I will be giving a presentation entitled “Leibniz on the Instincts of Machines of Nature and Souls” at the meeting of the Society for the History of Philosophy of Science (HOPOS) in Groningen this July.
Abstract for the presentation:
In recent years, scholars interested in Leibniz’s approach to the life sciences have shed light on Leibniz’s conception of living bodies as machines of nature. For Leibniz, living bodies are infinitely complex mechanisms whose organic structure is preformed by God. In this regard, there is no genuine generation or corruption within the course of nature; events such as bodily conception and death are rather moments within the larger development of a pre-given and infinitely complex mechanical structure. Leibniz, for the machine to truly be infinite in structure, each part must be a further machine of nature, in turn, such that there are infinitely many smaller machines of nature nested within the initial mechanical structure. Not only does Leibniz’s concept of the machine of nature represent an empirically informed model of the living body consistent with contemporary microscopical findings, it represents a mechanical account of life that is amenable to traditional natural theology insofar as it essentially incorporates divine design.
Commentators treating the machine of nature in Leibniz have not, however, sufficiently treated its correspondence with the immaterial soul. Overlooking this correspondence risks neglecting an crucial dimension of Leibniz’s account of the living being insofar as in Leibniz’s metaphysics, body and soul operate in parallel to each other according to a harmony preestablished by God. On this account, insofar as the body is an infinitely complex machine of nature whose movements are subject to divine preformation, the soul’s perceptions unfold alongside these bodily motions in a way subject to divine preformation in turn. Further, since the movements of the bodily machine of nature are in harmony with the perceptions of the soul, Leibniz argues that the soul corresponding to a particular machine of nature represents everything taking place within the machine’s organic structure. Thus, the soul confusedly represents an infinite number of bodily motions.
In this presentation, I argue that Leibniz develops a concept of instinct to connect soul and body and explain how the soul represents the infinite structure of the body. In short, I argue that both body and soul carry out their divinely preformed operations by virtue of an instinct implanted in them by God. I focus on the role of instinct in two texts: Leibniz’s Animadversions with the medical philosopher Georg Ernst Stahl – one of the most significant expositions of Leibniz’s conception of organic body and its relation to the soul – and the Theodicy. I show that Leibniz attributes the way that both body and soul change in harmony with one another to instinct. In the case of the body, instinct explains the infinite mechanical unfolding of organs, whereas in the soul, it explains how the perceptions of a finite soul represent the infinite number of events taking place at any given time in the body. The presentation thus contributes to ongoing discussions of Leibniz and the life sciences by drawing attention to Leibniz’s concept of instinct as an integral part of the living being that underpinning the correspondence of soul and body.