Big Gods were necessary but not sufficient for group expansion.

Evidence

Of course, Big Gods were a potent cause, but not the sole cause that led to the social expansion of some groups. Surely there are additional solutions to large-scale cooperation. Moreover, differential cultural success does not imply a moral hierarchy. But these groups would have been larger and more cooperative. These ever-expanding groups with high social solidarity, high fertility rates that ensure demographic expansion, and a stronger capacity to attract converts grew in size often at the expense of other groups. As they spread, they took their religious beliefs and practices with them, ultimately culminating in the morally concerned Big Gods of the major world religions. — Norenzayan, Ara, Big gods - how religion transformed…, 46

Categorization

• QUESTION: The book never fully specifies which ‘additional solutions’ to large-scale cooperation it means (economic institutions, kinship, warfare?); worth tracking through later chapters.