In The History of the Race Idea: From Ray to Carus, Eric Voegelin places the rise of the race idea in the context of the development of modern philosophy. The history of the race idea, according to Voegelin, begins with the post-Christian orientation toward a natural system of living forms. In the late seventeenth century, philosophy set about a new task - to oppose the devaluation of man's physical nature. By the middle of the eighteenth century the effort of philosophy was to place man, with his variety of physical manifestations throughout the world, within a systemic order of nature. Voegelin perceives the problem of race as the epitome of the difficulties presented by this new theoretical approach.