Tönnies’ distinctionsTönnies drew a sharp line between the realm of conceptualization (of sociological terms, including ‘normal types’) and the realm of reality (of social action). The first must be treated axiomatically and in a deductive way (pure sociology); the second, empirically and in an inductive way (applied sociology). Following Tönnies, reality (the second realm) cannot be explained without concepts, which belong to the first realm, or else you will fail because you try to define x by something derived from x. Tönnies’ ''Normaltyp'' was thus a conceptual tool created on a logical basis, an almost mathematical concept always open to subsequent refinement from a confrontation with the empirical evidence. The contrast with Weber’s ‘ideal type’ came from the latter’s ‘accentuation’ of certain elements of a real social process, which is under sociological (or historical) scrutiny - “the one-sided accentuation of one or more points of view ... of a great many diffuse, discrete, more or less present and occasionally absent ''concrete individual'' phenomena”, as Weber himself put it.Quoted in Alfred Schutz, ''The Phenomenology of the Social World'' (1997) p. 243 From Tönnies’ point of view, an ideal type cannot ''explain'' reality, because it is derived from reality by accentuation, but might help to ''understand'' reality. The normal type moved from abstract to concrete; the ideal type from concrete to abstract.
Weber's survivalNevertheless, Weber’s term survived in the sociological community, since his ''Idealtyp'' helped to understand social forces, and for him sociology had both to ''explain'' and to ''understand'' things – a daring combination, but successful in the eyes of many sociologists.