Religion appears in every known human society, from the smallest hunter-gatherer bands to the largest civilizations. It provides what no other institution fully replaces: a framework for meaning that explains why suffering exists, a moral community with shared obligations, rituals that mark life transitions, and a relationship to death that makes it bearable. Durkheim observed that even where the content of religious belief varies enormously, its social function — creating collective identity and shared moral reality — is universal.

What distinguishes religion from mere mythology or philosophy is the sacred: beliefs and objects that are set apart from ordinary life and treated with absolute seriousness, not subject to cost-benefit analysis. The sacred creates moral commitments that feel non-negotiable — things one would not do regardless of personal benefit. This makes religion enormously useful for social coordination: it creates reliable cooperators who will act according to shared norms even when no one is watching, because the sacred enforces behavior internally.

The persistence of religious belief in modern secular societies challenges simple rational-actor models of human behavior. People maintain religious commitments even when they conflict with material self-interest, accept beliefs that are empirically unverifiable, and perform costly rituals with no obvious material return. These patterns make more sense when we understand religion not as a claim about empirical facts but as a system for coordinating behavior, providing meaning, and creating community — functions that reason alone cannot fully replace.