QuestionsDo animals matter as much as we do?Our duties to animals are indirect: they are duties to ourselves
Do animals matter as much as we do?Humans first

Our duties to animals are indirect: they are duties to ourselves

Indirect duties to animals

Immanuel Kant 1724 · 1804Set the limits of reason; act from duty.
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What it claims

We have no direct duties towards animals. But being cruel to them is contrary to a duty to ourselves: our duties towards animals are indirect.

Why

Animals are not rational beings, but cruelty toward them weakens the compassion in us that serves morality.

The same idea through history
Immanuel Kant1785In the Groundwork, Kant states humanity as an end in itself, never merely as a means. Humanity here means rational nature: beings without reason are the only ones that may be treated as mere means.
Immanuel Kant1780In his lectures on ethics (known from students' notes), Kant already says that our duties to animals are indirect duties to humanity, and that whoever is cruel to them becomes hard in dealing with men too.
Immanuel Kant1797In the Doctrine of Virtue, he sets the limits: killing quickly and without pain, or putting them to work without excess, is allowed. Painful experiments done for mere speculation are to be rejected.
Thomas Aquinas1260In the Summa contra Gentiles (III, 112), Thomas places creatures without reason at the service of rational creatures. If Scripture forbids cruelty to animals, it is to turn people away from cruelty to other people.
In short

"Our duties to animals are indirect: they are duties to ourselves" is an argument by Immanuel Kant (Metaphysics of Morals, Doctrine of Virtue, §§ 16-17, 1797 (AA VI 442-443), 1785) on the question "Do animals matter as much as we do?" (answer: humans first). Its claim: We have no direct duties towards animals. But being cruel to them is contrary to a duty to ourselves: our duties towards animals are indirect. According to AskPhilosophy's logic check (Z3 solver), the argument is valid only if one grants a premise the author leaves unstated (P4). AskPhilosophy presents 3 objections, 0 of them with a documented reply, and the original text behind each premise, checked word for word.

Metaphysics of Morals, Doctrine of Virtue, §§ 16-17, 1797 (AA VI 442-443)
Valid with an implicit premise

For Kant, a duty is a moral constraint that comes from another's will: there must therefore be a rational being facing us. Now our experience shows us only one kind: human beings. Animals have no reason and are not conscious of themselves as subjects. So we have no direct duties towards them. This does not mean everything is allowed. Being violent and cruel to animals goes against a duty to ourselves: it blunts compassion for suffering, a natural disposition that helps us treat other men well. Our duties to animals are therefore indirect: they run through the humanity in us. Kant nonetheless allows killing them quickly and without pain, and putting them to work without excess. In the question "Do animals matter as much as we do?", this argument supports the "Humans first" camp: only rational beings matter in themselves.

P1Judging by reason alone, man has duties only towards man: a duty is a moral constraint coming from the will of a being, and that being must be a person, given in experience.
P2Animals are not rational beings: they are not self-conscious and are there merely as means to an end, which is man.
P3Being violent and cruel to animals blunts in man the sympathy with their suffering, and so gradually weakens a natural disposition that is very serviceable to morality towards other men.
P4 · implicit premiseWe have a duty to ourselves not to weaken in ourselves what serves morality.
So we have no direct duties towards animals. But being cruel to them is contrary to a duty to ourselves: our duties towards animals are indirect.

click a premise to reject it

If you accept every premise, logic forces you to accept the conclusion. So the debate is about the premises.
Checked by a logic solver: the premises cannot all be true while the conclusion is false.
Without the implicit premise: Without P4, the computer finds a case where cruelty to animals weakens our compassion without any duty forbidding it: the fact that cruelty hardens us is not enough to make it wrong, there must be a duty not to harden ourselves. This is the duty to oneself that Kant adds.
The argument is valid once the hidden premise P4 is added. P1 and P2 give the first half: no direct duty towards animals, since they are not rational beings. P3 and P4 give the second: cruelty weakens in us what serves morality, and we must not weaken it, so cruelty is forbidden, but as a duty to ourselves. Kant almost writes P4 ("contrary to the duty of man to himself"). Whoever rejects the conclusion can challenge P1 (a being without reason can still have rights), P2 (animals matter for themselves because they feel), or P3 (cruelty does not always harden: it is a claim about human psychology that experience may refute).
Analogy. A footballer owes nothing to his ball: the ball has no rights. But if he kicks it in a rage, he trains himself to brutality on the pitch. In the same way, for Kant, we owe nothing to the animal in itself, but by mistreating it we become harder on persons. Critics reply that an animal is not a ball: it suffers.

Objections

3

Each objection is a conversation: click to see who replies and where the debate stands.

Arthur Schopenhauer 1840 · attacks the conclusion

He judges this doctrine odious. In Kant's morality animals are mere "things", means fit for any use. If we must pity their suffering, it would only be for practice: we would train ourselves on them, as on beings of no worth, to feel compassion for our fellows. For him, compassion must be turned towards animals for their own sake.

no reply
see the argument
No reply possible: objection raised in 1840, after the author's death (1804).
Where the debate stands (our summary)Disputed. Schopenhauer targets a real consequence of the thesis: if animals count only as occasions for practice, their suffering has no weight by itself. Kant's defenders can reply that the doctrine still condemns cruelty (P3, P4). The basic question remains: why would this compassion serve morality if animal suffering were not itself an evil? (our summary).
Peter Singer 1974 · attacks premise 1

He argues that the capacity for suffering is the condition for having interests at all, and so for anyone to matter morally. Reserving duties to rational beings amounts to choosing an arbitrary criterion: it cannot be absurd to consider the interests of a being that can suffer, on the pretext that it does not reason.

no reply
No reply possible: objection raised in 1974, after the author's death (1804).
Where the debate stands (our summary)Open point. Singer and Kant are not speaking of the same thing: Kant says who can bind us (a rational being), Singer says who has interests that count (a being that suffers). A Kantian can grant that animals have interests and deny that they are persons to whom we have obligations. The disagreement concerns the nature of duties: reciprocity or suffering (our summary).
Christine Korsgaard 2018 · attacks premise 2

She offers a Kantian reading that gives animals a value of their own. For her, Kant's principles, properly understood, lead to the recognition that animals are ends in themselves: we owe them direct obligations, and not only duties to ourselves.

no reply
No reply possible: objection raised in 2018, after the author's death (1804).
Where the debate stands (our summary)Disputed. Korsgaard holds that one can be faithful to Kant and still contradict his conclusion on animals. Other Kantians hold that practical reason only grounds direct duties towards rational beings, as Kant himself writes. We have not read the book in full: its thesis is summarised from its general presentation (our summary).
What today's voices say
Criticize it
Peter SingerWhy should being self-conscious be what matters? Being able to feel pain should be enough to give animals direct moral standing.