Abstract
Fortunately for those of us who work on the topic, Ernie Sosa has devoted much of his (seemingly inexhaustible) intellectual energy to the problem of philosophical skepticism. And to great effect. With the three exceptions of Peter Unger, whose 1975 Ignorance: A Case for Scepticism is a grossly under-appreciated classic of epistemology; Timothy Williamson, whose 2000 Knowledge and its Limits is, I hope, on its way to being a less underappreciated classic; and Thomas Reid, I have benefitted more from Sosa’s wrestlings with skepticism than from anyone else’s work on the topic.