See 434d-439e. They have determined to their satisfaction what it is for a city to be just. Now they want to know if this definition can be applied to the soul. Since their definition of justice requires that the city have parts, it cannot be applied to the soul unless the soul also has parts. So Socrates is going to try to prove that the soul has parts, that they are three in number, and that their work in the soul corresponds to the work of the three parts of the city – “the rational part” of the soul corresponding to the rulers of the city, “the appetitive part” of the soul corresponding to the city’s laborers and craftsmen, and “the spirited part” of the soul corresponding to the auxiliaries. The key idea in his argument is stated at
436b-c: “the same thing cannot do or undergo opposite things . . . in the same respect, in relation to the same thing, at the same time.” He has in mind something like this: You are overweight and your doctor has put you on a low-calorie diet for health reasons. One night, the waitress rolls out the dessert tray, and you are face to face with Chocolate Sin Cake. You must have this cake. But clearly, this would be to break your diet and take a step closer to bad health, and you care about improving your health. You find yourself pulled in opposite directions (to eat and not to eat) with respect to the same thing (the cake) at the same time. Therefore, Socrates would say, your soul must have at least two distinct sources of motivation, an “appetitive” part to desire the cake and a “rational” part to desire health. The example Socrates gives in the present passage is of people who are thirsty, but – for some reason left unspecified – don’t want to drink. The concern in opposition to thirst could be any number of things: health again (the water might be dirty), or courtesy (your friend hasn’t finished giving the toast), or piety (the period of fasting has not ended), or group survival (you and the others in the lifeboat are down to your last pint of water). Socrates offers this example as proof that the soul has a rational as well as an appetitive part. How does he understand the difference between these two parts of the soul? He tells us that the appetitive part desires “the pleasures of food, sex, and those closely akin to them,” and that, of the appetites, the clearest examples are hunger and thirst. It appears then, at first glance, that the appetitive part is concerned with pains and
pleasures of the body, with sensual things. But this interpretation is too simple, for Socrates is going to give examples in Book VIII of people who are led by their appetitive part to dabble at times in politics and at other times in philosophy (or what they suppose is philosophy), and the pleasures involved in these activities are not, except accidentally, sensual. What characterizes the appetitive part is not so much its sensuality as the immediacy and narrowness of its concerns. Socrates is careful to point out that thirst, as a paradigm example of the appetitive part at work, is simply the desire for drink, not “for hot drink or cold, or much drink or little, or – in a word – for drink of a certain sort.” There are times of course, especially in the heat of summer, when one desires a cold drink. But in cases like this there are really two different desires at work: one for drink, and one for cooling down. What it is to be thirsty, as opposed to being both thirsty and overheated, is to crave one thing: drink (liquid water). Socrates’ thought appears to be that this sort of craving for some one thing – something that “hits the spot,” as we say, providing immediate gratification – is the essential characteristic of appetitive desire. These desires aren’t looking down the road towards what hitting the spot might lead to in the long run: obesity, poverty, drug addiction, social unrest (in the case of people who dabble in politics), or what have you. Appetitive desires are simply concerned with seeing that the spot gets hit. The desires of the rational part are different. They aspire to order things according to what is good, all things considered. Notice that Socrates is not saying the rational part is good and the appetitive part is evil, as if they functioned in the soul like an angel pulling in one direction and a devil pulling in the other. That this would be a silly view for him to hold is obvious if one just considers what it would be like, while remaining a flesh and blood human being, never to get thirsty or to feel the need to take your next breath (both appetitive desires). Besides, although it is true that the appetitive part gets people into trouble from time to time, the same can be said of the rational part. It is the rational part that mistakenly concocts poisonous medicines, for instance. Nevertheless, as Socrates will explain later, there is a special relationship between the rational part of the soul and goodness. The rational part ultimately desires to order things, not just according to what appears good, but according to what is good. It desires, in other words, the knowledge characteristic of wisdom.
● May it not be the case that our soul has just one part, and that, in the kind of situation Socrates has in mind, our one-part soul is just toggling quickly back and forth between alternative objects of desire (e.g., cake-health-cake-health-cake)? Suppose someone were to ask Socrates how he knows that we experience opposing desires at precisely the same time. How might he reply? (This oscillation theory of psychic conflict appears to have been advanced by the Stoics, a leading school of philosophy after the time of Plato. See Plutarch, “On Moral Virtue.”)
● Do appetitive desires ever oppose one another with respect to the same thing at the same time? If they were to do this, what would it mean?
● Why might Socrates think that thirst or hunger is a clearer example of appetitive desire than sexual desire?