One of the reasons why a historian may be suspicious of the use of the term Forerunner, while operating freely and frequently with its Latin equivalent “antecedent,” is its possible causative connotation. It might seem to imply a concept of history which presupposes determination by a pre-established divine plan or by its secular equivalent, immanent historical laws.
We do not feel that it should be the task of the historian of ideas to establish causal connections in the historical succession of these ideas. Rather, his goal should be, by drawing on these antecedents as illuminating parallels, to place ideas in their own context and point to their particular characteristics and their changing structures.
Accordingly the standard for a Forerunner cannot be that he “caused” the Reformation in one respect or another, for example, by exercising direct or indirect influence on Luther; the study of the Forerunner is determined rather by the wish to give Reformation thought its proper historical context.
The importance of the study of economic, political, social, and psychological factors is by no means denied by such a study.
On the contrary, the shift from a causal to a contextual reading of the history of thought has the advantage of not entering into competition with any of these approaches but provides instead a perspective for measuring the changes in the configuration of questions and answers.
Thus the use of the category of Forerunners does not function to establish the nature of the cause but to describe the structure of the change.
Heiko A. Oberman, “Forerunners of the Reformation”, New York, NY: Holt Rinehart and Winston, ©1965, pp. 38–39.