(Ph.D., U.C. Berkeley). He is a professor in the mathematics department. Most of his work lies in set theory, and in particular in Gödel’s program for strengthening the set-theoretic foundation of mathematics through the addition of strong axioms of infinity. Broader philosophical issues concerning meaning and evidence for mathematical statements come to the fore here. Steel’s paper “Mathematics Needs New Axioms” (Bulletin of Symbolic Logic, vol. 6 (2000), 422-433) discusses Gödel’s program, with special attention to questions of meaning and evidence.