Encyclopedia of Philosophy: PLATO'S REPUBLIC

« PLATO'S REPUBLIC Plato relied on the Theory of Ideas not only in the area of logic and metaphysics, but also in the theory of knowledge and in the foundations of morality.

To see the many different uses to which he put it in the years of his maturity, we cannot do better than to consider in detail his most famous dialogue, The Republic. The official purpose of the dialogue is to seek a definition of justice, and the thesis which it propounds is that justice is the health of the soul.

But that answer takes a long while to reach, and when it is reached it is interpreted in many different ways. The dialogue's first book offers a number of candidate definitions which are, one after the other, exploded by Socrates in the manner of the early dialogues.

The book indeed, may at one time have existed separately as a selfcontained dialogue.

But it also illustrates the essential structure of the entire Republic, which is dictated by a method to which Plato attached great importance and to which he gave the name ‘dialectic'. A dialectician operates as follows.

He takes a hypothesis, a questionable assumption, and tries to show that it leads to a contradiction: he presents, in the Greek technical term, an elenchus.

If the elenchus is successful, and a contradiction is reached, then the hypothesis is refuted; and the dialectician next puts to the test the other premisses used to derive the contradiction, subjecting them in turn to elenchus until he reaches a premiss which is unquestionable. All this can be illustrated from the first book of the Republic.

The first elenchus is very brief.

Socrates' old friend Cephalus puts forward the hypothesis that justice is telling the truth and returning whatever one has borrowed. Socrates asks: is it just to return a weapon to a mad friend? Cephalus agrees that it is not; and so Socrates concludes ‘justice cannot be defined as telling the truth and returning what one has borrowed'.

Cephalus then withdraws from the debate and goes off to sacrifice. In pursuit of the definition of justice, we must next examine the further premisses used in refuting Cephalus.

The reason why it is unjust to return a weapon to a madman is that it cannot be just to harm a friend.

So next, Polemarchus, Cephalus' son and the heir to his argument, defends the hypothesis that justice is doing good to one's friends and harm to one's enemies.

The refutation of this suggestion takes longer; but finally Polemarchus agrees that it is not just to harm any man at all.

The crucial premiss needed for this elenchus is that justice is human excellence or virtue.

It is preposterous, Socrates urges, to think that a just man could exercise his excellence by making others less excellent. Polemarchus is knocked out of the debate because he accepts without a mur-mur the premiss that justice is human excellence; but waiting in the wings is the sophist Thrasymachus, agog to challenge that hypothesis.

Justice is not a virtue or excellence, he says, but weakness and foolishness, because it is not in anyone's interest to possess it. On the contrary, justice is simply what is to the advantage of those who have power in the state; law and morality are only systems designed for the protection of their interests.

It takes Socrates twenty pages and some complicated forking procedures to checkmate Thrasymachus; but eventually, at the end of Book One, it is agreed that the just man will have a better life than the unjust man, so that justice is in its possessor's interests.

Thrasymachus is driven to agree by a number of concessions he makes to Socrates.

For instance, he agrees that the gods are just, that human virtue or excellence makes one happy.

These and other premisses need arguing for; all of them can be questioned and most of them are questioned elsewhere in the Republic, from Book Two onwards. Two people who have so far listened silently to the debate are Plato's brothers Glaucon and Adeimantus.

Glaucon intervenes to suggest that while justice may not be a positive evil, as Thrasymachus had suggested, it is not something worthwhile for its own sake, but something chosen as a way of avoiding evil.

To avoid being oppressed by others, weak human beings make compacts with each other neither to suffer nor to commit injustice.

People would much prefer to act unjustly, if they could do so with impunity – the kind of impunity a man would have, for instance, if he could make himself invisible so that his misdeeds passed undetected.

Adeimantus supports his brother, saying that among humans the rewards of justice are the rewards of seeming to be just rather than the rewards of actually being just, and with regard to the gods the penalties of injustice can be bought off by prayer and sacrifice.

If Socrates is really to defeat Thrasymachus, he must show that quite apart from reputation, and quite apart from sanctions, justice is in itself as much preferable to injustice as sight is to blindness and health is to sickness. In response, Socrates shifts from the consideration of justice in the individual to the consideration of justice in the city-state.

There, he says, the nature of justice will be written in larger letters and easier to read.

The purpose of living in cities is to enable people with different skills to supply each others' needs.

Ideally, if people were content with the satisfaction of their basic needs, a very simple community would suffice.

But citizens demand more than mere subsistence, and this necessitates a more complicated structure, providing, among other things, for a welltrained professional army. Socrates describes a city in which there are three classes.

Those among the soldiers most fitted to rule are selected by competition to form the upper class, called guardians; the remaining soldiers are described as auxiliaries; and the rest of the citizens belong to the class of farmers and artisans.

The consent of the governed to the authority of the rulers is to be secured by propagating ‘a noble falsehood', a myth according to which the members of each class have different metals in their souls: gold, silver, and bronze respectively.

Membership of classes is in general conferred by birth, but there is scope for a small amount of promotion and demotion from class to class. The rulers and auxiliaries are to receive an elaborate education in literature (based on a censored version of the Homeric poems), music (only edifying and martial rhythms are allowed) and gymnastic activity (undertaken by both. »