Final answer:
The decline of the significance of religion is termed secularization, a process where society moves towards secular beliefs and values with less influence from religion. Historical sociologists anticipated this change as society modernizes.
Step-by-step explanation:
The decline of significance of religion is called secularization. This concept interests sociologists and other social observers because it represents a pattern of change within a fundamental social institution. Secularization refers to the process by which society becomes less influenced by religion and more oriented towards secular beliefs and values. Notably, historical sociologists like Émile Durkheim, Max Weber, and Karl Marx, as well as psychoanalyst Sigmund Freud, predicted that the modernization of society would bring about a decrease in the influence of religion.
The secularization process has been documented through various polls and research studies, such as the Pew Research Poll, which shows a rise in the number of people who identify as having no religious affiliation. However, it is important to distinguish between those who are 'nones'—people with no religious affiliation, which may still hold spiritual beliefs—and agnostics or atheists, who have specific beliefs regarding the knowledge or existence of a god or gods. The complexity of religious life and emerging trends can be reflected in the context of the United States through the emergence of megachurches, the persistence of religious practices in secular contexts, and the impact of religion on social change.