Abstract
This paper argues that decision theory presupposes free will. Although decision theorists seldom acknowledge this, the way decision theory represents, explains, or rationalizes choice behaviour acquires its intended interpretation only under the assumption that decision-makers are agents capable of making free choices between alternative possibilities. Without that assumption, both normative and descriptive decision theory, including the revealed-preference paradigm, would have to be reinterpreted in implausible ways. The hypothesis that decision-makers have free will is therefore explanatorily indispensable for decision theory. If we regard explanatory indispensability as an indicator of reality in science, decision theorists should embrace the idea of free will.