No More Learning

1788

THE CRITIQUE OF PRACTICAL REASON

by Immanuel Kant

translated by Thomas Kingsmill Abbott


PREFACE.

This work is called the Critique of Practical Reason, not of the
pure practical reason, although its parallelism with the speculative
critique would seem to require the latter term. The reason of this
appears sufficiently from the treatise itself. Its business is to show
that there is pure practical reason, and for this purpose it
criticizes the entire practical faculty of reason. If it succeeds in
this, it has no need to criticize the pure faculty itself in order
to see whether reason in making such a claim does not presumptuously
overstep itself (as is the case with the speculative reason). For
if, as pure reason, it is actually practical, it proves its own
reality and that of its concepts by fact, and all disputation
against the possibility of its being real is futile.

With this faculty, transcendental freedom is also established;
freedom, namely, in that absolute sense in which speculative reason
required it in its use of the concept of causality in order to
escape the antinomy into which it inevitably falls, when in the
chain of cause and effect it tries to think the unconditioned.
Speculative reason could only exhibit this concept (of freedom)
problematically as not impossible to thought, without assuring it
any objective reality, and merely lest the supposed impossibility of
what it must at least allow to be thinkable should endanger its very
being and plunge it into an abyss of scepticism.

Inasmuch as the reality of the concept of freedom is proved by an
apodeictic law of practical reason, it is the keystone of the whole
system of pure reason, even the speculative, and all other concepts
(those of God and immortality) which, as being mere ideas, remain in
it unsupported, now attach themselves to this concept, and by it
obtain consistence and objective reality; that is to say, their
possibility is proved by the fact that freedom actually exists, for
this idea is revealed by the moral law.

Freedom, however, is the only one of all the ideas of the
speculative reason of which we know the possibility a priori (without,
however, understanding it), because it is the condition of the moral
law which we know. * The ideas of God and immortality, however, are
not conditions of the moral law, but only conditions of the necessary
object of a will determined by this law; that is to say, conditions of
the practical use of our pure reason. Hence, with respect to these
ideas, we cannot affirm that we know and understand, I will not say
the actuality, but even the possibility of them. However they are
the conditions of the application of the morally determined will to
its object, which is given to it a priori, viz. , the summum bonum.
Consequently in this practical point of view their possibility must be
assumed, although we cannot theoretically know and understand it. To
justify this assumption it is sufficient, in a practical point of
view, that they contain no intrinsic impossibility (contradiction).
Here we have what, as far as speculative reason is concerned, is a
merely subjective principle of assent, which, however, is
objectively valid for a reason equally pure but practical, and this
principle, by means of the concept of freedom, assures objective
reality and authority to the ideas of God and immortality. Nay,
there is a subjective necessity (a need of pure reason) to assume
them. Nevertheless the theoretical knowledge of reason is not hereby
enlarged, but only the possibility is given, which heretofore was
merely a problem and now becomes assertion, and thus the practical use
of reason is connected with the elements of theoretical reason. And
this need is not a merely hypothetical one for the arbitrary
purposes of speculation, that we must assume something if we wish in
speculation to carry reason to its utmost limits, but it is a need
which has the force of law to assume something without which that
cannot be which we must inevitably set before us as the aim of our
action.



{PREFACE ^paragraph 5}

* Lest any one should imagine that he finds an inconsistency here
when I call freedom the condition of the moral law, and hereafter
maintain in the treatise itself that the moral law is the condition
under which we can first become conscious of freedom, I will merely
remark that freedom is the ratio essendi of the moral law, while the
moral law is the ratio cognoscendi of freedom. For had not the moral
law been previously distinctly thought in our reason, we should
never consider ourselves justified in assuming such a thing as
freedom, although it be not contradictory. But were there no freedom
it would be impossible to trace the moral law in ourselves at all.



It would certainly be more satisfactory to our speculative reason if
it could solve these problems for itself without this circuit and
preserve the solution for practical use as a thing to be referred
to, but in fact our faculty of speculation is not so well provided.
Those who boast of such high knowledge ought not to keep it back,
but to exhibit it publicly that it may be tested and appreciated. They
want to prove: very good, let them prove; and the critical
philosophy lays its arms at their feet as the victors. Quid statis?
Nolint. Atqui licet esse beatis. As they then do not in fact choose to
do so, probably because they cannot, we must take up these arms
again in order to seek in the mortal use of reason, and to base on
this, the notions of God, freedom, and immortality, the possibility of
which speculation cannot adequately prove.

Here first is explained the enigma of the critical philosophy, viz. :
how we deny objective reality to the supersensible use of the
categories in speculation and yet admit this reality with respect to
the objects of pure practical reason. This must at first seem
inconsistent as long as this practical use is only nominally known.
But when, by a thorough analysis of it, one becomes aware that the
reality spoken of does not imply any theoretical determination of
the categories and extension of our knowledge to the supersensible;
but that what is meant is that in this respect an object belongs to
them, because either they are contained in the necessary determination
of the will a priori, or are inseparably connected with its object;
then this inconsistency disappears, because the use we make of these
concepts is different from what speculative reason requires. On the
other hand, there now appears an unexpected and very satisfactory
proof of the consistency of the speculative critical philosophy. For
whereas it insisted that the objects of experience as such,
including our own subject, have only the value of phenomena, while
at the same time things in themselves must be supposed as their basis,
so that not everything supersensible was to be regarded as a fiction
and its concept as empty; so now practical reason itself, without
any concert with the speculative, assures reality to a supersensible
object of the category of causality, viz. , freedom, although (as
becomes a practical concept) only for practical use; and this
establishes on the evidence of a fact that which in the former case
could only be conceived. By this the strange but certain doctrine of
the speculative critical philosophy, that the thinking subject is to
itself in internal intuition only a phenomenon, obtains in the
critical examination of the practical reason its full confirmation,
and that so thoroughly that we should be compelled to adopt this
doctrine, even if the former had never proved it at all. *



{PREFACE ^paragraph 10}

* The union of causality as freedom with causality as rational
mechanism, the former established by the moral law, the latter by
the law of nature in the same subject, namely, man, is impossible,
unless we conceive him with reference to the former as a being in
himself, and with reference to the latter as a phenomenon- the
former in pure consciousness, the latter in empirical consciousness.
Otherwise reason inevitably contradicts itself.



By this also I can understand why the most considerable objections
which I have as yet met with against the Critique turn about these two
points, namely, on the one side, the objective reality of the
categories as applied to noumena, which is in the theoretical
department of knowledge denied, in the practical affirmed; and on
the other side, the paradoxical demand to regard oneself qua subject
of freedom as a noumenon, and at the same time from the point of
view of physical nature as a phenomenon in one's own empirical
consciousness; for as long as one has formed no definite notions of
morality and freedom, one could not conjecture on the one side what
was intended to be the noumenon, the basis of the alleged
phenomenon, and on the other side it seemed doubtful whether it was at
all possible to form any notion of it, seeing that we had previously
assigned all the notions of the pure understanding in its
theoretical use exclusively to phenomena. Nothing but a detailed
criticism of the practical reason can remove all this
misapprehension and set in a clear light the consistency which
constitutes its greatest merit.

So much by way of justification of the proceeding by which, in
this work, the notions and principles of pure speculative reason which
have already undergone their special critical examination are, now and
then, again subjected to examination. This would not in other cases be
in accordance with the systematic process by which a science is
established, since matters which have been decided ought only to be
cited and not again discussed. In this case, however, it was not
only allowable but necessary, because reason is here considered in
transition to a different use of these concepts from what it had
made of them before. Such a transition necessitates a comparison of
the old and the new usage, in order to distinguish well the new path
from the old one and, at the same time, to allow their connection to
be observed. Accordingly considerations of this kind, including
those which are once more directed to the concept of freedom in the
practical use of the pure reason, must not be regarded as an
interpolation serving only to fill up the gaps in the critical
system of speculative reason (for this is for its own purpose
complete), or like the props and buttresses which in a hastily
constructed building are often added afterwards; but as true members
which make the connexion of the system plain, and show us concepts,
here presented as real, which there could only be presented
problematically. This remark applies especially to the concept of
freedom, respecting which one cannot but observe with surprise that so
many boast of being able to understand it quite well and to explain
its possibility, while they regard it only psychologically, whereas if
they had studied it in a transcendental point of view, they must
have recognized that it is not only indispensable as a problematical
concept, in the complete use of speculative reason, but also quite
incomprehensible; and if they afterwards came to consider its
practical use, they must needs have come to the very mode of
determining the principles of this, to which they are now so loth to
assent. The concept of freedom is the stone of stumbling for all
empiricists, but at the same time the key to the loftiest practical
principles for critical moralists, who perceive by its means that they
must necessarily proceed by a rational method. For this reason I beg
the reader not to pass lightly over what is said of this concept at
the end of the Analytic.

I must leave it to those who are acquainted with works of this
kind to judge whether such a system as that of the practical reason,
which is here developed from the critical examination of it, has
cost much or little trouble, especially in seeking not to miss the
true point of view from which the whole can be rightly sketched. It
presupposes, indeed, the Fundamental Principles of the Metaphysic of
Morals, but only in so far as this gives a preliminary acquaintance
with the principle of duty, and assigns and justifies a definite
formula thereof; in other respects it is independent. * It results
from the nature of this practical faculty itself that the complete
classification of all practical sciences cannot be added, as in the
critique of the speculative reason. For it is not possible to define
duties specially, as human duties, with a view to their
classification, until the subject of this definition (viz. , man) is
known according to his actual nature, at least so far as is
necessary with respect to duty; this, however, does not belong to a
critical examination of the practical reason, the business of which is
only to assign in a complete manner the principles of its possibility,
extent, and limits, without special reference to human nature. The
classification then belongs to the system of science, not to the
system of criticism.

{PREFACE ^paragraph 15}



* A reviewer who wanted to find some fault with this work has hit
the truth better, perhaps, than he thought, when he says that no new
principle of morality is set forth in it, but only a new formula.
But who would think of introducing a new principle of all morality and
making himself as it were the first discoverer of it, just as if all
the world before him were ignorant what duty was or had been in
thorough-going error? But whoever knows of what importance to a
mathematician a formula is, which defines accurately what is to be
done to work a problem, will not think that a formula is insignificant
and useless which does the same for all duty in general.



In the second part of the Analytic I have given, as I trust, a
sufficient answer to the objection of a truth-loving and acute
critic * of the Fundamental Principles of the Metaphysic of Morals- a
critic always worthy of respect- the objection, namely, that the
notion of good was not established before the moral principle, as he
thinks it ought to have been. *(2) I have also had regard to many of
the objections which have reached me from men who show that they have
at heart the discovery of the truth, and I shall continue to do so
(for those who have only their old system before their eyes, and who
have already settled what is to be approved or disapproved, do not
desire any explanation which might stand in the way of their own
private opinion. )



{PREFACE ^paragraph 20}

* [See Kant's "Das mag in der Theoric ricktig seyn," etc. Werke,
vol. vii, p. 182. ]

*(2) It might also have been objected to me that I have not first
defined the notion of the faculty of desire, or of the feeling of
Pleasure, although this reproach would be unfair, because this
definition might reasonably be presupposed as given in psychology.
However, the definition there given might be such as to found the
determination of the faculty of desire on the feeling of pleasure
(as is commonly done), and thus the supreme principle of practical
philosophy would be necessarily made empirical, which, however,
remains to be proved and in this critique is altogether refuted. It
will, therefore, give this definition here in such a manner as it
ought to be given, in order to leave this contested point open at
the beginning, as it should be. LIFE is the faculty a being has of
acting according to laws of the faculty of desire. The faculty of
DESIRE is the being's faculty of becoming by means of its ideas the
cause of the actual existence of the objects of these ideas.
PLEASURE is the idea of the agreement of the object, or the action
with the subjective conditions of life, i. e. , with the faculty of
causality of an idea in respect of the actuality of its object (or
with the determination of the forces of the subject to action which
produces it). I have no further need for the purposes of this critique
of notions borrowed from psychology; the critique itself supplies
the rest. It is easily seen that the question whether the faculty of
desire is always based on pleasure, or whether under certain
conditions pleasure only follows the determination of desire, is by
this definition left undecided, for it is composed only of terms
belonging to the pure understanding, i. e. , of categories which contain
nothing empirical. Such precaution is very desirable in all philosophy
and yet is often neglected; namely, not to prejudge questions by
adventuring definitions before the notion has been completely
analysed, which is often very late. It may be observed through the
whole course of the critical philosophy (of the theoretical as well as
the practical reason) that frequent opportunity offers of supplying
defects in the old dogmatic method of philosophy, and of correcting
errors which are not observed until we make such rational use of these
notions viewing them as a whole.



When we have to study a particular faculty of the human mind in
its sources, its content, and its limits; then from the nature of
human knowledge we must begin with its parts, with an accurate and
complete exposition of them; complete, namely, so far as is possible
in the present state of our knowledge of its elements. But there is
another thing to be attended to which is of a more philosophical and
architectonic character, namely, to grasp correctly the idea of the
whole, and from thence to get a view of all those parts as mutually
related by the aid of pure reason, and by means of their derivation
from the concept of the whole. This is only possible through the
most intimate acquaintance with the system; and those who find the
first inquiry too troublesome, and do not think it worth their while
to attain such an acquaintance, cannot reach the second stage, namely,
the general view, which is a synthetical return to that which had
previously been given analytically. It is no wonder then if they
find inconsistencies everywhere, although the gaps which these
indicate are not in the system itself, but in their own incoherent
train of thought.

I have no fear, as regards this treatise, of the reproach that I
wish to introduce a new language, since the sort of knowledge here
in question has itself somewhat of an everyday character. Nor even
in the case of the former critique could this reproach occur to anyone
who had thought it through and not merely turned over the leaves. To
invent new words where the language has no lack of expressions for
given notions is a childish effort to distinguish oneself from the
crowd, if not by new and true thoughts, yet by new patches on the
old garment. If, therefore, the readers of that work know any more
familiar expressions which are as suitable to the thought as those
seem to me to be, or if they think they can show the futility of these
thoughts themselves and hence that of the expression, they would, in
the first case, very much oblige me, for I only desire to be
understood: and, in the second case, they would deserve well of
philosophy. But, as long as these thoughts stand, I very much doubt
that suitable and yet more common expressions for them can be found. *

{PREFACE ^paragraph 25}



* I am more afraid in the present treatise of occasional
misconception in respect of some expressions which I have chosen
with the greatest care in order that the notion to which they point
may not be missed. Thus, in the table of categories of the Practical
reason under the title of Modality, the Permitted, and forbidden (in a
practical objective point of view, possible and impossible) have
almost the same meaning in common language as the next category,
duty and contrary to duty. Here, however, the former means what
coincides with, or contradicts, a merely possible practical precept
(for example, the solution of all problems of geometry and mechanics);
the latter, what is similarly related to a law actually present in the
reason; and this distinction is not quite foreign even to common
language, although somewhat unusual. For example, it is forbidden to
an orator, as such, to forge new words or constructions; in a
certain degree this is permitted to a poet; in neither case is there
any question of duty. For if anyone chooses to forfeit his
reputation as an orator, no one can prevent him. We have here only
to do with the distinction of imperatives into problematical,
assertorial, and apodeictic. Similarly in the note in which I have
pared the moral ideas of practical perfection in different
philosophical schools, I have distinguished the idea of wisdom from
that of holiness, although I have stated that essentially and
objectively they are the same. But in that place I understand by the
former only that wisdom to which man (the Stoic) lays claim; therefore
I take it subjectively as an attribute alleged to belong to man.
(Perhaps the expression virtue, with which also the Stoic made great show,
would better mark the characteristic of his school. ) The expression of
a postulate of pure practical reason might give most occasion to
misapprehension in case the reader confounded it with the
signification of the postulates in pure mathematics, which carry
apodeictic certainty with them. These, however, postulate the
possibility of an action, the object of which has been previously
recognized a priori in theory as possible, and that with perfect
certainty. But the former postulates the possibility of an object
itself (God and the immortality of the soul) from apodeictic practical
laws, and therefore only for the purposes of a practical reason.
This certainty of the postulated possibility then is not at all
theoretic, and consequently not apodeictic; that is to say, it is
not a known necessity as regards the object, but a necessary
supposition as regards the subject, necessary for the obedience to its
objective but practical laws. It is, therefore, merely a necessary
hypothesis. I could find no better expression for this rational
necessity, which is subjective, but yet true and unconditional.



In this manner, then, the a priori principles of two faculties of
the mind, the faculty of cognition and that of desire, would be
found and determined as to the conditions, extent, and limits of their
use, and thus a sure foundation be paid for a scientific system of
philosophy, both theoretic and practical.

Nothing worse could happen to these labours than that anyone
should make the unexpected discovery that there neither is, nor can
be, any a priori knowledge at all. But there is no danger of this.
This would be the same thing as if one sought to prove by reason
that there is no reason. For we only say that we know something by
reason, when we are conscious that we could have known it, even if
it had not been given to us in experience; hence rational knowledge
and knowledge a priori are one and the same. It is a clear
contradiction to try to extract necessity from a principle of
experience (ex pumice aquam), and to try by this to give a judgement
true universality (without which there is no rational inference, not
even inference from analogy, which is at least a presumed universality
and objective necessity). To substitute subjective necessity, that is,
custom, for objective, which exists only in a priori judgements, is to
deny to reason the power of judging about the object, i. e. , of knowing
it, and what belongs to it. It implies, for example, that we must
not say of something which often or always follows a certain
antecedent state that we can conclude from this to that (for this
would imply objective necessity and the notion of an a priori
connexion), but only that we may expect similar cases (just as animals
do), that is that we reject the notion of cause altogether as false
and a mere delusion. As to attempting to remedy this want of objective
and consequently universal validity by saying that we can see no
ground for attributing any other sort of knowledge to other rational
beings, if this reasoning were valid, our ignorance would do more
for the enlargement of our knowledge than all our meditation. For,
then, on this very ground that we have no knowledge of any other
rational beings besides man, we should have a right to suppose them to
be of the same nature as we know ourselves to be: that is, we should
really know them. I omit to mention that universal assent does not
prove the objective validity of a judgement (i. e. , its validity as a
cognition), and although this universal assent should accidentally
happen, it could furnish no proof of agreement with the object; on the
contrary, it is the objective validity which alone constitutes the
basis of a necessary universal consent.

{PREFACE ^paragraph 30}

Hume would be quite satisfied with this system of universal
empiricism, for, as is well known, he desired nothing more than
that, instead of ascribing any objective meaning to the necessity in
the concept of cause, a merely subjective one should be assumed, viz. ,
custom, in order to deny that reason could judge about God, freedom,
and immortality; and if once his principles were granted, he was
certainly well able to deduce his conclusions therefrom, with all
logical coherence. But even Hume did not make his empiricism so
universal as to include mathematics. He holds the principles of
mathematics to be analytical; and if his were correct, they would
certainly be apodeictic also: but we could not infer from this that
reason has the faculty of forming apodeictic judgements in
philosophy also- that is to say, those which are synthetical
judgements, like the judgement of causality. But if we adopt a
universal empiricism, then mathematics will be included.

Now if this science is in contradiction with a reason that admits
only empirical principles, as it inevitably is in the antinomy in
which mathematics prove the infinite divisibility of space, which
empiricism cannot admit; then the greatest possible evidence of
demonstration is in manifest contradiction with the alleged
conclusions from experience, and we are driven to ask, like
Cheselden's blind patient, "Which deceives me, sight or touch? " (for
empiricism is based on a necessity felt, rationalism on a necessity
seen). And thus universal empiricism reveals itself as absolute
scepticism. It is erroneous to attribute this in such an unqualified
sense to Hume, * since he left at least one certain touchstone (which
can only be found in a priori principles), although experience
consists not only of feelings, but also of judgements.



* Names that designate the followers of a sect have always been
accompanied with much injustice; just as if one said, "N is an
Idealist. " For although he not only admits, but even insists, that our
ideas of external things have actual objects of external things
corresponding to them, yet he holds that the form of the intuition
does not depend on them but on the human mind.



{PREFACE ^paragraph 35}

However, as in this philosophical and critical age such empiricism
can scarcely be serious, and it is probably put forward only as an
intellectual exercise and for the purpose of putting in a clearer
light, by contrast, the necessity of rational a priori principles,
we can only be grateful to those who employ themselves in this
otherwise uninstructive labour.

INTRODUCTION

INTRODUCTION.



Of the Idea of a Critique of Practical Reason.



The theoretical use of reason was concerned with objects of the
cognitive faculty only, and a critical examination of it with
reference to this use applied properly only to the pure faculty of
cognition; because this raised the suspicion, which was afterwards
confirmed, that it might easily pass beyond its limits, and be lost
among unattainable objects, or even contradictory notions. It is quite
different with the practical use of reason. In this, reason is
concerned with the grounds of determination of the will, which is a
faculty either to produce objects corresponding to ideas, or to
determine ourselves to the effecting of such objects (whether the
physical power is sufficient or not); that is, to determine our
causality. For here, reason can at least attain so far as to determine
the will, and has always objective reality in so far as it is the
volition only that is in question. The first question here then is
whether pure reason of itself alone suffices to determine the will, or
whether it can be a ground of determination only as dependent on
empirical conditions. Now, here there comes in a notion of causality
justified by the critique of the pure reason, although not capable
of being presented empirically, viz. , that of freedom; and if we can
now discover means of proving that this property does in fact belong
to the human will (and so to the will of all rational beings), then it
will not only be shown that pure reason can be practical, but that
it alone, and not reason empirically limited, is indubitably
practical; consequently, we shall have to make a critical examination,
not of pure practical reason, but only of practical reason
generally. For when once pure reason is shown to exist, it needs no
critical examination. For reason itself contains the standard for
the critical examination of every use of it. The critique, then, of
practical reason generally is bound to prevent the empirically
conditioned reason from claiming exclusively to furnish the ground
of determination of the will. If it is proved that there is a
[practical] reason, its employment is alone immanent; the
empirically conditioned use, which claims supremacy, is on the
contrary transcendent and expresses itself in demands and precepts
which go quite beyond its sphere. This is just the opposite of what
might be said of pure reason in its speculative employment.

However, as it is still pure reason, the knowledge of which is
here the foundation of its practical employment, the general outline
of the classification of a critique of practical reason must be
arranged in accordance with that of the speculative. We must, then,
have the Elements and the Methodology of it; and in the former an
Analytic as the rule of truth, and a Dialectic as the exposition and
dissolution of the illusion in the judgements of practical reason. But
the order in the subdivision of the Analytic will be the reverse of
that in the critique of the pure speculative reason. For, in the
present case, we shall commence with the principles and proceed to the
concepts, and only then, if possible, to the senses; whereas in the
case of the speculative reason we began with the senses and had to end
with the principles. The reason of this lies again in this: that now
we have to do with a will, and have to consider reason, not in its
relation to objects, but to this will and its causality. We must,
then, begin with the principles of a causality not empirically
conditioned, after which the attempt can be made to establish our
notions of the determining grounds of such a will, of their
application to objects, and finally to the subject and its sense
faculty. We necessarily begin with the law of causality from
freedom, that is, with a pure practical principle, and this determines
the objects to which alone it can be applied.

BOOK_1|CHAPTER_1

FIRST PART.



ELEMENTS OF PURE PRACTICAL REASON.



BOOK I. The Analytic of Pure Practical Reason.



CHAPTER I. Of the Principles of Pure Practical Reason.

{BOOK_1|CHAPTER_1 ^paragraph 5}



I. DEFINITION.



Practical principles are propositions which contain a general
determination of the will, having under it several practical rules.
They are subjective, or maxims, when the condition is regarded by
the subject as valid only for his own will, but are objective, or
practical laws, when the condition is recognized as objective, that
is, valid for the will of every rational being.



{BOOK_1|CHAPTER_1 ^paragraph 10}

REMARK.



Supposing that pure reason contains in itself a practical motive,
that is, one adequate to determine the will, then there are
practical laws; otherwise all practical principles will be mere
maxims. In case the will of a rational being is pathologically
affected, there may occur a conflict of the maxims with the
practical laws recognized by itself. For example, one may make it
his maxim to let no injury pass unrevenged, and yet he may see that
this is not a practical law, but only his own maxim; that, on the
contrary, regarded as being in one and the same maxim a rule for the
will of every rational being, it must contradict itself. In natural
philosophy the principles of what happens, (e. g. , the principle of
equality of action and reaction in the communication of motion) are at
the same time laws of nature; for the use of reason there is
theoretical and determined by the nature of the object. In practical
philosophy, i. e. , that which has to do only with the grounds of
determination of the will, the principles which a man makes for
himself are not laws by which one is inevitably bound; because
reason in practical matters has to do with the subject, namely, with
the faculty of desire, the special character of which may occasion
variety in the rule. The practical rule is always a product of reason,
because it prescribes action as a means to the effect. But in the case
of a being with whom reason does not of itself determine the will,
this rule is an imperative, i. e. , a rule characterized by "shall,"
which expresses the objective necessitation of the action and
signifies that, if reason completely determined the will, the action
would inevitably take place according to this rule. Imperatives,
therefore, are objectively valid, and are quite distinct from
maxims, which are subjective principles. The former either determine
the conditions of the causality of the rational being as an
efficient cause, i. e. , merely in reference to the effect and the means
of attaining it; or they determine the will only, whether it is
adequate to the effect or not. The former would be hypothetical
imperatives, and contain mere precepts of skill; the latter, on the
contrary, would be categorical, and would alone be practical laws.
Thus maxims are principles, but not imperatives. Imperatives
themselves, however, when they are conditional (i. e. , do not determine
the will simply as will, but only in respect to a desired effect, that
is, when they are hypothetical imperatives), are practical precepts
but not laws. Laws must be sufficient to determine the will as will,
even before I ask whether I have power sufficient for a desired
effect, or the means necessary to produce it; hence they are
categorical: otherwise they are not laws at all, because the necessity
is wanting, which, if it is to be practical, must be independent of
conditions which are pathological and are therefore only
contingently connected with the will. Tell a man, for example, that he
must be industrious and thrifty in youth, in order that he may not
want in old age; this is a correct and important practical precept
of the will. But it is easy to see that in this case the will is
directed to something else which it is presupposed that it desires;
and as to this desire, we must leave it to the actor himself whether
he looks forward to other resources than those of his own acquisition,
or does not expect to be old, or thinks that in case of future
necessity he will be able to make shift with little. Reason, from
which alone can spring a rule involving necessity, does, indeed,
give necessity to this precept (else it would not be an imperative),
but this is a necessity dependent on subjective conditions, and cannot
be supposed in the same degree in all subjects. But that reason may
give laws it is necessary that it should only need to presuppose
itself, because rules are objectively and universally valid only
when they hold without any contingent subjective conditions, which
distinguish one rational being from another. Now tell a man that he
should never make a deceitful promise, this is a rule which only
concerns his will, whether the purposes he may have can be attained
thereby or not; it is the volition only which is to be determined a
priori by that rule. If now it is found that this rule is
practically right, then it is a law, because it is a categorical
imperative. Thus, practical laws refer to the will only, without
considering what is attained by its causality, and we may disregard
this latter (as belonging to the world of sense) in order to have them
quite pure.



II. THEOREM I.

{BOOK_1|CHAPTER_1 ^paragraph 15}



All practical principles which presuppose an object (matter) of
the faculty of desire as the ground of determination of the will are
empirical and can furnish no practical laws.

By the matter of the faculty of desire I mean an object the
realization of which is desired. Now, if the desire for this object
precedes the practical rule and is the condition of our making it a
principle, then I say (in the first place) this principle is in that
case wholly empirical, for then what determines the choice is the idea
of an object and that relation of this idea to the subject by which
its faculty of desire is determined to its realization. Such a
relation to the subject is called the pleasure in the realization of
an object. This, then, must be presupposed as a condition of the
possibility of determination of the will. But it is impossible to know
a priori of any idea of an object whether it will be connected with
pleasure or pain, or be indifferent.
* The ideas of God and immortality, however, are
not conditions of the moral law, but only conditions of the necessary
object of a will determined by this law; that is to say, conditions of
the practical use of our pure reason. Hence, with respect to these
ideas, we cannot affirm that we know and understand, I will not say
the actuality, but even the possibility of them. However they are
the conditions of the application of the morally determined will to
its object, which is given to it a priori, viz. , the summum bonum.
Consequently in this practical point of view their possibility must be
assumed, although we cannot theoretically know and understand it. To
justify this assumption it is sufficient, in a practical point of
view, that they contain no intrinsic impossibility (contradiction).
Here we have what, as far as speculative reason is concerned, is a
merely subjective principle of assent, which, however, is
objectively valid for a reason equally pure but practical, and this
principle, by means of the concept of freedom, assures objective
reality and authority to the ideas of God and immortality. Nay,
there is a subjective necessity (a need of pure reason) to assume
them. Nevertheless the theoretical knowledge of reason is not hereby
enlarged, but only the possibility is given, which heretofore was
merely a problem and now becomes assertion, and thus the practical use
of reason is connected with the elements of theoretical reason. And
this need is not a merely hypothetical one for the arbitrary
purposes of speculation, that we must assume something if we wish in
speculation to carry reason to its utmost limits, but it is a need
which has the force of law to assume something without which that
cannot be which we must inevitably set before us as the aim of our
action.



{PREFACE ^paragraph 5}

* Lest any one should imagine that he finds an inconsistency here
when I call freedom the condition of the moral law, and hereafter
maintain in the treatise itself that the moral law is the condition
under which we can first become conscious of freedom, I will merely
remark that freedom is the ratio essendi of the moral law, while the
moral law is the ratio cognoscendi of freedom. For had not the moral
law been previously distinctly thought in our reason, we should
never consider ourselves justified in assuming such a thing as
freedom, although it be not contradictory. But were there no freedom
it would be impossible to trace the moral law in ourselves at all.



It would certainly be more satisfactory to our speculative reason if
it could solve these problems for itself without this circuit and
preserve the solution for practical use as a thing to be referred
to, but in fact our faculty of speculation is not so well provided.
Those who boast of such high knowledge ought not to keep it back,
but to exhibit it publicly that it may be tested and appreciated. They
want to prove: very good, let them prove; and the critical
philosophy lays its arms at their feet as the victors. Quid statis?
Nolint. Atqui licet esse beatis. As they then do not in fact choose to
do so, probably because they cannot, we must take up these arms
again in order to seek in the mortal use of reason, and to base on
this, the notions of God, freedom, and immortality, the possibility of
which speculation cannot adequately prove.

Here first is explained the enigma of the critical philosophy, viz. :
how we deny objective reality to the supersensible use of the
categories in speculation and yet admit this reality with respect to
the objects of pure practical reason. This must at first seem
inconsistent as long as this practical use is only nominally known.
But when, by a thorough analysis of it, one becomes aware that the
reality spoken of does not imply any theoretical determination of
the categories and extension of our knowledge to the supersensible;
but that what is meant is that in this respect an object belongs to
them, because either they are contained in the necessary determination
of the will a priori, or are inseparably connected with its object;
then this inconsistency disappears, because the use we make of these
concepts is different from what speculative reason requires. On the
other hand, there now appears an unexpected and very satisfactory
proof of the consistency of the speculative critical philosophy. For
whereas it insisted that the objects of experience as such,
including our own subject, have only the value of phenomena, while
at the same time things in themselves must be supposed as their basis,
so that not everything supersensible was to be regarded as a fiction
and its concept as empty; so now practical reason itself, without
any concert with the speculative, assures reality to a supersensible
object of the category of causality, viz. , freedom, although (as
becomes a practical concept) only for practical use; and this
establishes on the evidence of a fact that which in the former case
could only be conceived. By this the strange but certain doctrine of
the speculative critical philosophy, that the thinking subject is to
itself in internal intuition only a phenomenon, obtains in the
critical examination of the practical reason its full confirmation,
and that so thoroughly that we should be compelled to adopt this
doctrine, even if the former had never proved it at all. *



{PREFACE ^paragraph 10}

* The union of causality as freedom with causality as rational
mechanism, the former established by the moral law, the latter by
the law of nature in the same subject, namely, man, is impossible,
unless we conceive him with reference to the former as a being in
himself, and with reference to the latter as a phenomenon- the
former in pure consciousness, the latter in empirical consciousness.
Otherwise reason inevitably contradicts itself.



By this also I can understand why the most considerable objections
which I have as yet met with against the Critique turn about these two
points, namely, on the one side, the objective reality of the
categories as applied to noumena, which is in the theoretical
department of knowledge denied, in the practical affirmed; and on
the other side, the paradoxical demand to regard oneself qua subject
of freedom as a noumenon, and at the same time from the point of
view of physical nature as a phenomenon in one's own empirical
consciousness; for as long as one has formed no definite notions of
morality and freedom, one could not conjecture on the one side what
was intended to be the noumenon, the basis of the alleged
phenomenon, and on the other side it seemed doubtful whether it was at
all possible to form any notion of it, seeing that we had previously
assigned all the notions of the pure understanding in its
theoretical use exclusively to phenomena. Nothing but a detailed
criticism of the practical reason can remove all this
misapprehension and set in a clear light the consistency which
constitutes its greatest merit.

So much by way of justification of the proceeding by which, in
this work, the notions and principles of pure speculative reason which
have already undergone their special critical examination are, now and
then, again subjected to examination. This would not in other cases be
in accordance with the systematic process by which a science is
established, since matters which have been decided ought only to be
cited and not again discussed. In this case, however, it was not
only allowable but necessary, because reason is here considered in
transition to a different use of these concepts from what it had
made of them before. Such a transition necessitates a comparison of
the old and the new usage, in order to distinguish well the new path
from the old one and, at the same time, to allow their connection to
be observed. Accordingly considerations of this kind, including
those which are once more directed to the concept of freedom in the
practical use of the pure reason, must not be regarded as an
interpolation serving only to fill up the gaps in the critical
system of speculative reason (for this is for its own purpose
complete), or like the props and buttresses which in a hastily
constructed building are often added afterwards; but as true members
which make the connexion of the system plain, and show us concepts,
here presented as real, which there could only be presented
problematically. This remark applies especially to the concept of
freedom, respecting which one cannot but observe with surprise that so
many boast of being able to understand it quite well and to explain
its possibility, while they regard it only psychologically, whereas if
they had studied it in a transcendental point of view, they must
have recognized that it is not only indispensable as a problematical
concept, in the complete use of speculative reason, but also quite
incomprehensible; and if they afterwards came to consider its
practical use, they must needs have come to the very mode of
determining the principles of this, to which they are now so loth to
assent. The concept of freedom is the stone of stumbling for all
empiricists, but at the same time the key to the loftiest practical
principles for critical moralists, who perceive by its means that they
must necessarily proceed by a rational method. For this reason I beg
the reader not to pass lightly over what is said of this concept at
the end of the Analytic.

I must leave it to those who are acquainted with works of this
kind to judge whether such a system as that of the practical reason,
which is here developed from the critical examination of it, has
cost much or little trouble, especially in seeking not to miss the
true point of view from which the whole can be rightly sketched. It
presupposes, indeed, the Fundamental Principles of the Metaphysic of
Morals, but only in so far as this gives a preliminary acquaintance
with the principle of duty, and assigns and justifies a definite
formula thereof; in other respects it is independent. * It results
from the nature of this practical faculty itself that the complete
classification of all practical sciences cannot be added, as in the
critique of the speculative reason. For it is not possible to define
duties specially, as human duties, with a view to their
classification, until the subject of this definition (viz. , man) is
known according to his actual nature, at least so far as is
necessary with respect to duty; this, however, does not belong to a
critical examination of the practical reason, the business of which is
only to assign in a complete manner the principles of its possibility,
extent, and limits, without special reference to human nature. The
classification then belongs to the system of science, not to the
system of criticism.

{PREFACE ^paragraph 15}



* A reviewer who wanted to find some fault with this work has hit
the truth better, perhaps, than he thought, when he says that no new
principle of morality is set forth in it, but only a new formula.
But who would think of introducing a new principle of all morality and
making himself as it were the first discoverer of it, just as if all
the world before him were ignorant what duty was or had been in
thorough-going error? But whoever knows of what importance to a
mathematician a formula is, which defines accurately what is to be
done to work a problem, will not think that a formula is insignificant
and useless which does the same for all duty in general.



In the second part of the Analytic I have given, as I trust, a
sufficient answer to the objection of a truth-loving and acute
critic * of the Fundamental Principles of the Metaphysic of Morals- a
critic always worthy of respect- the objection, namely, that the
notion of good was not established before the moral principle, as he
thinks it ought to have been. *(2) I have also had regard to many of
the objections which have reached me from men who show that they have
at heart the discovery of the truth, and I shall continue to do so
(for those who have only their old system before their eyes, and who
have already settled what is to be approved or disapproved, do not
desire any explanation which might stand in the way of their own
private opinion. )



{PREFACE ^paragraph 20}

* [See Kant's "Das mag in der Theoric ricktig seyn," etc. Werke,
vol. vii, p. 182. ]

*(2) It might also have been objected to me that I have not first
defined the notion of the faculty of desire, or of the feeling of
Pleasure, although this reproach would be unfair, because this
definition might reasonably be presupposed as given in psychology.
However, the definition there given might be such as to found the
determination of the faculty of desire on the feeling of pleasure
(as is commonly done), and thus the supreme principle of practical
philosophy would be necessarily made empirical, which, however,
remains to be proved and in this critique is altogether refuted. It
will, therefore, give this definition here in such a manner as it
ought to be given, in order to leave this contested point open at
the beginning, as it should be. LIFE is the faculty a being has of
acting according to laws of the faculty of desire. The faculty of
DESIRE is the being's faculty of becoming by means of its ideas the
cause of the actual existence of the objects of these ideas.
PLEASURE is the idea of the agreement of the object, or the action
with the subjective conditions of life, i. e. , with the faculty of
causality of an idea in respect of the actuality of its object (or
with the determination of the forces of the subject to action which
produces it). I have no further need for the purposes of this critique
of notions borrowed from psychology; the critique itself supplies
the rest. It is easily seen that the question whether the faculty of
desire is always based on pleasure, or whether under certain
conditions pleasure only follows the determination of desire, is by
this definition left undecided, for it is composed only of terms
belonging to the pure understanding, i. e. , of categories which contain
nothing empirical. Such precaution is very desirable in all philosophy
and yet is often neglected; namely, not to prejudge questions by
adventuring definitions before the notion has been completely
analysed, which is often very late. It may be observed through the
whole course of the critical philosophy (of the theoretical as well as
the practical reason) that frequent opportunity offers of supplying
defects in the old dogmatic method of philosophy, and of correcting
errors which are not observed until we make such rational use of these
notions viewing them as a whole.



When we have to study a particular faculty of the human mind in
its sources, its content, and its limits; then from the nature of
human knowledge we must begin with its parts, with an accurate and
complete exposition of them; complete, namely, so far as is possible
in the present state of our knowledge of its elements. But there is
another thing to be attended to which is of a more philosophical and
architectonic character, namely, to grasp correctly the idea of the
whole, and from thence to get a view of all those parts as mutually
related by the aid of pure reason, and by means of their derivation
from the concept of the whole. This is only possible through the
most intimate acquaintance with the system; and those who find the
first inquiry too troublesome, and do not think it worth their while
to attain such an acquaintance, cannot reach the second stage, namely,
the general view, which is a synthetical return to that which had
previously been given analytically. It is no wonder then if they
find inconsistencies everywhere, although the gaps which these
indicate are not in the system itself, but in their own incoherent
train of thought.

I have no fear, as regards this treatise, of the reproach that I
wish to introduce a new language, since the sort of knowledge here
in question has itself somewhat of an everyday character. Nor even
in the case of the former critique could this reproach occur to anyone
who had thought it through and not merely turned over the leaves. To
invent new words where the language has no lack of expressions for
given notions is a childish effort to distinguish oneself from the
crowd, if not by new and true thoughts, yet by new patches on the
old garment. If, therefore, the readers of that work know any more
familiar expressions which are as suitable to the thought as those
seem to me to be, or if they think they can show the futility of these
thoughts themselves and hence that of the expression, they would, in
the first case, very much oblige me, for I only desire to be
understood: and, in the second case, they would deserve well of
philosophy. But, as long as these thoughts stand, I very much doubt
that suitable and yet more common expressions for them can be found. *

{PREFACE ^paragraph 25}



* I am more afraid in the present treatise of occasional
misconception in respect of some expressions which I have chosen
with the greatest care in order that the notion to which they point
may not be missed. Thus, in the table of categories of the Practical
reason under the title of Modality, the Permitted, and forbidden (in a
practical objective point of view, possible and impossible) have
almost the same meaning in common language as the next category,
duty and contrary to duty. Here, however, the former means what
coincides with, or contradicts, a merely possible practical precept
(for example, the solution of all problems of geometry and mechanics);
the latter, what is similarly related to a law actually present in the
reason; and this distinction is not quite foreign even to common
language, although somewhat unusual. For example, it is forbidden to
an orator, as such, to forge new words or constructions; in a
certain degree this is permitted to a poet; in neither case is there
any question of duty. For if anyone chooses to forfeit his
reputation as an orator, no one can prevent him. We have here only
to do with the distinction of imperatives into problematical,
assertorial, and apodeictic. Similarly in the note in which I have
pared the moral ideas of practical perfection in different
philosophical schools, I have distinguished the idea of wisdom from
that of holiness, although I have stated that essentially and
objectively they are the same. But in that place I understand by the
former only that wisdom to which man (the Stoic) lays claim; therefore
I take it subjectively as an attribute alleged to belong to man.
(Perhaps the expression virtue, with which also the Stoic made great show,
would better mark the characteristic of his school. ) The expression of
a postulate of pure practical reason might give most occasion to
misapprehension in case the reader confounded it with the
signification of the postulates in pure mathematics, which carry
apodeictic certainty with them. These, however, postulate the
possibility of an action, the object of which has been previously
recognized a priori in theory as possible, and that with perfect
certainty. But the former postulates the possibility of an object
itself (God and the immortality of the soul) from apodeictic practical
laws, and therefore only for the purposes of a practical reason.
This certainty of the postulated possibility then is not at all
theoretic, and consequently not apodeictic; that is to say, it is
not a known necessity as regards the object, but a necessary
supposition as regards the subject, necessary for the obedience to its
objective but practical laws. It is, therefore, merely a necessary
hypothesis. I could find no better expression for this rational
necessity, which is subjective, but yet true and unconditional.



In this manner, then, the a priori principles of two faculties of
the mind, the faculty of cognition and that of desire, would be
found and determined as to the conditions, extent, and limits of their
use, and thus a sure foundation be paid for a scientific system of
philosophy, both theoretic and practical.

Nothing worse could happen to these labours than that anyone
should make the unexpected discovery that there neither is, nor can
be, any a priori knowledge at all. But there is no danger of this.
This would be the same thing as if one sought to prove by reason
that there is no reason. For we only say that we know something by
reason, when we are conscious that we could have known it, even if
it had not been given to us in experience; hence rational knowledge
and knowledge a priori are one and the same. It is a clear
contradiction to try to extract necessity from a principle of
experience (ex pumice aquam), and to try by this to give a judgement
true universality (without which there is no rational inference, not
even inference from analogy, which is at least a presumed universality
and objective necessity). To substitute subjective necessity, that is,
custom, for objective, which exists only in a priori judgements, is to
deny to reason the power of judging about the object, i. e. , of knowing
it, and what belongs to it. It implies, for example, that we must
not say of something which often or always follows a certain
antecedent state that we can conclude from this to that (for this
would imply objective necessity and the notion of an a priori
connexion), but only that we may expect similar cases (just as animals
do), that is that we reject the notion of cause altogether as false
and a mere delusion. As to attempting to remedy this want of objective
and consequently universal validity by saying that we can see no
ground for attributing any other sort of knowledge to other rational
beings, if this reasoning were valid, our ignorance would do more
for the enlargement of our knowledge than all our meditation. For,
then, on this very ground that we have no knowledge of any other
rational beings besides man, we should have a right to suppose them to
be of the same nature as we know ourselves to be: that is, we should
really know them. I omit to mention that universal assent does not
prove the objective validity of a judgement (i. e. , its validity as a
cognition), and although this universal assent should accidentally
happen, it could furnish no proof of agreement with the object; on the
contrary, it is the objective validity which alone constitutes the
basis of a necessary universal consent.

{PREFACE ^paragraph 30}

Hume would be quite satisfied with this system of universal
empiricism, for, as is well known, he desired nothing more than
that, instead of ascribing any objective meaning to the necessity in
the concept of cause, a merely subjective one should be assumed, viz. ,
custom, in order to deny that reason could judge about God, freedom,
and immortality; and if once his principles were granted, he was
certainly well able to deduce his conclusions therefrom, with all
logical coherence. But even Hume did not make his empiricism so
universal as to include mathematics. He holds the principles of
mathematics to be analytical; and if his were correct, they would
certainly be apodeictic also: but we could not infer from this that
reason has the faculty of forming apodeictic judgements in
philosophy also- that is to say, those which are synthetical
judgements, like the judgement of causality. But if we adopt a
universal empiricism, then mathematics will be included.

Now if this science is in contradiction with a reason that admits
only empirical principles, as it inevitably is in the antinomy in
which mathematics prove the infinite divisibility of space, which
empiricism cannot admit; then the greatest possible evidence of
demonstration is in manifest contradiction with the alleged
conclusions from experience, and we are driven to ask, like
Cheselden's blind patient, "Which deceives me, sight or touch? " (for
empiricism is based on a necessity felt, rationalism on a necessity
seen). And thus universal empiricism reveals itself as absolute
scepticism. It is erroneous to attribute this in such an unqualified
sense to Hume, * since he left at least one certain touchstone (which
can only be found in a priori principles), although experience
consists not only of feelings, but also of judgements.



* Names that designate the followers of a sect have always been
accompanied with much injustice; just as if one said, "N is an
Idealist. " For although he not only admits, but even insists, that our
ideas of external things have actual objects of external things
corresponding to them, yet he holds that the form of the intuition
does not depend on them but on the human mind.



{PREFACE ^paragraph 35}

However, as in this philosophical and critical age such empiricism
can scarcely be serious, and it is probably put forward only as an
intellectual exercise and for the purpose of putting in a clearer
light, by contrast, the necessity of rational a priori principles,
we can only be grateful to those who employ themselves in this
otherwise uninstructive labour.

INTRODUCTION

INTRODUCTION.



Of the Idea of a Critique of Practical Reason.



The theoretical use of reason was concerned with objects of the
cognitive faculty only, and a critical examination of it with
reference to this use applied properly only to the pure faculty of
cognition; because this raised the suspicion, which was afterwards
confirmed, that it might easily pass beyond its limits, and be lost
among unattainable objects, or even contradictory notions. It is quite
different with the practical use of reason. In this, reason is
concerned with the grounds of determination of the will, which is a
faculty either to produce objects corresponding to ideas, or to
determine ourselves to the effecting of such objects (whether the
physical power is sufficient or not); that is, to determine our
causality. For here, reason can at least attain so far as to determine
the will, and has always objective reality in so far as it is the
volition only that is in question. The first question here then is
whether pure reason of itself alone suffices to determine the will, or
whether it can be a ground of determination only as dependent on
empirical conditions. Now, here there comes in a notion of causality
justified by the critique of the pure reason, although not capable
of being presented empirically, viz. , that of freedom; and if we can
now discover means of proving that this property does in fact belong
to the human will (and so to the will of all rational beings), then it
will not only be shown that pure reason can be practical, but that
it alone, and not reason empirically limited, is indubitably
practical; consequently, we shall have to make a critical examination,
not of pure practical reason, but only of practical reason
generally. For when once pure reason is shown to exist, it needs no
critical examination. For reason itself contains the standard for
the critical examination of every use of it. The critique, then, of
practical reason generally is bound to prevent the empirically
conditioned reason from claiming exclusively to furnish the ground
of determination of the will. If it is proved that there is a
[practical] reason, its employment is alone immanent; the
empirically conditioned use, which claims supremacy, is on the
contrary transcendent and expresses itself in demands and precepts
which go quite beyond its sphere. This is just the opposite of what
might be said of pure reason in its speculative employment.

However, as it is still pure reason, the knowledge of which is
here the foundation of its practical employment, the general outline
of the classification of a critique of practical reason must be
arranged in accordance with that of the speculative. We must, then,
have the Elements and the Methodology of it; and in the former an
Analytic as the rule of truth, and a Dialectic as the exposition and
dissolution of the illusion in the judgements of practical reason. But
the order in the subdivision of the Analytic will be the reverse of
that in the critique of the pure speculative reason. For, in the
present case, we shall commence with the principles and proceed to the
concepts, and only then, if possible, to the senses; whereas in the
case of the speculative reason we began with the senses and had to end
with the principles. The reason of this lies again in this: that now
we have to do with a will, and have to consider reason, not in its
relation to objects, but to this will and its causality. We must,
then, begin with the principles of a causality not empirically
conditioned, after which the attempt can be made to establish our
notions of the determining grounds of such a will, of their
application to objects, and finally to the subject and its sense
faculty. We necessarily begin with the law of causality from
freedom, that is, with a pure practical principle, and this determines
the objects to which alone it can be applied.

BOOK_1|CHAPTER_1

FIRST PART.



ELEMENTS OF PURE PRACTICAL REASON.



BOOK I. The Analytic of Pure Practical Reason.



CHAPTER I. Of the Principles of Pure Practical Reason.

{BOOK_1|CHAPTER_1 ^paragraph 5}



I. DEFINITION.



Practical principles are propositions which contain a general
determination of the will, having under it several practical rules.
They are subjective, or maxims, when the condition is regarded by
the subject as valid only for his own will, but are objective, or
practical laws, when the condition is recognized as objective, that
is, valid for the will of every rational being.



{BOOK_1|CHAPTER_1 ^paragraph 10}

REMARK.



Supposing that pure reason contains in itself a practical motive,
that is, one adequate to determine the will, then there are
practical laws; otherwise all practical principles will be mere
maxims. In case the will of a rational being is pathologically
affected, there may occur a conflict of the maxims with the
practical laws recognized by itself. For example, one may make it
his maxim to let no injury pass unrevenged, and yet he may see that
this is not a practical law, but only his own maxim; that, on the
contrary, regarded as being in one and the same maxim a rule for the
will of every rational being, it must contradict itself. In natural
philosophy the principles of what happens, (e. g. , the principle of
equality of action and reaction in the communication of motion) are at
the same time laws of nature; for the use of reason there is
theoretical and determined by the nature of the object. In practical
philosophy, i. e. , that which has to do only with the grounds of
determination of the will, the principles which a man makes for
himself are not laws by which one is inevitably bound; because
reason in practical matters has to do with the subject, namely, with
the faculty of desire, the special character of which may occasion
variety in the rule. The practical rule is always a product of reason,
because it prescribes action as a means to the effect. But in the case
of a being with whom reason does not of itself determine the will,
this rule is an imperative, i. e. , a rule characterized by "shall,"
which expresses the objective necessitation of the action and
signifies that, if reason completely determined the will, the action
would inevitably take place according to this rule. Imperatives,
therefore, are objectively valid, and are quite distinct from
maxims, which are subjective principles. The former either determine
the conditions of the causality of the rational being as an
efficient cause, i. e. , merely in reference to the effect and the means
of attaining it; or they determine the will only, whether it is
adequate to the effect or not. The former would be hypothetical
imperatives, and contain mere precepts of skill; the latter, on the
contrary, would be categorical, and would alone be practical laws.
Thus maxims are principles, but not imperatives. Imperatives
themselves, however, when they are conditional (i. e. , do not determine
the will simply as will, but only in respect to a desired effect, that
is, when they are hypothetical imperatives), are practical precepts
but not laws. Laws must be sufficient to determine the will as will,
even before I ask whether I have power sufficient for a desired
effect, or the means necessary to produce it; hence they are
categorical: otherwise they are not laws at all, because the necessity
is wanting, which, if it is to be practical, must be independent of
conditions which are pathological and are therefore only
contingently connected with the will. Tell a man, for example, that he
must be industrious and thrifty in youth, in order that he may not
want in old age; this is a correct and important practical precept
of the will. But it is easy to see that in this case the will is
directed to something else which it is presupposed that it desires;
and as to this desire, we must leave it to the actor himself whether
he looks forward to other resources than those of his own acquisition,
or does not expect to be old, or thinks that in case of future
necessity he will be able to make shift with little. Reason, from
which alone can spring a rule involving necessity, does, indeed,
give necessity to this precept (else it would not be an imperative),
but this is a necessity dependent on subjective conditions, and cannot
be supposed in the same degree in all subjects. But that reason may
give laws it is necessary that it should only need to presuppose
itself, because rules are objectively and universally valid only
when they hold without any contingent subjective conditions, which
distinguish one rational being from another. Now tell a man that he
should never make a deceitful promise, this is a rule which only
concerns his will, whether the purposes he may have can be attained
thereby or not; it is the volition only which is to be determined a
priori by that rule. If now it is found that this rule is
practically right, then it is a law, because it is a categorical
imperative. Thus, practical laws refer to the will only, without
considering what is attained by its causality, and we may disregard
this latter (as belonging to the world of sense) in order to have them
quite pure.



II. THEOREM I.

{BOOK_1|CHAPTER_1 ^paragraph 15}



All practical principles which presuppose an object (matter) of
the faculty of desire as the ground of determination of the will are
empirical and can furnish no practical laws.

By the matter of the faculty of desire I mean an object the
realization of which is desired. Now, if the desire for this object
precedes the practical rule and is the condition of our making it a
principle, then I say (in the first place) this principle is in that
case wholly empirical, for then what determines the choice is the idea
of an object and that relation of this idea to the subject by which
its faculty of desire is determined to its realization. Such a
relation to the subject is called the pleasure in the realization of
an object. This, then, must be presupposed as a condition of the
possibility of determination of the will. But it is impossible to know
a priori of any idea of an object whether it will be connected with
pleasure or pain, or be indifferent. In such cases, therefore, the
determining principle of the choice must be empirical and,
therefore, also the practical material principle which presupposes
it as a condition.

In the second place, since susceptibility to a pleasure or pain
can be known only empirically and cannot hold in the same degree for
all rational beings, a principle which is based on this subjective
condition may serve indeed as a maxim for the subject which
possesses this susceptibility, but not as a law even to him (because
it is wanting in objective necessity, which must be recognized a
priori); it follows, therefore, that such a principle can never
furnish a practical law.



{BOOK_1|CHAPTER_1 ^paragraph 20}

III. THEOREM II.



All material practical principles as such are of one and the same
kind and come under the general principle of self-love or private
happiness.

Pleasure arising from the idea of the idea of the existence of a
thing, in so far as it is to determine the desire of this thing, is
founded on the susceptibility of the subject, since it depends on
the presence of an object; hence it belongs to sense (feeling), and
not to understanding, which expresses a relation of the idea to an
object according to concepts, not to the subject according to
feelings. It is, then, practical only in so far as the faculty of
desire is determined by the sensation of agreeableness which the
subject expects from the actual existence of the object. Now, a
rational being's consciousness of the pleasantness of life
uninterruptedly accompanying his whole existence is happiness; and the
principle which makes this the supreme ground of determination of
the will is the principle of self-love. All material principles, then,
which place the determining ground of the will in the pleasure or pain
to be received from the existence of any object are all of the same
kind, inasmuch as they all belong to the principle of self-love or
private happiness.



{BOOK_1|CHAPTER_1 ^paragraph 25}

COROLLARY.



All material practical rules place the determining principle of
the will in the lower desires; and if there were no purely formal laws
of the will adequate to determine it, then we could not admit any
higher desire at all.