Darwinizing religion: William Irons' evolutionary theory of religion

This thesis examines William Irons' costly signaling theory of religion as an adaptation for intragroup cooperation. I provide a thorough exposition of Irons' theories of morality and religion and argue that Irons' description of religion as an extension of morality is more aptly the superimposition of religion onto morality, leading Irons to make theoretical arguments that do not justify his adaptive explanation. Establishing that religion is built on pre-existent non-religion-specific adaptations and contending that it is the most powerful hard-to-fake signal of commitment are not consistent with the claim that religion is an adaptation. In comparison to the adaptive approach, alternative evolutionary perspectives allow for a more sophisticated conceptualization and empirical testing of religion, and a survey of the coherency of Irons' arguments within those competing evolutionary frameworks reveals that they are consistent with a bio-cultural approach.