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 à 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 make abstraction of all the impediments to morality (sensuous desires), such a system of happiness, connected with and proportioned to morality, may be conceived as necessary, because freedom of volition—partly incited, and partly restrained by moral laws—would be itself the cause of general happiness; and thus rational beings, under the guidance of such principles, would be themselves the authors both of their own enduring welfare and that of others. But such a system of self-rewarding morality is only an idea, the carrying out of which depends upon the condition that every one acts as he ought; in other words, that all actions of reasonable beings be such as they would be if they sprung from a Supreme Will, comprehending in, or under, itself all particular wills. But since the moral law is binding on each individual in the use of his freedom of volition, even if others should not act in conformity with this law, neither the nature of things, nor the causality of actions and their relation to morality, determine how the consequences of these actions will be related to happiness; and the necessary connection of the hope of happiness with the unceasing endeavour to become worthy of happiness, cannot be cognized by reason, if we take nature alone for our guide. This connection can be hoped for only on the assumption that the cause of nature is a supreme reason, which governs according to moral laws.
I term the idea of an intelligence in which the morally most perfect will, united with supreme blessedness, is the cause of all happiness in the world, so far as happiness stands in strict relation to morality (as the worthiness of being happy), the ideal of the supreme Good. It is only, then, in the ideal of the supreme original good, that pure reason can find the ground of the practically necessary connection of both elements of the highest derivative good, and accordingly of an intelligible, that is, moral world. Now since we are necessitated by reason to conceive ourselves as belonging to such a world, while the senses present to us nothing but a world of phenomena, we must assume the former as a consequence of our conduct in the world of sense (since the world of sense gives us no hint of it), and therefore as future in relation to us. Thus God and a future life are two hypotheses which, according to the principles of pure reason, are inseparable from the obligation which this reason imposes upon us.
Morality per se constitutes a system. But we can form no system of happiness, except in so far as it is dispensed in strict proportion to morality. But this is only possible in the intelligible world, under a wise author and ruler. Such a ruler, together with life in such a world, which we must look upon as future, reason finds itself compelled to assume; or it must regard the moral laws as idle dreams, since the necessary consequence which this same reason connects with them must, without this hypothesis, fall to the ground. Hence also the moral laws are universally regarded as commands, which they could not be did they not connect à priori adequate consequences with their dictates, and thus carry with them promises and threats. But this, again, they could not do, did they not reside in a necessary being, as the Supreme Good, which alone can render such a teleological unity possible.
Leibnitz termed the world, when viewed in relation to the rational beings which it contains, and the moral relations in which they stand to each other, under the government of the Supreme Good, the kingdom of Grace, and distinguished it from the kingdom of Nature, in which these rational beings live, under moral laws, indeed, but expect no other consequences from their actions than such as follow according to the course of nature in the world of sense. To view ourselves, therefore, as in the kingdom of grace, in which all happiness awaits us, except in so far as we ourselves limit our participation in it by actions which render us unworthy of happiness, is a practically necessary idea of reason.
Practical laws, in so far as they are subjective grounds of actions, that is, subjective principles, are termed maxims. The judgements of moral according to in its purity and ultimate results are framed according ideas; the observance of its laws, according to maxims.
The whole course of our life must be subject to moral maxims; but this is impossible, unless with the moral law, which is a mere idea, reason connects an efficient cause which ordains to all conduct which is in conformity with the moral law an issue either in this or in another life, which is in exact conformity with our highest aims. Thus, without a God and without a world, invisible to us now, but hoped for, the glorious ideas of morality are, indeed, objects of approbation and of admiration, but cannot be the springs of purpose and action. For they do not satisfy all the aims which are natural to every rational being, and which are determined à priori by pure reason itself, and necessary.
Happiness alone is, in the view of reason, far from being the complete good. Reason does not approve of it (however much inclination may desire it), except as united with desert. On the other hand, morality alone, and with it, mere desert, is likewise far from being the complete good. To make it complete, he who conducts himself in a manner not unworthy of happiness, must be able to hope for the possession of happiness. Even reason, unbiased by private ends, or interested considerations, cannot judge otherwise, if it puts itself in the place of a being whose business it is to dispense all happiness to others. For in the practical idea both points are essentially combined, though in such a way that participation in happiness is rendered possible by the moral disposition, as its condition, and not conversely, the moral disposition by the prospect of happiness. For a disposition which should require the prospect of happiness as its necessary condition would not be moral, and hence also would not be worthy of complete happiness—a happiness which, in the view of reason, recognizes no limitation but such as arises from our own immoral conduct.
Happiness, therefore, in exact proportion with the morality of rational beings (whereby they are made worthy of happiness), constitutes alone the supreme good of a world into which we absolutely must transport ourselves according to the commands of pure but practical reason. This world is, it is true, only an intelligible world; for of such a systematic unity of ends as it requires, the world of sense gives us no hint. Its reality can be based on nothing else but the hypothesis of a supreme original good. In it independent reason, equipped with all the sufficiency of a supreme cause, founds, maintains, and fulfils the universal order of things, with the most perfect teleological harmony, however much this order may be hidden from us in the world of sense.
This moral theology has the peculiar advantage, in contrast with speculative theology, of leading inevitably to the conception of a sole, perfect, and rational First Cause, whereof speculative theology does not give us any indication on objective grounds, far less any convincing evidence. For we find neither in transcendental nor in natural theology, however far reason may lead us in these, any ground to warrant us in assuming the existence of one only Being, which stands at the head of all natural causes, and on which these are entirely dependent. On the other hand, if we take our stand on moral unity as a necessary law of the universe, and from this point of view consider what is necessary to give this law adequate efficiency and, for us, obligatory force, we must come to the conclusion that there is one only supreme will, which comprehends all these laws in itself. For how, under different wills, should we find complete unity of ends? This will must be omnipotent, that all nature and its relation to morality in the world may be subject to it; omniscient, that it may have knowledge of the
