The cogency of a scientific study utilizing historical data tends to be, unfortunately, very largely a matter of the methodological presuppositions of the reader. Indeed, the barriers to a more general and thorough scientific use of history are, for the most part, methodological. There are two such barriers: (1) the uncertainty as to the validity of an intensive scientific investigation of historical problems, and (2) the lack of a clear delineation of the fields of research.

Concerning the first, two problems must be considered: on the one hand, the nature of historical knowledge (the methodology of “history”) and on the other, the nature of scientific knowledge (the methodology of “science”). The predictive assumption of the present discussion is that to understand the essential identity of historical and scientific knowledge (though not of methods and problems) is to justify the scientific manipulation of data which are unquestionably historical. The thesis which is being argued here is that all data are historical, that all reality—whatever its level or type—is event-structured, that events have an existential dependence on one another, that therefore relationships of relevance and causation may be established, and that the determination of such relationships is the function of scientific research in any field.