My main areas of research are the philosophy of mind and epistemology.
One of my earliest interests was the debate between internalism vs. externalism about mental content. In my book, The Subject's Point of View (Oxford University Press, 2008) I defended an uncompromising internalism about the mental, and an equally uncompromising conception of the phenomenal availability of mental features. Perhaps unsurprisingly, I have great admiration for Descartes, and I have hoped to make a modest contribution to restoring his reputation after a century or so of bad press.
I studied the nature of perception, especially the nature of perceptual intentionality. I defended a view I call "constructivism" about perception. According to this account, there is a form of sensory consciousness which is a mere modification of the subject’s consciousness and does not intrinsically point to any external objects beyond itself. But when these sensory features come together in a characteristically organised structure, they start to point to an experience-independent world – they become perceptual experiences.
I have written a series of papers with Tim Crane on the nature of standing mental states (i.e. states which are not part of the stream of consciousness). We propose that attributing these states is comparable to scientific modelling: we greatly simplify reality in attributing these states to serve prediction and explanation.
In epistemology, I have written about the nature of knowledge. Knowledge is sometimes classified into different kinds depending on its subject matter: knowing things, knowing facts and know-how. I am interested in the distinctive nature of these kinds, as well as in the question of why they are all called "knowledge". I also studied the question of whether belief is a necessary condition for knowledge, and suggested that extended mind cases can be understood as cases of extended knowledge.