The proof of the existence of God may be attempted in three ways: we may argue the existence of a supreme cause either by starting from a definite experience (the special constitution and order of the sense-world, that is, its purposiveness), or from an indefinite experience (any existence whatever), or, finally, abstracting from all experience, from mere concepts a priori. But neither the empirical nor the transcendent nor the intermediate line of thought leads to the goal. The most impressive and popular of the proofs is the physico-theological argument. But even if we gratuitously admit the analogy of natural products with the works of human art (for the argument is not able to prove that the purposive arrangement of the things in the world, which we observe with admiration, is contingent, and could only have been produced by an ordering, rational principle, not self-produced by their own nature according to general mechanical laws), this can yield an inference only to an intelligent author of the purposive form of the world, and not to an author of its matter, only, therefore, to a world-architect, not to a world-creator. Further, since the cause must be proportionate to the effect, this argument can prove only a very wise and wonderfully powerful, but not an omniscient and omnipotent, designer, and so cannot give any definite concept of the supreme cause of the world. In leaping from the contingency of the purposive order of the world to the existence of something absolutely necessary and thence to an all-comprehensive reality, the teleological argument abandons the ground of experience and passes over into the cosmological argument, which in its turn is merely a concealed ontological argument (these two differ only in the fact that the cosmological proof argues from the antecedently given absolute necessity of a being to its unlimited reality, and the ontological, conversely, from supreme reality to necessary existence). The weaknesses of the cosmological argument in its first half consist in the fact that, in the inference from the contingent to a cause for it, it oversteps the boundary of the sense-world, and, in the inference from the impossibility of an infinite series of conditions to a first cause, it employs the subjective principle of investigation—to assume hypothetically a necessary ultimate ground in behalf of the systematic unity of knowledge—as an objective principle applying to things in themselves. The ontological argument, finally, which the two nominally empirical arguments hoped to avoid, but in which in the end they were forced to take refuge, goes to wreck on the impossibility of dragging out of an idea the existence of the object corresponding to it. Existence denotes nothing further than the position of the subject with all the marks which are thought in its concept—that is, its relation to our knowledge, but does not itself belong to the predicates of the concept, and hence cannot be analytically derived from the latter. The content of the concept is not enriched by the addition of being; a hundred real dollars do not contain a penny more than a hundred conceived dollars. All existential propositions are synthetic; hence the existence of God cannot be demonstrated from the concept of God. It is a contradiction, to be sure, to say that God is not almighty, just as it is a contradiction to deny that a triangle has three angles: if posit the concept I must not remove the predicate which necessarily belongs to it. If I remove the subject, however, together with its predicate (the almighty God is not), no contradiction arises, for in that case nothing remains to be contradicted.
Thus all the proofs for the existence of a necessary being are shown to be illusory, and the basis of speculative theology uncertain. Nevertheless the idea of God retains its validity, and the perception of the inability of reason to demonstrate its objective reality on theoretical grounds has great value. For though the existence of God cannot be proved, it is true, by way of recompense, that it cannot be disproved; the same grounds which show us that the assertion of his existence is based on a weak foundation suffice also to prove every contrary assertion unfounded. And should practical motives present themselves to turn the scale in favor of the assumption of a supreme and all-sufficient Being, reason would be obliged to take sides and to follow these grounds, which, it is true, are not objectively sufficient,[1] but still preponderant, and than which we know none better. After, however, the objective reality of the idea of God is guaranteed from the standpoint of ethics, there remains for transcendental theology the important negative duty ("censorship," Censor) of exactly determining the concept of the most perfect Being (as a being which through understanding and freedom contains the first ground of all other things), of removing from it all impure elements, and of putting an end to all opposite assertions, whether atheistic, deistic (deism maintains the possibility of knowing the existence of an original being, but declares all further determination of this being impossible), or (in the dogmatic sense) anthropomorphic. Theism is entirely possible apart from a mistaken anthropomorphism, in so far as through the predicates which we take from inner experience (understanding and will) we do not determine the concept of God as he is in himself, but only analogically[2] in his relation to the world. That concept serves only to aid us in our contemplation of the world,[3] not as a means of knowing the Supreme Being himself. For speculative purposes it remains a mere ideal, yet a perfectly faultless one, which completes and crowns the whole of human knowledge.
[Footnote 1: "They need favor to supply their lack of legitimate claims." Of themselves alone, therefore, they are unable to yield any theological knowledge, but they are fitted to prepare the understanding for it, and to give emphasis to other possible (moral) proofs.]
[Footnote 2: We halt at the boundary of the legitimate use of reason, without overstepping it, when we limit our judgment to the relation of the world to the Supreme Being, and in this allow ourselves a symbolical anthropomorphism only, which in reality has reference to our language alone and not to the object.]
[Footnote 3: We are compelled to look on the world as if it were the work of a supreme intelligence and will. "We may confidently derive the phenomena of the world and their existence from other (phenomena), as if no necessary being existed, and yet unceasingly strive after completeness in the derivation, as though such a being were presupposed as a supreme ground." In short, physical (mechanical) explanation, and a theistic point of view or teleological judgment.]
Thus the value of the Ideas is twofold. By showing the untenable ness of atheism, fatalism, and naturalism, they I clear the way for the objects of faith. By providing natural science with the standpoint of a systematical unity through teleological connection, they make an extension of the use of the understanding possible within the realm of experience,[1] though not beyond it. The systematic development of the Kantian teleology, which is here indicated in general outlines only, is found in the second part of the Critique of Judgment; while the practical philosophy, which furnishes the only possible proof, the moral proof, for the reality of the Ideas, erects on the site left free by the removal of the airy summer-houses of dogmatic metaphysics the solid mansion of critical metaphysics, that is, the metaphysics of duties and of hopes. "I was obliged to destroy knowledge in order to make room for faith." The transition from the impossible theoretical or speculative knowledge of things in themselves to the possible "practical knowledge" of them (the belief that there is a God and a future world) is given in the Doctrine of Method, which is divided into four parts (the Discipline, the Canon, the Architectonic, and the History of Pure Reason), in its second chapter. There, in the ideal of the Summum Bonum, the proof is brought forward for the validity of the Ideas God, freedom, and immortality, as postulates inseparable from moral obligation; and by a cautious investigation of the three stages of assent (opinion, knowledge, and belief) both doctrinal and moral belief are assigned their places in the system of the kinds of knowledge.
[Footnote 1: The principle to regard all order in the world (e.g., the shape of the earth, mountains, and seas, the members of animal bodies) as if it proceeded from the design of a supreme reason leads the investigator on to various discoveries.]
We may now sum up the results of the three parts of Kant's theoretical philosophy. The pure intuitions, the categories, and the Ideas are functions of the spirit, and afford non-empirical (erfahrungsfreie) knowledge concerning the objects of possible experience (and concerning the possibility of knowledge). The first make universal and necessary knowledge possible in relation to the forms under which objects can be given to us; the second make a similarly apodictic knowledge possible in relation to the forms under which phenomena must be thought; the third make possible a judgment of phenomena differing from this knowledge, yet not in conflict with it. The categories and the Ideas, moreover, yield problematical concepts of objects which are not given to us in intuition, but which may exist outside of space and time: things in themselves cannot be known, it is true, but they can be thought, a fact of importance in case we should be assured of their existence in some other way than by sensuous intuition.
The determination of the limits of speculative reason is finished. All knowing and all demonstration is limited to phenomena or possible experience. But the boundary of that which can be experienced is not the boundary of that which is, still less of that which ought to be; the boundary of theoretical reason is not the boundary of practical reason. We ought to act morally; in order to be able to do this we must ascribe to ourselves the power to initiate a series of events; and, in general, we are warranted in assuming everything the non-assumption of which makes moral action impossible. If we were merely theoretical, merely experiential beings, we should lack all occasion to suppose a second, intelligible world behind and above the world of phenomena; but we are volitional and active beings under laws of reason, and though we are unable to know things in themselves, yet we may and must postulate them—our freedom, God, and immortality. For not only that which is a condition of experience is true and necessary, but that, also, which is a condition of morality. The discovery of the laws and conditions of morality is the mission of practical philosophy.
%2. Theory of Ethics.%