Max Weber's understanding of the role of people's interests in determining their behavior has been widely misunderstood, because of a misinterpretation of a famous passage in which he analogizes interests to railway “switchmen.” Contrary to this widespread view, Weber does not see material self-interest as the driving force behind human action. Rather, he distinguishes between material and “ideal” interests; emphasizes the latter; and, arguably, suggests that even the former are, to a great extent, culturally constructed, not least because they rely on ideas about the way the world is. It is almost fair to say, then, that the notion that Weber reduces ideas to interests has things completely backwards.