Some people think that "eye for an eye" is just. That is about what the Pythagoreans used to teach. They used to say that whatever a person does to someone else, that person should get done to themselves. It is like the saying: "To have done unto you what you have done unto others, that is what justice is." This is called 'reciprocity' (or, 'tit-for-tat'), and it does not match up with the distributive or the rectificatory kinds of justice that we went over. Reciprocity is way too simple to work for all cases, and yet people want the justice of Rhadamanthus (the Greek demi-god that judges the dead when they come to the underworld, and decides what is to be done with them based on how they lived) -- they want this justice to mean nothing more than reciprocity.

Well, it is not hard to see how simple reciprocity can fail to be just. Take, for instance, the case where an officer of the law must strike a person in order to uphold the law (e.g. there is a drunken brawl and people are resisting arrest). Simple reciprocity would say that the just thing would be for the officer to be struck in return, but clearly that would not be right. On the other hand, suppose that someone strikes an officer of the law. That person ought not only to be struck in return (which is what simple reciprocity says), but, on top of that, be punished also.

We also note that whether the injured person gave their OK beforehand makes a big difference. And how can someone be OK with getting injured? Well, suppose, for instance, that two boxers spar with each other, and one knocks the other down. They are boxers and they are sparring: they agree to strike each other. Would it be just to then give the boxer that got knocked down a free shot to knock down the other boxer in return (which would be reciprocity)? Of course not, that is absurd.

Well, do we have nothing good to say about reciprocity? Yes, we do. Reciprocity of services (good and bad) is what holds a city together. People look to return evil for evil, and if they cannot do so then they think that they are a free citizen in name only, and they may as well be as slave to have to endure such abuse. And people also look to return good for good. If they cannot trade good for good, then there is no exchange, and if no one exchanges anything, there is no point in having a city. (This is why in the cities, there are temples dedicated to the Graces -- to returning good for good; that is what makes for grace: that someone does you a good, you graciously accept and look to return the favor, and even after that, be eager to help.)

Now let us work through how this reciprocal justice, or proportionate return, can happen. Let us say that we have a builder of houses and a maker of shoes. The builder wants a pair of shoes and the shoemaker wants a house. Well, if we take justice to mean reciprocity, then what would be a fair deal? We did say before that justice means equality. Does this mean here that the shoemaker can give the builder a pair of shoes and then, in order to reciprocate, the builder must give a house in return? Obviously not! A house is worth more than a pair of shoes, so the two are not equal.

Work is often not equal; some things take more time, effort, training, talent, etc. If people are forced to act as if the work is equal, when it is not, then they are not going to want to do work or trade with people that have easier work. So what is the solution? The work has to be made equal, somehow. The way it is made equal is by setting each piece of work, not against each other, but rather against a thing that measures them both. Imagine there are two pieces of gold jewelry, a bracelet and a necklace. How can they be measured? By weighing them.

And what about shoes and houses? What can measure both of them? Money can. Money is what measures the products of work. With money we can set things up to be equal. In this way, things that take more work can be fairly traded for things that take less work. How so? Well, think of it like scales, or a balance. Imagine that on one side is a house and on the other side is a pair of shoes. The balance is tilted way to the side with the house, because things are very unequal, one pair of shoes is worth way less. Now imagine putting one shoe after another into the balance. Slowly the side with the shoes goes down and the side with the house moves up. It keeps going like this until everything evens out. Finally, imagine that instead of houses and shoes in the balance, we use gold coins. With that in mind, we can see how money is what lets us make different things be equal with each other.

There would be no professions if people could only ever exchange one-for-one. Oh, it would be fine if doctors were to trade one-for-one the same thing with each other. But that does not really happen. It is more like the doctor and the farmer need what each other has. What each one gets, they must give the same value in return. But we just saw in the case of one pair of shoes for one house how absurd one-for-one would be. Even if it is 1000 shoes for 1 house, what is the builder supposed to do with 999 shoes that they do not need? What we need is a common standard that measures them both. This is money.

What money measures is how badly people need what each other has. Because people need what others have, we can form a society. If people did not need anything from each other, they would not exchange the things they do exchange and they would not associate with each other.

So money is something that is agreed on as a stand-in for demand. This is why the (Greek) word for money is like the (Greek) word for law. By law, money has the value that it has; money does not already have its value from nature (for if it did we would not need or have laws saying what value it has). The law can change the value of money or can make it useless (viz. useless for exchange).

Anyhow, let us look at how the builder and the shoemaker can make a fair, reciprocal proportion by using money as the measure. Here is how the proportion works:

builder's hours worked / rate per hour of the builder = shoemaker's hours worked / rate per hour of the shoemaker

If a builder works 1000 hours to make a house and values their labor at $100 an hour then they do $100,000 worth of work. And if the shoemaker values their labor at $200 per hour (charges twice as much), then the shoemaker would have to have spend only 500 hours (works half as much) making shoes to get to $100,000 worth, and so have a proportional return. If the shoemaker has to work more than 500 hours, then they will see the exchange as being not worth it for them. Likewise, after the builder has made the house, if they cannot get 1000 hours * $100/hour = $100,000 worth in exchange then they will not want to do the deal either. It is only when both sides get what they think that they are worth that they will do the deal.

The thing is that the work of some people is worth more than that of other people. Really, this is how it is. Those people whose work is worth more have to be able to get more for their work. If they do not, they will not do the work, and everyone will have to go without having benefits from it. Everyone wants a doctor when they need one. But who would be a doctor if one hour of their work trades for, say, one hour of running errands? Yet we know that we are going to have to have doctors. So we know that somehow doctors will have to be able to get more in exchange for the work they do. Money, again, makes this possible.

Money helps make for exchange, and societies have to have exchange in order to hold together. Man is, by nature, a social animal. People get the things that are good in life from each other. People do not get all that is good in life from themselves. But how do people get what is good from another person? They do it by exchange. If exchange is possible, people can specialize in a certain kind of work, and look to the good of that, and provide that for a society. One person is teacher, another is a doctor, and another builds houses. Because we have exchange, we can have a society where people can have shelter, education, and medicine. And if exchanges are just, fair, and equitable, people will want to keep on exchanging with each other. Why? Well, remember how we said that "justice is another's good". These fair and just exchanges are for the good of both sides. Because it is for their own good, people will keep on doing them.

[And if we are students of politics, looking to the good of the society, we must understand a bit about economy to understand what holds a society together, besides its laws. We must have an appreciation for money as well, to understand justice.]

We cannot always set up trades right when we want or need this or that thing. We might not have something we can do right away in order to have something to trade with. Likewise also, we may not have anything that we want right now for it to be worth it for us to do work. But if we have money, then we will always have something ready to give or take in exchange for something. Like all goods, how much money something is worth can change over time, but still, overall, it tends to keep steady. This is why all goods must have a price on them. If people know that they will be able to buy and sell things then they will always have reason to associate with each other. Money makes it so that goods are comparable, and it measures them, so that we can have different amounts of the goods, but both sides are worth the same, and so it is worth it to trade them.

Again, people do not associate if they cannot trade for what they need, and they will not trade if they do not think that what they get and give are worth the same, and they cannot do that unless they have some way to measure both sides. So you can see why having money set up as a way to do exchange is important for a state, and that is why we have laws about it.

Now it is pretty impossible that things which are very different from each other (e.g. houses and shoes) should be straight-up comparable, but when each of them can be compared with some third common thing (e.g. money), then it is possible. There has to be something that is a unit of measure, something which is fixed by agreement, or nomos (the Greek word for law), which is why it is called nomisma (the Greek word for money). Money is what makes things be comparable, because it measures both things, and so the two amounts are comparable. Again, think of the phrase "worth their weight in gold", and now imagine an amount of gold placed in scales that balance out. What each side is worth in gold is equal to what is on the other side.

Consider the following:

1 house = 1/2 gold bar

-and-

1 bed = 1/10 gold bar

Before, it may have been hard to figure out how to exchange beds for houses. For example, if someone asks you how many beds you want from them in order for it to be worth it to you to build them a house, you may have no idea. But because we can equate them both with money, we can see that 5 beds = 1 house. How so? Well, if one house is half a gold bar and one bed is worth a tenth, then the house is worth five times as much. It makes no difference whether you actually give five beds for a house or how much the five beds would sell for.

So we have gone through what is just and what is not just, now let us wrap up by talking about what that means. Doing what is just involves choosing a mean (an intermediate point) that is between being unjustly treated (i.e. getting ripped off) and treating someone else unjustly (i.e. ripping off someone else). One extreme is getting too much, or more than one's due, and the other extreme is getting too little, or less than one's due. The mean is getting what one is due, no more and no less. The just person will take care to settle things so that each person, both themselves and the other, get what they ought. This includes both things that people want (e.g. money) and things that they do not want (e.g. boring or risky work), but which they must share in anyways.

Justice is a virtue, since a just person takes the just action for the sake of justice. However, it is unlike the other virtues in that both extremes have the one name 'injustice'. And in a way, injustice is both an excess and a deficiency at the same time. This is because there are two people involved. If the one person gets too much, then that means that the other person must get too little (and vice versa). Allowing oneself to take less than what one is due is actually a vice, but it less a vice than it is to take more than what one is due. So we agree with the Platonists here, that to suffer from injustice is better than to profit from it, but still to render justice is what is best.

And at this point, we have gone through what it means for something to be just or unjust, and how to tell whether deals are just or unjust. So now let us move on and talk more about how justice relates to the law.