Evolutionism is a term commonly employed to designate a number of similar, usually nineteenth-century anthropological theories that attempt to account for the genesis and development of religion. Although the term evolutionism could be used to describe a collection of theologians such as Pierre Teilhard De Chardin (1881–1955) and others belonging to the school of theistic evolution, this article will focus strictly on the uses of the term within the development of anthropological science.

Evolutionist theories of religion's origin hold in common a presupposed "psychic unity of mankind"; that is, they assume that all human groups are possessed of a more or less common developmental pattern (though the shape of this pattern differs from theorist to theorist) and that therefore significant clues as to how religion originated—and in turn as to what religion essentially is—can be detected through a study of the religious lives of the world's "primitive...