On Plato's Tripartite Soul

In Plato’s Republic, Book 4, from 435c6 to 444e7, Socrates and Glaucon discuss the nature of the soul. Prior to this discussion, they sought to explain what justice is in the soul and used an analogy of a perfect city to represent the soul.

            The perfect city is composed of three classes: guardians, auxiliaries, and producers. Within the classes are four virtues: wisdom, courage, self-discipline, and justice; wisdom lies in the guardians, courage within the auxiliaries, self-discipline in the harmony between the classes, and justice is each class doing its own job (Rep. 427e10-434d1). Now, Socrates translates the city’s workings to that of the soul to define justice. The soul must be analogous to the city because certain cities have certain tendencies that are found in their citizens; the Thracians are spirited, the Athenians love wisdom, and the Phoenicians are good with money (Rep. 435e1-436a3). And if the perfect city has people who are spirited, wise, and good with money; so too does the soul. It is asked whether the soul is whole or is composed of multiple parts; for if it is whole, then it must be responsible for all tendencies. But if there are many parts, each part is responsible for its own tendency.

To determine if the soul has parts, Socrates enlists the aid of the principle of opposites: nothing can do opposite things in opposite places at the same time and in the same part (Rep. 436b8-c2). Firstly, Socrates counters two criticisms: a man nodding his head adheres to the principle because the head can be delineated from the torso; a spinning top adheres to the principle in that there are two respects (the axis is stationary, the circumference rotates) (Rep. 436c6-e8). Next, Socrates describes the existence of opposite motions in the soul. For example, a man is thirsty but cannot drink as the drink may kill him (e.g., a man stranded on an island surrounded by saltwater) (Rep. 439c1-6). This demonstrates the soul has parts due to the principle of opposites; a part that moves forwards, desires, and a part that retreats, aversions (Rep. 437b1-c9). To determine which part does which, Socrates uses examples that demonstrate conflicts in motivation. The first example is the thirsty man, his thirst is a bodily desire that is held back by the aversion to death (Rep. 439c1-6). This bodily desire is considered an appetite, and the aversion is considered reason (Rep. 439d5-10). The second example is a necrophile who enjoys viewing the dead, he desires to sate his lusts but is countered by his shame and anger to refrain (Rep. 439e8-440a4). His appetite moves forwards, but his shame and anger, called spirit, retreats (Rep. 440a6-c5). The last example lies in young children, who demonstrate feelings of anger but without reason, and Odysseus, whose rage compels him to fight the suitors but is held back by reason to not die (Rep. 441a8-c2). The spirit within them is opposed by reason (Rep. 440e1-441a7). It is evident that there are three parts to the soul: a rational part responsible for reason, a spirited part responsible for honor, and an appetitive part responsible for bodily desires (Rep. 442c4-d7).

This tripartition of the soul in the Republic, although differs from, is compatible with Plato’s soul in the Phaedo. In the Phaedo, the soul was purely rational, responsible only for thinking, and the body was the source of all desires (Phaedo 65c2-8). In the Republic, the soul is responsible for both thought and desire, along with intense emotion (Rep. 442c4-d7). Yet, in the two dialogues, the rational part of the soul governs the base desires and emotions, and a separation of the rational from the bodily (death in the Phaedo (Phaedo 65d1-3) and attaining the knowledge of Forms in the Republic (Rep. 519c8-d4)) should be welcomed and sought after.