By the 1920s in Central Europe, it had become a truism among intellectuals that natural science had "disenchanted" the world, and in particular had reduced humans to mere mechanisms, devoid of higher purpose. But could a new science of "wholeness" heal what the old science of the "machine" had wrought? Some contemporary scientists thought it could. These years saw the spread of a new, "holistic" science designed to nourish the heart as well as the head, to "reenchant" even as it explained. Critics since have linked this holism to a German irrationalism that is supposed to have paved the...