The proof (properly called ontological) resting upon a merely metaphysical natural concept concludes from the concept of the Being the most real of all, its absolutely necessary existence; for (it is said), if it did not exist, a reality would be wanting to it, viz. existence.—The other (which is also called the metaphysico-cosmological proof) concludes from the necessity of the existence somewhere of a thing (which must be conceded, for a being is given to us in self-consciousness), its complete determination as that of a Being the most real of all; for everything existing must be completely determined, but the absolutely necessary (i.e. that which we ought to cognise as such and consequently a priori) must be completely determined by means of its own concept. But this is only the case with the concept of a thing the most real of all. It is not needful to expose here the sophistry in both arguments, which has been already done elsewhere;[156] it is only needful to remark that neither proof, even if they could be defended by all manner of dialectical subtlety, could ever pass from the schools into the world, or have the slightest influence on the mere sound Understanding.

The proof, which rests on a natural concept that can only be empirical and yet is to lead us beyond the bounds of nature regarded as the complex of the objects of sense, can be no other than that derived from the purposes of nature. The concept of these cannot, it is true, be given a priori but only through experience; but yet it promises such a concept of the original ground of nature as alone, among all those which we can conceive, is suited to the supersensible, viz. that of a highest Understanding as Cause of the world. This, in fact, it completely performs in accordance with principles of the reflective Judgement, i.e. in accordance with the constitution of our (human) faculty of cognition.—But whether or not it is in a position to supply from the same data this concept of a supreme, i.e. independent intelligent Being, in short of a God or Author of a world under moral laws, and consequently as sufficiently determined for the Idea of a final purpose of the being of the world—this is the question upon which everything depends, whether we desire a theoretically adequate concept of the Original Being on behalf of our whole knowledge of nature, or a practical concept for religion.

This argument derived from physical Teleology is worthy of respect. It produces a similar effect in the way of conviction upon the common Understanding as upon the subtlest thinker; and a Reimarus[157] has acquired immortal honour in his work (not yet superseded), in which he abundantly develops this ground of proof with his peculiar thoroughness and lucidity.—But how does this proof acquire such mighty influence upon the mind? How does a judgement by cold reason (for we might refer to persuasion the emotion and elevation of reason produced by the wonders of nature) issue thus in a calm and unreserved assent? It is not the physical purposes, which all indicate in the World Cause an unfathomable intelligence; these are inadequate thereto, because they do not satisfy the need of the inquiring Reason. For, wherefore (it asks) are all those natural things that exhibit art? Wherefore is man himself, whom we must regard as the ultimate purpose of nature thinkable by us? Wherefore is this collective Nature here, and what is the final purpose of such great and manifold art? Reason cannot be contented with enjoyment or with contemplation, observation, and admiration (which, if it stops there, is only enjoyment of a particular kind) as the ultimate final purpose for the creation of the world and of man himself; for this presupposes a personal worth, which man alone can give himself, as the condition under which alone he and his being can be the final purpose. Failing this (which alone is susceptible of a definite concept), the purposes of nature do not satisfactorily answer our questions; especially because they cannot furnish any determinate concept of the highest Being as an all-sufficient (and therefore unique and so properly called highest) being, and of the laws according to which an Understanding is Cause of the world.

Hence that the physico-teleological proof convinces, just as if it were a theological proof, does not arise from our availing ourselves of the Ideas of purposes of nature as so many empirical grounds of proof of a highest Understanding. But it mingles itself unnoticed with that moral ground of proof, which dwells in every man and influences him secretly, in the conclusion by which we ascribe to the Being, which manifests itself with such incomprehensible art in the purposes of nature, a final purpose and consequently wisdom (without however being justified in doing so by the perception of the former); and by which therefore we arbitrarily fill up the lacunas of the [design] argument. In fact it is only the moral ground of proof which produces conviction, and that only in a moral reference with which every man feels inwardly his agreement. But the physico-teleological proof has only the merit of leading the mind, in its consideration of the world, by the way of purposes and through them to an intelligent Author of the world. The moral reference to purposes and the Idea of a moral legislator and Author of the world, as a theological concept, seem to be developed of themselves out of that ground of proof, although they are in truth pure additions.

Henceforward we may allow the customary statement to stand. For it is generally difficult (if the distinction requires much reflection) for ordinary sound Understanding to distinguish from one another as heterogeneous the different principles which it confuses, and from one of which alone it actually draws conclusions with correctness. The moral ground of proof of the Being of God, properly speaking, does not merely complete and render perfect the physico-teleological proof; but it is a special proof that supplies the conviction which is wanting in the latter. This latter in fact can do nothing more than guide Reason, in its judgements upon the ground of nature and that contingent but admirable order of nature only known to us by experience, to the causality of a Cause containing the ground of the same in accordance with purposes (which we by the constitution of our cognitive faculties must think as an intelligent cause); and thus by arresting the attention of Reason it makes it more susceptible of the moral proof. For what is requisite to the latter concept is so essentially different from everything which natural concepts contain and can teach, that there is need of a particular ground of proof quite independent of the former, in order to supply the concept of the original Being adequately for Theology and to infer its existence.—The moral proof (which it is true only proves the Being of God in a practical though indispensable aspect of Reason) would preserve all its force, if we found in the world no material, or only that which is doubtful, for physical Teleology. It is possible to conceive rational beings surrounded by a nature which displayed no clear trace of organisation but only the effects of a mere mechanism of crude matter; on behalf of which and amid the changeability of some merely contingent purposive forms and relations there would appear to be no ground for inferring an intelligent Author. In such case there would be no occasion for a physical Teleology; and yet Reason, which here gets no guidance from natural concepts, would find in the concept of freedom and in the moral Ideas founded thereon a practically sufficient ground for postulating the concept of the original Being in conformity with these, i.e. as a Deity, and for postulating nature (even the nature of our own being) as a final purpose in accordance with freedom and its laws—and all this in reference to the indispensable command of practical Reason.—However the fact that there is in the actual world for the rational beings in it abundant material for physical Teleology (even though this is not necessary) serves as a desirable confirmation of the moral argument, as far as nature can exhibit anything analogous to the (moral) rational Ideas. For the concept of a supreme Cause possessing intelligence (though not reaching far enough for a Theology) thus acquires sufficient reality for the reflective Judgement, but it is not required as the basis of the moral proof; nor does this latter serve to complete as a proof the former, which does not by itself point to morality at all, by means of an argument developed according to a single principle. Two such heterogeneous principles as nature and freedom can only furnish two different kinds of proof; and the attempt to derive one from the other is found unavailing as regards that which is to be proved.

If the physico-teleological ground of proof sufficed for the proof which is sought, it would be very satisfactory for the speculative Reason; for it would furnish the hope of founding a Theosophy (for so we must call the theoretical cognition of the divine nature and its existence which would suffice at once for the explanation of the constitution of the world and for the determination of moral laws). In the same way if Psychology enabled us to arrive at a cognition of the immortality of the soul it would make Pneumatology possible, which would be just as welcome to the speculative Reason. But neither, agreeable as they would be to the arrogance of our curiosity, would satisfy the wish of Reason in respect of a theory which must be based on a cognition of the nature of things. Whether the first, as Theology, and the second, as Anthropology, when founded on the moral principle, i.e. the principle of freedom, and consequently in accordance with the practical use [of Reason] do not better fulfil their objective final design, is another question which we need not here pursue.

The physico-teleological ground of proof does not reach to Theology, because it does not and cannot give any determinate concept, sufficient for this design, of the original Being; but we must derive this from quite another quarter, or must supply its lacuna by an arbitrary addition. You infer, from the great purposiveness of natural forms and their relations, a world-cause endowed with Understanding; but what is the degree of this Understanding? Without doubt you cannot assume that it is the highest possible Understanding; because for that it would be requisite that you should see that a greater Understanding than that of which you perceive proofs in the world, is not thinkable; and this would be to ascribe Omniscience to yourself.[158] In the same way, if you infer from the magnitude of the world the very great might of its Author, you must be content with this having only a comparative significance for your faculty of comprehension; for since you do not know all that is possible, so as to compare it with the magnitude of the world as far as you know it, you cannot infer the Almightiness of its Author from so small a standard, and so on. Now you arrive in this way at no definite concept of an original Being available for a Theology; for this can only be found in the concept of the totality of perfections compatible with intelligence, and you cannot help yourself to this by merely empirical data. But without such a definite concept you cannot infer a unique intelligent original Being; you can only assume it (with whatever motive).—Now it may certainly be conceded that you should arbitrarily add (for Reason has nothing fundamental to say to the contrary): Where so much perfection is found, we may well assume that all perfection is united in a unique Cause of the world, because Reason succeeds better both theoretically and practically with a principle thus definite. But then you cannot regard this concept of the original Being as proved by you, for you have only assumed it on behalf of a better employment of Reason. Hence all lamentation or impotent anger on account of the alleged mischief of rendering doubtful the coherency of your chain of reasoning, is vain pretentiousness, which would fain have us believe that the doubt here freely expressed as to your argument is a doubting of sacred truth, in order that under this cover the shallowness of your argument may pass unnoticed.

Moral Teleology, on the other hand, which is not less firmly based than physical,—which, indeed, rather deserves the preference because it rests a priori on principles inseparable from our Reason—leads to that which is requisite for the possibility of a Theology, viz. to a determinate concept of the supreme Cause, as Cause of the world according to moral laws, and, consequently, to the concept of such a cause as satisfies our moral final purpose. For this are required, as natural properties belonging to it, nothing less than Omniscience, Omnipotence, Omnipresence, and the like, which must be thought as bound up with the moral final purpose which is infinite and thus as adequate to it. Hence moral Teleology alone can furnish the concept of a unique Author of the world, which is available for a Theology.

In this way Theology leads immediately to Religion, i.e. the recognition of our duties as divine commands[159]; because it is only the recognition of our duty and of the final purpose enjoined upon us by Reason which brings out with definiteness the concept of God. This concept, therefore, is inseparable in its origin from obligation to that Being. On the other hand, even if the concept of the original Being could be also found determinately by the merely theoretical path (viz. the concept of it as mere Cause of nature), it would afterwards be very difficult—perhaps impossible without arbitrary interpolation [of elements]—to ascribe to this Being by well-grounded proofs a causality in accordance with moral laws; and yet without this that quasi-theological concept could furnish no foundation for religion. Even if a religion could be established by this theoretical path, it would actually, as regards sentiment (wherein its essence lies) be different from that in which the concept of God and the (practical) conviction of His Being originate from the fundamental Ideas of morality. For if we must suppose the Omnipotence, Omniscience, etc., of an Author of the world as concepts given to us from another quarter, in order afterwards only to apply our concepts of duties to our relation to Him, then these latter concepts must bear very markedly the appearance of compulsion and forced submission. If, instead of this, the respect for the moral law, quite freely, in virtue of the precept of our own Reason, represents to us the final purpose of our destination, we admit among our moral views a Cause harmonising with this and with its accomplishment, with the sincerest reverence, which is quite distinct from pathological fear; and we willingly submit ourselves thereto.[160]

If it be asked why it is incumbent upon us to have any Theology at all, it appears clear that it is not needed for the extension or correction of our cognition of nature or in general for any theory, but simply in a subjective point of view for Religion, i.e. the practical or moral use of our Reason. If it is found that the only argument which leads to a definite concept of the object of Theology is itself moral, it is not only not strange, but we miss nothing in respect of its final purpose as regards the sufficiency of belief from this ground of proof, provided that it be admitted that such an argument only establishes the Being of God sufficiently for our moral destination, i.e. in a practical point of view, and that here speculation neither shows its strength in any way, nor extends by means of it the sphere of its domain. Our surprise and the alleged contradiction between the possibility of a Theology asserted here and that which the Critique of speculative Reason said of the Categories—viz. that they can only produce knowledge when applied to objects of sense, but in no way when applied to the supersensible—vanish, if we see that they are here used for a cognition of God not in a theoretical point of view (in accordance with what His own nature, inscrutable to us, may be) but simply in a practical.—In order then at this opportunity to make an end of the misinterpretation of that very necessary doctrine of the Critique, which, to the chagrin of the blind dogmatist, refers Reason to its bounds, I add here the following elucidation.