For Kant one of the goals of any critique of pure reason is to answer the question,
how are a priori synthetic propositions possible? Because rationalists such as Eberhard
and Wolff took the principle of sufficient reason (hereafter, the PSR) as the principle of
all a priori synthetic judgments, understanding both the various formulations of this
principle and arguments in favor of its use as an axiom in metaphysical reasoning
provides an interesting back door to understanding The Critique of Pu…
Read moreFor Kant one of the goals of any critique of pure reason is to answer the question,
how are a priori synthetic propositions possible? Because rationalists such as Eberhard
and Wolff took the principle of sufficient reason (hereafter, the PSR) as the principle of
all a priori synthetic judgments, understanding both the various formulations of this
principle and arguments in favor of its use as an axiom in metaphysical reasoning
provides an interesting back door to understanding The Critique of Pure Reason. Despite
his statements in the First Critique rejecting the PSR as a principle of judgment1, I argue
that Kant was actually more sympathetic to the PSR than these passages alone would
suggest. The Kant-Eberhard Controversy suggests that, even though Kant explicitly
denies that the PSR can guide metaphysical reasoning, he actually presupposes its truth. I
show that Kant’s position is tenable because, like the rationalists, Kant accepts the
assumption that real essences exist and that they ground real possibility2; this leads him to
accept the truth of all clear statements of the PSR. Unlike the rationalists, however, he
does not accept the assumption that human understanding is isomorphic with real
essences. As a result, Kant rejects only the use of the PSR to determine a priori the
existence or properties of a thing. In this paper I hope to illuminate this position. I will
begin with a survey of the various formulations of the PSR that have been put forward by
Kant and his predecessors: Leibniz, Eberhard, and Wolff. Then I will examine Wolff and
Eberhard’s arguments in favor of the PSR along with Kant’s criticisms of these
arguments. Lastly, I will show why Kant rejected the very possibility of justifying this
use of the PSR while presupposing its truth.