QuestionsWhat makes something right?Virtue is a mean between two vices
What makes something right?Virtue

Virtue is a mean between two vices

The doctrine of the mean (Aristotle)

Aristotle 384 BC · 322 BCObserve, classify, reason: happiness through virtue.
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What it claims

Virtue is a disposition to choose the mean relative to us, fixed by the reason of the prudent person, between two vices, one of excess and one of defect. For example, courage stands between rashness and cowardice.

Why

Emotions can be felt too much or too little; like a good craftsman, we aim at the mean, which varies from person to person.

The same idea through history
Confucius500 BCA neighbouring idea, born with no link to Greece: in the Analects (6.27), Confucius calls the virtue that keeps to the mean (zhong yong) "the highest". It is not a source of Aristotle, but a parallel.
Aristotle335 BCNicomachean Ethics, book II: the version presented here, with the table of virtues (courage, temperance, liberality…) each placed between two vices.
Thomas Aquinas1271Summa Theologiae I-II, question 64: Thomas takes up the thesis ("moral virtue consists in a mean") and hands it on to the whole of medieval Christian ethics.
G. E. M. Anscombe1958"Modern Moral Philosophy": the morality of duty and obligation has lost its sense; better to start again from notions like "just" or "courageous", in Aristotle's way. The starting point of modern virtue ethics.
Alasdair MacIntyre1981After Virtue: modern morality is made of disconnected fragments; we must return to an Aristotelian ethics of the virtues, rooted in practices and traditions.
In short

"Virtue is a mean between two vices" is an argument by Aristotle (Nicomachean Ethics, II 6-7 (1106a-1107b), 335 BC) on the question "What makes something right?" (answer: virtue). Its claim: Virtue is a disposition to choose the mean relative to us, fixed by the reason of the prudent person, between two vices, one of excess and one of defect. For example, courage stands between rashness and cowardice. 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, 2 of them with a documented reply, and the original text behind each premise, checked word for word.

Nicomachean Ethics, II 6-7 (1106a-1107b)
Valid with an implicit premise

Is being brave never being afraid? For Aristotle, no: someone who fears nothing is rash, someone who fears everything is a coward. Virtue is not an extreme, it is the right measure, and that right measure depends on the person and the situation.

P1Moral virtue is about emotions and actions (fear, boldness, desire, anger, pity, pleasure, pain) that one can feel too much or too little, and in both cases one is wrong.
P2In every art, the good craftsman avoids too much and too little and aims at the mean: of a successful work we say that nothing can be added or taken away. But virtue is more exact and better than any art: so it too aims at the mean.
P3This mean is not a fixed point, like 6 between 2 and 10. It is relative to us: the ration that is too small for the athlete Milo is too large for a beginner. It is fixed by reason, as the prudent person would fix it.
P4 · implicit premiseVirtue and the two vices lie on a single scale: what tells them apart is more or less (fear, spending, anger). Too much and too little are therefore two opposite vices, and virtue stands between them.
Therefore virtue is a disposition to choose the mean relative to us, fixed by the reason of the prudent person, between two vices, one of excess and one of defect. For example, courage stands between rashness and cowardice.

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 world where virtue does aim at the right measure, but where vice is not just "too much" or "too little": for instance the miser and the generous person would not follow the same rule with more or less intensity, they would have different rules. Then "virtue lies between two vices" no longer follows.
The argument is valid once P4 is added. Aristotle does not state it as a premise: he assumes it when he moves from "one can do too much or too little" to "virtue lies between two vices". It is exactly what Kant attacks: for him, virtue and vice differ not in degree but in principle.
Analogy. A good cook salts neither too much nor too little, and the right amount depends on the dish. Nobody can write in advance "add 3 grams of salt" for every dish: the good cook's eye decides. For Aristotle, the same goes for anger, fear or generosity.

Objections

3

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

Kant 1797 · attacks premise 4

Aristotle's principle is false. Virtue and vice differ not in degree but in their principle. The miser is not a thrifty person who overdoes it: he has another rule of life (owning without ever enjoying), and so does the spendthrift (enjoying without keeping anything). If virtue were a diminished vice, one would pass from prodigality to avarice by going through good management, which is absurd.

Aristote replies
Aristotle 335 BC · Aristotle's anticipated reply
In its essence and definition, virtue is a mean; but from the point of view of what is good and excellent, it is an extreme, a peak.
The debate goes on (our summary) Aristotle's readers point out that his mean is not an average quantity (he says so himself: it is not 6 between 2 and 10): it is the right response, at the right time, towards the right people. Kant maintains that what makes the difference is the maxim followed, so that the notion of degree is useless for defining vice. The debate goes on: virtue of character (Aristotle) or right rule (Kant)?
Kant 1797 · attacks premise 3

"Do nothing too much or too little" says nothing at all: it is a tautology. Too much means "more than is good"; too little, "less than is good". This mean between two extremes, who will show it to me? The formula gives no definite principle.

Aristote replies
Aristotle 335 BC · Aristotle's anticipated reply
To what point and how far one deserves blame cannot be fixed in advance by reasoning, any more than for other things perceived by the senses: it depends on the particular cases, and it is perception that judges. Aristotle had warned from book I: in ethics one cannot demand the precision of mathematics.
The debate goes on (our summary) That is exactly the complaint: referring to the prudent person's judgment admits that there is no rule for finding the mean. Defenders of virtue ethics reply that this is a strength, not a flaw: no rule can replace the judgment of an experienced person. Kant grants as much for "wide" duties (one can err about more or less), but not for the principle of duty itself.
A limit Aristotle sets himself 335 BC · attacks premise 1

Not every action or emotion has a mean. Some are bad by their very name: spite, shamelessness, envy, and, among actions, adultery, theft, murder. One does not ask with whom, when and how to commit adultery: doing it is simply wrong.

no reply
Aristote never answered this objection.
The debate goes on (our summary) So Aristotle himself limits his thesis to emotions and actions that admit of more and less. But to know that an action is bad "by its very name", one must already know what is wrong: the mean does not help discover it. For critics, the doctrine describes virtue once we know it more than it helps us find it. Kant gives a related example: between truthfulness and lying there is no mean.