Some 30 years later, these two claims became the foundation stones for Bayesian decision theory. One focus of Mark Kaplan’s research has been to assess what there is for an epistemologist to learn from Bayesian decision theory. In a series of papers and the monograph, Decision Theory as Philosophy (Cambridge 1996), Kaplan has been arguing that, suitably formulated, Ramsey’s claims constitute essential contributions to epistemology.

But since the publication of that monograph, his attention has been increasingly drawn to the writings of another English philosopher, J. L. Austin. Austin, a force at Oxford for the 15 years after the end of the Second World War, was famous for having written, in “Other Minds” and Sense and Sensibilia, as if what we say while doing epistemology needs to accord faithfully with what we would say in ordinary life. Most would have used the word “infamous”. Not long after Austin’s death in 1960, there formed a durable consensus that his “ordinary language” approach to epistemology was fundamentally misguided, born of a failure to understand the nature of the epistemologist’s project. The second focus of Kaplan’s research has been to show that this consensus is based on a misreading of Austin. In another series of published works, culminating in the monograph, Austin’s Way with Skepticism: An Essay on Philosophical Method (Oxford 2018), Kaplan has argued that, far from being the product of some misunderstanding, Austin’s way of doing epistemology was in fact born of a telling critique of how epistemology has been done. Kaplan’s writings since have provided a further defense of this reading of Austin (and of Austin so read), as well as concrete examples of the progress in epistemology that can be made, once we resolve to do epistemology Austin’s way.

He is the author of Knowledge and Belief (Routledge, 1992), Truth: A Primer (Westview, 1995), and Hume’s Epistemology in the Treatise: A Veritistic Interpretation (Oxford University Press, 2014), as well as the editor of Socializing Epistemology (Rowman and Littlefield, 1994), Socializing Metaphysics (Rowman and Littlefield, 2003), and Theories of Truth (Blackwell, 2004). He is currently an associate editor of the journal Episteme. He has written on reliabilism and naturalistic epistemology, internalism and externalism in epistemology, and the relation between epistemology and cognitive science. He has also written on ancient skepticism and on the epistemologies of Descartes, Hume, and Peirce. His current interests are in social epistemology, social metaphysics, virtue epistemology, and Hume’s epistemology. In social epistemology, his particular interests include the epistemic status of testimony, the nature of group knowledge, and the social status of epistemic norms. In social metaphysics, he is concerned with the nature of groups and with social norms and conventions. He has an interest in virtue epistemology and cognitive abilities, and he has written on intelligence and curiosity. In Hume’s Epistemology in the Treatise, he argues for a reliabilist interpretation of Hume on knowledge and justification. He is also working on Hume’s philosophy of mind and theory of representation. He has an interest in Reid’s philosophy of mind and epistemology and expects to work on them in the future.

In a series of papers and books, culminating in Taking Frege at his Word (Oxford 2021), Joan Weiner offers an alternative to the standard interpretation, one designed to make sense of Frege’s writings in the light of his own characterizations of his project. Read in this way, Frege does not hold many of the views traditionally attributed to him. This result, Weiner argues, makes Frege’s work more, not less, important for us today. For, she argues, many current writings about semantics have difficulties making sense of good scientific methodology. Frege’s writings, properly understood, offer us a way around these difficulties and they offer solutions to apparently intractable puzzles about vagueness and the nature of numbers. Weiner’s research has been supported by the National Science Foundation, the American Philosophical Society, the National Endowment for the Humanities, the Bogliasco Foundation, and the Guggenheim Foundation.