Not all are equal in Plato’s Republic or Aristotle’s Nichomachean Ethics and Politics. Plato and Aristotle argue that people possess a certain natural ability that determines their role in society. The fundamental character of one’s soul, in part, determines this natural ability. As not all humans have the same capabilities, Plato and Aristotle are proposing that the hierarchical social organization purportedly based on merit is ideal. This view of human purpose serves as the cornerstone for their arguments. Plato organizes his ideal city, or kallipolis, around this principle. Aristotle extends this view to the extreme in his discussion of slavery, which he argues that this almost subhuman class is part of a natural, harmonious order. It may seem that Plato’s kallipolis and Aristotle’s conception of slavery would be ideal entry points for further investigating their conceptions of human nature. Readers should consider that what they present as objective, self-contained arguments about human purpose, may in fact be defined to justify the proposed social organization, one of inequality and “natural” hierarchy. While Aristotle and Plato may present their views on the human soul as biologically determined fact, they may ultimately be recognizing that what it means to be human is largely a social construction that changes in accordance to social needs.
The first basic assertion that is made by Plato and Aristotle about human nature is that people are, according to fundamental differences in their natures, suited to fill different roles in society, that natural aptitude is destiny. What must be made clear, however, is whether Plato and Aristotle intend to say that this nature is biologically determined (absolute) or socially constructed (relative). In this pursuit, it would be helpful to first look at how Plato and Aristotle approach the notion of nature or the natural. Aristotle believes that what is natural can be empirically determined. He says, “If one were to see how [a city-state develops] naturally from the beginning, one would, in this case as in others, get the best view of [it]” (Politics 2). Social hierarchy, he observes, emerges quickly in nature “for the sake of survival” (Politics 2). In Republic, Plato follows a similar path of reasoning, as he introduces the idea of the kallipolis. Socrates posits, “I think a city comes to be because none of us is self-sufficient, but we all need many things” (Republic 369b). Aristotle then presents what will become his main teleological argument in Politics. He says that “each thing’s nature, for example, that of a human being, a horse, or a household, is the character it has when its coming-into-being has been completed.” He continues, “Moreover, that for the sake of which something exists, that is to say, its end, is best, and self-sufficiency is both end and best” (Politics 3).
The idea of self-sufficiency is at the core of Plato and Aristotle’s discourse on human nature, because ultimately, they define human purpose in order to create a self-sufficient society. The distinction here is between a pragmatic definition (which they actually offer) and a universal definition of human nature (which it may appear that they offer). Plato recognizes that specialization in one area increases productivity; he writes that “more plentiful and better-quality goods are more easily produced if each person does one thing for which he is naturally suited, does it at the right time, and is released of having to do any of the others” (Republic 370c). Aristotle opens his Politics making arguments similar to those of Plato. Aristotle says, “For if something is capable of rational foresight, it is a natural ruler and master, whereas whatever can use its body to labor is ruled and is a natural slave” (Politics 2). Aristotle acknowledges that “everything is defined by its task and by its capacity” and that, in fact, “the city-state is natural and prior in nature to the individual” (Politics 4). He finally arrives at his definition of humanness by saying that “anyone who cannot form a community with others, or who does not need to because he is self-sufficient, is no part of a city-state, he is either a beast or a god” (Politics 5). These opening pragmatic, functionalistic views of humans provide the framework for Plato and Aristotle’s future arguments about the ideal city and slavery, respectively.
The organization of Plato’s kallipolis mirrors the organization of man’s soul. The tripartition of man’s soul, into the rational, appetitive, and spirited parts, corresponds with the three main roles of people within the kallipolis, the guardian, the auxiliary, and the craftsman (Republic 439d). Just as the three parts of the soul must be in correct proportion, being ruled by the rational, the city must be in an appropriate equilibrium of ruling and being ruled. Describing how the healthy city would function, Socrates says, “To produce health is to establish the components of the body in a natural relation of control and being controlled, one by another” (Republic 444d). Plato introduces the Phoenician myth of metals as an analogy to his idea of each person having a natural role in the society. He describes a city of brothers, where god “mixed some gold into those who are adequately equipped to rule, because they are the most valuable, silver in those who are auxiliaries and iron and bronze in the farmers and craftsmen” (Republic 415a). This is a convenient and appropriate myth for Plato’s purposes, as one cannot tell from birth what kind of metal he has in him. There is a limited amount of mobility in the kallipolis, as “if an offspring of the guardians is inferior, he must be sent off to join the other citizens and that, if the others have an able offspring, he must join the guardians.” If someone is either unsuited or unhappy in his position in society, in this ideal city, he “is to be directed to what he is naturally suited for” (Republic 423c-d). However, mobility that goes against nature is dangerous and can result in civil war and perversions of aristocracy such as oligarchy. Socrates warns that “the intermixing of iron with silver and bronze with gold that results will engender lack of likeness and unharmonious inequality, and these always breed war and hostility where they arise” (Republic 546c). Plato’s definition of human nature, while seemingly fluid (in that one settles naturally into his ideal role), is predicated on the idea that each person has one specific role to play. Plato’s argumentation here is somewhat elusive, as any problems arise in his system (such as an unhappy craftsman or a greedy ruler) can be diffused by simply saying that they were in a role for which they were unsuited.
Aristotle struggles with the question of whether or not slavery is natural, whether some humans are slaves by nature, and it is no surprise; he needs the slave class for his self-sufficient city to work, but he feels uncomfortable stripping them entirely of their humanity. On one hand, he recognizes the natural tendency for “a ruling element and a subject [to] appear, whenever a number of constituents, are combined into a common thing” (Politics 7). But he cites fundamental deficiencies in the soul of the slave as the primary justification for their subordinate status. He states that “the deliberative par of the soul is entirely missing from the soul” (Politics 23). However, Aristotle recognizes that in order for the slave to be human, and he does state that “slaves are human and have a share in reason” (Politics 22), they must have some share in virtue. Consistent with his functionalist definitions, Aristotle argues that “the soul by nature contains a part that rules and a part that is ruled, and each of them has a different virtue” (Politics 23).
It is important to remember here how Aristotle has defined virtue in the Nichomachean Ethics, as something that is divinely inspired. Slaves, Aristotle would seem to be arguing here, are biologically determined to be as such, of you lack virtue you cannot learn it. This sense of determinism is also found in Ethics, when Aristotle says that “no one assigns to a slave a share in happiness, unless he assigns to him a share in human life” (Ethics 263). Aristotle is particularly crafty in his argumentation throughout the Politics, careful to not to extend certain arguments too far, so as not to jeopardize his somewhat dubious arguments about slavery. For example, Aristotle begins a very modern discussion of equality and merit that seems as though it would lead him to reconsider his stance on slavery. He acknowledges that some people are mistakenly promoted or punished for a quality irrelevant to the subject at hand. He provides an example where “those who are superior in complexion, or height, or any other good whatsoever will get more of the things with which political justice is concerned” (Politics 86). Ultimately, Aristotle says that “for the superiority in wealth in birth would have to contribute to the performances, but in fact they contribute nothing to it” (Politics 86). This argument, if extended to slaves, would become problematic for Aristotle. He has already acknowledged that slaves made captive (by law) are separate from slaves by nature. Are not the slaves being punished for their birth, then? The question of slavery is complex, but Aristotle cannot give it a fair treatment because he must censor himself as to makes sure that his conclusions do not compromise his larger view of political society. If one of the last pieces of a large, carefully assembled puzzle does not fit, it sometimes is best to simply force it.
The fact that both Aristotle and Plato define human nature in a way that fits into their proposed societal structure does not entirely discredit what they are saying. Throughout their texts, they have other venues to investigate human nature that seem less tainted by their functionalist goals. Education, for example, plays an essential role in a just city or moderate soul and also adds insight into how Aristotle and Plato define human nature. Both authors, in their views on education, emphasize the malleability of human character. Plato writes that “good education and upbringing, when they are preserved, produce good natures, and useful natures, who are in turn well educated, grow up even better than their predecessors” (Republic 423e). He goes on to warn heavily against the possibly corrupting force of poetry and music, as people are bound to want to imitate them; teachers “must guard as carefully as they can against any innovation in music and poetry or in physical training that is counter to the established order” (Republic 424b). Aristotle, although significantly less emphatic about possible sources of corruption. However, he does place equally great importance on the education of youth, as “states of character arise out of like activities” (Ethics 29). Habituation is an important instructor; gaining practical wisdom, after all, takes much time and experience. An important distinction must be emphasized here, as virtue is something regarded by both Aristotle and Plato as something that cannot be taught, but rather is innate or god-given, a divine determination left as ambiguous about who is naturally virtuous and who is not. Aristotle writes that practical wisdom will be “of no use to those who have not virtue” (Ethics 154). He later says that education “isn’t the craft of putting sight into the soul?[it] takes for granted that sight is there but isn’t turned the right way or looking where it ought to look, and it tries to redirect it properly” (Republic 518d).
Ultimately, Plato and Aristotle have produced texts that, in the teleological spirit, aim to construct and describe the best political society and to define the aims of human life. As this is the primary goal, it is not surprising that they have defined human nature in such a way that is consistent with their other argumentation. This strategy seems that it is more appropriate for Aristotle than Plato, however, because Aristotle acknowledges that his rhetorical strategy is based empirically and is limited, while Plato is an adherent to the Forms and the absolute. I would argue that Plato and Aristotle fail to make convincing arguments supporting biological determinism. However, it seems that between the lines there is an acknowledgement that these definitions of human nature and purpose are socially relative. After all, the philosopher who has perfected his soul and reason must either be exiled or made king, depending on how the society receives him.