The term derives from a woman named Sheila Larson, who is quoted by Robert N. Bellah et al. in their book Habits of the Heart as following her own "little voice" in a faith she calls "Sheilaism".
[1] In chapter 9 of their 1985 book Habits of the Heart, Robert N. Bellah, Richard Madsen, William M. Sullivan, Ann Swidler, and Steven M. Tipton discuss how religion in America has moved from being highly public and unified, as it was in colonial New England, to extremely private and diverse.
The columnist Don Kahle concluded that Sheila "has a code of ethics, but it's no longer connected to a sacred text or an observing deity.
Their perspective was very much in line with the prevailing view of sociologists since the 1960s who saw such highly individualized religious experience as proof of a larger decline in the importance of religion in the United States as a whole.
"[6] The cultural critic Hal Niedzviecki juxtaposes Sheilaism with Judyism, the joke religion created by comedian Judy Tenuta.
"[7] Recent scholarship has re-evaluated Sheilaism, noting that even those who claim a particular organized denomination and regularly attend church often have highly individualized perceptions of their faith.