The dialogues of Plato allegedly do no more than report the teaching of Socrates, but much of what is found in these works is surely Plato’s own invention. Their composition spans a period of years such that one must distinguish between the early, the middle, and the late works, with sometimes dramatic departures found across these periods. In the broadest terms, the dialogues address four core problems: the problem of the knowable (ontology and metaphysics); the problem of knowledge (epistemology and psychology); the problem of conduct (ethics); and the problem of governance (political and social science).
How can one ever be sure that one knows anything? Is complete skepticism the most philosophically defensible position?
In Meno the young challenger taunts Socrates, who claims to be searching for the truth. Such an inquiry is impossible since if one does not know what the truth is, there is no starting point and if one does know, there is no need for the search in the first place. Socrates’ reply takes advantage of the fact that Meno’s servant is a young, uneducated “barbarian.” He questions the boy about geometric figures drawn in the sand. As the boy answers each yes or no, Socrates leads him to a version of the Pythagorean Theorem. The exercise illustrates the central precept of Socrates’ theory of knowledge: knowledge is a reminiscence. The knower possesses rather than learns the truth. Thus understood, knowledge of what is abidingly true cannot arise from sensory commerce with the world of changing things; it can arise only from an essentially intuitive and rational awareness that is possessed by the soul itself.
In Plato’s Republic the state (polis) is taken to be the enlargement of the individual. To learn what it is that makes the person good it becomes useful to ask what constitutes the good state. By constructing the perfect state, the philosopher must comprehend the attributes that define the perfected human being. In Book 3 of The Republic citizens are categorized as being made of gold, silver, brass, or iron, the point being that they are framed so differently by the gods that of necessity some rule and others serve. This illustrates the strong hereditarian element in Platonic psychology but tends to mask the comparably great emphasis placed on early education and lifelong discipline; education is to be very carefully orchestrated. Those epic poems that present the gods as lacking virtue are among those to be forbidden, as are works of fiction and “panharmonic” music.
Plato’s psychology is nativistic but leaves ample room for developmental influences. He explicitly endorses a multistage theory of cognitive development. In Laws, for example, the Athenian stranger asserts that virtue and vice are known to the young only as pleasure and pain and that, since children instinctively love what is pleasurable and hate what is painful, the principal task of the educator is to make sure that true virtue becomes the object of love. Moreover, there are critical periods of development when the lessons of virtue are most effectively conveyed by music, since virtue fundamentally is a harmonious relationship between body and mind. This aim is furthered by close contact between parent and infant. by the rhythmic rocking of the young. The same theme is sounded in The Republic, in which the young are depicted as being out of harmony: Reason and passion have yet to establish the unique accord that constitutes virtue. Music and dance and other gymnastics must be employed because the very young mind is not yet able to assimilate rational principles directly. Thus, early education uses metaphor, not literal lesson. Nonetheless, the success of such education finally depends on the “quality of the wax.” and only under rare circumstances will the children of a lower class qualify for the life of a Guardian, that is, one chosen to be trained to protect the city-state and devote himself to its security. If harmony is the goal, the sources of dissonance must be removed. As some of these are genetic accidents of nature, they must be “exposed” (Le.. to the elements). In any case, eugenic breeding can reduce such mistakes to a minimum.
Plato’s theory of pleasure, it should be noted, is not to be confused with asceticism. Rather, it distinguishes three different types of pleasurable and painful experience. Some feelings are entirely bodily: the itch that can be soothed by scratching. Both body and soul participate in other feelings, such as a painful hunger relieved by anticipation of food. Some feelings, such as longing and love, only arise within the soul. Where body and soul are jointly engaged, the emotions are rich in cognitive content, but there can be feelings of the body without such content.
In The Republic Socrates likens the soul to the state. As the state contains three classes (merchants, auxiliaries, and counselors), the soul is occupied by three principles: the rational, the appetitive, and the passionate. The virtuous person is one who has harmonized these three principles such that reason controls appetite, and passion, as an auxiliary to reason, strengthens resolve. The view of reason and appetite as opposing forces is as old as the Homeric epics and as current as psychoanalytic theory. Where the balance is incomplete, where the three composites are in discord, the soul is sick and dying. While men and states are born with the capacity for such harmony, the capacity is actualized only under the leadership and guidance of the philosophically enlightened. Without this guidance the pleasures and pains of the flesh, which are the only sources of control for the child, continue to dominate the life of the adult. Addiction to the world of appearances only furthers the body’s hold on the soul; the body being the soul’s prison (desmoterion). On this account, both madness and ignorance are diseases calling for a form of therapy. The mad and the unjust both have ruling appetites to which reason becomes subservient.