Plato's Republic

Why do men behave justly? Is it because they fear societal punishment? Are they trembling before notions of divine retribution? Do the stronger elements of society scare the weak into submission in the name of law? Or do men behave justly because it is good for them to do so? Is justice, regardless of its rewards and punishments, a good thing in and of itself? How do we define justice? Plato sets out to answer these questions in the Republic. He wants to define justice, and to define it in such a way as to show that justice is worthwhile in and of itself. He meets these two challenges with a single solution: a definition of justice that appeals to human psychology, rather than to perceived behavior.

Plato's strategy in the Republic is to first explicate the primary notion of societal, or political, justice, and then to derive an analogous concept of individual justice. In Books II, III, and IV, Plato identifies political justice as harmony in a structured political body. An ideal society consists of three main classes of people--producers (craftsmen, farmers, artisans, etc.), auxiliaries (warriors), and guardians (rulers); a society is just when relations between these three classes are right. Each group must perform its appropriate function, and only that function, and each must be in the right position of power in relation to the others. Rulers must rule, auxiliaries must uphold rulers' convictions, and producers must limit themselves to exercising whatever skills nature granted them (farming, blacksmithing, painting, etc.) Justice is a principle of specialization: a principle that requires that each person fulfill the societal role to which nature fitted him and not interfere in any other business.

At the end of Book IV, Plato tries to show that individual justice mirrors political justice. He claims that the soul of every individual has a three part structure analogous

to the three classes of a society. There is a rational part of the soul, which seeks after truth and is responsible for our philosophical inclinations; a spirited part of the soul, which desires honor and is responsible for our feelings of anger and indignation; and an appetitive part of the soul, which lusts after all sorts of things, but money most of all (since money must be used to fulfill any other base desire). The just individual can be defined in analogy with the just society; the three parts of his soul achieve the requisite relationships of power and influence in regard to one another. In a just individual, the rational part of the soul rules, the spirited part of the soul supports this rule, and the appetitive part of the soul submits and follows wherever reason leads. Put more plainly: in a just individual, the entire soul aims at fulfilling the desires of the rational part, much as in the just society the entire community aims at fulfilling whatever the rulers will.

The parallels between the just society and the just individual run deep. Each of the three classes of society, in fact, is dominated by one of the three parts of the soul. Producers are dominated by their appetites--their urges for money, luxury, and pleasure. Warriors are dominated by their spirits, which make them courageous. Rulers are dominated by their rational faculties and strive for wisdom. Books V through VII focus on the rulers as the philosopher kings.

In a series of three analogies--the allegories of the sun, the line, and the cave--Plato explains who these individuals are while hammering out his theory of the Forms. Plato explains that the world is divided into two realms, the visible (which we grasp with our senses) and the intelligible (which we only grasp with our mind). The visible world is the universe we see around us. The intelligible world is comprised of the Forms--abstract, changeless absolutes such as Goodness, Beauty, Redness, and Sweetness that exist in permanent relation to the visible realm and make it possible. (An apple is red and sweet, the theory goes, because it participates in the Forms of Redness and Sweetness.) Only the Forms are objects of knowledge, because only they possess the eternal unchanging truth that the mind--not the senses--must apprehend.

Only those whose minds are trained to grasp the Forms--the philosophers--can know anything at all. In particular, what the philosophers must know in order to become able rulers is the Form of the Good--the source of all other Forms, and of knowledge, truth, and beauty. Plato cannot describe this Form directly, but he claims that it is to the intelligible realm what the sun is to the visible realm. Using the allegory of the cave, Plato paints an evocative portrait of the philosopher's soul moving through various stages of cognition (represented