Nicomachean Ethics

than any art, it follows that virtue also must aim at the mean⁠—virtue of course meaning moral virtue or excellence; for it has to do with passions and actions, and it is these that admit of excess and deficiency and the mean. For instance, it is possible to feel fear, confidence, desire, anger, pity, and generally to be affected pleasantly and painfully, either too much or too little, in either case wrongly; but to be thus affected at the right times, and on the right occasions, and towards the right persons, and with the right object, and in the right fashion, is the mean course and the best course, and these are characteristics of virtue. And in the same way our outward acts also admit of excess and deficiency, and the mean or due amount.
Virtue, then, has to deal with feelings or passions and with outward acts, in which excess is wrong and deficiency also is blamed, but the mean amount is praised and is right⁠—both of which are characteristics of virtue.
Virtue, then, is a kind of moderation (μεσότης τις) 26 inasmuch as it aims at the mean or moderate amount (τὸ μέσον).
Again, there are many ways of going wrong (for evil is infinite in nature, to use a Pythagorean figure, while good is finite), but only one way of going right; so that the one is easy and the other hard⁠—easy to miss the mark and hard to hit. On this account also, then, excess and deficiency are characteristic of vice, hitting the mean is characteristic of virtue:

“Goodness is simple, ill takes any shape.”

Virtue, then, is a habit or trained faculty of choice, the characteristic of which lies in moderation or observance of the mean relatively to the persons concerned, as determined by reason,  i.e. by the reason by which the prudent man would determine it. And it is a moderation, firstly, inasmuch as it comes in the middle or mean between two vices, one on the side of excess, the other on the side of defect; and, secondly, inasmuch as, while these vices fall short of or exceed the due measure in feeling and in action, it finds and chooses the mean, middling, or moderate amount.
Regarded in its essence, therefore, or according to the definition of its nature, virtue is a moderation or middle state, but viewed in its relation to what is best and right it is the extreme of perfection.
But it is not all actions nor all passions that admit of moderation; there are some whose very names imply badness, as malevolence, shamelessness, envy, and, among acts, adultery, theft, murder. These and all other like things are blamed as being bad in themselves, and not merely in their excess or deficiency. It is impossible therefore to go right in them; they are always wrong: rightness and wrongness in such things ( e.g. in adultery) does not depend upon whether it is the right person and occasion and manner, but the mere doing of any one of them is wrong.
It would be equally absurd to look for moderation or excess or deficiency in unjust cowardly or profligate conduct; for then there would be moderation in excess or deficiency, and excess in excess, and deficiency in deficiency.
The fact is that just as there can be no excess or deficiency in temperance or courage because the mean or moderate amount is, in a sense, an extreme, so in these kinds of conduct also there can be no moderation or excess or deficiency, but the acts are wrong however they be done. For, to put it generally, there cannot be moderation in excess or deficiency, nor excess or deficiency in moderation.

VII
But it is not enough to make these general statements [about virtue and vice]: we must go on and apply them to particulars [ i.e. to the several virtues and vices]. For in reasoning about matters of conduct general statements are too vague, 27 and do not convey so much truth as particular propositions. It is with particulars that conduct is concerned: 28 our statements, therefore, when applied to these particulars, should be found to hold good.
These particulars then [ i.e. the several virtues and vices and the several acts and affections with which they deal], we will take from the following table. 29
Moderation in the feelings of fear and confidence is courage: of those that exceed, he that exceeds in fearlessness has no name (as often happens), but he that exceeds in confidence is foolhardy, while he that exceeds in fear, but is deficient in confidence, is cowardly.
Moderation in respect of certain pleasures and also (though to a less extent) certain pains is temperance, while excess is profligacy. But defectiveness in the matter of these pleasures is hardly ever found, and so this sort of people also have as yet received no name: let us put them down as “void of sensibility.”
In the matter of giving and taking money, moderation is liberality, excess and deficiency are prodigality and illiberality. But both vices exceed and fall short in giving and taking in contrary ways: the prodigal exceeds in spending, but falls short in taking; while the illiberal man exceeds in taking, but falls short in spending. (For the present we are but giving an outline or summary, and aim at nothing more; we shall afterwards treat these points in greater detail.)
But, besides these, there are other dispositions in the matter of money: there is a moderation which is called magnificence (for the magnificent is not the same as the liberal man: the former deals with large sums, the latter with small), and an excess which is called bad taste or vulgarity, and a deficiency which is called meanness; and these vices differ from those which are opposed to liberality: how they differ will be explained later.
With respect to honour and disgrace, there is a moderation which is high-mindedness, an excess