There can be little doubt that religious life has changed within recent centuries in western Europe. But how to describe and how to define this change is highly controversial. The relationship between the object of historiography and the methods to get hold of it is at stake. In this situation the so-called ‘linguistic turn’ indicates a new awareness of the concepts used for the description of historical change. In the 1960s and 1970s it was a widely accepted strategy of historians to adopt some kind of theoretical model from other disciplines, mainly from political and social sciences, and to apply it to past societies. But this strategy seems less acceptable today, and it is not difficult to see the reasons for the growing reluctance among historians to go on in the same way as before: there has been a long discussion about the usefulness of the master-concepts of social sciences such as ‘modernisation’ and ‘social differentiation’, which I do not want to go into here. Today we may sharpen and modify them in order to accommodate them to new experiences and new needs of scientific research. But in any case we have to accept the fact that the concepts which serve to describe historical change are part of this change themselves. It seems to become more and more obvious that the scientific language can no longer be excluded from being the object of historical investigation and reserved to systematic constructions.