Nicomachean Ethics

are stated elsewhere with sufficient precision, and these we will adopt.
Two parts of the soul are distinguished, an irrational and a rational part.
Whether these are separated as are the parts of the body or any divisible thing, or whether they are only distinguishable in thought but in fact inseparable, like concave and convex in the circumference of a circle, makes no difference for our present purpose.
Of the irrational part, again, one division seems to be common to all things that live, and to be possessed by plants⁠—I mean that which causes nutrition and growth; for we must assume that all things that take nourishment have a faculty of this kind, even when they are embryos, and have the same faculty when they are full grown; at least, this is more reasonable than to suppose that they then have a different one.
The excellence of this faculty, then, is plainly one that man shares with other beings, and not specifically human.
And this is confirmed by the fact that in sleep this part of the soul, or this faculty, is thought to be most active, while the good and the bad man are undistinguishable when they are asleep (whence the saying that for half their lives there is no difference between the happy and the miserable; which indeed is what we should expect; for sleep is the cessation of the soul from those functions in respect of which it is called good or bad), except that they are to some slight extent roused by what goes on in their bodies, with the result that the dreams of the good man are better than those of ordinary people.
However, we need not pursue this further, and may dismiss the nutritive principle, since it has no place in the excellence of man.
But there seems to be another vital principle that is irrational, and yet in some way partakes of reason. In the case of the continent and of the incontinent man alike we praise the reason or the rational part, for it exhorts them rightly and urges them to do what is best; but there is plainly present in them another principle besides the rational one, which fights and struggles against the reason. For just as a paralyzed limb, when you will to move it to the right, moves on the contrary to the left, so is it with the soul; the incontinent man’s impulses run counter to his reason. Only whereas we see the refractory member in the case of the body, we do not see it in the case of the soul. But we must nevertheless, I think, hold that in the soul too there is something beside the reason, which opposes and runs counter to it (though in what sense it is distinct from the reason does not matter here).
It seems, however, to partake of reason also, as we said: at least, in the continent man it submits to the reason; while in the temperate and courageous man we may say it is still more obedient; for in him it is altogether in harmony with the reason.
The irrational part, then, it appears, is twofold. There is the vegetative faculty, which has no share of reason; and the faculty of appetite or of desire in general, which in a manner partakes of reason or is rational as listening to reason and submitting to its sway⁠—rational in the sense in which we speak of rational obedience to father or friends, not in the sense in which we speak of rational apprehension of mathematical truths. But all advice and all rebuke and exhortation testify that the irrational part is in some way amenable to reason.
If then we like to say that this part, too, has a share of reason, the rational part also will have two divisions: one rational in the strict sense as possessing reason in itself, the other rational as listening to reason as a man listens to his father.
Now, on this division of the faculties is based the division of excellence; for we speak of intellectual excellences and of moral excellences; wisdom and understanding and prudence we call intellectual, liberality and temperance we call moral virtues or excellences. When we are speaking of a man’s moral character we do not say that he is wise or intelligent, but that he is gentle or temperate. But we praise the wise man, too, for his habit of mind or trained faculty; and a habit or trained faculty that is praiseworthy is what we call an excellence or virtue.

Book II

Moral Virtue

I
Excellence, then, being of these two kinds, intellectual and moral, intellectual excellence owes its birth and growth mainly to instruction, and so requires time and experience, while moral excellence is the result of habit or custom (ἔθος), and has accordingly in our language received a name formed by a slight change from ἔθος. 19
From this it is plain that none of the moral excellences or virtues is implanted in us by nature; for that which is by nature cannot be altered by training. For instance, a stone naturally tends to fall downwards, and you could not train it to rise upwards, though you tried to do so by throwing it up ten thousand times, nor could you train fire to move downwards, nor accustom anything which naturally behaves in one way to behave in any other way.
The virtues, 20 then, come neither by nature nor against nature, but nature gives the capacity for acquiring them, and this is developed by training.
Again, where we do things by nature we get the power first, and put this power forth in act afterwards: as we plainly see in the case of the senses; for it is not by constantly seeing and hearing that we acquire those faculties, but, on the contrary, we had the power first and then used it, instead of acquiring the power by the