Selecting for Celibacy: Cultural Evolution and the Puzzling Case of Buddhist Celibacy

Buddhist celibacy provides an example of religious behaviour which appears puzzling from the vantage point of genetic selection, but whose maintenance can be partially explained because of the dynamics of cultural selection. In this thesis, I examine how and why celibacy is maintained and perpetuated within Buddhism and how this relates to the explanations cultural selection offers for costs within groups. I argue that celibacy is adaptive because it divides Buddhist communities into two parts, stimulating innate tendencies towards in-group cooperation without the need for an outside group. Because Buddhist celibates are also materially non-productive their presence necessitates increased cooperative behaviours in lay communities. I argue that the endurance of the parts of Buddhist traditions which are necessary to maintaining celibate practise provides evidence that cultural selection has shaped the tradition to perpetuate and reinforce celibacy, a behaviour which is adaptive because it promotes cooperative behaviours within a divided cultural group. Celibacy increases the cultural fitness of Buddhist communities.