Philosophy Things

Plato, Republic: Human Soul

In Plato’s Republic, Socrates presents a “Principle of Opposites” in an attempt to distinguish between two parts of a human soul; 1) the part of reason (rational), and 2) the part of appetite (non-rational). Socrates uses this division to illustrate how it is possible for a soul to engage in opposing actions simultaneously towards the same object, for example, a person stranded at sea who desires both to drink seawater and not drink seawater. Later, Socrates presents a third division of the soul, calling it the part of “spirit,” and argues that “provided it hasn’t been corrupted by a bad upbringing” (441a), it will align itself with what the rational part of the soul desires. Ultimately, using this division, Socrates claims that any person whose soul’s parts are functioning well (well-ordered), and not interfering with one another, is a just person, similar to how a well-functioning body is a healthy one.

The Principle of Opposites, “the same thing will not be willing to do or undergo opposites in the same part of itself, in relation to the same thing, at the same time” (436b), proposes that it is not possible for a single entity to have opposing desires, or rather, opposing motivations to possess some object. However, Plato realizes that people often do in fact have conflicting desires about a single object at the same time. In order to resolve this issue and remain in accordance with the Principle of Opposites, Plato partitions the human soul into two parts, claiming that one distinct part of the soul (the part of reason) can possess the opposing desire of another distinct part of the soul (the part of appetite). By identifying a dominant object of desire, such as seawater, Plato exhibits how conflicting desires of whether or not to drink seawater is between one’s “reason” and one’s “appetitive” parts of the soul.

The “appetitive” or “non-rational” part of the soul is responsible for seeing that a person’s basic needs are met, such as food, drink, sex, etc. Due to its non-rational nature, the appetitive part of the soul, using the example of a person stranded at sea, would desire to drink the seawater without considering the negative effects of doing so, such as dehydration, increased thirst, etc. Its sole purpose is to ensure that all bodily desires are met, and it does not take into account whether or not those desires are good for the soul overall. It is this lack of virtue that allows for the appetitive partition of the soul to grow potentially without limit, taking over the other parts of the soul.

The “reason” or “rational” part of the soul is the smallest part of the soul and is responsible for making reasoned judgments about what is best for the soul overall. Plato argues that this part is what distinguishes between good and bad desires, and is able to always choose the good as a consequence of always desiring what is best for the soul overall. In the example of the person stranded at sea, the reason part of the soul would take into consideration the adverse effects of drinking seawater, reason that drinking seawater causes dehydration and an increased thirst, see that those things are bad for the soul overall, and consequently desire not to partake in drinking it.

The “spirit” or “honor” part of the soul is different from the reason and appetite parts in that its sole responsibility is to crush appetite and align itself with reason. Plato argues that this part is the source of honor, anger, shame, and pride, but that its main purpose is to enforce the desires of reason. To illustrate that the spirit part of the soul is not aligned with the appetitive part of the soul, Plato uses the story of Leontius’ sexual desire for pale young boys. He tells how Leontius was walking by some pale young corpses and “had an appetite to look at them, but at the same time he was disgusted and turned away” (440a). After struggling with his desires to both look and not look, Leontius gave into his sexual appetitive desires and “pushed his eyes wide open and rushed towards the corpses, saying, ‘Look for yourselves, you evil wretches, take your fill of the beautiful sight!’” (440a). Plato then illustrates how the spirited part of the soul is more aligned with reason (rather than appetite), and says that when an injustice has been done, spirit will get angry, fight for what is just, and act “not ceasing from noble actions until either wins, dies, or calms down, [or] called to heel by the reason within him, like a dog by a shepherd” (440d). Reason, then, is the part of the soul that rules over not just the appetitive part, but the spirited part of the soul as well. The role of the spirited part is to execute the desires of reason, which are the desires that are best for the soul overall.

In structuring the three parts of a soul the way he has, Plato is able to conclude that a well-functioning soul is a just one; similar to how a well-functioning body is healthy. He draws this analogy based on the belief that every part has a function, and every function has a potential excellence. An excellent function for a soul, he argues, is when it “does not allow any part of himself to do the work of another part or allow the various classes within him to meddle with each other” (443d). In other words, there is a hierarchical structure to how a “just” soul is to be ordered: the appetitive part handles all of one’s bodily desires, the reason part rules over the entire soul, making rational judgments about what is best for the soul overall, and the spirited part enforces what reason desires. A just soul, therefore, is when the well-ordered, harmonious nature of the soul is achieved.