Ever since its beginnings, sociology has featured a trend to statements on trends such as the secularization, politicization, economization, mediatization, aestheticization, or juridification of society. These statements can be unfolded only against the background of functional differentiation and therefore call for a systematic reflection of functional differentiation as a whole. Most sociological research, however, implies rather than applies the concept of functional differentiation, or centers on one or few function systems without much further reflection as to why the focus is on the observed and not the unobserved function systems. Addressing this research gap, the present thesis gives evidence to the assumption that the identity of modern societies and their organizations is as much about function system (p)references in decision-making as it is about specific configurations of variables like age, culture, or gender.