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 parison 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
plete）； 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 plete use of speculative reason； but also quite
inprehensible； and if they afterwards came to consider its
practical use； they must needs have e 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 plete
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 plete 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。
*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 be 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。）
*＇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 monly 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 being 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 posed 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 pletely
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
plete exposition of them； plete； 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 th