of words, gains nothing from it.
What the argument gets right
What is true
The argument arises from a legitimate and important concern: protecting vulnerable human beings against any criterion that grades people's value by performance. That concern is right, and the disability rights movement is right to distrust theories that measure the value of a life by cognitive capacity. Any decent ethics needs to shield these cases.
There's also something right in the idea of a form of life: it makes sense to say a being is deprived of something its species normally has, and that's a useful tool for assessing wellbeing.
But
What the argument can't do is use that concern to exclude animals. Protecting vulnerable humans doesn't need the species norm: it rests on sentience, which they have in abundance, and which animals have too. The sentientist criterion protects exactly those A11 wants to protect, without having to transfer properties from one individual to another.
Connections
Usually comes before
Usually comes after
Go deeper in Questão de Ética
Chapters from the open-access collection A Journey Through Animal Ethics that discuss this argument in more detail:
- Is What Matters Belonging to the Same Species as Those… Vol. I, ch. 6
- What Is the Argument from Species Overlap? Vol. II, ch. 2
References
Provisional author-date format. The links indicate the sources checked in writing this chapter.
Philosophy
- The case for the use of animals in biomedical research. *New England Journal of Medicine*, 315.
- Eating meat and eating people. Philosophy, 53.
- Natural Goodness. Oxford University Press.
- The scope of the argument from species overlap. Journal of Applied Philosophy, 31(2).
- Speciesism and the argument from misfortune. Journal of Applied Philosophy, 15(2).
- The Ethics of Killing.
- Ética e animais: um guia de argumentação filosófica, pp. 165-166 (in Portuguese).
Psychology
- The moral standing of animals. *Journal of Personality and Social Psychology*, 116(6).
- The Essential Child; Psychological essentialism.