The professor in Philosophy at the University of Aarhus, Svend Ranulf, at the time of Geiger's professorship there in Sociology, wrote a textbook about social science methodology, making arguments against some social scientists' methodologies. In particular, he argued against Geiger. Ranulf had been an applicant for the professorship position that Geiger was awarded in 1938. Ranulf alluded in his textbook that the methodologies of some sociologists, among them Theodor Geiger, could lead to a new Nazi movement. In 1946 Geiger wrote and published a short book, "Ranulf Contra Geiger, an Attack and an Offensive Defense". In this book, Geiger outlined very carefully what his methodologies were, emphasizing that empirical sociology is built on concepts but is a quantitative study of social processes and phenomena. He validated one point made by Ranulf, that data should be collected in a non-biased way but he also defended that concepts come prior to data collection in research, and although such concepts may need revision after collection of data is through, any data collection without a conceptual foundation is illogical. In response to Ranulf's opposition to qualitative data and interpretation, Geiger argued that these were okay for analysis as long as the researcher maintained a value-free approach.