Aristotle’s Dysfunctional “Function Argument”

The following is an essay I wrote today for a philosophy class.

David Hume outlined the fundamental problem of moral philosophy:

I cannot forbear adding to these reasonings an observation, which may, perhaps, be found of some importance. In every system of morality, which I have hitherto met with, I have always remark'd, that the author proceeds for some time in the ordinary way of reasoning, and establishes the being of a God, or makes observations concerning human affairs; when of a sudden I am surpriz'd to find, that instead of the usual copulations of propositions, is, and is not, I meet with no proposition that is not connected with an ought, or an ought not. This change is imperceptible; but is, however, of the last consequence. For as this ought, or ought not, expresses some new relation or affirmation, 'tis necessary that it should be observ'd and explain'd; and at the same time that a reason should be given, for what seems altogether inconceivable, how this new relation can be a deduction from others, which are entirely different from it. But as authors do not commonly use this precaution, I shall presume to recommend it to the readers; and am persuaded, that this small attention wou'd subvert all the vulgar systems of morality, and let us see, that the distinction of vice and virtue is not founded merely on the relations of objects, nor is perceiv'd by reason.[1]

Aristotle’s system of morality, while certainly not vulgar, fails to bridge this is-ought gap. It fails for two reasons. First, the function of a thing cannot necessarily be determined merely by its distinctive qualities in relation to other like things. Second, Aristotle takes for granted that humans are purposefully designed.

For Aristotle, eudaimonia, defined as either “happiness” or “flourishing,” is the highest end. In order to achieve this end, one must exhibit arête – virtue or excellence – through ones character. Happiness consists in exercising these character traits throughout ones life.

How do we determine which character traits are virtuous? Aristotle suggests we look at the function of a human being. Just as the function of a hammer is to pound nails – the better it pounds nails, the more excellent the hammer – so too, the function of a human is to exercise reason, the “activity of the soul in accord with virtue, and indeed with the best and most complete virtue, if there are more virtues than one.”[2] The better a person exercises his virtuous reason, the more excellent the person.

Why is reason the function of man? Aristotle observes the biological fact that human beings are the only species that can engage in rational discourse. Since this is what sets humanity off from other species, this is the essence, or purpose, of man as distinct from other animals.

It is difficult to see how this reasoning follows. Just because a thing has distinctive properties in relation to other like things does not mean that these distinctive properties are its function. Consider a tall tree in a forest of shorter trees. Is tallness the purpose or function of this tree? Not necessarily. Its property of tallness may help it better achieve its purpose, perhaps by gathering more sunlight and rain water than its fellow trees. If we were to define a single purpose of a tree, knowing what we know now of evolution, we would say that a tree’s purpose is to survive long enough to successfully reproduce. This is the purpose nature “intended” for all living things. Unless we first assume that trees and people and all other things which exist were designed by a conscious creator for a specific reason, we cannot conclude anything about the purpose of these things other than reproductive success.

Aristotle seems to make this assumption of design, when he observes that sculptors and craftsman have specific function (by definition), as do the products of their efforts.[3] So too, Aristotle observes that all of the parts of our bodies serve a specific function as well. But even this is not entirely true. Vestigial organs, for example, may have once served an important purpose for our evolutionary ancestors, but no longer serve that same (or any) purpose today. And even if it was the case that all of our component parts serve a specific function, it would be a category error of composition to conclude that since the parts of a whole have a certain property, the whole has that property. For example, it would be incorrect to conclude from the fact that all of the ingredients in a stew are found in nature, that this stew is also found in nature.

It is simply not the case that all things, or even all living things, necessarily have a purpose. It is possible that they do, but Aristotle has not given us sufficient reason to accept this conclusion. And without knowing the purpose of man, we cannot say what man ought to do, at least using Aristotle’s virtue ethics.[4]

fn1. A Treatise of Human Nature, Book III: Of Morals, Part I: Of Virtue and Vice in General, Section I: Moral Distinctions Not Deriv'd From Reason

fn2. Nicomachean Ethics, 1098a16-20

fn3. Ibid., 1097b30-34

fn4. I found the entry on Aristotle's ethics in the Stanford Encyclopedia of Philosophy very helpful in writing this piece.

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Addressing Hume instead of

Addressing Hume instead of Aristotle, methinks the problem is that he expects morality to be deductive. One could recast his argument to oppose, say, the physical sciences and it would be exactly as effective (i.e., not very.) How can we move from observations ("is") to predictions ("ought") deductively? We can't! Physics, like ethics, requires inductive reasoning.

In fact, Hume does challenge

In fact, Hume does challenge the legitimacy of induction, using precisely the same argument you mentioned. See here.

That said, Hume is not saying that morality needs to be deductive. He is merely criticizing one kind of moral argument, on the grounds that the causal connection from "is" to "ought" is rarely if ever explained. There are other ways to make moral arguments which are not susceptable to Hume's criticism.

That was a fun read, as I'm

That was a fun read, as I'm currently in a class that is discussing Aristotle. Thanks.

I'm no expert on what

I'm no expert on what aristotle knew and when he knew it.
But could we translate "purpose" as "function"? And by function i mean something like an ecological niche. The tall tree seeks to fill the niche of getting the lion's share of the sunlight. The hammer with a good design and utility is more likely to be replicated. The function of humans might be language using, or toolmaking, or reason, or something like that. Animals that reason and communciate can compete effectively. Toolmaking animals that reason and communciate can be supercompetitors, expanding into new niches by making new tools. Herd animals communicate. If they developed reason and language, would that help or hurt? If a tree could reason, it isn't very clear how that would give an evolutionary advantage.
I'm not claiming aristole did or didn't have a good handle on genetics and memetics, but his ideas stay useful if we can fit them into how we think about things now. His idea of eudamonism is still kicking around, still useful. The idea that as individuals we have an inner nature that we should follow and build on is a useful one in refuting utiliarian or collectivist ideas.

The trouble with comments is

The trouble with comments is that they aren't editable. Tallness is not he function of the tree, but say this tree has a gene (set of genes) for tallness, a trait. The tree with the gene for tallness competes with the other trees. Tallness may be an advantage or disadvantage in that ecosystem. The trait is the function of the gene. The tall tree is using a different evolutionary strategy than the shorter trees. Memes also have functions. The function of the language ability genes is that they make memetics possible, so social evolution can replace biological evolution.
That increases adaptabilty, so it's a useful function and gets selected for. I'm not clear how much of this aristotle groked, but he at least had some clues.

AA, I used purpose and


I used purpose and function interchangeably in my presentation, so that isn't a problem. But I don't think function solves the problem. The property of tallness is not the ultimate function of a tree; it is a proximate function which allows the tree to pursue its ultimate function (survival in order to successfully reproduce). The same is true for humans.

Hammers have a single function because they have a purposeful designer, but even that is not so clear. Besides pounding nails, a hammer can also remove nails with the other side of its head. Suppose someone found an even better purpose for hammers - perhaps opening cans. We cannot determine a priori what a thing's purpose it is; it depends on how it is used.

For a response, read

For a response, read Jennifer Whiting's paper "Aristotle's Function Argument: a Defense" in ANCIENT PHILOSOPHY 8 (1988): 33-48.

I believe that most people

I believe that most people interpet the function argument in wholly different way than was intended by Aristotle. Looking at the generation of animals and the way Aristotle uses [idion] to describe mans peculiar characteristic as the rational principle he means that this is the last thing in man which is developed by nature, and that which is developed last by nature is considered; at least the activity or exercise of this principle to be the good for that agent. In man we see that the rational principle is indeed the last thing to be deveolped and so this can hold as a true premise. Also the confusion between artists having a function and man having a function can simply be resolved by pointing out that man is a product of nature

Nature > Man and Art or crafts are a product of man M
Man > Art/Craft

and Aristotle explicitly says that Art is an imitation of nature.

and in regards to the move Aristotle makes which some believe is a fallacy of composition i.e. (body parts have a function so should the whole)
The point is that body parts serve as sub-servient to the body just as a navigation system on a plane has it's own function but it is interwoven in achieving a greater function that being a sucessful flight.

well sorry about any mistakes I am in the middle of writing a paper and had little time just wanted to point some things out thanks and happy trails