Marx, Mill, Hegel, Nietzsche, Kierkegaard, Emerson, Darwin, Freud and Weber brought to the nineteenth century new realms of thought, which still continue to wield substantial influence today. As a result, the study of history, science, psychology, philosophy, sociology and religion have never been the same. These heirs to rationalism began to explore the full range of human experience--which became a matter of philosophical and theological interest,...