Knowledge ascriptions, such as 'Sam knows that Obama is president of the United States', play a central role in our cognitive and social lives. For example, they are closely related to epistemic assessments of action. As a result, knowledge ascriptions are a central topic of research in both philosophy and science. In this collection of new essays on knowledge ascriptions, world class philosophers offer novel approaches to this long standing topic. The contributions exemplify three recent approaches to knowledge ascriptions. First, a linguistic turn according to which linguistic phenomena and theory are an important resource for providing an adequate account of knowledge ascriptions. Second, a cognitive turn according to which empirical theories from, for example, cognitive psychology as well as experimental philosophy should be invoked in theorizing about knowledge ascriptions. Third, a social turn according to which the social functions of knowledge ascriptions to both individuals and groups are central to understanding knowledge ascriptions. In addition, since knowledge ascriptions have figured very prominently in discussions concerning philosophical methodology, many of the contributions address or exemplify various methodological approaches. The editors, Jessica Brown and Mikkel Gerken, provide a substantive introduction that gives an overview of the various approaches to this complex debate, their interconnections, and the wide-ranging methodological issues that they raise.

On Folk Epistemology explores how we ascribe knowledge to ourselves and others. Empirical evidence suggests that we do so early and often in thought as well as in talk. Since knowledge ascriptions are central to how we navigate social life, it is important to understand our basis for making them. A central claim of the book is that factors that have nothing to do with knowledge may lead to systematic mistakes in everyday ascriptions of knowledge. These mistakes are explained by an empirically informed account of how ordinary knowledge ascriptions are the product of cognitive heuristics that are associated with biases. In developing this account, Mikkel Gerken presents work in cognitive psychology and pragmatics, while also contributing to epistemology. For example, Gerken develops positive epistemic norms of action and assertion and moreover, critically assesses contextualism, knowledge-first methodology, pragmatic encroachment theories and more. Many of these approaches are argued to overestimate the epistemological significance of folk epistemology. In contrast, this volume develops an equilibristic methodology according to which intuitive judgments about knowledge cannot straightforwardly play a role as data for epistemological theorizing. Rather, critical epistemological theorizing is required to interpret empirical findings. Consequently, On Folk Epistemology helps to lay the foundation for an emerging sub-field that intersects philosophy and the cognitive sciences: The empirical study of folk epistemology.

Scientific Testimony concerns the roles of scientific testimony in science and society. The book develops a positive alternative to a tradition famously expressed by the slogan of the Royal Society Nullius in verba ("Take nobody's word for it"). This book argues that intra-scientific testimony-i.e., testimony between collaborating scientists-is not in conflict with the spirit of science or an add-on to scientific practice. On the contrary, intra-scientific testimony is a vital part of science. This is illustrated by articulating epistemic norms of intra-scientific testimony and arguing that they are vital to scientific methodology on a par with other scientific norms governing scientific observation and data analysis. The book also provides an account of public scientific testimony-i.e., scientific testimony to the lay population. This is done by integrating philosophical resources with empirical research on the science of science communication. For example, various misconceptions about science and folk epistemological biases are diagnosed as factors that contribute to science skepticism. This diagnosis provides the basis for developing novel norms for science communication that are sensitive to the psychological and social obstacles to laypersons' uptake of it. Finally, the volume discusses how public scientific testimony is best embedded in society and argues that it is critical for societies that pursue the ideals of deliberative democracy. Scientific Testimony draws on philosophy of science, social epistemology, and empirical research to provide a wide-ranging account of the roles of scientific testimony within scientific practice and within the wider society.