Definition of religion

The following definition is from Scott Atran, In Gods We Trust, 2003, pg 4:

"Roughly, religion is (1) a community's costly and hard-to-fake commitment (2) to a counterfactual and counterintuitive world of supernatural agents (3) who master people's existential anxieties, such as death and deception."

Graham Oppy gives the following definition of religion, following Atran's, and psychologist Ara Norenzayan's, lead (Four Views on Christianity and Philosophy, pg 22):

". . . in almost all human societies we find

1. widespread belief in gods, ancestor spirits, and other nonnatural agents;

2. hard-to-fake public expressions of costly material commitments to those nonnatural agents in the form of offerings or sacrifices of goods, property, time, and perhaps even life;

3. mastering of people's existential anxieties concerning death, deception, disease, catastrophe, pain, loneliness, injustice, want, and loss, by these costly commitments to nonnatural agents;

4. ritualized, rhythmic, sensory coordinations of items 1, 2, and 3 in communion, congregation, and intimate fellowship; and

5. evolutionary canalization and convergence of items 1, 2, 3, and 4 that tend toward passionate, communal displays of costly commitments to supernatural agents."

Keith Yandell provides two compatible definitions (Philosophy of Religion, 2nd ed., pg 10 & 11):

". . . a religion is a conceptual system that provides an interpretation of the world and the place of human beings in it, bases an account of how life should be lived given that interpretation, and expresses this interpretation and lifestyle in a set of rituals, rites, institutions, and practices."

"A religion proposes a diagnosis (an account of what it takes to be the basic problem facing human beings) and a cure (a way of permanently and desirably solving that problem) . . ."

Ben Clements, approaching the issue from a legal perspective, defines religion in the following way ("Defining Religion in the First Amendment: A Functional Approach", Cornell Law Review, Volume 74, Issue 3, 1989):

" . . . religion can be defined as a comprehensive belief system that addresses the fundamental questions of human existence, such as the meaning of life and death, man's role in the universe, and the nature of good and evil, and that gives rise to duties of conscience."

Clements responds to objections from underinclusiveness, overinclusiveness, risk of fraudulent religious claims, and risk of undue interference with government activity.

Notably, he clarifies that 'comprehensive' needn't mean addressing every question known to man, but rather that the belief system is wide-ranging (perhaps 'broad' would be the better word).