The Enlightenment model of progress can be termed the "suppression and revival" version, as an account of how Western civilization began with the ancient Greeks and progressed through Roman civilization, but then was suppressed the arrival of the Christian Church as the dominant cultural force in the West. Enlightenment thought was based on the idea that there exists in nature one kind of reason that rejects bigotry and theology, and that arose independently of the religious constrictions of the Middle Ages; the rise of various philosophical ethical theories that competed with one another was the result. The Enlightenment idea of a vast separation, a cultural transition of such depth that it is often called a "revolution," was first challenged in the late nineteenth century and not as a result of postmodernist ideas. Kant elaborates his vision of a natural progression of human history to a cosmopolitan society.