...In the Republic, Socrates — Plato’s spokesperson in the dialogue — attempts to develop a parallel between justice in the city and justice in the individual. In this paper I will argue that Plato has not shown that the parts of a city that must be in harmony for civic justice are the same as the parts of a person’s soul that must be in harmony for individual justice. This will not prove that harmony in the soul is irrelevant to individual justice. There may, after all, be harmony among the soul’s parts even if those parts are nothing like those of a city. If I am right, however, there is an important gap in Plato's view of justice in that the details of justice in the individual remain obscure.
...Plato’s goal in Book IV is to provide arguments for a close analogy between justice in the city and justice in the individual. He is convinced that his account of justice will be more easily seen in the case of the city and that the very same account will illuminate individual justice (369a). Concentrating on justice in the city also allows Socrates to explore the parts of the city in terms of intelligible roles played by individuals. In a just city people suited to produce goods will be the producers, those suited to protect the city will be its protectors or guardians, and those suited to rule will be the rules. Justice is the harmony that results from everyone doing her part in the overall structure of the city.
...Plato claims that justice in an individual relies on a harmony between corresponding parts of an individual soul. Therefore, Plato must show that the parts of the soul are the same as the parts of the city. Socrates presents the following argument:
Well, then, we are surely compelled to agree that each of us has within himself the same parts and characteristics as the city? Where else would they come from? It would be ridiculous for anyone to think that spiritedness didn't come to be in cities from such individuals as the Thracians, Scythians, and others who live to the north of us who are held to possess spirit, or that the same isn't true of the love of learning, which is mostly associated with our part of the world, or the love of money, which one might say is conspicuously displayed by the Phoenicians and Egyptians (435e).
...The position in this passage seems to be that there is no alternative explanation for the origin of the natural characteristics of a city other than that those characteristics are present in some individuals in the city. That is why he says, "Where else would [the characteristics] come from?" So, finding natural characteristics in a city is, for Plato, evidence for those same characteristics in the individuals that make up that city. Later Socrates says, “We are pretty much agreed that the same number and the same kinds of classes as are in the city are also in the soul of each individual” (441c). This suggests that the issue is important to Plato. Given the nature of the argument, if it is possible to give an alternative explanation for the origin of the characteristics of the city, then Plato will be unable to draw the precise parallel that he is after.
...With this argument as background, Plato turns to investigating the parts of the individual soul that correspond to the parts of a city. He concludes that there is an appetitive part, a rational part, and a spirited part. Even though Plato tries to motivate each of these parts of the soul on independent grounds, he ultimately seems to be relying on the discussion of the city to guide his inquiry into the kinds of parts he expects to find in the soul. For example, he argues that there must be something that sometimes prevents thirsty people from drinking. He labels this the rational part of the soul (439d). The sort of case Plato seems to have in mind is where a person on a lifeboat has an overwhelming thirst, but knows that the water in the ocean is too salty to safely consume. It is the rational part of the soul that maintains control over the appetite in this case. The reason he identifies the part as rational, however, is that he is attempting to link up his account of justice in the individual to the account he has already given of justice in the city. It appears that the only reason he has to identify the rational part as a single ruling part of the soul is because ruling is a part of a just city.
...Plato’s position would be convincing if he were correct in thinking that a city-level part could only have come from an individual that had a corresponding part in her soul. It is not the case, however, that every characteristic of a large system like a city can be found in each of the subparts of that system. Characteristics of a large system can sometimes emerge as a result of the interaction of the entities that make up the system. The latter may not be at all like the former with respect to their natural parts. For example, when we say that an ecological system is resilient against environmental change, we are not committed to the view that any of the particular organisms that make up the ecological system are resilient. In fact, the organisms in a resilient ecological system may be individually fragile. This mismatch between the natural characteristics of a large system and its components may be the case with respect to the relationship between a city and the individuals that make up a city. Suppose we follow Plato in accepting that a well-functioning city naturally needs a specific ruler or group of rulers. Even if this is correct, a ruling part does not need to be present in any individual soul because rulership may be a characteristic that results from the interaction of individuals who individually lack a ruling part.
...To take a more specific case from the Republic, spiritedness in a city doesn't necessarily need to arise in spiritedness in the Thracians and Scythians as Socrates claims (435e). Sometimes groups of people are spirited in Plato’s sense because they are in a group. None of the individuals needs to be spirited or have a spirited part of her soul. Rather, the combination of individual non-spirited souls can yield spiritedness at the level of the group. Finally, to return to the example of the person on the lifeboat, it may not be a single ruling part of her soul that keeps her from drinking. It may be a different set of appetites acting in concert, or a set of behavioral impulses that cannot be mapped onto the parts of the city. These possibilities show that there is no guarantee that city-level parts and person-level parts will be identical. Plato seems to be relying on such a guarantee.
...It may seem puzzling that a new and distinct characteristic can appear in a larger system when it is not present in any of the parts. My view is that, when several different characteristics interact in particular ways, they generate new characteristics through their interaction. The individually fragile organisms of an ecosystem can interact in such a way that allows the whole system to be resilient. Resilience is the sort of characteristic of a system that can result from many fragile parts coordinating. The parts of a city that Plato identifies can be thought of us arising in the same way.
...Is Plato’s ability to draw a precise parallel between parts of a city and parts of a soul crucial to his theory of justice? It might be thought that harmony is the central component of Plato’s account, and he might argue that the failure of a precise parallel between the city and the individual in terms of parts is irrelevant. I maintain that the precise parallel is important because the details of justice in the individual rely on the specific relationship between the parts of the soul. According to Plato, an individual would not be just if her appetitive part ruled over her rational and spirited part. Instead, justice in the individual will involve the rational part governing the appetitive part with the help of spirit (442a). This shows that the specific identity of the parts is important for understanding what individual justice is. The mere fact of harmony would leave mysterious what justice is in the individual. Therefore, Plato needs his precise parallel to be successful. Alternatively, Plato might seek some way of specifically identifying the parts of the soul without referencing the parts of a city. He could then give an account of their harmonious and just relationship that is based specifically on the nature of those parts.
...In his pursuit of a theory of justice for an individual, Plato relies on the natural parts of a city to illuminate the natural parts of a soul. I have tried to show in this paper that he has not given a convincing argument for that parallel.
References
Plato. Republic. Trans. G.M.A. Grube. Indianapolis: Hackett Publishing, 1992.