I specialize in epistemology and cognitive science. I write on the epistemologies of perception and testimony from a proper function reliabilist point of view, among other issues in epistemology, at the intersections of philosophy of psychology, philosophy of biology, and philosophy of language. As for epistemic warrant (epistemic justification), I've argued that warrant consists in the normal functioning of the belief-forming process when the process has forming true beliefs reliably as an etiological function, such that the process reliably induces true beliefs in normal conditions when functioning normally.