242 Kant: A Biographyhe does not answer the question directly. He seems to be primarily inter¬
ested not in the general question of what we can know, but in the narrower
question of what can be known with absolute certainty and without any
qualification. In his terminology, this question is "What can we know a
priori and in complete isolation from experience?"^15 Put differently, what
Kant tries to answer is the question of whether the kind of knowledge
sought by metaphysicians — including himself— is possible. The bulk of his
work is meant to show that traditional metaphysics rests on a fundamen¬
tal mistake, since it presupposes that we can make substantive knowledge
claims about the world independent of experience, and Kant argues that
we cannot validly make such claims.
Kant calls the claims of traditional metaphysics "synthetic a priori judg¬
ments," and he argues that it is impossible to know anything a priori about
the world as it is independent of experience. But he does not simply fol¬
low the route of previous empiricist philosophers, who considered all knowl¬
edge to be derived from experience alone and thus tried to trace all
knowledge back to sensation and reflection. Kant thought, rather, that all
knowledge has an a priori component. As he had already argued in the In¬
augural Dissertation, we supply the form to the knowable world. Indeed,
the formal aspects of the knowable world are constituted by the cognitive
apparatus that we, and every other finite being like us, must have; and it is
this cognitive apparatus that allows us to make synthetic a priori judgments
about the world. These synthetic a priori claims are not about reality per se.
They are about reality only as it is experienced by beings such as we are.
Only because we possess certain cognitive principles that enable us to ex¬
perience the world can we make synthetic a priori claims about the world
as it appears to us. For that very reason, these claims cannot be claims about
the world as it is independent of our conceptual apparatus. Thus meta¬
physics can tell us only about the presuppositions of experience, or the
conditions that must be fulfilled for any experience whatsoever. Kant now
calls all investigations about the possibility of a priori knowledge "transcen¬
dental," and thus refers to his inquiries as "transcendental philosophy."
Kant describes these a priori epistemic conditions as "forms" to which
knowledge is necessarily subject. He now distinguishes three such forms,
namely, (1) the forms of sensibility, (2) the forms of the understanding,
and (3) the forms of reason.
The first of these, the forms of sensibility, are space and time. They are
not characteristics of "things in themselves," but are merely subjective con¬
ditions for our knowledge of the world. However, because we cannot but