Metaphysics, Philosophy

Aristotle’s Nicomachean Ethics presents an account of virtue that relates it to the function of man, that for the sake of which man exists.1 According to Aristotle, man, by virtue of being what he is, i.e., human, has a characteristic function which provides the basis for understanding what it means to be virtuous, and, conversely, vicious. From the human good, which Aristotle identifies with the doing well of man’s characteristic activity (érgon), virtue is inferred to be that which perfects man qua rational agent.

Some have objected, however, that Aristotle does not conclusively establish the existence of a human function and so cannot argue for virtue on those grounds.2 If man did not have a function, then neither would there be a human good (at least of the kind relevant to Aristotle), rendering the Aristotelian account of virtue moot at best, and invalid at worst. 

The purpose of this article is twofold: to suggest in outline a new defense of Aristotle’s function argument so as to give it a more solid foundation, and to thereby reconstruct his account of virtue without altering the basic structure of his argument. In particular, it will be shown that belief in a human function is prerequisite to every action,3 and that a universally binding notion of virtue follows naturally therefrom.  

Every action is directed towards an end. When a man acts, he does so with purpose, intending to realize a specific goal. To achieve that goal, he must employ certain means which, from the outset, he deems efficacious in bringing about the desired result. Indeed, even the simplest actions which involve nothing else but one’s own body follow this basic principle. A man speaks in order to communicate, and he does so by moving his mouth and vibrating his vocal cords. When he is distressed by the sight of something unpleasant, he reorients his gaze by turning his head in order to avoid looking at it. And when bothered by an itch, he scratches himself by curling his fingers and moving his arm in order to relieve the discomfort. In every action, man uses at least some parts of his physical body, locating them in a framework where each has a designated function. This function is constrained by the goal of the action, that for the sake of which the former is carried out.  

Belief in a human function is thus a precondition for action, for no one could act without employing his body in relation to some end or purpose. In order to speak, I must presuppose that my vocal cords exist for the sake of producing sounds. In order to walk, I must presuppose that my legs exist for the sake of locomotion.4 Even those parts of my body not directly involved in walking perform a relevant function. For without my vital organs and their related parts, I would not be able to walk at all. In the context of walking, their function is to sustain my very ability to walk.

Every action, therefore, effects a unity of the bodily parts by establishing between them relations that converge towards a single end. This end confers a function upon each of those parts, which exhausts itself in the action once the goal has been achieved. But while a particular function may be transitory, the class to which it belongs is not. What is of interest here is not whether man has this or that specific function, but rather what kind of function is realized in each and every action. That is, we must identify the highest genus of human functions, that which contains all of its particulars.5

Following Aristotle, let us consider human life in each of its three aspects: the vegetative, the sensitive, and the rational.6 For the human function will correspond to one of these. Man either acts for the sake of “nutrition and growth,”7 responding to perceptual inputs, or exercising his reason (lógos).

In light of the basic activities performed by his bodily parts, it may seem that man is no different from a plant. Both seek to maintain a level of existence involving nothing more than mere survival. A plant uses its roots to absorb water from the soil, and it does so in order that it may live. Likewise, and for the same purpose, it converts sunlight into energy, extracts oxygen from the atmosphere, and deploys defense mechanisms against unwanted pathogens.

What other kind of function have our organs and their related parts? The heart pumps blood throughout the body, the lungs draw in air from the environment, and the stomach digests food, all for the purpose of sustaining life. On the surface, it would appear that no meaningful distinction could be drawn between man and even the simplest organisms. But common sense tells us otherwise. Even the fool knows that man possesses something which plants characteristically lack. What could this be? 

Unlike plants, man has the ability to reason about ends and apprehend them as ends. He knows what an end is; the concept of end has meaning to him. For man, the organs have a purpose; they exist in order to sustain life. The heart beats in order to pump blood, and the lungs expand in order to draw in air. Plants, on the other hand, just are. They do not know what they do nor why they do them. The seed spreads its roots throughout the soil, and we say that it does this in order to absorb water and nutrients, but it does not even know that it does this, let alone why. Lacking the sensory faculty, plants live in complete unawareness of their environment, behaving only in accordance with a process pre-determined by nature.8

But animals, too, are incapable of reasoning about their ends. While their apparent capacity for perception may allow them to choose an end in any given situation, they still cannot recognize their ends as ends.9 For example, a hawk may swoop down on a rabbit that she has spotted from above in order to obtain food for her young, but she cannot apprehend this as the goal of her hunt. As philosopher Philippa Foot has pointed out in her discussion of St. Thomas,

animals [do not] have knowledge of the realm of means and ends as humans do. In a way they can be said to have this knowledge, since they go for one thing to get another. But here, too, … they do not have the kind of knowledge of the relation that human beings have.10

The human function is, therefore, neither vegetative nor sensitive, for every action involves a dimension of rationality that is absent in both plants and animals.  

Following Ockham, the voluntarist may respond that reason has no direct influence on action and so cannot be said to play any role in determining the human function. More particularly, he may argue that reason is subordinate to another faculty which guides and constrains its operation. In his A Treatise of Human Nature (1739), philosopher David Hume writes:

[R]eason alone can never be a motive to any action of the will… [It] is … incapable of preventing volition, or of disputing the preference with any passion or emotion. … Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them.11

In the Humean view, reason is not sovereign over the passions but rather subservient to them. The passions impel us to choose what they incline us towards, and reason discovers the means by which we can attain them. In other words, reason merely affirms what the passions have already chosen. Its activities are the ex-post realization of the propensity to “avoid or embrace what will give us … uneasiness or satisfaction.”12

Now, this objection neglects the normativity of the passions. For we evaluate their objects on the basis of certain criteria. In finding something pleasant or unpleasant, we recognize that which makes it so and judge accordingly. Wine is pleasant because of its good taste. A rotting corpse is unpleasant because of its bad smell. Furthermore, we apprehend pleasure as pleasure and pain as pain. We recognize the thisness of each, the what it‘s like to experience it. Sexual pleasure is enjoyable because it feels like this. To hear a mother crying is painful because it sounds like this. Contra Hume, then, reason is a precondition for experiencing the passions, for if man did not first reason about their objects, he would have nothing to find pleasant or unpleasant to begin with.  

Having established the primacy of reason over the lower faculties, we concur with Aristotle in defining the human function as “activity of the soul in accord with reason or requiring reason.”13 For reason is prior to action. In order to act, we must rationally choose an end on the basis of certain criteria and then direct ourselves towards achieving that end. And this ability is uniquely human; it belongs to neither plants nor animals. St. Thomas says that

to act for the sake of an end is to order one’s action to [that] end. But this is the work of reason, … [so] it does not belong to those things that lack reason.14

Since every function is performed either well or poorly by that which possesses it, so is the case with man. Aristotle writes:

[T]he function of a [kind of thing] … is the same in kind as the function of an excellent individual of the kind.15

For example, the function of a scale is to measure weight, and that of a good scale is to do this well. Likewise, a good soldier will excel at fighting, and a good hunter will excel at hunting. Aristotle continues:

Now each function is completed well by being completed in accord with the virtue proper [to that kind of thing]. And so the human good proves to be activity of the soul in accord with virtue…16

In other words, virtue is that which perfects man qua rational agent and makes him good at his characteristic activity. If man has a function, a that for the sake of which he is what he is, then so is there a human good, which is the highest perfection of this function. And this is precisely what virtue effects; it qualifies man so as to make him good. We have thus seen that a universally binding notion of virtue follows naturally from the human function. Once it has been admitted that man has a function, the possibility of qualifying his performance of this as good or bad renders necessary the existence of virtue.

  1. See Aristotle, Nicomachean Ethics, Book I, Ch. 7.
  2. See Whiting, Aristotle’s Function Argument: A Defense, p. 34. Whiting writes: “The first objection attacks the move from (a) (the function of a man or what it is to be a man) to (b) (what it is to be a good man) on the ground that this requires that men, like bodily parts or craftsmen and their tools, have instrumental functions or virtues which presuppose their being good or useful for some further ends or purposes. But, the objection continues, men as such do not have instrumental functions or purposes, so the move from (a) to (b) is unwarranted.”
  3. Here defined as purposeful behavior on the part of human beings.
  4. This does not imply that vocal cords and legs cannot have other functions as well.
  5. This shall henceforth be referred to as the human function.
  6. See Aristotle, On The Soul, 412a-430a.
  7. Aristotle, and Reeve C. D. C. Nicomachean Ethics. Indianapolis: Hackett Publishing Company, 2014, 1098a1.
  8. To be understood as the principle of motion. See Aristotle, Physics, 192b22-3. Aristotle writes: “[N]ature is a principle or cause of being moved and of being at rest in that to which it belongs primarily, in virtue of itself and not accidentally.”
  9. See Aquinas, Summa Theologiae, First Part of the Second Part, Question I, Article II. St. Thomas writes: “[T]here are many things which do not know the end, or which lack knowledge entirely, such as creatures without senses, or which do not grasp the formality of the end, such as brute animals” (my emphasis).
  10. Foot, Philippa. Natural Goodness. Oxford University Press, 2001, p. 54 (emphasis in original).
  11. Hume, David, Peter Harold Nidditch, and Lewis Amherst Selby-Bigge. A Treatise of Human Nature. Oxford: Clarendon Press, 1978, pp. 413-15.
  12. Ibid., p. 414.
  13. Aristotle, and Reeve C. D. C. Nicomachean Ethics. Indianapolis: Hackett Publishing Company, 2014, 1098a7-8.
  14. Thomas, and Ralph McInerny. Thomas Aquinas: Selected Writings. London: Penguin, 1998, p. 485 (my emphasis).
  15. Aristotle, and Reeve C. D. C. Nicomachean Ethics. Indianapolis: Hackett Publishing Company, 2014, 1098a9-10.
  16. Ibid., 1098a16-7 (my emphasis).