Richard Sellin is characterized by his "grand theory" of history, which posits that Western civilization's spiritual journey follows recurring 2,000-year cycles rather than a linear progression. He is known for arguing that while technology advances linearly, human spirituality and social structures recycle through phases of theocracy and secularism. His writing in the late 1990s was notable for its dismissal of "Y2K hoopla", correctly predicting that the new millennium would not bring a sudden apocalypse or paradise but rather a slow evolution into a new spiritual phase. His primary contribution is The Spiritual Gyre: The Recurring Phase of Western History, published by Lost Coast Press