ARISTOTLE: NICOMACHEAN ETHICS
The Highest Good
Aristotle’s argument that there must be a highest good (1.2):
(1) We do not choose everything for the sake of something else.
Proof: Otherwise there would be an infinite regress, which is clearly false.
(2) If we do not choose everything for the sake of something else, then there is some end
that we pursue for its own sake.
(3) Hence there is some end that we pursue for its own sake [from (1) and (2)].
(4) If there is some end that we desire for its own sake, then this is the most ‘complete’
end, i. e. everything else is pursued for the sake of it.
(5) If there is a most complete end, then this will be the highest good, since we pursue it
for its own sake.
Therefore: There is a highest good [from (3), (4), (5)].
Each end is complete, but the first type is more compete (1.7):
(1) The highest good must be a complete end.
(2) Either (a) there is only one complete end, or (b) there are several complete ends.
(3) If (a), then this is the highest good, and it is unique.
(4) If (b), then they can be ordered in a scale from the least to the most complete.
(5) The most complete will then be the highest good and, again, it will be the only one.
Therefore: There is only one highest good.
The Function Argument.
Aristotle proposes that we could find out what ‘happiness’is “if we grasp the
characteristic activity (function’) of a human being”.
First, note that we use evaluative terms of things other than human beings and their
actions. In particular, plants, animals, and artifacts are often called “good” and “better or
worse off.” We speak of good horses, or of a plant doing well, or of one knife as better
than another. Second, notice that such judgments are largely independent of preferences
—both of ours and of the things thus evaluated (and most artifacts do not have
preferences at all). Hence these judgments are in a cerain way objective, rather than
subjective. Third, it is clear that when we use evaluative terms in these ways, we are
claiming that something is good of its kind, e. g. a good pencil, a good chair, etc.. This
usage is also clearly independent of our desires and preferences, and hence objective.
Hence we may generalize this notion to that of functional excellence: something is good
with respect to a given role or function it possesses. This is an evaluative notion which is
independent of (small-scale) shifts in human preferences and behavior. Note that it
include two logical components: the notion of a function, and the idea that things can
“flourish” or do well in their role. Fourth, we extend this analysis to human beings.After
all, if we can make such judgments about plants, why not about us? But since we are
seeking the good for humans, we want to find features that characterize the “human
function”—that is, something distinctively human. (Note that this is logically distinct
from the preceding reasons.) Hence human flourishing will be a matter of excellence at
that “function” which makes us peculiarly or distinctively human. Thus happiness is a
matter of flourishing qua human being.  Thus “the human good turns out to be activity of the soul in accordance with virtue,
and if there are several virtues, in accordance with the best and most complete, over the
course of a complete life” (1.7 1098a16–18). The activity in question is, of course,
exercise of the rational principle.
The “Doctrine of the Mean”
Moral virtue is a relative mean between excess and deficiency in emotions and actions.
Corollary: Moral virtue is determined objectively by a rational principle, such as some-