Abstract

Locke, Leibniz, and the Logic of Mechanism MARTHA BRANDT BOLTON l~ EARLY MECHANIST PHILOSOPHERS demanded a new standard of perspicuity in the natural sciences. They accused others of "explaining" phenomena in terms of obscurely defined, unconfirmed, and uninformative causes. These complaints were leveled, not just at the real qualities and forms of Scholastics, but also against the sympathetic attractions of Hermetics and the sophic prin- ciples of the Spagyrites. These competitors to mecha- nism could at best demonstrate that a certain effect occurs and claim to state why it does. Mechanists aspired to explain how phenomena are produced. 1 Beyond that, however, philosophers in the broadly "mechanist" movement shared no single account of what this sort of explanation involves. They were too diverse, not only in their views on the central notions of material sub- stance, cause, and force, but also with respect to their standards of intelligibil- ity. In this paper, however, I want to isolate one mechanist model of explana- tion with intellectual virtues that strongly recommended it in some quarters. I will argue specifically that it influenced Leibniz and Locke. This favored form of mechanism opens a deep problem, because it con- flicts with the existence of causal interaction between bodies and minds. 2 It is not just that the model does not apply beyond the realm of intercorporeal ' Much of the work of documenting this trait..