Skepticism and the Prediction Objection

It is an influential and often repeated objection to external world skepticism that skeptical theories lead to implausible predictions about the patterns of ordinary epistemic discourse and thought. Since skepticism entails that we know nothing, or only very little, about the external world, the skeptic seems unable to explain why competent speakers constantly ascribe such knowledge to both themselves and others. Uncontroversial facts about every day communication hence appear to present a strong reason to reject skeptical conditions on knowledge. In this paper, however, I argue that this objection to skepticism underestimates the means that a skeptic has available to account for people's anti-skeptical assertions and judgments. A modest and highly plausible error theory enables the proponents of a familiar type of skeptical underdetermination principle to provide a compelling explanation of our linguistic and doxastic behavior. So there is a type of skepticism with a powerful response to the charge that skeptical theories lead to unacceptable predictions.