Historically, many thinkers have assumed that religion has a natural origin, but today researchers in the biosciences typically assume that its natural origin falls within the scope of evolutionary theory. For all scientific theories of religion, the general aim has always been to identify empirically the causal processes that operate in all human behaviors that are manifested in the phenomenon of religion. In our day, sociobiologists, evolutionary psychologists, and neuroscientists have advanced theories about the evolutionary causes of religious cognition and behavior. Although the life and behavioral sciences are becoming increasingly unified under the overarching paradigm of evolutionary theory, a consensus on the evolutionary explanation of religion – its development and function – may not quite yet be on the horizon.