LARS TO/NDERThe first set of limits has to do with the way we justify the categorical imperative.
Kant argues that we cannot grasp the imperative the way we grasp conventional objects
in time and space, which are subject to what he calls the ‘‘speculative usage of reason,’’^30
simply because the imperative itself does not appear in any concrete manner. Even so,
although the imperative is nonphenomenal, it is still necessary for us to know whether it
respects the discipline of reason. Only if it does can we accept the imperative as legitimate.
Kant solves this problem by introducing a second mode of reason—‘‘practical reason’’—
which is not subject to any critical deduction but instead is what makes critical deduction
possible in the first place. This implies that all we must demonstrate is that there is practi-
cal reason and that this kind of reason is sufficient to determine the will without the
influence of any empirical condition. However, because this assumes what we seek to
prove—that is, the categorical imperative—Kant finds it unreasonable to question the
imperative itself. Instead, he argues that we should accept it as a fact of what it means to
be reasonable, something without which intelligent individuals could not be who they
are. Kant argues this in a passage that establishes the apodictic character of the moral law:
the ‘‘moral law is given, as an apodictically certain fact, as it were, or pure reason, a fact
of which we are a priori conscious, even if it be granted that no example could be found
in which it has been followed exactly.’’^31
The second set of limits to the practice of critical reasoning has to do with what Kant
calls ‘‘postulates of pure practical reason.’’ These postulates, which may appear to be so
‘‘out-dated’’ that we should eliminate them from the Kantian corpus altogether, include:
(1) the immortality of the soul, which is necessary for the perfection of the moral law; (2)
human freedom, affirmatively regarded, which is necessary for the possibility of human
agents’ not being subject only to the laws of nature; and (3) the existence of a divine
creator—that is, God—who is necessary for the existence of a world other than that of
the senses, that is, the existence of the nonphenomenal, intelligent world.^32 As I said, it is
tempting to eliminate these postulates, especially because not even Kant believes that it is
possible to demonstrate their validity by way of reason alone. They are indeed postulates
and not, say, arguments. Even so, Kant insists that we affirm the postulates. Why? Because
they establish the condition under which a finite being will obey the moral law, accepting
the way in which it determines the will that directs his or her actions. The postulates in
that sense make intelligent individuals—those with an ability to be reasonable—feel rever-
ence for the moral law. What is more, the postulates provide the same individuals with a
sense of orientation within the domain of action, since the postulates determine their
perceptions of what is morally right in any given case. This alone makes it necessary not
only to state but also to affirm the validity of the three postulates.
We can now turn to the reason why these two sets of limitations—that is, the apodic-
tic certainty of the moral law and the three postulates of pure practical reason—prevent
Kant from appreciating the unique nature of not only toleration but also tolerance. The
main point is that the moral law and the three postulates are committed to a certain kind
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