 In four of the six fields, namely grammar, rhetoric, music, and astrology, Sextus admits non-technical versions into the skeptic’s life, while subjecting all theoretical claims to skeptical examination. For example, he distinguishes between the ordinary ability to read and write on the one hand and grammar as a technical discipline on the other, or the ability to play a musical instrument on the one hand and music theory on the other (cf. Corti 2015b on why this kind of contrast does not come up in the books on arithmetic and geometry, Corti 2015c on Sextus’ attack on the Platonic-Pythagorean notion of the Two, and Corti forthcoming).