The tendency to claim God as an ally for our partisan value and ends ... is the source of all religious fanaticism. — Reinhold Niebuhr

Once considered exclusively a matter of religion, theology, or scriptural correctness, use of the term "fundamentalism" has recently undergone metaphorical expansion into other domains and other forms of absolutist ideological expression. In the public and media portrayal of fundamentalism in particular, political militancy has superseded concern over texts, as one gathers from the identification of fundamentalisms in non-Abrahamic religion zones such as South Asia — for instance, the Hindu Rashtriya Swayamsevak Sangh (RSS). In the present section we focus on religious fundamentalism.

Religious fundamentalists often have a point: there really are drastic challenges and threats to what they hold dear and what is worth holding dear. They feel that their rich heritages are being marginalized. They resent the rational superficializing of religious themes and symbols. Dedicated to changing a world they see as godless, their aim is not necessarily to preserve or recreate the past. Inhabiting the modern technical world, they attempt to cast off its pernicious, dehumanizing, materialistic philosophy.

But none of this is what constitutes them fundamentalists.

What constitutes them religious fundamentalists is that they lay claim to preaching and practicing "the unvarnished word of God" as revealed in the Bible, the Koran, or some other text deemed sacred. This claim undergirds their larger assertion that their authority comes directly from God and thus their program for reform and transformation is, in principle, beyond criticism.

Religious fundamentalisms engage in "selective retrieval" — the picking and choosing of certain "fundamentals." The serviceable fundamentals are used for setting boundaries, for attracting one's kind and alienating other kinds, for demarcating. The result is always an exclusive or separatist movement and a Manichaean world view: there is no place for mediators between "the people of God" and "the enemy of God."

With absolutism comes authoritarianism: it is impossible for religious fundamentalists to argue or settle anything with people who do not share their commitment to a specific authority. The enemies of fundamentalisms everywhere are relativism (particularly moral relativism), pluralism, ambiguity, uncertainty.

In fundamentalist hands, the complex, multivocal, ambiguous treasury of mysteries is reduced to a storehouse of raw materials to be ransacked as needed for building a political or religious program. Fundamentalisms prosper because they succeed in providing satisfying explanations and motivations for millions.

Negatively characterized, fundamentalism lies in the inability to imagine or penetrate the unthinkable or unthought, or to venture into uncharted ideological territory.