Skeptical science : the Pyrrhonian critique of technai in Against the Professors (M I-VI)

The central question of this dissertation is “What is the character of a skeptical expertise?” Sextus Empiricus, our primary source for Pyrrhonian skepticism, tells us that a skeptic has the ability to oppose thoughts and appearances in any number of ways in order to create an equally weighted dispute which results in epochē, the suspension of judgment (Outlines of Pyrrhonism [=PH] I 8). Scholars have debated the extent to which skeptics eschewed beliefs, but one thing is clear, the skeptic does not assent to the dogmatic claims of philosophy and science (PH I 13). This raises to group of related puzzles since Sextus also says that skeptics accept certain forms of expertise (technai) (PH I 24). If skeptics accept and practice certain technai, but also suspend judgment about all scientific or philosophical beliefs, what kind of science do they practice? I answer this question by interpreting Sextus' treatise Against the Professors (M I-VI), which offers his most thorough look at particular subjects of expertise. 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. Pyrrhonists did not ground the scientific domain in first principles in the way that many ancient philosophers of science do. Finally, the skeptical expertise is normative, but strictly in a relativistic sense. Scientific norms are tied to relative utility rather than truth. No expertise can be countenanced that offers theoretical rewards, just as no theoretical objects may be signified. Skeptical expertise is not some grand solution, but it achieves what is needed for practical purposes.