Plato, in writing about the place of the individual within his conception of a just society, divides the human soul into three Meros, or parts: Logos (reason), Thumos (spirit/emotion) and Eros (appetite). In such a conception, reason is supreme, subjugating Thumos to perform its will and crushing appetite to the bare minimum measure necessary for survival. In making such distinctions, Plato assumes that the function of the soul is to better the state of society, or in his view to be dikaios (just). An itemization, such as Plato’s, of the human soul, implies both divisibility and scope; though Plato uses his three-parts-of-the-human-soul thesis metaphorically, he himself proves that the same part of the same item cannot possibly act in two ways, thereby implying that the soul may have an unlimited amount of contradictory or separate impulses within each meros of the human soul. Several notable problems exist with Plato’s conception of the human soul, however; as Plato himself emphasizes at the beginning of his dialogue, it is impossible to arrive at a conception of the human soul scientifically, and as such, Plato’s view of the soul is based more on his view of the perfect society than it is on pure logic. Indeed, Plato’s ideas are self-serving, while is conception of the human soul is distorted by his view of Dikaisune (justice/morality). The soul instead must be viewed as a separate entity within the human being, driven not by society but by an internal, quintessential life force within the human being.
The assumptions Plato makes about the human soul are predicated on his axiom that being just is the highest level a human can strive for. For logically, it must naturally be possible to attain this level of Dikaisune; however, such a level clearly must be more difficult to reach than the level of adikia (injustice/wrongoing), or else most people would be moral human beings, capable of the intellectual reasoning necessary to reach the level of justice. Therefore, the goal of a human being is to strive to abhor injustice while adhering to Plato’s standard of justice; the soul thus becomes a vehicle for realization of this goal. As Plato views justice as best expressed when each f the three classes (Rulers, Auxiliaries and Subjects) stays within its jurisdiction and each person performs his own task without infringing on anyone else’s, both the purpose of the soul and the makeup of the soul reflect the components of his societal aims. Reason is given prominence within the soul, in order to prevent each of the classes from acting within their own self-interests and corrupting society. Since the goal of both the soul and the society are to pursue justice, they must consist of the same essential Meros that are key to achieving justice, whether within society or the individual.
Plato’s conception of the human soul thus expands to incorporate every quality or attribute necessary to reach justice. For if the soul is the vehicle through which justice is achieved, the human soul must be inclusive of every attribute related to justice, whether positive or negative; all positive attributes are labeled as Logos and strengthened through the thumos that expresses and carries out their will, while all negative attributes are labeled as Eros, inherently contradictory to the conception of a just society and thus relegated to the bottom of the soul, meant to be completely subjugated and conquered by reason. One already may see a problem with Plato’s conception, namely the question of why Eros is part of the human soul at all if it is contrary to the soul’s goal; for though some aspects of Eros, e.g. the desire for food and reproduction, are necessary for the continuation of society, nevertheless many other negative attributes are included as well that need to be completely eliminated and thus shouldn’t be included within the essential human soul, if they play no part in the soul’s goal of achieving justice. It then follows that Plato includes injustice and justice together within the soul; Plato onjly felt the need to do so because of his need to divide the soul into parts, and thus give the conception of the soul unlimited scope. Such divisions and such great scope thus allow Plato to subtly mix in psuche into the soul; “personality” is thus the subject of “self-discipline”, the quality of one positive element controlling a negative one. As Plato’s conception of the soul is based on society, and a critical component of society is self-discipline, it is apparent that Plato views the personality as a part of the soul, relevant to all three classes and creating harmony between them. From his example, it is apparent how broad Plato’s conception of the human soul really is, incorporating character traits, personality, desires, and essentially all qualities of the human being not of a directly physical nature.
Plato’s assumption that the soul must be a proponent of societyal aims gives rise to several negative implications on the personal level as well. For should a human not lvie in Plato’s society, his soul’s contribution of justice is in vain. For if a person is moral amidst a society of immorality, according to Plato, such a person’s efforts are wasted as his morality is for the purpose of creating a moral society, and not for any religious purposes or self-interest. Additionally, by framing the conception of the soul in reference to society, the individual loses significance and is relegated to his assigned role in society. For it is juts for a slave to do his job; so too, then, justice isn’t defined by the human soul’s inherent components, but rather by the individual’s place of society.
When discussing the conception of the human soul, then, it is imperative not to make Plato’s mistake of framing the soul in reference to something else; rather, the soul must be viewed as its own entity that cooperates with other impulses but that isn’t inclusive of those impulsive. The human soul must stem from itself, possessing its own vitality and powering itself, as opposed to being determined by external factors. For when those external factors are nullified (for instance, society degenerating), the soul is left in an awkward place. Furthermore, it is important as well to define the purpose of the soul along similar lines, i.e. as viewed by itself and with no other entity in mind. Plato’s bias ultimately stemmed from his acknowledgement at the outset of his discussion that he would proceed along nonscientific grounds instead of using his previous method of proving what a concept is by proving what the concept cannot be. Had Plato employed this second approach, his conception of the soul would certainly not be as broad as it is; as he followed the first approach, however, he positively defined the soul, assigning to it qualities remarkably similar to those of his society, and as such replicating the “soul” of his society within the soul of the individual. In fairness to Plato, however, assumptions must be made about the human soul when defining it, or else one could never really define the soul. The conception of the human soul as an inherent entity within the human, merely combining with the mind and body yet remaining distinct from the two, assumes that the soul exists, and that it has a function. As evidenced by Plato’s errors, however, it is a mistake to define the human soul in terms of its goal; the difficulty of defining the soul tus emerges. It would be difficult to define the soul without the personal bias allowing one to assume that it exists; it would be exponentially more difficult to prove that such a view is correct by way of science as opposed to by way of philosophy. Thus, the human soul is a concept impossible to define, and it is up to the individual or the religious beliefs of the individual to determine which view to adopt personally; yet no individual can scientifically claim that their conception is any better than that of their friend.