LEE, Mi-Kyoung. Epistemology after Protagoras: Responses to Relativism in Plato, Aristotle, and Democritus.

Gilbert, Christopher

LEE, Mi-Kyoung. Epistemology after Protagoras: Responses to Relativism in Plato, Aristotle, and Democritus. Oxford: Oxford University Press, 2005. 254 pp. Cloth, $74.00--Mi-Kyoung Lee has produced an engaging study of the development of skepticism in ancient Greece. Although arguments against the possibility of knowledge--and responses thereto-were common during the Hellenistic period, the great works of the Classical period hardly give skepticism a second thought. Were great minds like Plato and Aristotle blithely unaware of the threat posed by skepticism? Lee's answer is that the questions and arguments of Hellenistic period skeptics were not unprecedented, for a nascent form of skepticism had already been debated in the Classical period. The relativism of Protagoras' measure doctrine--"Man is the measure of all things"--was a challenge to Classical epistemologies, for it implied that no one could ever be mistaken about anything. Plato, Aristotle, and Democritus all recognized this challenge, and their responses to it shaped the debate over skepticism in the Hellenistic period.

Sifting through the testimony of later philosophers, Lee explains how Protagoras's measure doctrine should be understood. On the basis of views that other thinkers attributed to Protagoras and their responses to those views, Lee argues that Protagoras did not defend a theory about truth itself, such as truth-relativism (nothing is true simpliciter, things are only true relative to particular individuals in particular contexts). Rather, the measure doctrine asserts fact-relativism--the idea that every property or state of affairs is relative to particular individuals. Thus, Protagoras had a nonrelativized notion of truth, but he claimed that things actually are as they appear to us; each and every human being can determine what is true simply by consulting his own beliefs.

Although Protagoras did not develop a full-fledged relativist epistemology, Plato did. In the Theaetetus, Plato offers a "Secret Doctrine" on behalf of Protagoras. This doctrine, which Plato introduces so that he can then refute it, is a set of metaphysical theses meant to explain and justify Protagoras' measure doctrine. At its heart are two ideas: (1) the Heraclitean claim that all things are constantly changing, and (2) total relativity--the claim that "nothing is anything by itself, but is so only relative to something else" (p. 86). In Lee's view, Plato's Secret Doctrine and his attack thereupon constitute, hot a conclusive refutation of Protagoras, but a Classical experiment in thinking about relativism.

Aristotle is more explicit than Plato on the skeptical implications of relativism. In Metaphysics book 4, chapter 5, Aristotle identifies three beliefs as leading to the conclusion that the truth about things can never be known: (P) the Protagorean measure doctrine; (H) the Heraclitean idea that all is in flux; and (C) the contradictionist claim that everything both is and is not the case. Aristotle responds to the skeptical implications of these ideas, hot by attacking skepticism itself, but by identifying and undermining the faulty assumptions that lie behind beliefs (P), (H), and (C). All three beliefs test on the mistaken idea that thinking is like perceiving--that the mind's thinking is a purely passive affection caused by the objects of thought. Beliefs (P), (H), and (C) also presuppose that all of reality is matedal--that to be is to be perceivable. Lee thus demonstrates that Aristotle was "genuinely interested in engaging with and fending off [skeptical] challenges to his own realist and objectivist assumptions" (p. 253).

Although neither a relativist nor a skeptic, Democritus was the Classical philosopher whose ideas were most akin to those of Protagoras. Democritus held that a thing has a sensible quality if and only if it appears to have that quality to some perceiver. So sensible qualities really are as they appear to us, for that is all sensible qualities are--our sense perceptions tell us only how things affect our senses, not what things are like in themselves. In order to know what things are like in themselves, Democritus argued, our minds must grasp that which is too fine for the senses to discern--namely, atoms and the void. Democritus thus embraced a qualified version of the Protagorean measure doctrine. The senses are (incomplete) measures of truth because knowledge is impossible without sensation--without sense data, our minds would have nothing about which to think. Human beings (as both sensing and thinking things) are complete measures of truth because when we think carefully about the things that cause our sensations, we are capable of understanding the truth about those things.

This book is thoroughly researched, well argued, and clearly written. Lee's analysis of epistemological issues is technically rigorous, but she gives plenty of everyday examples to make the finer points clear to nonspecialists. I would especially urge anyone interested in Plato's Theaetetus to read Lee's fifth chapter, which offers an excellent explication of a very difficult section of that dialogue.--Christopher Gilbert, Cuesta College.