448 Notes to Pages 91-92
"real influx") awaken an inner principle of the monad that ultimately explains the
action ("ideal influx"). Real influx is ultimately based on ideal influx. Even Erd-
mann must admit that Baumgarten's "ideal influx" is identical to the theory of
preestablished harmony. Erdmann's claim that Baumgarten had "completely aban¬
doned" Leibniz's theory seems to me to rest on his failure to take seriously the
"phenomenal" character of real influx in Baumgarten (and Kant). Ideal influx
provides the foundation for real influx. For an important argument against this
claim, see Eric Watkins, "The Development of Physical Influx in Early Eighteenth
Century Germany: Gottsched, Knutzen, and Crusius," Review of Metaphysics 49
(1995), pp. 295-339, "Kant's Theory of Physical Influx," Archiv für Geschichte
der Philosophie 77 (1995), pp. 285-324, and "From Pre-established Harmony to
Physical Influx: Leibniz's Reception in 18th Century Germany," Perspectives on
Science 6 (1998), pp. 136-201. Watkins views Kant more as a follower of
Knutzen's. I see him as a follower of Baumgarten. There is at least the following
difference between Knutzen and Kant: Knutzen was arguing for real physical in¬
flux. Kant said, "Physical influx in the true sense of the term, however, is ex¬
cluded. There exists a universal harmony (influxus physicus proprie sic dictus ex-
cluditur, et est rerum harmonia universalis)." See Kant, Theoretical Philosophy,
1755-1770, p. 44 (Ak 1, p. 415). Though Kant took pains to differentiate uni¬
versal harmony from preestablished harmony, the two were close enough from
the Pietistic point of view. Indeed, Kant's claim that substances do not just agree
with one another (as Leibniz said), but actually "mutually depend" on one another,
might have seemed worse to the Pietists.- Ak 1, p. 171.
- It is likely that he would have rejected even at that time the idea that the univer¬
sal harmony was preestablished. See Chapter 2 of this volume. Michael Friedman,
Kant and the Exact Sciences (Cambridge: Harvard University Press, 1992), claims
that "Kant attempts to revise the Leibniz-Wolffian monadology in light of New¬
tonian physics," that his "primary notion of active force is not that of an internal
principle" but "that of an action exerted by one substance on another substance,"
and that Kant in this way has "imported Newton's second law of motion into the
very heart of the monadology" (p. 5). I agree with Friedman on this. Susan Meld
Shell, The Embodiment of Reason (Chicago: University of Chicago Press, 1996),
pp. 10-30, has a nice summary of Kant's position. Still, her claim that in The True
Estimation of Living Forces Kant "is flatly at odds with the claims of the Leibniz
Wolffian school" (p. 28) seems to me not quite correct. In his most significant
claims about what she describes as "cognitive dualism," Kant was close to
Gottsched, his philosophical predecessor in Königsberg. The most extensive
account of the problem of physical influx and its relation to Leibniz-Wolffian
philosophy is found in Gerd Fabian, Beitrag zur Geschichte des Leib-Seele Problems
(Lehre von derprästabilierten Harmonie-und vom psychophysischen Parallelismus in
der Leibniz-Woljfschen Schule) (Langensalza: Hermann Beyer & Söhne, 1925). - Friedman claims that substances are connected by their mutual relations, and not
by preestablished harmony. This seems to be true. But there is a difference be¬
tween what connects them and the principle that governs this connection.