They come to the home of old Cephalus who is concerned about death and the darkness of the Underworld, and this prompts him to think about how he had lived his life (I, 328B–331d). First he thought a meaningful life was one of bodily pleasure; then he thought it was money (he made a bundle with a shield-manufacturing company); but now he thinks it might be what the “old foggies” had said all along: it was a life of justice. The dialogue consists in probing what justice really is, beginning with common opinions that Socrates proceeds to take apart. The opening argument moves up in complexity as Socrates refutes one character after another, but the characters seem to move down in motivational structure. Cephalus presents a commercial understanding of justice: paying what is owed. His son Polemarchus presents a civic view where justice is helping the citizens and allies and harming enemies. Thrasymachus presents a “realist” view: he claims it is the benefit of the stronger who make the laws in their own self-interest; but for the average person it is obeying those laws.
In the main argument that follows in the first book, Socrates claims a parallel between the city and the soul (that is, the conscious life of human beings): it is the city that shapes the soul and the soul that reinforces the city (II, 368d). He constructs three levels of a city, moving up from a level of biological necessity (providing food, clothing, and shelter by a division of labor) to a city of luxury that becomes “bloated and feverish,” and on further up to a “purged” city that orders the chaos of the luxurious city.7
Setting up his argument about the nature of justice as right order of the soul, Glaucon introduces the legend of the Ring of Gyges (I, 359d). Gyges was a shepherd who fell in a hole that led to an underground cave in which a corpse was laid out with a ring on its finger. Gyges took the ring and discovered that when, at the fireside with his fellows, he turned the ring around, he disappeared. He then used the ring to seduce the queen and to kill the king.
Through this story, Glaucon is asking us to perform a mental experiment. Suppose you had such a ring, what would you do? Most people would probably say they would continue to do what they usually do. But if it was discovered that the ring made one disappear from the gods as well, then what would they do? Fyodor Dostoevsky in Brothers Karamazov has one of his characters, Ivan, say, If there is no God, all is permitted.8 God’s watching is what keeps naturally disorderly people in place, for he is ready to punish and reward. Plato has Socrates argue from the premise of disappearance from men and gods, and argue that there is an intrinsic order and disorder to the soul, with consequences of satisfaction and dissatisfaction for how we think and act, whether seen or not, whether rewarded or punished externally or not. In effect, the right order of the soul lies in its being oriented by love of the Good as the principle of the Whole. This directly parallels being moved by the love of God rather than by the stick and carrot of punishments and rewards in an afterlife.
3.
The classes in the purged city parallel the levels of the soul: the biologically desirous level (pleasure- and money-loving artisans), the competitive level (victory- and honor-loving military), and the rational level (learning- and wisdom-loving guardians) (IV, 427d–445e). The development of the higher levels of the soul entails restriction of the lower. The three levels are the basis for the introduction of what the Catholic Catechism calls “the four cardinal virtues.” (They are called “cardinal”—from the Latin cardo, meaning “hinge”—because human flourishing hinges upon them.) Prudence (practical wisdom) belongs to the rational level, fortitude to the competitive level, and temperance to the submission of the lower levels to the higher. Justice consists in each level “doing its own thing,” with the lower not attempting to take over the role of the higher and the higher fulfilling its proper functions. The major question that remains is whether the work of the rational level consists solely in “looking down” to ordering the appetites or whether its major task is rather “to look up” to contemplate the order of the cosmos (VII, 529a).
The argument continues up to the level of the famous “philosopher-king” (V, 473d) and on to the study of that which he seeks, “the Good” as “principle of the Whole” (VI, 505a–509c).9 The Good is presented at first metaphorically as “the sun of the intelligible world,” the Top of the cosmos, the ultimate Up. Just as seeing can view the seen only in the light provided ordinarily by the sun, so also intellect can grasp the intelligible only “in the light” of the Good. In the famous Cave Allegory human beings in general are presented as chained from birth down in a dark cave looking at shadows (VII, 514a–517a). Someone frees them from the chains and forces them to “turn their heads around” (reflect) to see what produces the shadows. Someone then drags them up outside where they are at first dazzled by the light of the sun. Then they are put back down in the cave.
The allegory needs “cashing in”: what does it really mean? That is the task of the Line of Knowledge which begins to “remove the chains” that tie us to thinking only in terms of sensory images (VI, 509e–511e). The ascent from the sensory to the intelligible is presented through the Line, the real center of the work, and indeed, the spindle around which philosophy has developed ever since. We have developed aspects of the Line in our Phenomenology of the Mailbox. So it is crucially important to understand what is going on there.
3.
In attempting to explain his notion of philosopher-king, Socrates draws a line between the lovers of beautiful things, the highpoint of education in the purged city, and the lovers of the vision of Beauty itself. Socrates further says that what makes a philosopher a philosopher is the study of the Good, for which he gives the image of the sun. So he has drawn a line, so to speak, twice: one distinguishing the lovers of beautiful things from the lovers of the vision of Beauty itself, the other distinguishing the realm of the visible from that of the intelligible, though we are not told what that means. That is the job of the Line of Knowledge.
Socrates’s treatment begins with a line drawn according to any proportion and subdivided by the same proportion. We are invited to move from looking in the light of its visual presence to “turning our heads around,” that is, reflecting. If we do so, we may come to see “intellectually” that, no matter what proportion we take, the central segments will always be equal. What we discover is a geometric theorem. Socrates then asks us to reflect metaphorically, something we have been accustomed to doing from the very beginning by thinking in terms of the metaphorical pairs up/down, light/dark. Such reflection is one of the basic features of poetry, which is thus a kind of intellectual activity, but one tied to imagery. The philosophic task is to get beyond images to the intelligible.
The Line is taken to stand for the different relations between states of mind and manifest objects, arranged from lowest to highest. On the side of the objects we have images, then things that produce the images (both manifest through sensation), then mathematical objects (the theorem we grasped when reflecting upon the visible line), and then the level of what Socrates calls “Forms” (the Greek term is eidos, from which we got the expression “eidetic features” in “Phenomenology of the Mailbox”). The level of Forms is the level of philosophic reflection. We are invited to think about the eidetic differences between a visible object (the drawn line) and an intelligible object (the theorem), between the objects of sight and the objects of insight or intellection. Socrates places the level of the sensory (of which the visible is an instance) under the general heading of “Becoming” (Greek genesis), noting that everything sensible and indeed our own life is subject to change: it exists in time. The upper levels (mathematics and philosophy) are placed under the general heading of “Being” or “Beingness” (Greek ousia). The drawn line that I see with my eyes was generated and will be destroyed. It appeared in a stretch of space within a span of time. But the theorem, and the Forms involved in theorems and things that are their instances, are not limited to a given span of time or stretch of space and thus confined to an individual instance: they apply whenever and wherever their instances are found. They exist as