140 Kant: A Biographythe anti-Leibnizianism that many scholars have perceived in this piece just
does not seem to be there. The real reasons for all concepts are contained
in the "activity of our mind. External objects may contain the conditions
why they originate in one way or the other, but not the power to create
them."^193 On the other hand, there is clearly foreshadowed Kant's later
acceptance of Hume's critique of causality. There need be no contradic¬
tion here. Mendelssohn, a little earlier, had argued that Hume's analysis
of causality is compatible with Leibniz's view, and Kant may have held the
194
same view.
Though The Only Possible Argument, perhaps his most important book
of this period, also has a publication date of 1763, it goes back to a much
earlier period. Indeed, its origin can be traced back at least to the fifties,
when Kant was working on cosmogony, and a rudimentary version of the
argument is already present in the Nova Dilucidatio. As Kant himself points
out: "The observations, which I present here, are the fruits of lengthy re¬
flection. Because many other commitments have prevented me from
devoting the necessary time to it, these observations show characteristic
signs of haste and are incomplete."^195 It is not hard to guess at the "com¬
mitments" to which Kant is alluding. Though there may have been other
philosophical projects, they were mostly social obligations.^196 Kant cer¬
tainly finished the essay before the middle of December of 1762. He had
probably been working on this book for quite some time. Borowski reported
that before he published it, he lectured for an entire semester on a "Critique
of the Proofs for the Existence of God."^197
In The Only Possible Argument Kant tried to show that the argument
from design or the physico-theological proof of the existence of God is
insufficient. It can at best prove God as a craftsman, but not God as the
creator of matter itself. He also rejects the arguments of Descartes and
Wolff, who try to prove God's existence by concepts alone. The ontologi-
cal argument, as Descartes devised it, cannot work because "existence is
not a predicate at all."^198 Wolff's argument, based on the empirical con¬
cept of existence and the notion of an independent thing, also fails. Kant
argued that "what is under investigation here is whether the fact that some¬
thing is possible does not presuppose something existent, and whether
that existence, without which not even the internal possibility can occur,
does not contain such properties as we combine together in the concept of
God."^199 His answer is that it does. "The internal possibility of all things
presupposes some existence or other."^200 Accordingly, there must be some¬
thing whose nonexistence would cancel all internal possibility whatsoever.
This is a necessary thing. Kant then tried to show that this necessary thing