Darwin's Cathedral

Darwin's Cathedral: Evolution, Religion, and the Nature of Society (ISBN 9780226901350) is a 2002 book by David Sloan Wilson which proposes that religion is a multi-level adaptation—i.e., a product of cultural evolution developed through multi-level selection.

Summary of the book
Wilson posits that religions are adaptive systems that have evolved to enhance their adherents' survival and reproductive success. He draws parallels between religious practices and biological traits, suggesting that religious behaviors can be understood as mechanisms that promote group cooperation and cohesion.

The book applies multilevel selection theory (a theory developed by Wilson), which considers the evolutionary impact of selection operating at various levels (e.g., genes – on the biological level, individuals, and groups). Wilson argues that religious groups, which often promote altruistic behavior among members, can be seen as units of selection in their own right.

Wilson examines several case studies of religious traditions and communities, including Calvinism in Geneva, Balinese water temples, and the early Christian church. These case studies illustrate how religious beliefs and practices have contributed to the success and longevity of these groups by fostering cooperation and group solidarity. The book highlights the role of religion in creating a sense of belonging and shared identity among members. Religious rituals and moral codes are seen as tools for maintaining social order and reducing conflict within groups. Wilson challenges the secularization theory, which predicts a decline in religious influence in modern societies. He argues that the adaptive benefits of religion ensure its persistence, even in secular contexts.

Therefore, Wilson’s evolutionary approach has implications on contemporary social issues. Wilson suggests that understanding the adaptive functions of religion can inform policy-making and strategies for addressing social challenges.

Reception
The Journal of the American Academy of Religion called it "a welcome book because it unsettles everybody, evolutionary biologist and religious believer alike". Jared Diamond in the New York Review of Books called it a "thought-provoking book" which "will stimulate each reader to examine his or her personal view of religion's future".