Plato on wisdom, courage, temperance and justice, from The Republic, Book IV.
Socrates proceeds: But where amid all this is justice? Son of Ariston, tell me where. Light a candle and search the city, and get your brother and the rest of our friends to help in seeking for her. ‘That won’t do,’ replied Glaucon, ‘you yourself promised to make the search and talked about the impiety of deserting justice.’ Well, I said, I will lead the way, but do you follow. My notion is, that our State being perfect will contain all the four virtues—wisdom, courage, temperance, justice. If we eliminate the three first, the unknown remainder will be justice.
First then, of wisdom: the State which we have called into being will be wise because politic. And policy is one among many kinds of skill,—not the skill of the carpenter, or of the worker in metal, or of the husbandman, but the skill of him who advises about the interests of the whole State. Of such a kind is the skill of the guardians, who are a small class in number, far smaller than the blacksmiths; but in them is concentrated the wisdom of the State. And if this small ruling class have wisdom, then the whole State will be wise.
Our second virtue is courage, which we have no difficulty in finding in another class—that of soldiers. Courage may be defined as a sort of salvation—the never-failing salvation of the opinions which law and education have prescribed concerning dangers. You know the way in which dyers first prepare the white ground and then lay on the dye of purple or of any other colour. Colours dyed in this way become fixed, and no soap or lye will ever wash them out. Now the ground is education, and the laws are the colours; and if the ground is properly laid, neither the soap of pleasure nor the lye of pain or fear will ever wash them out. This power which preserves right opinion about danger I would ask you to call ‘courage,’ adding the epithet ‘political’ or ‘civilized’ in order to distinguish it from mere animal courage and from a higher courage which may hereafter be discussed.
Two virtues remain; temperance and justice. More than the preceding virtues temperance suggests the idea of harmony. Some light is thrown upon the nature of this virtue by the popular description of a man as ‘master of himself’—which has an absurd sound, because the master is also the servant. The expression really means that the better principle in a man masters the worse. There are in cities whole classes—women, slaves and the like—who correspond to the worse, and a few only to the better; and in our State the former class are held under control by the latter. Now to which of these classes does temperance belong? ‘To both of them.’ And our State if any will be the abode of temperance; and we were right in describing this virtue as a harmony which is diffused through the whole, making the dwellers in the city to be of one mind, and attuning the upper and middle and lower classes like the strings of an instrument, whether you suppose them to differ in wisdom, strength or wealth.
And now we are near the spot; let us draw in and surround the cover and watch with all our eyes, lest justice should slip away and escape. Tell me, if you see the thicket move first. ‘Nay, I would have you lead.’ Well then, offer up a prayer and follow. The way is dark and difficult; but we must push on. I begin to see a track. ‘Good news.’ Why, Glaucon, our dulness of scent is quite ludicrous! While we are straining our eyes into the distance, justice is tumbling out at our feet. We are as bad as people looking for a thing which they have in their hands. Have you forgotten our old principle of the division of labour, or of every man doing his own business, concerning which we spoke at the foundation of the State—what but this was justice? Is there any other virtue remaining which can compete with wisdom and temperance and courage in the scale of political virtue? For ‘every one having his own’ is the great object of government; and the great object of trade is that every man should do his own business. Not that there is much harm in a carpenter trying to be a cobbler, or a cobbler transforming himself into a carpenter; but great evil may arise from the cobbler leaving his last and turning into a guardian or legislator, or when a single individual is trainer, warrior, legislator, all in one. And this evil is injustice, or every man doing another’s business. I do not say that as yet we are in a condition to arrive at a final conclusion. For the definition which we believe to hold good in states has still to be tested by the individual. Having read the large letters we will now come back to the small. From the two together a brilliant light may be struck out…
Socrates proceeds to discover the nature of justice by a method of residues. Each of the first three virtues corresponds to one of the three parts of the soul and one of the three classes in the State, although the third, temperance, has more of the nature of a harmony than the first two. If there be a fourth virtue, that can only be sought for in the relation of the three parts in the soul or classes in the State to one another. It is obvious and simple, and for that very reason has not been found out. The modern logician will be inclined to object that ideas cannot be separated like chemical substances, but that they run into one another and may be only different aspects or names of the same thing, and such in this instance appears to be the case. For the definition here given of justice is verbally the same as one of the definitions of temperance given by Socrates in the Charmides, which however is only provisional, and is afterwards rejected. And so far from justice remaining over when the other virtues are eliminated, the justice and temperance of the Republic can with difficulty be distinguished. Temperance appears to be the virtue of a part only, and one of three, whereas justice is a universal virtue of the whole soul. Yet on the other hand temperance is also described as a sort of harmony, and in this respect is akin to justice. Justice seems to differ from temperance in degree rather than in kind; whereas temperance is the harmony of discordant elements, justice is the perfect order by which all natures and classes do their own business, the right man in the right place, the division and co-operation of all the citizens. Justice, again, is a more abstract notion than the other virtues, and therefore, from Plato’s point of view, the foundation of them, to which they are referred and which in idea precedes them. The proposal to omit temperance is a mere trick of style intended to avoid monotony.