Substantive Definition: Max Weber 1905 - religion is belief in a superior or supernatural power that is above nature and cannot be explained scientifically
Substantive = exclusive
Functional: Durkheim 1915 - defines religion in terms of contribution it makes to social integration rather than a specific belief in god or the supernatural
Functional: Milton Yinger 1970 - religion answers the 'ultimate questions'
Functional = inclusive
Constructionist: not possible for a single fixed definition