Religious extremist

Fundamentalism usually has a religious connotation that indicates unwavering attachment to a set of irreducible beliefs. However, fundamentalism has come to be applied to a tendency among certain groups—mainly, though not exclusively, in religion—that is characterized by a markedly strict literalism as it is applied to certain specific scriptures, dogmas, or ideologies, and a strong sense of the importance of maintaining ingroup and outgroup distinctions, leading to an emphasis on purity and the desire to return to a previous ideal from which advocates believe members have strayed. Rejection of diversity of opinion as applied to these established "fundamentals" and their accepted interpretation within the group is often the result of this tendency.

Depending upon the context, fundamentalism can be a pejorative rather than a neutral characterization, similar to the ways that calling political perspectives "right-wing" or "left-wing" can, for some, have negative connotations.

Christian fundamentalism has been defined by George Marsden as the demand for a strict adherence to certain theological doctrines, in reaction against Modernist theology. The term was originally coined by its supporters to describe what they claimed were five specific classic theological beliefs of Christianity, and that developed into a Christian fundamentalist movement within the Protestant community of the United States in the early part of the 20th century. Fundamentalism as a movement arose in the United States, starting among conservative Presbyterian theologians at Princeton Theological Seminary in the late 19th century. It soon spread to conservatives among the Baptists and other denominations around 1910 to 1920. The movement's purpose was to reaffirm key theological tenets and defend them against the challenges of liberal theology and higher criticism.

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