QuestionsDo animals matter as much as we do?For a little flesh, we deprive a being of light and life
Do animals matter as much as we do?A duty of compassion

For a little flesh, we deprive a being of light and life

Plutarch's vegetarian argument; why Pythagoras abstained from flesh

Plutarque c. 46 · c. 120Eating flesh deprives a living being of light and life for a little pleasure; what is astonishing is that anyone ever began.
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What it claims

It is eating flesh that should astonish us, not abstaining from it: we should abstain.

Why

We have plenty to eat without killing: eating flesh takes a living being's life from it without any necessity.

The same idea through history
Pythagoras500 BCTradition says Pythagoras abstained from flesh, and links this to the idea that the soul passes from one body to another, animals included. No text by him survives: we know him through stories. Plutarch opens his discourse by citing him, but shows that the real question lies elsewhere: the astonishing thing is eating flesh, not abstaining.
Plutarque100In the two discourses "On the Eating of Flesh" (the second is incomplete), Plutarch argues that one need not kill to eat and that one deprives a being of life for a slight pleasure. He does not rest on transmigration: he speaks of it as a belief whose proof is lacking, and keeps his argument.
Porphyre270Porphyry, a Neoplatonist, takes up and develops the argument in On Abstinence, a long treatise on refusing to eat flesh; he discusses in particular the Stoic thesis that we owe no duties of justice to beings without reason.
Michel de Montaigne1580Montaigne cites Plutarch in "Of Cruelty" and takes from him the concern for a kindness extended to every creature that feels.
In short

"For a little flesh, we deprive a being of light and life" is an argument by Plutarque (Moralia, "On the Eating of Flesh" (De esu carnium), I and II, c. 100, 100) on the question "Do animals matter as much as we do?" (answer: a duty of compassion). Its claim: It is eating flesh that should astonish us, not abstaining from it: we should abstain. 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, 1 of them with a documented reply, and the original text behind each premise, checked word for word.

Moralia, "On the Eating of Flesh" (De esu carnium), I and II, c. 100
Valid with an implicit premise

People often ask: why did Pythagoras abstain from eating flesh? Plutarch turns the question around in the first line: what astonishes him is what motive, or what courage, led the first man to bring to his lips the flesh of a dead beast. The first men could excuse themselves by necessity. We, he says, who have plenty to live on, kill "for a little flesh": we take from a being the sunlight and the life it has a right to by nature. He adds that the human body is not made for this food: no hooked beak, no claws, no sharp teeth. In the question "Do animals matter as much as we do?", he defends the "A duty of compassion" camp: he asks for restraint and pity, without saying that animals are our equals. The two discourses are works of persuasion: some see in them an exercise in eloquence rather than a system.

P1We now have plenty to feed on without killing: the first men could plead necessity, we cannot. What drives us to slaughter is therefore not a need.
P2Eating flesh deprives a living being of the soul, the sunlight and the span of life it was born to enjoy, and this for a small pleasure.
P3The human body resembles none of those made for eating flesh: no hooked beak, no claws, no rough teeth, no stomach strong enough. Nature seems to turn us away from this food.
P4 · implicit premiseWhen we deprive a living being of its life without needing to, for a pleasure, and for a food our own body does not even seem made to receive, we do wrong: we must abstain.
Therefore it is eating flesh that should astonish us, not abstaining from it: we should abstain.

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 killing is not necessary, takes the animal's life and does not suit our body, yet there is no duty to abstain: it would be merely regrettable or unhealthy. P4 is what makes it a moral fault.
The argument is valid with the hidden premise P4. P1, P2 and P3 give three facts: killing is not necessary, it takes the animal's life, and our body does not seem made for this food. To draw a duty to abstain from them, we need P4: depriving a being of its life without need is wrong. Plutarch does not write it as a rule, but his whole discourse presupposes it and is indignant at it. Whoever rejects the conclusion can challenge P1 (is flesh necessary?), P3 (is reasoning from the shape of the body reliable?), or P4 (does a pleasure never justify killing an animal?).
Analogy. If you are told that fireworks cause the death of many birds each year, and that we can do without them, you first ask why they are set off. For Plutarch likewise, the one who kills without need must justify the act, not the one who abstains.

Objections

3

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

Chrysippus (according to Cicero) 210 BC · attacks the conclusion

The Stoics hold that beings without reason exist for the sake of rational beings, and that between men and beasts there is no bond of right: we therefore owe them no justice. What is done to beasts cannot then be an injustice.

Plutarque replies
P
Plutarch 100 · Plutarch's reply
Plutarch himself reports the Stoics' remark: "We have nothing to do with brute beasts." He answers that we have nothing to do with perfumes and foreign spices either, and yet the Stoics banish them from the table because they are useless. If they banish the useless, they should banish flesh too.
P
Porphyry 270
Porphyry takes up the discussion with the Stoics on justice towards animals in book III of On Abstinence and pursues it far longer than Plutarch, whose text breaks off just as he announces that he will examine this point.
Where the debate stands (our summary)Disputed, and still open. The Stoics make justice depend on a shared reason; Plutarch and Porphyry make it depend on the capacity to suffer and to live. Plutarch's text stops where he was about to treat the question of justice (999b): his full answer is lost. The basic disagreement, still alive today, is whether duties of justice require reason (our summary).
Aristotle 330 BC · attacks premise 3

He holds that nature makes nothing incomplete and nothing in vain, and that, as plants exist for the sake of animals, the other animals exist for the sake of man: the tame for use and food, the wild, for the most part, for food and for his needs. For him, nature thus meant us to feed on them.

no reply
We have not yet found a direct reply by Plutarque in the texts.
Where the debate stands (our summary)Disputed. Aristotle writes before Plutarch, who does not cite him here. They read nature in opposite directions: for Aristotle it put animals at our service; for Plutarch our body shows that it did not make us to eat them. Each relies on an idea of what nature "wants", an idea modern science no longer lets us invoke without caution (our summary).
Academy of Nutrition and Dietetics (Melina, Craig, Levin) 2016 · attacks premise 1

In its position paper on vegetarian diets, this learned society concludes that well-planned vegetarian diets, including vegan ones, can suit all stages of life. This supports Plutarch's idea that flesh is not necessary. But the paper adds that vegans must make sure of a reliable source of vitamin B12: a diet without flesh therefore needs planning, and it is not the shape of the body that decides what one may eat.

no reply
No reply possible: objection raised in 2016, after the author's death (120).
Where the debate stands (our summary)Partly disputed. On the central fact, modern evidence goes Plutarch's way: flesh is not indispensable for healthy adults in countries where one can choose. But it sets aside his reasoning from teeth and body. The disagreement then turns to ethics: if we can do without, must we? That is P4, and science does not settle it. We have not read the paper in full: this presentation summarises its general conclusion (our summary).