There are two basic approaches to defining religion: a substantive approach, which focuses on the content of belief; and a functional approach, which focuses on what the belief system does for the individual or community. As James Davison Hunter explains:
The substantive model generally delimits religion to the range of traditional theism: Judaism, Christianity, Islam, Hinduism and so on. The functional model, in contrast, is more inclusive. By defining religion according to its social function, the functional model treats religion largely as synonymous with such terms as cultural system, belief system, meaning system, moral order, ideology, world view and cosmology.
In other words, a functional definition describes religion as “a set of beliefs, actions and emotions, both personal and corporate, organized around the concept of an Ultimate Reality. This Reality may be understood as a unity or a plurality, personal or nonpersonal, divine or not, and so forth, differing from religion to religion.” Such a definition clearly encompasses the worldview of Secular Humanism.
U.S. courts have moved from a generally substantive definition of religion (where the religion must affirm a transcendent deity) to a functional definition of religion even including Secular Humanism. For example, in United States v. Kauten (2d Cir. 1943), conscientious objector status was granted to Mathias Kauten, not on the basis of his belief in God, but on the basis of his “religious conscience.” The court concluded: “Conscientious objection may justly be regarded as a response of the individual to an inward mentor, call it conscience or God, that is for many persons at the present time the equivalent of what has always been thought a religious impulse.” Thus, the court clearly adopted the functional definition of religion as opposed to a substantive or distinctly theistic one….
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