The Republic is all about justice versus injustice, and Plato argues here that self-mastery is similar to the just mastering of a city. He suggests that arranging the three parts of the soul (the calculating, spirit, and desire) as a musician would “three notes in a harmonic scale” (443d) will create a harmonious soul, and thus a harmonious life in which a man will be able to achieve justice and, in my opinion, dear Glaucon, personal power. This draws a parallel to what Plato believes to be the way to a just city: the three parts that make up a city (the deliberate, money-making, and auxiliaries) also existing in harmony with one another.

What Plato’s argument in this section comes down to is that harmony in the soul (thus, the ability to have self-mastery or personal power) comes to be when each of the three parts of the soul “minds its own business” (441d). I disagree: while the calculating part makes well-reasoned choices and the spirited part is responsible for the health and (as Sarah mentioned) emotions of the body, the desire is kept subdued by the two, and thus the soul is able to rule the body justly. If calculation and spirit did not work together to rule desire, would not desire, like a powerful thirst, overcome that part in the soul “forbidding them to [drink]” (439b)? In the three factions of a city, to which Plato repeatedly compares the three parts of the soul, the parts must also work together to create justice. For what good is the auxiliary (by which Plato means the guardians) without the deliberative, just ruler to command it? While Plato makes a reasonable point in that, in some cases, each faction of the soul must mind its own business, it is imperative that the three components of the soul work together to create a harmonious and just being.

-Emma T.