The Motivational Structure of the Soul in Plato’s Republic

Plato is well known for his views on metaphysical dualism, idealistic justice, the soul, and on proper social relations. His views on these subjects – particularly those contained within the Republic – have been enormously influential for millennia. In the Republic, Plato argues that the social world of Kallipolis should be structured into three stratum – the ruling class, the auxiliary class, and the producing class. When these three classes work together harmoniously, each fulfilling their proper roles, the city can be considered just. In Book IV of the Republic, Plato argues that justice is the same for individuals as it is for cities. Like cities, human souls are divided into three distinct parts that must work together to function harmoniously. In this paper, I’ll (1) explain how Plato demonstrates that the soul has three parts, (2) show how these parts relate to one another, and (3) show that each of these parts are independent agents of human motivation.

In Book IV of the Republic, Plato demonstrates that the human soul is divided into three parts. He begins with the assumption that one thing cannot simultaneously “stand still and move” (436c). If something is behaving divergently, there must be multiple parts comprising that thing. If one were to claim, for example, that a man both moved and stood still – moving his hands and head while standing in place – we would recognize that this was possible because there are different parts comprising a body (436d). This means that, if the human soul behaves in opposing ways, there must be multiple parts comprising the soul. Plato then demonstrates that hunger and thirst are desires of the soul (437e), but that there are some men who are thirsty who are not willing to drink (439c). In these men, there is something in the soul that is both bidding them and forbidding them to drink. These divergent attitudes must come from two different aspects of the soul (439d) – one which calculates and one which loves hungers, and thirsts.

Having demonstrated that there are at least two parts of the soul, Plato wonders whether there may be a third party that plays a supportive role to the rational part of the soul, but that differs from the appetitive part of the soul. Plato reasons that, “Anger sometimes makes war against the desires as one thing against something else” (440a). For example, when Leonitus saw corpses lying in the road after a public execution, he was both disgusted and intrigued – he both desired to look and was repulsed by the sight. When our desires motivate us to act in a way that our rational mind forbids, we experience a rousing of spirit in defense of reason. Plato reasons that this spirit must be the third part of the soul. To support his claim, Plato demonstrates that this third portion of the soul mirrors the middle stratum of society, serving in an auxiliary role in support of reason (441a). On this account, the calculating part of the soul mirrors the rational governing body of Plato’s Republic, the spirit part of the soul mirrors the auxiliary stratum of society, and the appetitive part of the soul mirrors the producing class at the bottom. At this point, Plato has demonstrated that there are three parts to the soul and now seeks to demonstrate how they relate to one another.

In the second part of his argument, Plato shows how each of the three parts of the soul relates to one another. To begin, Plato provides examples of the proper functioning of the rational and spirited parts of the soul. When the spirited part of the soul excels, it may produce courage, valor, or a sense of competitiveness. Similarly, when the rational part of the soul excels, it produces wisdom and the hunger for further knowledge (442c). Because this calculating part of the soul has access to reason and knowledge, it knows how best to govern the other two parts of the soul. In a properly functioning soul, the rational part of the soul rules the spirit, which in turn governs the appetite (441c). The appetite must be kept in check by the two dominant parts of the soul that know best what the body needs. A properly functioning appetite is moderated in accordance with the dictates of reason and spirit.

Plato demonstrates that justice is done when the three parts of the soul function in harmony. When each part of the soul functions in accordance with its own nature, with the two subordinate parts subjecting themselves to the rule of the calculating part, they produce a harmony based upon moderation (Lorenz, 2003). In Book IV, Plato describes a man who is just and virtuous:

He doesn't let each part in him mind other people's business or the three classes in the soul meddle with each other, but really sets his own house in good order and rules himself; he arranges himself, becomes his own friend, and harmonizes the three parts, exactly like three notes in a harmonic scale, lowest, highest and middle. (443d)

In individual men and women, justice is exactly this – the excellence of function, harmony, and moderation of the soul (444a). Injustice, on the other hand, occurs when one part of the soul meddles with the business of another part (444b). When the appetitive parts of the soul try to govern, it may produce gluttony or inappropriate lust. When the spirited part of the soul tries to govern, it may produce a harmful degree of competitiveness, jealousy, or anger. The interaction between each aspect of the tripartite soul produces virtues and vices relevant to each of the three categories.

In the Republic, each of the three aspects of the soul motivates action independently. In Book IV, Plato explains how the appetites affect how one is inclined to act. The most basic desires of the appetitive soul are food, drink, and sex, each of which may be modified by additions (Irwin, p. 209). One may desire some particular type of food, a certain drink, or a sexual partner. The love of money is a secondary appetite that adults come to desire quite strongly, as it is a means of acquiring each of the other appetites (Annas, p. 113). Clarifying his position on the appetites, Plato mentions the desire for physical exercise, the desire to be warmed up when cold, and the aversion to pain. Each of these appetites has roots in immediate bodily experience and physiological needs. Though some desires involve complex modifications to the basic bodily needs, these modifications evolve out of experiences of physical pleasure (e.g. consuming lobster, having a pleasurable experience, and generating the desire to eat lobster again in the future). On this account, the appetite is the basest motivator and must be governed by the other two parts of the soul.

The spirit motivates action through emotion. Spirit strives for power, victory, and good repute (Cooper, p. 200), and pursues the executive virtues of effectiveness, single-mindedness, and strength of character. It experiences the moral senses of shame, outrage, and offense at injustice and desires to assert itself in the public life of the community. It motivates individuals to distinguish themselves competitively, to take pride in their accomplishments, and to esteem others who are virtuous. Plato frequently presents anger as an example of spirit, portraying it as the expression of the competitive desire to preserve self-esteem (Cooper, p. 204). Like appetite – and unlike reason – spirit can be experienced by children and by animals. It is different from appetite because it involves a self-referencing that is essential to both esteem and self-esteem. It is different from reason (1) because it treats the “good” as secondary the desire for competition or esteem, and (2) because the spirits desires do not originate in rational reflection, but lived experience and interaction with others (Cooper, p. 205). On Plato’s account in the Republic, the spirit’s competitiveness and desire for esteem is a source of motivation that is independent of the appetite or rational faculties.

The rational part of the soul has a dual function, desiring both knowledge and governance. On this account, the reason is not mere knowledge or belief, but the impulse to “figure things out and know the truth (Cooper, p. 190). The desire to know the truth is irreducible to its instrumental function – people often want to know things that don’t benefit them in some practical way. The rational part of the soul lusts after knowledge in the same way that the appetitive part of the soul desires food, drink, or sex. It also comes equipped with a desire to govern the other two parts of the soul, to apply the knowledge it obtains, and to pursue the good life (Cooper, p. 194). The rational part of the soul prioritizes the “good” over other concerns and uses this standpoint to govern well. Neither the spirit nor the appetite prioritizes the good above other concerns – the spirit prioritizes competitiveness and esteem, while the appetite prioritizes the satisfaction of bodily pleasures. The rational part of the soul is an essential moderating force that is characteristic of humanity.

In this paper, I’ve outlined Plato’s argument that human souls are divided into three distinct parts that must work together to function harmoniously. I explained Plato’s argument that the soul has three parts – because unified bodies cannot produce opposite actions, and because the soul has disparate desires, these desires must originate from a multi-faceted, tripartite soul. I showed how each of these three parts relates to one another in Plato’s Republic, providing examples of their proper function. I also sought to show that each of these parts are independent agents of human motivation – that reason, spirit, and appetite are unique forces that catalyze human behavior and interact to produce both virtues and vices. Plato’s account of the tripartite soul claims that justice is the same for individuals as it is for cities – like cities, the elements of the soul must work together harmoniously, each playing its proper role in order to excel. Though contemporary philosophers may find Plato’s theory primitive or out of date, his theory of the tripartite soul has been enormously influential for thousands of years. Understanding Plato’s motivational theory of the soul remains relevant in the 21st century.

References

Annas, J. (1981). An introduction to Plato’s Republic. Oxford: Clarendon Press.

Plato. (1968). The Republic. Trans. A. D. Bloom. New York: Basic Books.

Cooper, J. (1984). Plato’s theory of human motivation. History of Philosophy Quarterly, 1, 3-21.

Irwin, T. (1995). Plato’s ethics. New York: Oxford University Press.

Lorenz, H. (2003). Ancient theories of soul. Stanford University. Retrieved March 24, 2014, from http://plato.stanford.edu/entries/ancient-soul/