Abstract

Williamson has a strikingly economical way of showing how justified true belief can fail to constitute knowledge: he models a class of Gettier cases by means of two simple constraints. His constraints can be shown to rely on some unstated assumptions about the relationship between reality and appearance. These assumptions are epistemologically non-trivial but can be defended as plausible idealizations of our actual predicament, in part because they align well with empirical work on the metacognitive dimension of experience.