I work on issues in ethics, epistemology, and the philosophy of action. In ethics, I am interested in the contributions that intentions make to the evaluative and deontic status of actions. In epistemology I work on issues related to skepticism, epistemic circularity and perceptual knowledge. I believe that a good way to think about philosophical problems is to see them in the perspective of the history of the discipline, and much of my work has at least some historical aspect.