 (viii) Logic, Physics, Ethics, and the “disciplines.” The special arguments of the skeptic are directed against particular theories in the three disciplines of Hellenistic philosophy: logic, physics, and ethics. In addition, they address the so-called disciplines, namely grammar, rhetoric, geometry, arithmetic, astrology, and music-theory. Sextus’ treatments of logic divide up into two main topics: sign and criterion (cf. Bett 2005 on signs). This structure reflects central concerns of Hellenistic epistemology as well as of ancient skepticism. Skepticism looks for a ‘decider’ between conflicting appearances and thoughts. A decider could be something evident. Dogmatic philosophers associate the evident with the criterion of truth. For something to serve the role of criterion, it cannot be equally disputed as the matters it helps to decide. Or something non-evident could take on the role of decider. For that to be the case, the skeptics argue, it would have to be conclusively revealed by a sign or proof. If there is no compelling theory of the criterion and no compelling account of sign and proof, then there is nothing that can decide between several conflicting views. Sextus’ treatises on logic thus are not simply a collection of individual arguments against various dogmatic theories. Their main line of thought sketches a route into skepticism. Along these lines, Vlasits (2020b) argues that Sextus’ treatment of logic in PH 2 is unified. Sextus’ argument is structured such as to lead to suspension of judgment on the methodologies of the dogmatists. The final section of M 8 (463–81) formulates a challenge for the skeptic that scholars interested in self-refutational arguments have examined (Castagnoli 2010): does the skeptic aim to prove that proof does not exist (Sienkiewicz 2022)?