There is nonetheless a gap between this semantic question about the nature of musical content and the problem of aesthetic value itself-a gap that Weber's own work registers with implacable lucidity, but that most subsequent historicisms have been at pains to disguise or conceal. There is just as surely a fundamental difference in emphasis as there is a spiritual kinship between Weber's interpretation of musical evolution in terms of the process of rationalization and Spengler's program for the morphology of cultures: