Review of Ernest Sosa, Knowing Full Well

The substance of the book derives from Sosa’s inaugural Soochow Lectures in Philosophy, delivered at Soochow University in Taipei in 2008. The overriding thesis of the book is that epistemic normativity is a species of a more general and familiar kind of normativity: viz. performance normativity. More specifically, Sosa’s claim is that beliefs are cognitive performances evaluable in terms of norms and principles that apply to performances more broadly, and that knowledge is a cognitive performance that satisfies these norms. After laying out this account with characteristic care and precision, Sosa considers its bearing on several issues and debates in epistemology, including the Gettier problem, the value problem, contextualism, the nature of perceptual experience, testimony, and epistemic circularity.

Readers already familiar with Sosa’s influential work in epistemology are likely to wonder how this volume figures relative to two of his other recent and similarly themed works: A Virtue Epistemology (Oxford: Oxford University Press, 2007) and Reflective Knowledge (Oxford: Oxford University Press, 2009). In A Virtue Epistemology, Sosa introduced the idea that knowledge is a cognitive performance and applied this model to a host of epistemological issues. In this regard, its project is similar to that of Knowing Full Well. However, the present account of the performative aspects of knowledge is more detailed and nuanced than what is found in Sosa’s previous work. Knowing Full Well also extends this account in new directions and applies it to new problems. Sosa’s other recent book, Reflective Knowledge, mainly addresses the problem of epistemic circularity. While Knowing Full Well contains a chapter on epistemic circularity that draws on some of this work, its overlap with Reflective Knowledge is minimal. In short, Knowing Full Well is best viewed as elaborating on, further defending, and extending positions that Sosa has gestured at or developed previously. It is worth reading even for those already well acquainted with his work.