David Christensen received his Ph.D. from UCLA in 1987 and taught for 20 years at the University of Vermont before coming to Brown in 2007. His main research interests are in epistemology (formal and informal).
His book, Putting Logic in its Place, investigates the role of logic in constraining rational beliefs and degrees of confidence. He's also written papers on this topic and others, such as: What determines whether a given bit of evidence supports or refutes a given theory? Can thinking about the meanings of our words help us resist skepticism? Does the fact that one believes something provide some justification for continuing to believe it? How should one's beliefs be affected by one's knowing that other people, who are equally informed, rational and intelligent, believe differently?
Christensen is currently working on questions about how our theory of rational belief should in general accommodate one's doubts about one's own cognitive reliability.