In his discussion of the forms of legitimate domination Weber notes that rational, legal domination is frequently combined with an important element of plebiscitarian democracy. He also suggests that the fact that the chief may be represented as the servant or agent of the people "naturally does nothing whatever to disprove the quality of dominance" (Weber 1978, p. 215). The element of democracy, then, does not mean here that the people rule. Rather it serves in the legitimation of a distinctively modern form of rule that combines a bureaucratic state and significant elements of charismatic domination. Ideas of popular sovereignty and the considerably weaker idea of the mandate are certainly invoked in these societies, and not only when elections are in the air. They play a significant part in political life, but they do not describe it properly. Weber's argument on this point exemplifies an important cautionary thesis concerning the role of ideas in social life. There is a clear sense in which ideas about the workings of particular social institutions may be embedded in the social institutions themselves and may function as essential lubricants in their day-to-day activities, but it does not follow that those ideas properly describe the institutions in which they operate. The ideas of democracy and popular sovereignty are well-known examples. Another example is the idea of politics as class struggle, which has played an important part in socialist and labor movement politics for much of the modern period. This paper makes a similar point about the idea of the person as rational actor. It is a ubiquitous component of Western social thought, figuring prominently both in the life of modern societies and in our attempts to make sense of it. The first part of this paper identifies what is involved in that idea. Next I go on to use a more general model of the actor, considered simply as a locus of decision and action, to under- mine the idea of the person as rational actor. It is necessary to distinguish 1) a capacity to employ conceptual tools and devices to construct a connected chain of reasoning or argumentation, and 2) the rationality (or otherwise) of the tools employed. What matters is to investigate what those tools and other devices are, rather than to make any prior assumptions about their rationality. The final section considers the implications of this argument for our understanding of what Weber calls the "specific and peculiar rationalism of modern culture" (1978, p. 26). [ABSTRACT FROM AUTHOR]