Colin Marshall talks to Steven E. Landsburg, professor of economics at the University of Rochester, Slate's "Everyday Economics" columnist and author of The Big Questions: Tackling the Problems of Philosophy with Ideas from Mathematics, Economics and Physics. A pioneer in the popular-economics genre with his 1993 book The Armchair Economist, Landsburg now focuses his quantitative mind on issues of epistemology, ontology, morality and otherwise that have heretofore remained mostly untouched by such analysis.