Leibniz: Body, Substance, Monad - Daniel Garber

Abstract

Daniel Garber's last book is one of several publications on Leibniz's notion of substance (others are by D. Rutherford, C. Mercer, P. Lodge, L. Brandon), and may be seen as a challenge to Leibnizian idealism. Garber repeatedly asks the question ‘How should we understand the relations between the bodies that we experience and the monads that are, in some sense, their metaphysical foundation?’. In his preface, he warns readers that he has always ‘wondered how someone so smart as [Leibniz] was supposed to be could believe in something so strange’. This remark alone seems to justify his writing the book. In pursuing his initial question, Garber wonders about the mysterious relation between the monads and the bodies experienced in everyday life. Unlike most commentators, who consider the monads to be the starting‐point in understanding Leibniz's philosophy, Garber prefers to start with an analysis of the physical world in order to answer this question. Ch. 1 explains how Leibniz's first thoughts about the physical world came close to those of Hobbes and Descartes. Chs 2–4 show how Leibniz reaches his conception of corporeal substance in his attempt to solve the double problem of the unity and individuality of bodies. A material substance is at first defined as a body associated with a substantial form; then Garber explains how Leibniz apprehends the body as a passive force, and the substantial form as an active force. Ch. 5 discusses the notion of distinct and confused expression used by Leibniz to characterize, respectively, the active and passive force in bodies. It is clearly stated that between 1680 and 1690, in Leibniz's so‐called middle period, ‘expression’ did not have the mental connotation it has in the monadology. Ch. 6 analyses how the laws of nature combined with theological laws explain everything that exists. This leads to a presentation of the famous notion of the two kingdoms, the ‘kingdom of power’ and the ‘kingdom of wisdom’, referring respectively to the ‘efficient causes’ and ‘final causes’ at work in the world. Garber interprets these as a metaphor, although there is nothing in Leibniz's text to justify not taking them literally.