A normative historiography of philosophy: room for internalism and externalism

Change in the human past, studied by historians, includes changes in philosophy's past, which can be explained by causes, motives and reasons. In the case of philosophy, must explanatory antecedents of change always be philosophical? Should philosophers ever treat non-philosophical reasons as belonging to the history of philosophy? Saying 'never' is absolutely internalist, while 'sometimes' rejects this absolutely internalist rule. To show that 'sometimes' is the better answer, I examine two case histories from the early modern period: these cases, framed by a taxonomy of historical narrative, eliminate absolute internalism.