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 comforting 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 completeness 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 commands 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 the supposition of a supreme intelligence； the admission of this existence is therefore connected with the consciousness of our duty； although the admission itself belongs to the domain of speculative reason。 Considered in respect of this alone； as a principle of explanation； it may be called a hypothesis； but in reference to the intelligibility of an object given us by the moral law （the summum bonum）； and consequently of a requirement for practical purposes； it may be called faith； that is to say a pure rational faith； since pure reason （both in its theoretical and practical use） is the sole source from which it springs。 From this deduction it is now intelligible why the Greek schools could never attain the solution of their problem of the practical possibility of the summum bonum； because they made the rule of the use which the will of man makes of his freedom the sole and sufficient ground of this possibility； thinking that they had no need for that purpose of the existence of God。 No doubt they were so far right that they established the principle of morals of itself independently of this postulate； from the relation of reason only to the will； and consequently made it the supreme practical condition of the summum bonum； but it was not therefore the whole condition of its possibility。 The Epicureans had indeed assumed as the supreme principle of morality a wholly false one； namely that of happiness； and had substituted for a law a maxim of arbitrary choice according to every man's inclination； they proceeded； however； consistently enough in this； that they degraded their summum bonum likewise； just in proportion to the meanness of their fundamental principle； and looked for no greater happiness than can be attained by human prudence （including temperance and moderation of the inclinations）； and this as we know would be scanty enough and would be very different according to circumstances； not to mention the exceptions that their maxims must perpetually admit and which make them incapable of being laws。 The Stoics； on the contrary； had chosen their supreme practical principle quite rightly； making virtue the condition of the summum bonum； but when they represented the degree of virtue required by its pure law as fully attainable in this life； they not only strained the moral powers of the man whom they called the wise beyond all the limits of his nature； and assumed a thing that contradicts all our knowledge of men； but also and principally they would not allow the second element of the summum bonum； namely； happiness； to be properly a special object of human desire； but made their wise man； like a divinity in his consciousness of the excellence of his person； wholly independent of nature （as regards his own contentment）； they exposed him indeed to the evils of life； but made him not subject to them （at the same time representing him also as free from moral evil）。 They thus； in fact； left out the second element of the summum bonum namely； personal happiness； placing it solely in action and satisfaction with one's own personal worth； thus including it in the consciousness of being morally minded； in which they Might have been sufficiently refuted by the voice of their own nature。 The doctrine of Christianity；* even if we do not yet consider it as a religious doctrine； gives； touching this point； a conception of the summum bonum （the kingdom of God）； which alone satisfies the strictest demand of practical reason。 The moral law is holy （unyielding） and demands holiness of morals； although all the moral perfection to which m