354 Kant: A BiographyKant's answer came in two parts. First, he addressed Eberhard's claim
that he had established the objective reality of concepts going beyond
sense perception, and second, he argued against Eberhard's proposed so¬
lution to the problem of synthetic a priori judgments. Appealing to math¬
ematical concepts, Eberhard had tried to show that we do have concepts
that are independent of sense perception but yet are objectively real. Kant
denies this, insisting that without corresponding intuitions, mathematical
concepts cannot be shown to have objects. He also rejects Eberhard's de¬
fense of the concept of sufficient reason as an objectively real concept. His
attempt to prove the principle of sufficient reason from the principle of
contradiction fails, because (r) the proposition to be proved is ambiguous,
(2) the proof lacks unity and really consists of two proofs, (3) Eberhard
contradicts himself in some of his conclusions, and (4) the principle he
purports to prove is simply false, if it is applied to things. "The teaching
of the Critique therefore stands firm."^93 Similarly, Eberhard commits many
errors in trying to prove the concept of a simple being as a legitimate con¬
cept independent of experience, and his attempts at ascending to the non-
sensible from the sensible prove only that he misunderstood major portions
of the Critique of Pure Reason.
In the second section, Kant shows that Eberhard misunderstood what the
Critique means not only by "dogmatic," but also by "synthetic judgments
a priori." Because of this, Eberhard makes a number of claims that are
simply false. Thus he maintains that Kant wanted "to deny to metaphysics
all synthetic judgments."^94 But the Critique did not do that. It only denied
that they were possible apart from experience. Since Eberhard does not even
understand the problem Kant wanted to solve in the Critique, his remarks
about the dispensability of the enterprise can safely be ignored.
Kant concludes by discussing Leibnizian philosophy, and by trying to
show that Eberhard misunderstood that as well. Kant sees Leibniz's sys¬
tem as characterized by three doctrines, namely, the principle of sufficient
reason, the monadology, and the doctrine of preestablished harmony.
Eberhard wants to construe the principle of sufficient reason as objective,
but Leibniz thought it was subjective, and he seems to "expose Leibniz to
ridicule just when he thinks he is providing him with an apology."^95 Eber¬
hard also misunderstands the monadology when he tries to show that
bodies consist of simples. It is the intelligible substrate of bodies, not the
bodies themselves, that consist of simples for Leibniz. Similar things can
be said about Eberhard's understanding of preestablished harmony. The
three Critiques are quite compatible with this aspect of Leibniz. The agree-