Despite its title, Leibniz's Specimen dynamicum, published in the 1695 Acta eruditorum, brings important conceptual innovations. It seems in particular to reveal a decisive shift in the ontological status that Leibniz grants to local motion, by which every corporeal change is to be explained. On the one hand, I propose to question the very disjunction between derivative forces (which produce local motion) and primitive forces. On the other hand, I will question the conception of passivity, which characterizes primary matter, as resistance to motion.
The Leibnizian thesis about the nature of motion is not without ambiguities. On the one hand, Leibniz holds a relativist conception of motion, based on the principle of equivalence of hypotheses; on the other, he tends to admit of absolute motion through his conception of active force. However, he supposes absolute motion as explaining the heterogeneity of phenomena, and he accounts for the determination of a subject of motion by applying the principle de maximis et minimis to the formulation of the most intelligible or simple hypothesis, which seems to imply that force owns an inherent architectonic disposition.
This paper examines Leibniz's conception of elasticity as a fundamental structural principle of matter and its role in the development of Leibniz's metaphysics of corporeal substances. More specifically, it focuses on the function of elasticity as a necessary condition for the storage and distribution of force within living bodies and as a structural requirement for physiological organization. This function meets the need to substantiate Leibniz's idea of a natural perpetual motion characterizing the internal economy of forces in living beings. The employment of elasticity to articulate this view points to the emergence of a metaphysics of real bodies-i.e., those of corporeal substances-conceived as structures that require the cooperation of other corporeal substances to realize the distribution of forces.
In the Dynamica de potentia, Leibniz works out the theoretical design of the dynamics, a "new science of power and action". Our investigation aims at showing how from abstract concepts of the parameters of motion Leibniz draws the principle of determination of formal action and how, on the basis of geometrically framed models, he infers sufficient causal reasons for a possible system of abstract bodies and motions and applies them toward the deduction of the actual dynamical laws. In this way, what pertains to metaphysics in this dynamical theory becomes readily apparent.
The invention of the dynamics as a new science closely relates to Leibniz's writing of the Dynamica de potentia in 1689-90. A few months earlier, in the Phoranomus, Leibniz had proposed a definition of power as the quantity of effect accomplished without expense of force. This article explores manuscript formulations that led from here to a definition of formal action as measured by mvs (mass times space times speed) or mv2 in the unit of time: hence an a priori demonstration of the principles of abstract dynamics centered around the notion of absolute power. The metaphysical implications of this conceptual framework distinguish Leibniz's dynamics from the historical mainstream of classical mechanics.
