VIII.: —Of Belief from a Requirement of Pure Reason.

A want or requirement of pure reason in its speculative use leads only to a hypothesis; that of pure practical reason to a postulate; for in the former case I ascend from the result as high as I please in the series of causes, not in order to give objective reality to the result (e. g. the causal connexion of things and changes in the world), but in order thoroughly to satisfy my inquiring reason in respect of it. Thus I see before me order and design in nature, and need not resort to speculation to assure myself of their reality, but to explain them I have to pre-suppose a Deity as their cause; and then since the inference from an effect to a definite cause is always uncertain and doubtful, especially to a cause so precise and so perfectly defined as we have to conceive in God, hence the highest degree of certainty to which this pre-supposition can be brought is, that it is the most rational opinion for us men . On the other hand, a requirement of pure practical reason is based on a duty, that of making something (the summum bonum) the object of my will so as to promote it with all my powers; in which case I must suppose its possibility, and consequently also the conditions necessary thereto, namely, God, freedom, and immortality; since I cannot prove these by my speculative reason, although neither can I refute them. This duty is founded on something that is indeed quite independent on these suppositions, and is of itself apodictically certain, namely, the moral law; and so far it needs no further support by theoretical views as to the inner constitution of things, the secret final aim of the order of the world, or a presiding ruler thereof, in order to bind me in the most perfect manner to act in unconditional conformity to the law. But the subjective effect of this law, namely, the mental disposition conformed to it and made necessary by it, to promote the practically possible summum bonum, this pre-supposes at least that the latter is possible, for it would be practically impossible to strive after the object of a conception which at bottom was empty and had no object. Now the above-mentioned postulates concern only the physical or metaphysical conditions of the possibility of the summum bonum ; in a word, those which lie in the nature of things; not, however, for the sake of an arbitrary speculative purpose, but of a practically necessary end of a pure rational will, which in this case does not choose, but obeys an inexorable command of reason, the foundation of which is objective, in the constitution of things as they must be universally judged by pure reason, and is not based on inclination; for we are in nowise justified in assuming, on account of what we wish on merely subjective grounds, that the means thereto are possible or that its object is real. This then is an absolutely necessary requirement, and what it pre-supposes is not merely justified as an allowable hypothesis, but as a postulate in a practical point of view; and admitting that the pure moral law inexorably binds every man as a command (not as a rule of prudence), the righteous man may say: I will that there be a God, that my existence in this world be also an existence outside the chain of physical causes, and in a pure world of the understanding, and lastly, that my duration be endless; I firmly abide by this, and will not let this faith be taken from me; for in this instance alone my interest, because I must not relax anything of it, inevitably determines my judgment, without regarding sophistries, however unable I may be to answer them or to oppose them with others more plausible.

In order to prevent misconception in the use of a notion as yet so unusual as that of a faith of pure practical reason, let me be permitted to add one more remark. It might almost seem as if this rational faith were here announced as itself a command, namely, that we should assume the summum bonum as possible. But a faith that is commanded is nonsense. Let the preceding analysis, however, be remembered of what is required to be supposed in the conception of the summum bonum, and it will be seen that it cannot be commanded to assume this possibility, and no practical disposition of mind is required to admit it; but that speculative reason must concede it without being asked, for no one can affirm that it is impossible in itself that rational beings in the world should at the same time be worthy of happiness in conformity with the moral law, and also possess this happiness proportionately. Now in respect of the first element of the summum bonum, namely, that which concerns morality, the moral law gives merely a command, and to doubt the possibility of that element would be the same as to call in question the moral law itself . But as regards the second element of that object, namely, happiness perfectly proportioned to that worthiness, it is true that there is no need of a command to admit its possibility in general, for theoretical reason has nothing to say against it; but the manner in which we have to conceive this harmony of the laws of nature with those of freedom has in it something in respect of which we have a choice, because theoretical reason decides nothing with apodictic certainty about it, and in respect of this there may be a moral interest which turns the scale.

I had said above that in a mere course of nature in the world an accurate correspondence between happiness and moral worth is not to be expected, and must be regarded as impossible, and that therefore the possibility of the summum bonum cannot be admitted from this side except on the supposition of a moral Author of the world. I purposely reserved the restriction of this judgment to the subjective conditions of our reason, in order not to make use of it until the manner of this belief should be defined more precisely. The fact is that the impossibility referred to is merely subjective, that is, our reason finds it impossible for it to render conceivable in the way of a mere course of nature a connexion so exactly proportioned and so thoroughly adapted to an end, between two sets of events happening according to such distinct laws; although, as with everything else in nature that is adapted to an end, it cannot prove, that is, show by sufficient objective reasons, that it is not possible by universal laws of nature.

Now, however, a deciding principle of a different kind comes into play to turn the scale in this uncertainty of speculative reason. The command to promote the summum bonum is established on an objective basis (in practical reason); the possibility of the same in general is likewise established on an objective basis (in theoretical reason, which has nothing to say against it). But reason cannot decide objectively in what way we are to conceive this possibility; whether by universal laws of nature without a wise Author presiding over nature, or only on supposition of such an Author. Now here there comes in a subjective condition of reason; the only way theoretically possible for it, of conceiving the exact harmony of the kingdom of nature with the kingdom of morals, which is the condition of the possibility of the summum bonum; and at the same time the only one conducive to morality (which depends on an objective law of reason). Now since the promotion of this summum bonum, and therefore the supposition of its possibility, are objectively necessary (though only as a result of practical reason), while at the same time the manner in which we would conceive it rests with our own choice, and in this choice a free interest of pure practical reason decides for the assumption of a wise Author of the world; it is clear that the principle that herein determines our judgment, though as a want it is subjective, yet at the same time being the means of promoting what is objectively (practically) necessary, is the foundation of a maxim of belief in a moral point of view, that is, a faith of pure practical reason. This, then, is not commanded, but being a voluntary determination of our judgment, conducive to the moral (commanded) purpose, and moreover harmonizing with the theoretical requirement of reason, to assume that existence and to make it the foundation of our further employment of reason, it has itself sprung from the moral disposition of mind; it may therefore at times waver even in the well-disposed, but can never be reduced to unbelief.