The way in which people espouse and enact their religious beliefs and values constitutes a religious orientation. For example, Christians follow the way of life that Jesus taught, using the Bible as a guide, while agnostics subscribe to a religious orientation rooted in doubt—believing that humans can neither prove nor disprove God's existence. Often, diverse religious subcultures form based on common religious orientations. This entry first describes various approaches to defining and measuring religious orientation and diversity. It then examines the implications for religious diversity of exclusivist, inclusivist, and pluralistic religious philosophies and suggests principles that can help ensure the existence of religious diversity.