From Pre-established Harmony to Physical Influx: Leibniz's Reception in Eighteenth Century Germany
- From Pre-established Harmony to Physical Influx: Leibniz’s Reception in Eighteenth Century Germany
In the present essay I shall be concerned with the reception of Leibniz in Germany during approximately the first half of the eighteenth century. Since others (Barber 1955, Beck 1969, Saine 1987, Überweg 1894–1902, Wundt 1945, Wilson 1994, Zeller 1873) have already presented overviews of the reception of Leibniz’s philosophy as a whole during this period, 1 I [End Page 136] shall focus on how one of Leibniz’s most important and peculiar doctrines, namely Pre-established Harmony, was received in this period. In the first section I shall briefly present Leibniz’s views on Pre-established Harmony and explain how it was modified by Leibniz’s most important advocate in Germany, Christian Wolff. I shall also give some indication as to how Wolff’s philosophy in general and Pre-established Harmony in particular gained immediate acceptance (in the early 1720s). The second section will highlight some of the most important objections that the Pietists raised against Wolff’s version of Pre-established Harmony and Wolff’s defense against those objections (from circa 1723–27). The third section will consider how one main alternative to Pre-established Harmony, namely Physical Influx, emerged in a tentative way within the Wolffian school (from the mid 1720s to 1734). 2 In the fourth section I shall explain how Physical Influx was then developed not only to respond to Leibniz’s and the Pietists’s objections but also to allow for a more sophisticated positive explanation of physical influx (1735). 3 In the fifth section I shall describe how one last attempt was made (in the late 1730s and early 1740s) to rescue Pre-established Harmony by taking explicit recourse to Leibniz’s rather than Wolff’s position. In the sixth section I shall briefly indicate how, this last rescue attempt notwithstanding, Physical Influx established itself, albeit with important exceptions, as the standard view (in the 1740s and 1750s). Thus, I shall attempt to show how throughout the course of Leibniz’s reception in Germany during the first half of the eighteenth century a gradual shift occurred from Pre-established Harmony to Physical Influx.
I. Leibniz and Wolff on Pre-established Harmony
As a first approximation, Leibniz’s Pre-established Harmony 4 consists in the claims that no finite substance can act on any other finite substance 5 and that any changes that occur in a substance are due rather to that substance’s own causal efficacy; Pre-established Harmony implies both a denial of inter-substantial causation and an assertion of intra-substantial [End Page 137] causation. Accordingly, the main alternatives to Pre-established Harmony are Occasionalism, which denies all finite causation whatsoever (i.e., both inter- and intra-substantial causation amongst finite substances), and a view that Leibniz dubs “influxus physicus”, or Physical Influx, which asserts inter-substantial causation. 6 Since almost no German philosopher in this period accepts Occasionalism (despite the fact that it is discussed by virtually everyone interested in the debate), 7 it is possible to focus primarily on Physical Influx. Leibniz’s main objections to Physical Influx are twofold. First, it is inconceivable how one substance could act on another substance, given that it is absurd to hold that an accident could migrate from one substance to another. Second, Physical Influx violates the laws of nature, since if the mind could act on the body, then there would be more motion in the world after this act than before it, which contradicts the law of the conservation of motion as described by Descartes. 8
One of Leibniz’s important motivations for his assertion of intra-substantial causation is his account of substance. Leibniz defines a substance in terms of a complete concept, that is, a concept which contains within itself all that will ever be true of that substance. Accordingly, the changes that occur in a substance are merely the result of the unfolding of its complete concept, a process that occurs through the spontaneous activity of the basic force of appetition that each substance possesses. Since each substance contains all of its predicates within itself, there is no...
