condition of the summum bonum。 This then must be possible； as well
as its object； since it is contained in the mand to promote the
latter。 Now； the perfect accordance of the will with the moral law
is holiness； a perfection of which no rational being of the sensible
world is capable at any moment of his existence。 Since；
nevertheless； it is required as practically necessary； it can only
be found in a progress in infinitum towards that perfect accordance；
and on the principles of pure practical reason it is necessary to
assume such a practical progress as the real object of our will。
Now； this endless progress is only possible on the supposition of an
endless duration of the existence and personality of the same rational
being （which is called the immortality of the soul）。 The summum bonum；
then； practically is only possible on the supposition of the
immortality of the soul； consequently this immortality； being
inseparably connected with the moral law； is a postulate of pure
practical reason （by which I mean a theoretical proposition； not
demonstrable as such； but which is an inseparable result of an
unconditional a priori practical law。
This principle of the moral destination of our nature； namely；
that it is only in an endless progress that we can attain perfect
accordance with the moral law； is of the greatest use； not merely
for the present purpose of supplementing the impotence of
speculative reason； but also with respect to religion。 In default of
it； either the moral law is quite degraded from its holiness； being
made out to be indulgent and conformable to our convenience； or else
men strain their notions of their vocation and their expectation to an
unattainable goal； hoping to acquire plete holiness of will； and so
they lose themselves in fanatical theosophic dreams； which wholly
contradict self…knowledge。 In both cases the unceasing effort to
obey punctually and thoroughly a strict and inflexible mand of
reason； which yet is not ideal but real； is only hindered。 For a
rational but finite being； the only thing possible is an endless
progress from the lower to higher degrees of moral perfection。 The
Infinite Being； to whom the condition of time is nothing； sees in this
to us endless succession a whole of accordance with the moral law； and
the holiness which his mand inexorably requires； in order to be
true to his justice in the share which He assigns to each in the
summum bonum； is to be found in a single intellectual intuition of the
whole existence of rational beings。 All that can be expected of the
creature in respect of the hope of this participation would be the
consciousness of his tried character； by which from the progress he
has hitherto made from the worse to the morally better； and the
immutability of purpose which has thus bee known to him； he may
hope for a further unbroken continuance of the same； however long
his existence may last； even beyond this life；* and thus he may
hope； not indeed here； nor in any imaginable point of his future
existence； but only in the endlessness of his duration （which God
alone can survey） to be perfectly adequate to his will （without
indulgence or excuse； which do not harmonize with justice）。
*It seems； nevertheless； impossible for a creature to have the
conviction of his unwavering firmness of mind in the progress
towards goodness。 On this account the Christian religion makes it e
only from the same Spirit that works sanctification； that is； this
firm purpose； and with it the consciousness of steadfastness in the
moral progress。 But naturally one who is conscious that he has
persevered through a long portion of his life up to the end in the
progress to the better； and this genuine moral motives； may well
have the forting hope； though not the certainty； that even in an
existence prolonged beyond this life he will continue in these
principles； and although he is never justified here in his own eyes；
nor can ever hope to be so in the increased perfection of his
nature； to which he looks forward； together with an increase of
duties； nevertheless in this progress which； though it is directed
to a goal infinitely remote； yet is in God's sight regarded as
equivalent to possession； he may have a prospect of a blessed
future； for this is the word that reason employs to designate
perfect well…being independent of all contingent causes of the
world； and which； like holiness； is an idea that can be contained only
in an endless progress and its totality； and consequently is never
fully attained by a creature。
V。 The Existence of God as a Postulate of Pure Practical Reason。
In the foregoing analysis the moral law led to a practical problem
which is prescribed by pure reason alone； without the aid of any
sensible motives； namely； that of the necessary pleteness of the
first and principle element of the summum bonum； viz。； morality；
and； as this can be perfectly solved only in eternity； to the
postulate of immortality。 The same law must also lead us to affirm the
possibility of the second element of the summum bonum； viz。； happiness
proportioned to that morality； and this on grounds as disinterested as
before； and solely from impartial reason； that is； it must lead to the
supposition of the existence of a cause adequate to this effect； in
other words； it must postulate the existence of God； as the
necessary condition of the possibility of the summum bonum （an
object of the will which is necessarily connected with the moral
legislation of pure reason）。 We proceed to exhibit this connection
in a convincing manner。
Happiness is the condition of a rational being in the world with
whom everything goes according to his wish and will； it rests；
therefore； on the harmony of physical nature with his whole end and
likewise with the essential determining principle of his will。 Now the
moral law as a law of freedom mands by determining principles；
which ought to be quite independent of nature and of its harmony
with our faculty of desire （as springs）。 But the acting rational being
in the world is not the cause of the world and of nature itself。 There
is not the least ground； therefore； in the moral law for a necessary
connection between morality and proportionate happiness in a being
that belongs to the world as part of it； and therefore dependent on
it； and which for that reason cannot by his will be a cause of this
nature； nor by his own power make it thoroughly harmonize； as far as
his happiness is concerned； with his practical principles。
Nevertheless； in the practical problem of pure reason； i。e。； the
necessary pursuit of the summum bonum； such a connection is postulated
as necessary： we ought to endeavour to promote the summum bonum；
which； therefore； must be possible。 Accordingly； the existence of a
cause of all nature； distinct from nature itself and containing the
principle of this connection； namely； of the exact harmony of
happiness with morality； is also postulated。 Now this supreme cause
must contain the principle of the harmony of nature； not merely with a
law of the will of rational beings； but with the conception of this
law； in so far as they make it the supreme determining principle of
the will； and consequently not merely with the form of morals； but
with their morality as their motive； that is； with their moral
character。 Therefore； the summum bonum is possible in the world only
on the supposition of a Supreme Being having a causality corresponding
to moral character。 Now a being that is capable of acting on the
conception of laws is an intelligence （a rational being）； and the
causality of such a being according to this conception of laws is
his will； therefore the supreme cause of nature； which must be
presupposed as a condition of the summum bonum is a being which is the
cause of nature by intelligence and will； consequently its author；
that is God。 It follows that the postulate of the possibility of the
highest derived good （the best world） is likewise the postulate of the
reality of a highest original good； that is to say； of the existence
of God。 Now it was seen to be a duty for us to promote the summum
bonum； consequently it is not merely allowable； but it is a
necessity connected with duty as a requisite； that we should
presuppose the possibility of this summum bonum； and as this is
possible only on condition of the existence of God； it inseparably
connects the supposition of this with duty； that is； it is morally
necessary to assume the existence of God。
It must be remarked here that this moral necessity is subjective；
that is； it is a want； and not objective； that is； itself a duty；
for there cannot be a duty to suppose the existence of anything （since
this concerns only the theoretical employment of reason）。 Moreover； it
is not meant by this that it is necessary to suppose the existence
of God as a basis of all obligation in general （for this rests； as has
been sufficiently proved； simply on the autonomy of reason itself）。
What belongs to duty here is only the endeavour to realize and promote
the summum bonum in the world； the possibility of which can
therefore be postulated； and as our reason finds it not conceivable
except on