As early as the 1920s, Mannheim (1980, p. 84) criticized the way natural-scientific psychology had anchored is logic of empirical research. Unlike many others, however, he was able to successfully work out his own theories. His work co-founded a research tradition, which is currently of great interest to the social sciences; psychology, however, has remained largely unaffected. For Mannheim, the essential one-sidedness of nomothetic, natural-scientifically oriented methodology lies in its hypostatizing "one type of knowledge"—i.e., theoretical knowledge, abstracted from existential relations and exclusively geared towards universal validity, as it is—"as knowledge per se" and "one type of concepts—the so-called exact concepts, which have their origin […] in definitions' (Mannheim, 1982, p. 217)—as the only type of concept suitable for scientific endeavour.