Cognitive scientists of religion and evolutionary theorists alike have been increasingly arguing in recent years that religion is "natural" in the sense of being motivated by core, evolved psychological intuitions. Atheism, and irreligion more generally, appear to pose problems for the naturalness hypothesis, especially considering the significant proportion of people in contemporary societies who reject supernatural beliefs. Although Geertz and Markússon clarify why the naturalness hypothesis does not imply religious determinism, they fail to weigh adequately the more conservative prediction, that of religious probabilism. Furthermore, unlike cognitive scientific accounts favoring the naturalness hypothesis, the authors base their argument...