  The most important part of PH II is the long discussion of the ‘criterion’ (or ‘standard’, as Annas and Barnes translate it) of truth (see especially Striker 1974: 1990b; Brunschwig 1988). Not only is it philosophically extremely rich, but it plays a crucial role in the dialectic of the contemporary scholarly debate as to whether the Pyrrhonian skeptic can have beliefs. The notion of a criterion of truth was central to the epistemologies of both the Stoics and Epicureans: