Plato and Aristotle have similar perspectives about human function. They also share some of their ideas about how human function is related to other philosophical notions such as virtue, good, justice, and the soul. According to Aristotle the chief good (and the human function, which has its end in itself) is happiness. But his definition of happiness is different from what ordinary people usually think.
Happiness is neither pleasure nor wealth, nor is it even a kind of honor (Nicomachean Ethics, Chapter 5). It is rather a final state and all human activities attempt to reach this final state. Plato holds that the human function is justice and that it ensures happiness for both the individual and the society when practiced correctly. But this ideal of justice is not for individuals who have special professions or “crafts. ” Justice is rather an ideal that every person should pursue for himself/herself.
While their definitions seem to be more or less similar, the two philosophers differ on the relative importance of these notions. That is to say, while according to Plato justice is the most important ideal (and happiness is its derivative), Aristotle holds the opinion that happiness is the most significant good which has its end in itself. A correct definition of happiness however is not simple pleasure, according to Aristotle, but a state of moral well-being (which assumes both justice and virtue.)
The two philosophers agree on the issue that in order to be happy, we must exercise our human function (and reach the ideals this function requires). They also seem to agree that the human function (justice for Plato, happiness for Aristotle) is impossible to exercise without being virtuous. All these concepts refer to each other and they sometimes even seem more or less equal. This paper will therefore argue that the two philosophers share similar views on the nature of the human function and how happiness and virtue relate to this notion.
It will also be argued, however, that they disagree on the relative importance of these concepts (and that some of their philosophical definitions are different). The human function in Book I of Plato’s Republic is defined towards the end of the book, on pages 29 to 31. Plato’s definition of the human function comes after a long and complex argument on the nature of wealth, justice, craft, and virtue (and how they all refer to each other). Plato does not seem to favor the particular idea that justice is a kind of craft [techne] (Republic, 7.)
“Craft” here is taken to mean something similar to “business” or “expertise” and some crafts mentioned in that part of the dialogue are: cooking, medicine, boatbuilding, horse breeding, being the captain of a ship, lyre playing, “soldiery and musicianship” etc (Republic 6-9). What all these crafts have in common is that they are individualistic and not universal. Justice will therefore differ from this definition because the exercise of justice is a universal goal. Justice therefore cannot be a kind of techne and there are two major reasons for this exclusion.
The first reason is that if justice is a kind of techne, then only those who have justice as their profession would be expected to exercise justice, as opposed to all human beings (only those who have justice as their profession). It makes no difference whether an individual is a cook or a doctor or a boat-builder or a horse breeder in that regard: every professional individual is expected to be just and virtuous in his/her life. The second reason is related to the earlier discussion about the nature of wealth and how it relates to happiness and morality.
If justice is a kind of techne, that would mean that the person who exercises justice could make money out of it, being a professional. “Justice” in that regard would be nothing but another kind of business to earn a living. Plato however rejects this idea very strongly: justice cannot be bought or sold. Justice is a kind of human good but it is neither material nor has a fixed price. Justice is superior to wealth, since it is “a thing more valuable than even a large quantity of gold” (Republic, 13). When we come to the final pages of Book I, we see that Socrates gives the example of the human body to illustrate what justice means.
The specific function of the human ear is to hear, the specific function of the human eye is to see, etc. And the function of the human body as a whole is to be healthy and harmonious. The soul has the special function of ruling over the body in a way that will ensure the happiness of the whole. That is the say, the soul is responsible for both its own happiness and the well-being of the body (which it commands). There are strong political implications of this statement: the rulers of a city are responsible for the happiness of the people they rule (like good shepherds).
Moving over to Aristotle, we see that the Nicomachean Ethics opens with a similar discussion about the nature of crafts and how they refer to notions of justice. Aristotle claims that “where there are ends apart from the actions, it is the nature of the products to be better than the activities” (Nicomachean Ethics, Chapter 1). This distinction is of great importance. Aristotle draws a line between goals and actions: actions are towards the fulfillment of goals. Aristotle, like Plato, lists several professions and remarks that these “arts” have specific goals.
The art of strategy has as its goal victory, the “medical art” has as its goal health, the art of shipbuilding has as its goal the construction of a vessel, etc (Nicomachean Ethics, Chapter 1). But these specific goals cannot stand for the human function by themselves. Just like Plato, Aristotle dismisses the idea that justice is any kind of craft. Chapter 2 of Nicomachean Ethics explains this idea powerfully. According to Aristotle, politics is the “most authoritative art and that which is most truly the master art. ” Politics “uses the rest of the sciences” and therefore “the end of this science must include those of the others.
” Aristotle also claims that this goal (justice) is the same for both “a single man and for a state. ” We may perhaps paraphrase this as: justice for individuals concerns ethics, justice for society concerns politics. We may furthermore claim that, while the human function on the level of individuals is the exercise of virtue, the human function on the level of societies would be political justice. When an individual is virtuous he can reach happiness. When a community exercises justice (or has just rulers) they can reach happiness as a whole.
Plato and Aristotle reach very similar conclusions and even though they seem to be discussing justice on an individual level at first, soon we understand that their real intention is to discuss politics. The conclusions they draw (and even the examples they use) concern communities and in particular, the city-state [polis]. Another important aspect of the human function is the exercise of reason. Aristotle, in the Nicomachean Ethics, defines reason as the characteristic human trait (the main distinction between an animal and human being).
According to Aristotle, biological facts such as “nutrition and growth” cannot be considered as characteristically human traits. Even the “life of perception” cannot be called the human function because “it also seems to be common to the horse, the ox, and every animal” (Nicomachean Ethics, Chapter 7). Aristotle finally arrives at a definition of the human function which includes virtue, reason, and goodness: “human good turns out to be the activity of soul in accordance with virtue, and if there are more than one virtue, in accordance with the best and most complete” (Nicomachean Ethics, Chapter 7).
The human good (or the human function) is therefore the activity of the rational soul and not the human body. “By human virtue we mean not that of the body but that of the soul; and happiness also we call an activity of soul” says Aristotle (Nicomachean Ethics, Chapter 13). Plato, interestingly, uses the same example of the soul to explain justice. “Justice is a soul’s virtue” is what Socrates says in Book I of The Republic. The soul (which is rational) is superior to the body just as a good ruler is superior to the people he rules over.
Both Aristotle and Plato have same approach on whether virtue has an essential role in the pursuit of happiness. Neither Plato nor Aristotle can imagine happiness without justice and virtue. The relation between virtue and happiness, according to Aristotle, is the relation between an activity and a product. When we consider the totality of his arguments in Book I, it becomes clear that virtue is the activity and happiness is the product. Happiness therefore is superior to virtue: virtue is how an individual reaches happiness.
Happiness is its own purpose: it is a final state and all human activities attempt to reach this state. Whether Plato would make such a distinction is unclear. His definition of virtue is somewhat different from the modern term. According to Plato, virtue is not exclusively moral (even though the moral aspect is perhaps the most important). Plato defines virtue [arete] as what makes a good dog good, or a good horse good, or a good human good, etc (Republic, 10-11). Arete in this sense “applies to things (such as knives) which are not moral agents” (footnote, page 11).
Socrates however, through Book I of The Republic, refutes Thrasymachus’ view that justice is simply the advantage of the stronger. Thrasymachus’ view is amoral and Plato rejects this view very strongly. From this we may perhaps infer that the most important aspect of virtue is its moral aspect. This definition of arete is also a description of the human function (i. e. what makes a human a human). The two philosophers, therefore, are in agreement on the issue that virtue, reason, and justice are significant aspects of human happiness.
The four concepts are interrelated and each would be a good candidate for the human function. Aristotle formulates the human function as “the activity of soul in accordance with virtue. ” Plato however does not reach at a fixed formula by the end of Republic, Book I. We are told that humans indeed have a function (just as organs like ears and eyes do, on page 29) and that it is impossible for the whole to be healthy unless every part is performing its function in a satisfactory manner.
We are also told that every specific organ or individual has a specific kind of virtue without which they would “perform their function badly” (Republic, 30). The final addition to this argument is that it is impossible for a human being to be happy without the exercise of virtue and justice (Republic, 31). However, the exact definition of justice (without which it is impossible to define happiness) is not given at the end of Book I.
Socrates makes an admission of this inability towards the end: “for when I do not know what justice is, I will hardly know whether it is a kind of virtue or not, or whether a person who has it is happy or unhappy” (Republic, 31). The two philosophers therefore share similar views on the nature of reason, happiness, justice, and virtue: all these concepts are interrelated and necessary for each other to exist. However, even though Aristotle gives a formal definition of the human function by the end of Book I in Nicomachean Ethics, Plato does not. He raises the question but the answer is not yet given.