Weber’s Lacuna: Medieval Religion and the Roots of Rationalization Lutz Kaelber Few works in twentieth-century social thought have received as much attention as Max Weber’s The Protestant Ethic and the Spirit of Capitalism, which appeared in its original form in 1904–5. 1 Weberian scholars and critics have focused on the links between religion and the modern economy, but have overlooked an important component of Weber’s study—medieval religion. Analyzing the cultural significance of modern ascetic rationalism, Weber initially wanted to extend the PE stepping back in time and study the historical development of methodical rational ways of life preceding the Reformation. Between publication of the PE essays and his death in 1920, Weber then specified his research agenda and elaborated on his earlier views. First these specifications and elaborations were made as a response to a series of writings by Ernst Troeltsch, particularly The Social Teachings of the Christian Churches and Groups, 2 and later while preparing a study on The Christianity of the Occident as part of his Collected Essays in the Sociology of Religion. The purpose of this essay is to provide an analysis of Weber’s views on medieval religion as they evolved between 1904–5 and 1920, and to [End Page 465] show how Weber linked his explorations of medieval religion to his larger intellectual agenda, appropriating and transcending ideas current in contemporary historical and religious scholarship. Furthermore, I hope to demonstrate that the conclusions of the few existing studies of Weber’s views on this topic have to be revised. His remarks on medieval religion were not confined to the conceptualization of structural transformations in the Middle Ages; 3 nor did they contain the notion of medieval Christianity as a step backward in the course of Western rationalization. 4 On the contrary, Weber was interested in religious contributions and impediments to a rationalization of conduct in different groups in the Middle Ages, and while he saw largely impediments in orthodox lay religion, he presumed the existence of precursors to Calvinist ascetic rationalism in fringe and heterodox religious movements. In the development of his thought Weber’s interest in this topic runs through three phases: first, the years 1904–5, when the PE was published, containing the cornerstones of a sociological treatment of medieval religion; second, the years between 1906 and 1910, in which Ernst Troeltsch supplemented Weber’s treatment and elicited his response; and third, the years between 1910 and 1920, when Weber began to put medieval Christianity in the context of a comparative typology and historical analysis of religious rationalizations in the major world religions. The Protestant Ethic of 1904–5 5 In the PE Weber set himself the task of analyzing the contribution of religious factors in the early-modern period to the emergence of one constitutive component of modern culture, that is, methodical behavior based on the idea of a calling. Yet Weber’s intellectual interests went beyond this topic and era. The overarching issue was the cultural significance of Protestantism’s “ascetic rationalism,” which was to be studied for both later and earlier periods. In delineating the meaning of this concept, Weber was careful to point out that ascetic rationalism of a religious providence was just one among many empirical forms the generic concept of rationalism could designate: [End Page 466] “One can very well ‘rationalize’ life according to very different ultimate points of view and in different directions; ‘rationalism’ is a historical concept that encompasses a world of differences.” 6 It was therefore necessary to provide a specification of the term, for which Weber took a cue from the economist Werner Sombart. In his Modern Capitalism (1902) Sombart had characterized the distinguishing feature of the modern capitalist economy as thorough “calculability” (Rechenhaftigkeit). Calculability denotes the precise, encompassing structuring of means for the achievement of capitalist profit. Weber found Sombart’s characterization highly accurate, 7 but also differed from him in two important aspects. First, he viewed calculability as a manifestation of a larger underlying process—ascetic rationalism. For Weber ascetic rationalism manifested itself in the thorough calculability of all social spheres, and it was not merely an institutional characteristic, as Sombart had defined it. Ascetic...