Luther 7
persistent question of how such judgments are possible. According to Kant, this is the
key to resolving the tension between Hume and Leibniz, empiricism and rationalism. In
opposition to Hume, Kant purports to demonstrate that synthetic a priori knowledge is
possible, and against Leibniz, he attempts to show that pure reason alone, operating
without experience, leads only to illusion.
27
Instead, he revises the principles of both
rationalism and empiricism in light of the validity and certainty of the synthetic
judgments of geometry and physics. Kant believes, therefore, that if synthetic a priori
judgments could be explained or justified in these areas, they would also be justified in
metaphysics.
In solving the problem of synthetic a priori judgments, Kant substitutes a new
hypothesis concerning the relation between the mind and its object. This revision is his
“Copernican Revolution.”
28
It is clear that Hume’s assumption that the mind, in forming
its concepts, must conform to its objects leads to a dead end. Hume’s theory only works
for a posteriori judgments. Synthetic a priori judgments cannot be validated by
experience. For instance, a line is often defined as the shortest distance between two
points, but one certainly cannot experience every possible line. If Hume is correct, it
follows that the mind only has information about particular objects. Nevertheless, the
mind makes judgments about all objects, even those that it has not yet experienced. This
knowledge provides reliable information about the nature of things.
Since this knowledge, which is both synthetic and a priori, could not be explained
by the assumption that the mind conforms to its objects, Kant tries a new hypothesis
regarding the relation between the mind and its objects.
29
He is not suggesting that the
mind creates objects, but rather his Copernican revolution consists in saying that the mind
brings something to the objects it experiences. So, while knowledge begins with
experience, the mind is an active agent doing something with the objects it experiences.
Kant’s revolution in epistemology shows that the object is nothing in itself independent
of the subject, but rather is constituted only through the a priori conditions of the subject
of knowledge. Put another way, objects of knowledge do not appear of their own accord
but must be brought to appearance by the transcendent subject.
27
Ibid., pp. 55-58.
28
Ibid., pp. 22-25.
29
Ibid., pp. 54-55.
Convention