for pure reason。 A will is purely animal （arbitrium brutum） when it is
determined by sensuous impulses or instincts only； that is； when it is
determined in a pathological manner。 A will； which can be determined
independently of sensuous impulses； consequently by motives
presented by reason alone； is called a free will （arbitrium
liberum）； and everything which is connected with this free will；
either as principle or consequence； is termed practical。 The existence
of practical freedom can be proved from experience alone。 For the
human will is not determined by that alone which immediately affects
the senses； on the contrary； we have the power； by calling up the
notion of what is useful or hurtful in a more distant relation； of
overing the immediate impressions on our sensuous faculty of
desire。 But these considerations of what is desirable in relation to
our whole state； that is； is in the end good and useful； are based
entirely upon reason。 This faculty； accordingly； enounces laws；
which are imperative or objective laws of freedom and which tell us
what ought to take place； thus distinguishing themselves from the laws
of nature； which relate to that which does take place。 The laws of
freedom or of free will are hence termed practical laws。
Whether reason is not itself； in the actual delivery of these
laws； determined in its turn by other influences； and whether the
action which； in relation to sensuous impulses； we call free； may not；
in relation to higher and more remote operative causes； really form
a part of nature… these are questions which do not here concern us。
They are purely speculative questions； and all we have to do； in the
practical sphere； is to inquire into the rule of conduct which
reason has to present。 Experience demonstrates to us the existence
of practical freedom as one of the causes which exist in nature；
that is； it shows the causal power of reason in the determination of
the will。 The idea of transcendental freedom； on the contrary；
requires that reason… in relation to its causal power of mencing
a series of phenomena… should be independent of all sensuous
determining causes； and thus it seems to be in opposition to the law
of nature and to all possible experience。 It therefore remains a
problem for the human mind。 But this problem does not concern reason
in its practical use； and we have； therefore； in a canon of pure
reason； to do with only two questions； which relate to the practical
interest of pure reason： Is there a God？ and； Is there a future
life？ The question of transcendental freedom is purely speculative；
and we may therefore set it entirely aside when we e to treat of
practical reason。 Besides； we have already discussed this subject in
the antinomy of pure reason。
SECTION II。 Of the Ideal of the Summum Bonum as a Determining
Ground of the Ultimate End of Pure Reason。
Reason conducted us； in its speculative use； through the field of
experience and； as it can never find plete satisfaction in that
sphere； from thence to speculative ideas… which； however； in the end
brought us back again to experience； and thus fulfilled the purpose of
reason； in a manner which； though useful； was not at all in accordance
with our expectations。 It now remains for us to consider whether
pure reason can be employed in a practical sphere； and whether it will
here conduct us to those ideas which attain the highest ends of pure
reason； as we have just stated them。 We shall thus ascertain
whether； from the point of view of its practical interest； reason
may not be able to supply us with that which； on the speculative side；
it wholly denies us。
The whole interest of reason； speculative as well as practical； is
centred in the three following questions：
1。 WHAT CAN I KNOW？
2。 WHAT OUGHT I TO DO？
3。 WHAT MAY I HOPE？
The first question is purely speculative。 We have； as I flatter
myself； exhausted all the replies of which it is susceptible； and have
at last found the reply with which reason must content itself； and
with which it ought to be content； so long as it pays no regard to the
practical。 But from the two great ends to the attainment of which
all these efforts of pure reason were in fact directed； we remain just
as far removed as if we had consulted our ease and declined the task
at the outset。 So far； then； as knowledge is concerned； thus much；
at least； is established； that； in regard to those two problems； it
lies beyond our reach。
The second question is purely practical。 As such it may indeed
fall within the province of pure reason； but still it is not
transcendental； but moral； and consequently cannot in itself form
the subject of our criticism。
The third question： If I act as I ought to do； what may I then
hope？… is at once practical and theoretical。 The practical forms a
clue to the answer of the theoretical； and… in its highest form…
speculative question。 For all hoping has happiness for its object
and stands in precisely the same relation to the practical and the law
of morality as knowing to the theoretical cognition of things and
the law of nature。 The former arrives finally at the conclusion that
something is （which determines the ultimate end）； because something
ought to take place； the latter； that something is （which operates
as the highest cause）； because something does take place。
Happiness is the satisfaction of all our desires； extensive； in
regard to their multiplicity； intensive； in regard to their degree；
and protensive； in regard to their duration。 The practical law based
on the motive of happiness I term a pragmatical law （or prudential
rule）； but that law； assuming such to exist； which has no other motive
than the worthiness of being happy； I term a moral or ethical law。 The
first tells us what we have to do； if we wish to bee possessed of
happiness； the second dictates how we ought to act； in order to
deserve happiness。 The first is based upon empirical principles； for
it is only by experience that I can learn either what inclinations
exist which desire satisfaction； or what are the natural means of
satisfying them。 The second takes no account of our desires or the
means of satisfying them； and regards only the freedom of a rational
being； and the necessary conditions under which alone this freedom can
harmonize with the distribution of happiness according to
principles。 This second law may therefore rest upon mere ideas of pure
reason； and may be cognized a priori。
I assume that there are pure moral laws which determine； entirely
a priori （without regard to empirical motives； that is； to happiness）；
the conduct of a rational being； or in other words； to use which it
makes of its freedom； and that these laws are absolutely imperative
（not merely hypothetically； on the supposition of other empirical
ends）； and therefore in all respects necessary。 I am warranted in
assuming this； not only by the arguments of the most enlightened
moralists； but by the moral judgement of every man who will make the
attempt to form a distinct conception of such a law。
Pure reason； then； contains； not indeed in its speculative； but in
its practical； or； more strictly； its moral use； principles of the
possibility of experience； of such actions； namely； as； in
accordance with ethical precepts； might be met with in the history
of man。 For since reason mands that such actions should take place；
it must be possible for them to take place； and hence a particular
kind of systematic unity… the moral… must be possible。 We have
found； it is true； that the systematic unity of nature could not be
established according to speculative principles of reason； because；
while reason possesses a causal power in relation to freedom； it has
none in relation to the whole sphere of nature； and； while moral
principles of reason can produce free actions； they cannot produce
natural laws。 It is； then； in its practical； but especially in its
moral use； that the principles of pure reason possess objective
reality。
I call the world a moral world； in so far as it may be in accordance
with all the ethical laws… which； by virtue of the freedom of
reasonable beings； it can be； and according to the necessary laws of
morality it ought to be。 But this world must be conceived only as an
intelligible world； inasmuch as abstraction is therein made of all
conditions （ends）； and even of all impediments to morality （the
weakness or pravity of human nature）。 So far； then； it is a mere idea…
though still a practical idea… which may have； and ought to have； an
influence on the world of sense； so as to bring it as far as
possible into conformity with itself。 The idea of a moral world has；
therefore； objective reality； not as referring to an object of
intelligible intuition… for of such an object we can form no
conception whatever… but to the world of sense… conceived； however； as
an object of pure reason in its practical use… and to a corpus
mysticum of rational beings in it； in so far as the liberum
arbitrium of the individual is placed； under and by virtue of moral
laws； in plete systematic unity both with itself and with the
freedom of all others。
That is the answer to the first of the two questions of pure
reason which relate to its practical interest： Do that which will
render thee worthy of happiness。 The second question is this： If I
conduct myself so as not to be unworthy of happiness； may I hope
thereby to obtain happiness？ In order to arrive at the solution of
this question； we must inquire whether the principles of pure
reason； which prescribe a priori the law； necessarily also connect
this hope with it。
I say； then； that just as the moral principles are necessary
according to reason in its practical use； so it is equally necessary
according to reason in its theoretical use to assume that every one
has ground to hope for happiness in the measure in which he has made
himself worthy of it in his conduct； and that therefore the system
of morality is inseparably （though only in the idea of pure reason）
connected with that of happiness。
Now in an intelligible； that is； in the moral world； in the
conception of which we mak