In the Nicomachean Ethics, Aristotle claims that the human good, defined as happiness, lies in the rational activity of the soul in accordance with virtue (1098a.12-18). To this purpose, he employs an argument, the function argument, which details an account of the human good lying in the peculiar function of a human being. In this essay, I reconstruct Aristotle’s function argument and defend it from a plausible objection.
In Book I, Aristotle states that the good is “that at which all things aim” (1094a.3). Such a good, then, would be at the top of a hierarchy of ends because it would be the only thing that is never chosen for the sake of something else, but always for itself. For humans, this ultimate good is happiness (1097b.5-6). According to Aristotle, the good of any given thing can be found in that thing’s function, and it is good when it performs that function well; i.e. the good ‘x’ does the function of an x well. For example, the good sculptor does what a sculptor does well. This can also be extended to eyes, hands, feet, and humans (1097b. 25-34). Thus, to be a good human just means to perform the function of a human well. Then, we must discover the function of a human being to discover what happiness (the human good) would look like (1097b.20-33). Aristotle anatomizes several possibilities for the function of a human being: the life (or function) of nutrition and growth, which is common to all living things, but is most distinctive of plants; the life of sense-perception, which is common to all animals; and the life of rational activity, which includes the exercise of thought and an obedience to reason (1097b.30-1098a.5). According to Aristotle, this third life, or function, is a peculiar function of human beings. Therefore, the human good consists of rational activity performed well or “in accordance with virtue” (1098a.15-17).
One plausible objection to Aristotle’s account of the human good might take issue with Aristotle’s account of the human function. Namely, humans perform numerous functions that are “peculiar to man,” so what distinguishes rational activity as the single function that underlies the human good? (1097b.33)? For example, if humans are unique in their capacity to engage in arguments over Twitter.com, this might be one possible contender for the human function. If this is the case, then the human good might consist of starting as many arguments on Twitter as possible, or some other variant of what being good at arguing on Twitter might look like. Another example might include a function not necessarily rooted in technology. For instance, humans are uniquely capable of participating in religious cults. Does that mean, in order to live a good life, I must devote myself to participating in as many religious cults as possible, or doing so as excellently as possible?
This objection does not argue for these functions as viable conceptions of the good life but rather notes that humans have many peculiar characteristics and capacities which set them apart from other living things, and that ‘peculiarity’ is not a sufficient condition for the human function. This objection stems from a very particular reading of Aristotle’s phrasing that, in regards to the human function, “we are seeking what is peculiar to man” (1097b.33). Here, peculiarity is interpreted as distinctness. Thus, in searching for the peculiar function of human beings, we find many functions that human beings are distinct in their capacity for. The function argument’s conclusion that the human function consists of rational activity, then, seems to fall apart.
In response, I would provide an apter interpretation of Aristotle’s “peculiar to man” condition, one which also avoids a contradiction with Aristotle’s conception of the contemplative life. Aristotle’s “peculiar to man” condition can be read as an extension of the implied premise that human life looks drastically different from other living things–how humans do what they do is different from how other living things do what they do. Therefore, our function won’t be the same. This is not to say that each type of living thing, including humans, must have a function distinct from every other sort of living thing, but that, if the sort of lives they lead look drastically different from one another, they must have different functions. For example, living things that partake in the life of sense-perception are all animals, including humans, oxen, horses, etc. Horses and oxen have, more or less, the same function (no distinctness required); that is, their lives are mostly determined and shaped by their capacity for sense-perception (1098a.2-3). Human life, on the other hand, is not predominantly determined by sense-perception, according to Aristotle; it is determined by rational activity. For Aristotle, we are most fully human when we are not only perceiving but also using reason. “Peculiar to man” can then be interpreted as what is essential to human beings and their way of life.
The interpretation of Aristotle’s “peculiar to man” condition as distinctness, moreover, would contradict Aristotle’s claim that contemplation, a form of rational activity, is the function (or activity) of the gods: “if you take away from a living being action, and still more production, what is left but contemplation? Therefore the activity of god, which surpasses all others in blessedness, must be contemplative; and of human activities, therefore, that which is most akin to this must be most of the nature of happiness” (1178b.20-23). That Aristotle believes that humans and gods both partake in rational activity indicates that, in searching for a function “peculiar to man,” Aristotle was not looking for a distinct function of humans, but rather the essential function, one which determines the very nature of their being. Whether other beings partake in this essential function is irrelevant to Aristotle’s argument about the human good.