Skeptical Science: The Pyrrhonian Critique of Technai in Against the Professors (M I-VI)
How can the Pyrrhonian skeptic live his life without holding beliefs? This is one of the most puzzling questions about ancient skepticism. Sextus Empiricus gives us an answer in his Outlines of Pyrrhonism (PH): The skeptic is able to follow the appearances. But when Sextus includes the acceptance of forms of expertise (technai) among the appearances (PH I 24), the mystery deepens. Sextus, who was a medical doctor himself, says that the skeptic does not assent to the dogmatic claims of philosophy and science (PH I 13). How can he claim both to live without beliefs and to accept certain sciences? Or to put it another way, if skeptics accept and practice certain technai, but also suspend judgment and avoid holding all scientific or philosophical beliefs, what kind of science do they practice? Obviously, the notion of skeptical technē cannot be, for example, that of Plato's Socrates who insists in the dialogue Gorgias that the expert must grasp the nature of things in her particular domain in order to explain each of them (465a). Thus, the central question of my dissertation is “What is skeptical expertise?”
I answer the central question by examining Sextus' under-appreciated treatise Against the Professors (M I-VI), which offers his most thorough look at particular subjects of expertise (he attacks grammar, rhetoric, geometry, arithmetic, astrology, and music). I argue for the following characteristics of skeptical technai: First, an adequate skeptical expertise is constituted by a collection of correlated observed phenomena (what he calls commemorative signs) established empirically through repeated observations, and always open to revision. The objects of these technai are limited to observable domains; that is, both the sign and the signified can in some sense be observed. All the same, commemorative signs allow the skeptic to predict future observable occurrences. Second, skeptical expertise is a non-axiomatic or, more generally, non-foundationalist science. It does not ground the scientific domain in first principles in the way that we observe, for example, in Aristotle's scientific theory. Moreover, this science is neither explanatory nor a means to gain knowledge of the world. While the notion of a non-explanatory science may seem incoherent to some, skeptical science is a clear forerunner to certain forms of modern scientific anti-realism (e.g. Duhem 1954). My account shows that Sextus' vision of scientific investigation is truly meant to be grounded in the appearances.
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