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With the Critique, the “tribunal of pure reason” had passed a sentence on theoretical metaphysics that was universally valid and promised a lasting peace between the parties to the dispute: The pretensions of dogmatic reason have been dismissed once and for all since it has been shown that there cannot in principle be any theoretical cognition outside of possible experience. The fundamental objections of skeptical reason are also overruled, since it has been shown that, in relation to possible experience, a priori cognition is indeed real and demonstrable: “Reason, when employed apart from all experience, can know propositions entirely a priori, and as necessary, or it can know nothing at all. Its judgments, therefore, are never opinions; either it must abstain from all judgment, or must affirm with apodictic certainty” (A775).
However, if we go on to ask just what it is, according to this sentence, that can be known by theoretical reason with apodictic certainty, the answer is sobering to say the least:
1) All appearances are, in their intuition, extensive magnitudes (A162).
2) In all appearances, sensation and the real, which is its object, has intensive magnitude, that is, a degree (A166).
3) All appearances contain the permanent (substance) as the object itself and the transitory as its mere determination, that is, as a way in which the object exists (A182).
4) Everything that happens, that is, begins to be,presupposes something upon which it follows according to a rule (A189).
5) All substances, so far as they coexist, stand in thoroughgoing community, that is, in mutual interaction (A211).
6) That which agrees with the formal conditions of experience, that is, with the conditions of intuition and of concepts, is possible
(A218).
42
7) That which is bound up with the material conditions of experience, that is, with sensation, is
actual(A218).
8) That which in its connection with the actual is determined inaccordance with universal conditions of experience, is (that is, exists as) necessary(A218).
That is all that theoretical reason can know a priori. We cannot help but ask whether this answer is worth the effort that went into finding it.
As Kant puts it, “It is humiliating to human reason that it achieves nothing in its pure [i.e. theoretical] employment, and indeed stands in need of a discipline to check its extravagancies, and to guard it against the deceptions which arise therefrom . . . The greatest and perhaps the sole use of all philosophy of pure reason is therefore only negative; since it serves not as an organon for the extension but as a discipline for the limitation of pure reason, and, instead of discovering truth, has only the modest merit of guarding against error” (A795).
For Kant, of course, there is more to the task of philosophy than just this, for besides its theoretical employment there is also a practical employment of reason: “Consequently, if there be any correct employment of pure reason, in which case there must also be a canon1 of its employment, the canon will deal not with the speculative but with the practical employment of reason. This practical employment of reason we shall now proceed to investigate” (A797). The ultimate signifi cance of the task of the Critique was that in restricting theoretical reason’s claims to knowledge, it secured to morality a fi eld exclusively its own: the Critique was to be followed not only by a metaphysics of nature, but also by a metaphysics of morals. For Kant was convinced that practical reason contains pure laws— the moral laws— which we can know a priori and which are not subject to a dialectic, thus allowing for a canon of the proper use of reason. The lesson of Rousseau, Kant believed, was that even the philosophically uneducated know what it is moral to do, so that the task of philosophy consists merely in explicating and bringing into view the underlying principle. In the Critique’s Doctrine of Method, in the chapter on ‘The Canon of Pure Reason’, Kant writes that he is justifi ed in assuming that there actually are such pure moral laws which command the will in a completely a priori manner, in that he can appeal “not only to the
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1
“I understand by a canon the sum- total of the a priori principles of the c
43
proofs employed by the most enlightened moralists, but to the moral judgment of every man, in so far as he makes the effort to think such a law clearly” (A807). Note, however, that Kant is not concerned here with the question, ‘Whatought I to do?’, which as such is a purely practical question and hence “not transcendental but rather moral, and cannot, therefore, in and by itself, form a proper subject for treatment in this critique” (A805). The question that Kant treats is rather: ‘If I do what I ought to do, what may I then hope?’ As he emphasizes, this question is at once both practical and theoretical and therefore still part of the present subject. For it can serve to explain why reason, in spite of the dialectic and the theoretical agnosticism to which it leads, time and again ventures beyond the limits of experience and is compelled to confront three problems constituting he ultimate purpose of reason: the freedom of the will, the immortality of the soul, and the existence of God. The practical question, What ought I to do?, provides merely the “guiding thread” for answering the theoretical question. What is meant by this?
Since the answer to the fi rst, practical, question is: ‘Do that through which thou becomest worthy of being happy’, the second question comes
to mean: ‘If I behave as I must in order to be worthy of happiness, may I
hope
thereby
to obtain happiness?’ In other words, Kant is asking whether
the principles of pure reason, which prescribe the moral law a priori, also
necessarily connect the hope of happiness with it. And, he claims, indeed
it can: “I maintain that just as the moral principles are necessary accord-
ing to reason in its
practical
employment, it is in the view of reason, in
the fi eld of its
theoretical
employment, no less necessary to assume that
everyone has ground to hope for happiness in the mea sure in which he
has rendered himself by his conduct worthy of it, and that the system of
morality is therefore inseparably— though only in the idea of pure reason—
bound up with that happiness” (A809). How does Kant arrive at this
conclusion?
We can imagine a possible world in which all human action takes place
in accord with the moral laws. In such a moral world, whose idea abstracts
from all obstacles to morality, we ourselves would be the authors of both
our own happiness and that of others, for the moral law prescribes that
we further “what is best in the world, alike in ourselves and in others”
(A819), i.e. each must make the happiness of others his duty. In such a
world, the proportionality of virtue and happiness must therefore be
“con-
ceived as necessary” (A809). Moral happiness is the result of a reciprocal
44
exercise of virtue and is thus largely in
dependent of nature.2 In addition to such moral happiness, Kant also acknowledges physical happiness,
which is dependent on nature and consists in the maximal satisfaction of
our sensuous desires (cp. A800, 806). Since my various desires are often
in confl ict with each other, so that the fulfillment
of one precludes the fulfillment of another, the task of reason is to
establish an order that allows for the greatest possible
satisfaction overall. As a sensuous being with needs and desires, I
inevitably pursue such happiness, but it is ulti-
mately empirically contingent and, without morality, it is not actually
true happiness.3
True happiness, which would reign in a moral world in exact
proportion to virtue, thus presupposes that everyone does what
he ought” (A810). In our actual world that is not, of course, the case.
Hence the
moral happiness of individuals is
defactounachievable; physical happiness, on the other hand, is
subject to empirical contingencies and stands in a merely contingent
relation to one’s own morality. Additionally, in our world we
cannot abstract from the obstacles to morality. Not infrequently, moral
demands starkly confl ict with one’s own desires, so that moral action
entails physical disadvantages for oneself. Nevertheless, the
obligatory force of this categorical ‘thou shalt’ remains unaffected by all
such concerns. Reason therefore fi nds itself compelled to assume a differ-
ent connection between morality and happiness. For it is after all one and
the same reason which both posits the moral law and is responsible for
the equally paramount task— called “prudence” (A800, 806)—
of promoting my empirical happiness. Were the two fundamental demands
of morality and prudence irreconcilable, reason would either despair or,
at
the very least, be deterred from morality. Under such circumstances being
moral would be extremely imprudent, for it would be in no way to my
advantage. Though the moral law would allow us to conceive the idea of
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2
“. . . inasmuch as freedom, partly inspired and partly restricted by moral laws,
would itself be the cause of general happiness, since rational beings, under the
guidance of such principles, would themselves be the authors both of their own
enduring well- being and of that of others” (A809).
3
In refl ection 6907, written during the period in which Kant was at work on the
Critique,
we read: “Happiness is twofold: either that which is an effect of the free
choice (Willkühr) of rational beings in themselves, or that which is only a contin-
gent and external effect dependent on nature. By way of actions which are mutually
directed toward each other, rational beings can create True Happiness (
die Wahre Glükseeligkeit) which is in dependent of everything in nature and without it nature
cannot produce happiness in the proper sense” (19:202).
45
a perfect action, it could never provide any motivation to act. But such a
state of affairs is irreconcilable with the categorical obligatory force of the
law: “Since there are practical laws which are absolutely necessary, that is,
the moral laws, it must follow that if these necessarily presuppose the ex-
istence of any being as the condition of the possibility of their
obligatory
power,
this existence must be
postulated
” (A633– 34, cp. 815). In order
for the moral law actually to motivate actions, a proportion between vir-
tue and happiness must at least be
possible,
even if experience does not
appear to offer suffi cient evidence of such a proportion. For Kant, however,
the possibility of such a proportion is only given on the assumption of a
just God and a life after death.
Morality, by itself, constitutes a system. Happiness, however,
does not do so, save in so far as it is distributed in exact propor-
tion to morality. But this is possible only in the intelligible world,
under a wise Author and Ruler. Such a Ruler, together with life in
such a world, which we must regard as a future world, reason
fi nds itself constrained to assume; otherwise it would have to re-
gard the moral laws as empty fi
gments of the brain, since without
this postulate the necessary consequence which it itself connects
with these laws could not follow. . . . It is
necessary
that the
whole course of our life be subject to moral maxims; but it is
impossible
that this should happen unless reason connects with
the moral law, which is a mere idea, an operative cause which
determines for such conduct as is in accordance with the moral
law an outcome, either in this or in another life, that is in exact
conformity with our supreme ends. Thus without a God and
without a world invisible to us now but hoped for, the glorious
ideas of morality are indeed objects of approval and admiration,
but not springs of purpose and action.
For they do not fulfi
ll in
its completeness that end which is natural to every rational being
and which is determined a priori
by that same
pure reason
(A811– 13, emphasis added).
Thus the theoretical and practical interests of reason are at last united in
the idea of the highest good of a future world in which virtue and happi-
ness correspond. We must be able to conceive of ourselves as belonging
to such a world if reason is to accord with itself. “Thus God and a future
life are two postulates which, according to the principles of pure reason,
are inseparable from the obligation which that same reason imposes
upon us” (A811)
46
With this I can conclude my present discussion of the
Critique of Pure
Reason.
There is just one last point to which I would like to call atten-
tion. If the discovery of the main transcendental question and the prob-
lem of the antinomy had shown that prior to the Critique there could not
have been any scientifi c philosophy based in pure reason, after the com-
pletion of this work Kant can now hold out the prospect of perfecting
such a science “in a short time” (Axx), indeed “before the end of the pres-
ent century” (A856). Since this science is “nothing but the
inventory of all our possession through pure reason, systematically arranged,” all that
is required for its perfection is the enumeration of all the derivative con-
cepts (for which Kant desires the “assistance of a fellow worker” [Axxi],
as well as the systematic exposition of all possible cognition through
pure concepts: “Such a system of pure (speculative) reason I hope myself
to produce under the title Metaphysics of Nature.It will be not half as
large, yet incomparably richer in content than this present critique, which
has as its fi rst task to discover the sources and conditions of the possibil-
ity of such a metaphysics” (Axxi).
Before Kant could begin working out the system in detail, however, he
had planned a short book intended to facilitate understanding of the
Critique.
As mentioned above, Kant was aware of the extraordinary dif-
fi culties that such a completely new “mode of thought” and the compre-
hension of the underlying “plan” was bound to cause the unprepared
reader. The Critique had only just left the press when he communicated
to Marcus Herz that he knew he could not at fi rst expect many readers
who would carefully study his book, but that he was contemplating a
plan for rendering the work more popular. That was not possible at the
outset, “because the whole system of this sort of knowledge had to be
exhibited in all its articulation” (10:269), but it could happen now that
that had been accomplished. He presented this simpler plan two years
later in the form of the Prolegomena to Any Future Metaphysics That
Will be Able to Come Forward as Science
(1783).
Whereas the Critique was forced to take the more diffi cult path of
investigating reason itself and, “without relying on any fact what ever,” to
derive cognition from its original sources, the Prolegomena were to be a
kind of preparatory exercise: “they ought more to indicate what needs to
be done in order to bring a science into existence if possible than to pres-
ent the science itself. They must therefore rely on something already
known to be dependable” (4:274– 75). So, in contrast to
the Critique,they take an acknowledged “fact” as the starting point.
47
It is mathematics and pure natural science in which Kant fi
nds such a
starting point. For he sees both sciences as containing synthetic knowl-
edge which is at once both apodictically certain and in
de pendent of experience, and thus a priori. Since the propositions of metaphysics (assum-
ing its possibility) are also synthetic and a priori, it seems natural to ask
whether the conditions of possibility of synthetic a priori judgments in
mathematics and pure natural science are not also the conditions under
which such judgments would be possible in metaphysics. “We have therefore some at least
uncontested synthetic cognition a priori, and we do not
need to ask whether it is possible (for it is actual), but only: how is it possible,
in order to be able to derive, from the principle of the possibility
of the given cognition, the possibility of all other synthetic
cognition a priori”
(4:275). Hence “the main transcendental question” on which the plan of
the Prolegomena is based is not ‘How can a priori representations
veridically refer to objects in general?’, as in the Critique, but
rather: ‘How are synthetic judgments a priori possible?’ (cp. 4:280,
276).
The method of the Prolegomenahas both advantages and disadvantages.
The main advantage is that since the text begins with somethingfamiliar
to the reader which is then analyzed step by step, the steps of
theargument are easier to follow. The whole is thus capable of a
certain popularity which the more strictly academic exposition of the
Critique could not have hoped for. It is also far easier to recognize
here than in the Critique what is crucial for the possibility of
synthetic judgments a priori:
namely the ideality of space and time. As Kant emphasizes, it is “the sole
means for solving this problem” (4:377). The fundamental disadvantage
is that the regressive- analytic method leads to a result which is valid only
conditionally, valid, that is, only to the extent that the premise (the “fact”)
is correct. For though Kant is certain for his part that the propositions of
mathematics and pure natural science are synthetic a priori, it is certainly
possible to doubt that they are as Hume, for example, had done. The
Prolegomena,therefore, can only supplement the Critique or follow upon it,
not replace it. The method of the Prolegomena is useful against
dogmatism because it makes clear the limits of possible knowledge from
pure
reason. It is less successful against skepticism, however, because it presup-
poses that there really are synthetic judgments a priori, instead of deriving
them from the possibility of thought (apperception) as in the subjective
deduction of the categories. And of course this method also excludes mo-
rality from transcendental philosophy; its possibility cannot be derived
from that of pure mathematics and natural science.
48
Just as Kant was busy with the composition of the
Prolegomena, the first review of the Critique
was published in the Göttingische Anzeigen
von gelehrten Sachen.
The importance of this review for the further development of Kant’s philosophy cannot be overestimated and hence I
will deal with it here in somewhat greater detail
48
Just as Kant was busy with the composition of the Prolegomena,the first review of the Critique was published in the Göttingische Anzeigen von gelehrten Sachen.
The importance of this review for the further development of Kant’s philosophy cannot be overestimated and hence I will deal with it here in somewhat greater detail.
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