On the contrary, the growth of a diverse range of methodologies consistent with the requirements of science, and the appearance of philosophical theories to justify them, were both symptoms of a deep-seated and all-pervading intellectual mood that had dominated western thought since the first half of the nineteenth century. In this sense, the popularity of philosophical theories supporting the extension of scientific methods to the study of social phenomena was itself due to the power of the dominant intellectual climate within which they emerged. Rudolph Carnap, one of the principal architects of this supportive philosophy, described, in the preface to his famous Aufbau, how his philosophical theories and the prevalent intellectual outlook were mutually reinforcing: