Abstract

One of the most puzzling features of Leibniz's philosophy is his insistence that bodies, material things located in space and time, are in reality "aggregates of monads"--infinite collections of immaterial, mind-like substances. Since the 18th century, this position has often met with incredulity. In this study, I develop an interpretation of Leibniz's view which defends it against the charge of obvious incoherence. I argue that the aggregate thesis rests on Leibniz's assertion of a necessary conceptual relation between the essences of matter and monad, and that this assertion is consistent with his denying that material things are spatial aggregates of unextended substances. The proposition that a body is in essence an aggregate of monads is supported by what I call Leibniz's "analyzability thesis" . According to AT, a complete analysis of the concept of body terminates in the concept of a plurality of monads. Leibniz defends AT through two complementary analyses of our phenomenal conception of body: the first begins with the simple notion of body as a composite of spatial parts, the second with the physicist's notion of body as extension endowed with force. ;Leibniz's account of the reality of body is an unusual one. Its most striking feature is his rejection of the assumption that for perceptions as though of bodies to be grounded in reality there must exist, independent of minds, extended beings located in space and time. Leibniz's interest in the issue of the reality of body pertains almost exclusively to the essence or nature of bodies. What is real about bodies, he believes, is that their essence is analyzable in terms of the essence of substantial or per se real beings. Consequently, bodies derive the possibility of their existence from the prior existence of monads. This conclusion is consistent with Leibniz's denying that there is a demonstrative relation between the appearances of bodies and reality. The most that can be known with certainty is that if something is the veridical perception of a body, then it is "well-founded" in the reality of certain monads.