Ignorance or disregard of our evolutionary heritage, and of the fundamental biological, emotional, cognitive, and social similarities on which much in everyday human life and thought depend, can lead to speculative philosophies and empirical programs that misconstrue the natural scope and limits of our species-specific abilities and competencies. The intellectual and moral consequences of this misconstrual have varying significance, both for ourselves and for others, for example, in the ways relativism informs currently popular notions of "separate but equal" cultural worlds whose peoples are in some sense incommensurably different from ourselves and from one another. Relativism aspires directly to mutual tolerance of irreducible differences. Naturalism-the evolutionary-based biological and cognitive understanding of our common nature and humanity-aims first to render cultural diversity comprehensible. If anything, evolution teaches us that from one or a few forms wondrously many kinds will arise.

Mature cognitions of folkpsychology and agency include metarepresentation. This involves the ability to track and build a notion of self over time, to model other minds and worlds, and to represent beliefs about the actual world as being true or false. It also makes lying and deception possible. This threatens any social order. But this same metarepresentational capacity provides the hope and promise of open-ended solutions to problems of moral relativity. It does so by enabling people to conjure up counterintuitive supernatural worlds that cannot be verified or falsified, either logically or empirically. Religious beliefs minimally violate ordinary intuitions about the world, with its inescapable problems, such as death. This frees people to imagine minimally impossible worlds that seem to solve existential dilemmas, including death and deception.

Religious ritual invariably offers a sacrificial display of commitment to supernatural agents that is materially costly and emotionally convincing. Such ritual conveys willingness to cooperate with a community of believers by signaling an open-ended promise to help others whenever there is true need. These expensive and sincere displays underscore belief that the gods are always vigilant and will never allow society to suffer those who cheat on their promises. Such a deep devotion to the in-group habitually generates intolerance toward out-groups. This, in turn, leads to constant rivalry and unending development of new and syncretic religious forms.