Why Be Good? Plato

Pick a Category

Why Be Good? Plato

Introduction to Plato

Plato, one of the most influential philosophers in Western history, was born in Athens, Greece, around 427 or 428 BCE. He belonged to an aristocratic family and was initially inclined towards a career in politics. However, his encounter with the renowned philosopher Socrates profoundly impacted his life and set him on a path of philosophical inquiry. After Socrates’ execution in 399 BCE, Plato became a dedicated student of his teacher’s ideas and developed his own philosophical system. In 387 BC, he established a school known as the Academy, where many of the most notable philosophers and mathematicians of the next several generations received their training. Among them was Aristotle, who studied at the Academy for twenty years with Plato as his teacher.

Plato’s philosophical works were written as dramatic dialogues in which two or more characters engage each other in philosophical conversation, often without reaching any decisive conclusion on the topics at hand. This unique approach to philosophical writing draws the reader into Plato’s inquiry, inviting them to reflect on the arguments from the dialogue as a firsthand witness to the conversation would, and leaving them to draw their own conclusions on the issues raised.

The text you’ll read below is a dialogue from Book II of the Republic, Plato’s most famous work. Here, Socrates (Plato’s teacher, and the main speaker in many of Plato’s dialogues) is speaking with Plato’s brothers, Glaucon and Adeimantus, about the nature and value of justice. As they discuss, Glaucon asks one of the central questions in moral philosophy: why should anyone care about being moral or just?

Republic, Book II 357a-358a

Prior to this, Socrates has been extolling the importance of justice to his friends.  

  • Glaucon: Socrates, do you want to seem to have persuaded us that it is better in every way to be just than unjust, or do you want to truly convince of us this?
  • Socrates: I want truly to convince you, if I can…
  • Glaucon: Well, then, you certainly aren’t doing what you want. Tell me, do you think there is a kind of good we welcome, not because we desire what comes from it, but because we welcome it for its own sake—joy, for example, and all the harmless pleasures that have no results beyond the joy of having them?
  • Socrates: Certainly, I think there are such things.
  • Glaucon: And if there a kind of good we like for its own sake and also for the sake of what comes from it—knowing, for example, and seeing and being healthy? We welcome such things, I suppose, on both counts.
  • Socrates: Yes.
  • Glaucon: And do you also see a third kind of good, such as physical training, medical treatment when sick, medicine itself, and the other ways of making money? We’d say that these are onerous, but beneficial to us, and we wouldn’t choose them for their own sakes, but for the sake of the rewards and other things that come from them.
  • Socrates: There is also this third kind. But what of it?
  • Glaucon: Where do you put justice?

Key Principle

Three Kinds of Good

Here Plato distinguishes three kinds of good. Try to think of your own examples then click for some of ours.

  • Instrumental Goods: Things that are valuable only insofar as they help us achieve something else that is good
  • Intrinsic Goods: Things that are valuable purely for their own sake
  • Instrumental and Intrinsic Goods: Things that are valuable both in themselves and because they help us achieve other goods

With this distinction in mind, Socrates will argue that justice is both instrumentally and intrinsically good. This would show that justice belongs to the highest kind of good, and that it is the sort of thing that people ought to desire for its own sake (and not just because it’s to their advantage to appear just, since then people will trust them).

Republic, Book II 358a-358d Glaucon’s Challenge

Socrates: I myself put it among the finest goods, as something to be valued by anyone who is going to be blessed with happiness, both because of itself and because of what comes from it.

Glaucon: That isn’t most people’s opinion. They’d say that justice belongs to the onerous kind, and is to be practiced for the sake of the rewards and popularity that come from a reputation for justice, but is to be avoided because of itself as something burdensome.

Socrates: I know that’s the general opinion. Thrasymachus faulted justice on these grounds a moment ago and praised injustice, but it seems I am a slow learner.

Glaucon: Come then, and listen to me well, and see whether you still have that problem. I’m not yet satisfied by the argument on either side. I want to know what justice and injustice are and what power each one has when it’s by itself in the soul. I want to leave out of account their rewards and what comes from each of them. So, if you agree, I’ll renew the argument of Thrasymachus. I’ll state what kind of thing people consider justice to be, I’ll argue that all who practice it do so unwillingly, as something necessary, not as something good, and I’ll argue that they have good reason to act as they do, for the life of an unjust person is, they say, much better than a just one.

I’m going to speak at length in praise of the unjust life, and in doing so I’ll show you the way I want to hear you praising justice and denouncing injustice. But see whether you want me to do that or not.

Socrates: I want that most of all. Indeed, what subject could someone with any understanding enjoy discussing more often?


Glaucon’s Hypothesis About Justice: Book II, 358e-359b

Glaucon: Injustice is naturally good and to suffer injustice is bad, but the badness of suffering it so far exceeds the goodness of doing it that those who have tasted both, but who lack the power to do it and avoid suffering it, decide that it is profitable to come to an agreement with each other and neither do injustice nor suffer it. As a result, they begin to make laws and covenants, and what the law commands they call lawful and just. This, they say, is the origin and essence of justice. It is intermediate between the best and the worst. The best is to do injustice without paying the penalty; the worst is to suffer it without being able to take revenge. Justice is a mean between these two extremes. People value it not as a good but because they are too weak to do injustice with impunity.

  • See if you can outline the argument Glaucon is giving here. The conclusion of the argument—the claim it attempts to establish—is that justice is a purely instrumental good. What are the main reasons given to support this claim (the argument’s “premises”), and how do they work together to provide this support?

Thought Experiment

The Ring of Gyges

Glaucon continues his argument with a thought experiment:

We can see most clearly that those who practice injustice do it unwillingly and because they lack the power to do injustice, if in our thoughts we grant to a just and an unjust person the freedom to do whatever they like. We can then follow both of them and see where their desires would lead. And we’ll catch the just person red-handed traveling the same road as the unjust. The reason for this is the desire to outdo others and get more and more. This is what anyone’s nature naturally pursues as good, but nature is forced by law into the perversion of treating fairness with respect.

The freedom I mentioned would be most easily realized if both people—the just and the unjust—had the power they say the ancestor of Gyges of Lydia possessed. The story goes that he was a shepherd in the service of the ruler of Lydia. There was a violent thunderstorm, and an earthquake broke open the ground and created a chasm at the place where he was tending his sheep. Seeing this, he was filled with amazement and went down into it. And there, in addition to many other wonders of which we’re told, he saw a hollow bronze horse. There were window-like openings in it, and peeping in, he saw a corpse, which seemed to be of more than human size, wearing nothing but a gold ring on its finger. He took the ring and and came out of chasm. He wore the ring at the usual monthly meeting that reported to the king on the state of the flocks. And as he was sitting among the others, he happened to turn the setting of the ring towards himself to the inside of his hand. When he did this, he became invisible to those sitting near him, and they went on talking as if he had gone. He wondered at this, and, fingering the ring, he turned the setting outwards again and became visible. So he experimented with the ring to test whether it indeed had this power—and it did. If he turned the setting inward, he became invisible; if he turned it outward, he became visible again. When he realized this, he at once arranged to become one of the messengers sent to report to the king. And when he arrived there, he seduced the king’s wife, attacked the king with her help, and took over the kingdom.

Let’s suppose, then, that there were two such rings, one worn by a just and the other by an unjust person. Now, no one, it seems, would be so incorruptible that he would stay on the path of justice or stay away from other people’s property, when he could take whatever he wanted from the marketplace with impunity, go into people’s houses and have sex with anyone he wished, kill or release from prison anyone he wished, and do all the other things that would make him like a god among humans.

No one believes justice to be a good when it is kept private, since, wherever either person thinks he can do injustice with impunity, he does it. Indeed, every man believes that injustice is far more profitable to himself than justice. And any exponent of this argument will say he’s right, for someone who didn’t want to do injustice, given this sort of opportunity, and who didn’t touch other people’s property would be thought wretched and stupid by everyone aware of the situation, though, of course, they’d praise him in public, deceiving each other for fear of suffering injustice.

As for the choice between lives we’re discussing, we’ll be able to make a correct judgment about that only if we separate the most just and the most unjust. Otherwise we won’t be able to do it. Here’s the separation I have in mind. We’ll subtract nothing from the injustice of an unjust person and nothing from the justice of a just one, but we’ll take each to be complete in his own way of life. An unjust person’s successful at attempts at injustice must remain undetected, if he is to be fully unjust. Anyone who is caught should be thought inept, for the extreme of injustice is to be believed to be just without being just. We must allow that, while doing the greatest injustice, he has nonetheless provided himself with the greatest reputation for justice.

Having hypothesized such a person, let’s now in our argument put him beside a just man, who is simple and noble and who, as Aeschylus says, doesn’t want to be believed to be good but to be so. We must take away his reputation, for a reputation for justice would bring him honor and rewards, so that it wouldn’t be clear whether he is just for the sake of justice itself of for the sake of those honors and rewards. We must strip of him everything except justice and make his situation the opposite of an unjust person’s. Though he does no injustice, he must have the greatest reputation for it, so that he can be tested as regards justice unsoftened by his bad reputation and its effects. Let him stay like that unchanged until he dies—just, but all his life believed to be unjust. In this way, both will reach the extremes, the one of justice and the other of injustice, and we’ll be able to judge which of them is happier.

Adeimantus’s Plea

This section of the Republic ends with Adeimantus (Plato’s other brother) giving a plea to Socrates:

Adeimantus: Don’t merely give us a theoretical argument that justice is stronger than injustice, but tell us what each itself does, because of its own powers, to someone who possesses it, that makes injustice bad and justice good. You agree that justice is one of the greatest goods, the ones that are worth getting for the sake of what comes from them, but much more so for their own sake. Therefore, praise justice as a good of that kind, explaining how—because of its very self—it benefits its possessors and how injustice harms them.

The remainder of the Republic is Plato attempting to do just this. His solution will be to argue that to be happy, one must have a balanced soul—one where the appetites and emotions are regulated by reason. Those who give in to their appetites, like Gyges’ ancestor in Glaucon’s thought experiment, are destined to misery.