On the "Soul" Book IV of Plato’s Republic
Claims made in book IV of Plato’s Republic that are obviously important to the discussion carried out in the text up to that point are the claims Socrates makes about justice that parallel the claims he made about the structure of the class system in the ideal city. At 433a Socrates reminds his interlocutors that justice (dikaiosune: righteousness) in the ideal city has exactly the same structure as the classes around which the ideal city is organized.
Justice, I think, is exactly what we said must be established throughout the city when we were founding it—either that or some form of it. We stated, and often repeated, if you remember, that everyone must practice one of the occupations in the city for which he is naturally best suited. . . . Moreover, we’ve heard many people say and have often said ourselves that justice is doing one’s own work and not meddling with what isn’t one’s own. . . . Then, it turns out that this doing one’s own work—provided that it comes to be in a certain way—is justice (433a-b). . . . Therefore, from this point of view also, the having and doing of one’s own would be accepted as justice (433e-434a).
Arguably it is grounding this assertion in "nature" that makes it important to the discussion at hand. Recall that Plato seems intent on having Socrates respond to the relativism of the Sophists, specifically Protagoras who asserts that ‘mortals are the measure of all things,’ and Gorgias who said that even if there were some sort of absolute or divine standard, mortals could not discover it by virtue of the fact that they are, after all, only mortals (In some sense one can see in this set of concerns that to which Augustine will respond with his insistence on the necessity of divine revelation. In Augustine’s view mortals are forever lost unless God takes the initiative to bridge the gap between humanity and divinity. In Augustine’s thinking mortals are incapable of "realizing" or "actualizing" the will of God on their own, they require the gifts of "Grace" and "Faith." It is easy to see that these elements are not part of Sophistic thought. A question we may consider involves wondering to what extent notions like "Grace" and "Faith" are at work in the Socratic thought of the Republic.). We can think about the appeal to Nature that Socrates makes in much the same way that we thought about the appeals to Nature made by the early Pre-Socratic figures. There will be, however, a few important differences to observe between the early Pre-Socratics and Socrates, namely, the appeal to Nature as an "arche" is provisional in that it is a ground that is itself grounded.
It is because the citizens have a particular Nature that they have a particular task, or a particular role to play in the city. It is based upon this philosophy of Nature that the definition of justice is grounded. Socrates needs something to which he can appeal as a ground that has two qualities, the quality of fixity, and the quality of change. Keep in mind that it is because of the problems posed by change (see Parmenides) that the Sophists turned to the notion of "convention." So, Socrates turns to Nature because while it can be characterized by change it also allows for a notion of fixity. Additionally the notion of Nature is understood to be immediately related to being in the world since the Greeks understood that they were naturally beings. Thus Socrates has responded to the claims of those Sophists who assert that even if there is a universal standard it is one to which mortals have no access. Mortals, by virtue of being natural, must, therefore, have access to nature as a ground, and this ground operates as a fixed standard informing citizens on their place in the ideal city.
At 436b Socrates will push this philosophy of nature a bit harder: "It is obvious that 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." Here Plato has Socrates set up the discussion about the soul. The soul will ground the nature of the city by grounding the nature of the citizens. It is for that reason that we see a parallel in the tripartite structure of the ideal city and the tripartite structure of the ideal soul. The ideal city has three classes and the subjects within each class have a particular nature disposing them to be well suited for their particular class and the tasks of their class. In the same fashion the soul is divided into three principle parts with each part having a particular nature. When Socrates makes the assertion we find at 436b he is laying the groundwork for looking at the whole soul as being composed of multiple parts. If a soul can desire one thing (like alcoholics who may desire drinking alcohol), but will another (like alcoholics who resist taking a drink of alcohol when that is what they desire) it seems to follow logically that these two moments suggest that one soul is composed of at least two parts because, according to the reasoning Socrates employs here, one thing cannot have opposing interests in itself in relation to the same thing. The soul may be one thing, but it is one thing composed of multiple parts, one part that may desire what another part may resist. Socrates offers two discussions supporting this thesis, one concerned with objects that can be said to be in motion and motionless at the same time, and one concerned with the desire to drink (thirst) and the resistance to taking the drink one desires.
At 439d Socrates distinguishes between these two moments identifying one as that part of the soul known as the "rational" ("that which forbids in such cases come into play. . . as a result of rational calculation. . ."), and the other that desires as the "irrational appetitive part" ("the part with which it lusts, hungers, thirsts, and gets excited by other appetites. . ."). Thus he establishes the first two extreme parts of the soul that are "fighting in a civil war" [439b] (and since the structure of the soul does parallel the structure of the classes composing the ideal city we should wonder about what this relationship between the two extreme parts of the soul say about the two most extreme classes of the ideal city. If the rational part of the soul parallels the ruling class, and the irrational part of the soul parallels the working class, are we to suppose that these two classes, by "nature," exist in a state of "civil war"? ).
The third part of the soul is identified as the "spirited part" which is "far from being [appetitive], for in the civil war in the soul it aligns itself far more with the rational part" [440e].
The argument is thus, the ideal city is structured in exactly the same way in which the ideal soul is structured, that is, each part of the ideal city, like each part of the ideal soul has a proper work established by nature. The citizens of each class have a proper work for which they are best suited according to nature in exactly the same way that each of the three parts of the soul have a role for which they are properly suited by nature in the ideal soul: "And we surely haven’t forgotten that the city was just because each of the three classes in it was doing its own work. . . . Then we must also remember that each one of us in whom each part is doing its own work will himself be just and do his own" [441d].
It is critical to keep in mind what Plato wants Socrates to accomplish in this text. Socrates is moving his interlocutors away from an "opinion" (doxa) that cannot be well-grounded to convictions that are, or at least appear to be better grounded. That is, Socrates wishes to move his interlocutors away from conventional, arbitrary, and relative opinions, to what he understands as the "truth." We should, then, read the philosophy of nature espoused by Socrates as essential to understanding the discussion of Plato’s Republic. At the heart of this philosophy of nature is the soul. The soul is for Socrates that fixed ground in the world of change that maps out, at least structurally, how we should organize our lives in relation to each other. Nature orders the soul and the soul, in turn, is the ordering principle for the city. Socrates will, of course, make a move to argue for what orders Nature, but for the moment it is important to understand how and why Plato had Socrates turn to a discussion of the soul.
One of the questions we might raise in relation to the role of the soul in the argument for Socrates’ ideal city is this: "If Socrates believes it is important to move his interlocutors away from views based upon opinion, what argument can he provide for why the belief in soul is not an opinion. How does anyone "know" they have a soul? Are not all beliefs in soul simply that, "beliefs" in soul?