Introduction: Logic and Methodology in the Early Modern Period

Introduction

Being mainly concerned with the origins and development of formal logic, current “histories of logic” often devote scarce, if any, space to logic in the early modern period. In standard narratives, emphasis is put, on one side, on Aristotle’s Organon and on the Stoics’ logic of propositions, and on the other side, on the development of mathematical logic from Boole and Frege on (Scholz 1931; Bochenski 1956; Kneale 1962; Blanché 1970). The picture often emerging from such reconstructions represents early modern philosophers—net of their criticisms of Aristotelian syllogism— as largely estranged from the discipline. It is true that, the medieval period’s concern with semantic and inference issues has been accounted for (Prantl 1855–1870; Ashworth 1988; Biard 1989, 1997; Gabbay and Woods 2008). But it is as if there were a “mise en sommeil de la logique” in the seventeenth century (Blanché 1970, p. 174). Our purpose, in this special issue, is to take a stand against this view.

In addition to providing an incomplete image of the development of logic in general, such depiction of early modern logic also limits our understanding of the new forms of rationality which emerged during the period and especially their connection with the rise of modern science. Light is generally shed on a supposed “shift of emphasis from problems connected with purely formal logic towards the epistemological and psychological aspects of human cognition” (Nuchelmans 1998, p.104). But resort to epistemology and psychology as disciplinary categories supposedly qualified to account for the general features of early modern logic is only illuminating at first sight. This gesture does indeed reveal the wideness in scope of such logic: in this era, logic’s purpose is to teach how to accurately arrange and order mental materials in order to reason without error. It involves both theories of ideas and of the operations of the intellect, and descriptions of the knowledge acquisition process. In other words, in the early modernperiod, presentations of the steps for the building of a reasoning, of forms of reasoning and of their uses are commonly closely intertwined with remarks about the acquisition of ideas and about the grooming of the cognitive faculties. This is a complex intertwinment. However, the elucidation of its philosophical import is not made fully possible by a mere reference to epistemology and psychology of knowledge. It is true that these terms properly indicate the kind of issues frequently addressed within the field of seventeenth century logic (Hatfield 1997; Michael 1997). Still, as such, they do not sufficiently clarify the philosophical agenda they are used to account for. It is not just that they are anachronistic. It is not just that their convenient advocacy is commonly part of an exemption strategy from thorough investigation into the institutional, scientific and cultural reasons for the many reshapings of the systems of knowledge that early modernlogic stems from. Most of all, it is that, within the framework of the traditional narratives of the history of early modernlogic, epistemology and psychology, on the one hand, formal logic, on the other hand, are commonly treated as mutually exclusive terms. It is as if the seventeenth-century treatment of logic in non exclusively formal terms were tantamount to a rejection of this essential component of logic (MacFarlane 2000), or at least, to an indifference towards it.

We suggest that such narratives do not accurately describe the shape taken by this discipline in this historical period: they are not focused on the task of emphasizing the concrete philosophical import of what they call the “epistemological turn” in logic. Rather, they state bluntly that “these developments were on the whole not good for logic; certainly they were not good for formal logic” (Michael 1997, p.2). In this respect, they constitute stepping stones for an methodologically poorly-oriented archeology of modern logic: while they aim at identifying when and why logic and psychology began to be set apart from one another, they consider any attempt to deal with them altogether as an error. In so doing, they make use of criteria which are foreign to seventeenth century actor categories...