Faith (as habitus, not as actus) is the moral attitude of Reason as to belief in that which is unattainable by theoretical cognition. It is therefore the constant principle of the mind, to assume as true, on account of the obligation in reference to it, that which it is necessary to presuppose as condition of the possibility of the highest moral final purpose[152]; although its possibility or impossibility be alike impossible for us to see into. Faith (absolutely so called) is trust in the attainment of a design, the promotion of which is a duty, but the possibility of the fulfilment of which (and consequently also that of the only conditions of it thinkable by us) is not to be comprehended by us. Faith, then, that refers to particular objects, which are not objects of possible knowledge or opinion (in which latter case it ought to be called, especially in historical matters, credulity and not faith), is quite moral. It is a free belief, not in that for which dogmatical proofs for the theoretically determinant Judgement are to be found, or in that to which we hold ourselves bound, but in that which we assume on behalf of a design in accordance with laws of freedom. This, however, is not, like opinion, without any adequate ground; but, is grounded as in Reason (although only in respect of its practical employment), and adequately for its design. For without this, the moral attitude of thought in its repudiation of the claim of the theoretical Reason for proofs (of the possibility of the Objects of morality) has no permanence; but wavers between practical commands and theoretical doubts. To be incredulous means to cling to maxims, and not to believe testimony in general; but he is unbelieving, who denies all validity to rational Ideas, because there is wanting a theoretical ground of their reality.[154] He judges therefore dogmatically. A dogmatical unbelief cannot subsist together with a moral maxim dominant in the mental attitude (for Reason cannot command one to follow a purpose, which is cognised as nothing more than a chimera); but a doubtful faith can. To this the absence of conviction by grounds of speculative Reason is only a hindrance, the influence of which upon conduct a critical insight into the limits of this faculty can remove, while it substitutes by way of compensation a paramount practical belief.
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If, in place of certain mistaken attempts, we wish to introduce a different principle into philosophy and to promote its influence, it makes us highly contented to see how and why those attempts must have disappointed us.
God, freedom, and immortality, are the problems at the solution of which all the equipments of Metaphysic aim, as their ultimate and unique purpose. Now it was believed that the doctrine of freedom is needed for practical philosophy only as its negative condition; but that on the other hand the doctrine of God and of the constitution of the soul, as belonging to theoretical philosophy, must be established for themselves and separately, in order afterwards to unite both with that which the moral law (possible only under the condition of freedom) commands, and so to constitute a religion. But we can easily see that these attempts must fail. For from mere ontological concepts of things in general, or of the existence of a necessary Being, it is possible to form absolutely no determinate concept of an original Being by means of predicates which can be given in experience and can therefore serve for cognition. Again a concept based on experience of the physical purposiveness of nature could furnish no adequate proof for morality, or consequently for cognition of a Deity. Just as little could the cognition of the soul by means of experience (which we only apply in this life) supply us with a concept of its spiritual immortal nature, a concept which would be adequate for morality. Theology and Pneumatology, regarded as problems of the sciences of a speculative Reason, can be established by no empirical data and predicates, because the concept of them is transcendent for our whole cognitive faculty.—The determination of both concepts, God and the soul (in respect of its immortality) alike, can only take place by means of predicates, which, although they are only possible from a supersensible ground, must yet prove their reality in experience; for thus alone can they make possible a cognition of a quite supersensible Being.—The only concept of this kind to be met with in human Reason is that of the freedom of men under moral laws, along with the final purpose which Reason prescribes by these laws. Of these two [the moral laws and the final purpose] the first are useful for ascribing to the Author of Nature, the second for ascribing to man, those properties which contain the necessary condition of the possibility of both [God and the soul]; so that from this Idea a conclusion can be drawn as to the existence and constitution of these beings which are otherwise quite hidden from us.
Thus the ground of the failure of the attempt to prove God and immortality by the merely theoretical path lies in this, that no cognition whatever is possible of the supersensible in this way (of natural concepts). The ground of its success by the moral way (of the concept of freedom) is as follows. Here the supersensible (freedom), which in this case is fundamental, by a determinate law of causality that springs from it, not only supplies material for cognition of other supersensibles (the moral final purpose and the conditions of its attainability), but also establishes its reality in actions as a fact; though at the same time it can furnish a valid ground of proof in no other than a practical point of view (the only one, however, of which Religion has need).
It is thus very remarkable that of the three pure rational Ideas, God, freedom, and immortality, that of freedom is the only concept of the supersensible which (by means of the causality that is thought in it) proves its objective reality in nature by means of the effects it can produce there; and thus renders possible the connexion of both the others with nature, and of all three together with Religion. We have therefore in us a principle capable of determining the Idea of the supersensible within us, and thus also that of the supersensible without us, for knowledge, although only in a practical point of view; a principle this of which mere speculative philosophy (which could give a merely negative concept of freedom) must despair. Consequently the concept of freedom (as fundamental concept of all unconditioned practical laws) can extend Reason beyond those bounds, within which every natural (theoretical) concept must remain hopelessly limited.
General remark on Teleology
If the question is, what rank the moral argument, which proves the Being of God only as a thing of faith for the practical pure Reason, maintains among the other arguments in philosophy, it is easy to set aside the whole achievement of this last; by which it appears that there is no choice, but that our theoretical faculty must give up all its pretensions before an impartial criticism.
All belief must in the first place be grounded upon facts, if it is not to be completely groundless; and therefore the only distinction in proofs that there can be is that belief in the consequence derived therefrom can either be grounded on this fact as knowledge for theoretical cognition, or merely as faith for practical. All facts belong either to the natural concept which proves its reality in the objects of sense, given (or which may possibly be given) before all natural concepts; or to the concept of freedom, which sufficiently establishes its reality through the causality of Reason in regard of certain effects in the world of sense, possible through it, which it incontrovertibly postulates in the moral law. The natural concept (merely belonging to theoretical cognition) is now either metaphysical and thinkable completely a priori, or physical, i.e. thinkable a posteriori and as necessary only through determinate experience. The metaphysical natural concept (which presupposes no determinate experience) is therefore ontological.
The ontological proof of the being of God from the concept of an original Being is either that which from ontological predicates, by which alone it can be thought as completely determined, infers absolutely necessary being; or that which, from the absolute necessity of the being somewhere of some thing, whatever it be, infers the predicates of the original Being. For there belongs to the concept of an original Being, inasmuch as it is not derived from anything, the unconditioned necessity of its presence, and (in order to represent this) its complete determination by its [mere][155] concept. It was believed that both requirements were found in the concept of the ontological Idea of a Being the most real of all; and thus two metaphysical proofs originated.