Religions may draw upon scientific explanations of the world, in part, as a reliable way of knowing what the world is like, about which they seek to discern its ultimate meaning. However, “testing” of religious understandings of the world is incidental, implicit and informal in the course of the life of the religious community in the world. Religious understanding draws from both subjective insight and traditional authority. Therefore, some people view religion as based on nothing more than personal opinion or “blind faith,” and so, as immune to rational thought. However, this is an erroneous judgment. Virtually all of the historic religions include traditions of rational reflection.