Nicomachean Ethics

​In this way they are equal and associated, because this equality can occur in their case. Let the farmer be A, food C, the shoemaker B, and his equalized work D. If it were not possible to have reciprocal action in this way, there would be no association. And that need holds things together as if being some single thing is shown by the fact that when they are not in need of one another, either both or one of them, they do not make an exchange—unlike when someone needs what another has, for example wine, offering in return the export of corn. Therefore, this must be equalized. And for future exchange, if one needs nothing at present, money is as it were our guarantor that exchange will be possible if a need should arise; for it must be possible for one who brings this to receive what he needs. Now this itself also suffers the same thing, for it is not always worth the same; nevertheless, it tends to remain more stable. Therefore, all things must have a price set on them; for in this way there will always be exchange, and if there is exchange, there will be association. Money, then, like a measure, equalizes by making things comparable; for there would not be association if there were no exchange, nor exchange if there were no equality, nor equality if there were no comparability. In truth, then, it is impossible for things so greatly different to become comparable, but in relation to need it is sufficiently possible. There must, then, be some single thing, and this by agreement; for which reason it is called “money”; for this makes all things comparable, since all things are measured by money. Let a house be A, ten minae B, and a bed C. A is half of B, if the house is worth five minae, or equal to it; and the bed C is a tenth part of B. It is clear, then, how many beds are equal to a house, namely, five. It is clear that exchange was conducted in this way before money existed; for it makes no difference whether five beds are given for a house, or the value of five beds. Regarding what the unjust is and what the just is, have been said. These having been defined, it is clear that just action is a mean between doing injustice and suffering injustice; for the one is to have too much, and the other to have too little. And justice is a sort of mean, not in the same way as the other virtues, but because it relates to a mean, while injustice relates to the extremes. And justice is that by which the just man is said to be a doer, by choice, of what is just, and to be distributer both between himself and another, and between another and another, not in such a way as to award more of the desirable to himself and less to his neighbor, and of the harmful the reverse, but to award what is equal according to proportion, and similarly in distributing between another and another. Injustice, on the contrary, relates to the unjust; and this is excess and defect of the beneficial or the harmful, contrary to proportion. Therefore, injustice is excess and defect, because it is concerned with excess and defect—in one’s own case, excess of what is unconditionally beneficial and defect of what is harmful; while in the case of others, though as a whole similarly, the distribution is contrary to proportion, in whichever direction it happens to turn. And of the unjust act, the lesser evil is to suffer injustice, and the greater is to do injustice. Regarding, then, justice and injustice, what the nature of each is, let it have been spoken of in this manner, and similarly regarding the just and the unjust in general.