In assembling an array of disciplines to study religion, nature and culture, the International Society for the Study of Religion, Nature and Culture presents an opportunity for progress through cross-fertilization and synthesis. In so doing, the Society also challenges us to communicate with each other despite our differing assumptions. Such communication requires, first, that we explicitly define our terms, not least the three terms central to the society’s name. Ideally, our definitions will be at once substantive, applicable cross-culturally, and explicitly embedded in theory. Fortunately, current scholarship makes such definitions appear possible. In the case of the term religion, for example, cognitive science supports defining it, broadly yet substantively, as a system of thought and action for interpreting and influencing the world, built on anthropomorphic premises. Anthropomorphism, in turn, may be theorized as the inevitable consequence of a strategy of perception for an ambiguous world: namely, guess first at what matters most. Similarly broad, substantive definitions appear possible for nature and culture as well.