Abstract

In the Nicomachean Ethics, Aristotle says that the good person is the standard and measure of what is good, fine, pleasurable and so on, and that virtue is in a mean relative to us. Both these claims are strikingly reminiscent of Protagoras's famous doctrine that man is the measure of all things. My aim is to see how closely they are related. This raises general questions about the metaphysical status of moral properties and perceptual qualities, and about the comparative merits of realism and subjectivism and conventionalism about moral properties. ;Protagoras's measure doctrine is meant as a response to the sceptic's argument from conflicting appearances. According to Protagoras, whenever two parties 'disagree' over whether x is really F or not, we need not suspend belief about which party is right because both are correct: Each individual human being is the measure of all things. Protagoras means his theory to apply to all things alike, including moral and perceptual qualities, and he assimilates knowledge to perception. ;Aristotle's measure doctrine also is a response to the sceptic's argument. Moreover, like Protagoras, Aristotle accepts the parallel between moral and perceptual qualities, and he treats ethical wisdom as analogous to perception. ;A startling corollary of Protagoras's doctrine is that the objects of perception and the objects of morality are not prior to our views of them . Aristotle's accounts of the objects of perception are intended to avoid this feature of the Protagorean account . So are his accounts of justice , and of goods and pleasures . ;According to Aristotle, the good person is the measure because his views accurately detect the truth, not because they constitute it. Furthermore, Aristotle is not thereby committed to the counterintuitive claim that what is good or pleasurable for the bad person is not really good or pleasurable for him, as some have suggested. Despite first appearances, Aristotle's measure doctrine enables him to account for conflicting appearances and variation in ethical matters without espousing scepticism or any unwelcome aspects of the Protagorean view