You are here

Chapter III: Kant’s Doctrine of Rational Faith

Kant's critique of speculative theology is not his last word on the problem of the relation of man and God, between philosophy and religion, reason and faith. The most important doctrine concerning this subject is not contained in the Critique of Pure Reason, but in the Critique of Practical Reason and in Kant's later works. The negative attitude toward knowledge of God is no longer maintained in these later books. Kant goes on to admit that there is a kind of natural religion which even the critical standpoint cannot deny. To be sure, Kant qualifies the nature of this religion in a way which excludes almost all knowledge from it. The right attitude toward God, Kant teaches, is not theoretical, it is practical; it is an attitude of the moral will, not of the thinking intellect; of a faith based upon a practical need, not upon speculative reasons. “In the whole faculty of reason it is the practical reason only that can help us to pass beyond the world of sense, and give us knowledge of a supernatural order and connection.\…”1

This knowledge, however, is a strictly practical one, and “cannot be extended further than is necessary for pure practical purposes.” It is in no sense a speculative or metaphysical knowledge; it contains nothing about the nature of its object. Out of practical ideas “we can form no conception that would help to the knowledge of the object”; they “can never be used for a theory of supernatural beings, so that on this side they are quite incapable of being the foundation of a speculative knowledge, and their use is limited simply to the practice of the moral law.”2

This famous doctrine proclaiming the “primacy of the practical reason” is even more significant with respect to Kant's protestant outlook than is the refutation of all speculative theology. As Luther stressed the primacy of faith against any objective guarantee on the part of man, so Kant defended the primacy of faith against any objective knowledge of God. Of course, Luther and Kant do not mean the same thing when they speak of faith. Luther means belief in the word of God as revealed in Scripture, especially in the Gospel; Kant means rational faith. But despite this difference, which must be examined carefully, there is common ground for both Luther and Kant to stand on. Both mean by faith a relation of man to God, not founded on objective facts but rather on our conscience; both mean a practical relation, i.e., a relation which concerns primarily man's will in its moral aspect; both mean, therefore, something that affects a person as a person and not something that would satisfy the human intellect or reason in general.

This is expressed by Kant when he says that the belief in God is a belief for “the pure practical purpose” of promoting morality, that this belief is based upon the consciousness of duty, and that, therefore, the validity of this belief cannot be separated from a personal moral attitude toward life and reality. “\… 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, \…; 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 judgement.\…”3 It is an interest of mine in so far as I am a moral person striving after moral ideals. It is a subjective personal interest; but it is not a merely personal, i.e., a selfish interest, rather an interest of morality, i.e., of moral reason. This interest, not a theoretical insight or a proof of any other intellectual surety determines my judgment. I, as a “righteous man,” involved in moral duties, believe in God. The requirement of reason in this case is of a personal kind, it depends, as Kant says, on a “subjective condition of reason.” Kant's doctrine of moral belief in God thus appears to be the first step in the doctrine of Kierkegaard that not thought but the existent thinker alone can be related to God; that not a philosophic system but the living man alone, the sinner and he who repents, can judge about the existence of God; that the standpoint of the believing man, therefore, must always be “existential.”

Kant himself felt that his doctrine was in complete agreement with the Christian conception of faith. Whether or not he is right in this respect we shall consider soon. In any case he approached the Christian faith by emphasizing the moral character of our belief in God, and by concluding that God must be represented as the moral Author of the world. The idea of God, as interpreted by moral reason, is the idea of the head of the moral kingdom, of the highest moral lawgiver and judge who rules over man's conscience; God, thus conceived of, is the only warrantor for a just agreement between our moral worth and our happiness. God is not the first cause or ruler of the physical Universe as Aristotle taught. He is first of all the Lord in relation to us as willing persons subject to the moral law. Kant, however, is, even in this point, not as remote from the old speculative theology as he himself seems to have assumed. The idea of God traditionally united both the theoretical and the practical reason, and it is hard to say which reason, theoretical or practical, was superior in Aristotle, in the medieval thinkers, and in modern representatives of natural religion. All these had a practical interest as outlined by Kant, when they conceived of God. It is true Kant was the first to advance in the direction of an “existential” standpoint, and so in the direction of a religious and not only a theological philosophy. But on the other hand, the idea of God as the lawgiver, judge, and governor of the moral world and as the moral Author of the Universe as a whole is as old as the attempts to create a Christian philosophy. And it might even be said that the primacy of the moral reason was first proclaimed by Plato, who taught that the idea of the Good had the highest rank in the realm of ideas. And it may be recalled also that Aristotle's God moves the world not as a physical agent or force, but by means of that love toward Him which lives in all things and in all beings, and which is motivated by the idea that He represents the highest good, summum bonum.

Finally it should be added that medieval thinkers, such as Duns Scotus and Occam, had come rather near Kant's standpoint. They limited or even rejected the right and realm of speculative theology in order to “make room for faith” like Kant; they opposed philosophy and theology as theoretical and practical disciplines; and they asserted that the will and not the intellect should be made the center of metaphysics as it is the center of man. Of course, there is one weighty difference between these Catholic thinkers and Kant: they based their positions on revealed religion, not on “practical reason”; their theology was “practical,” because they held that spiritual love toward God and not ethical reflection was the root of faith and of all theological wisdom. It remains to be considered whether they were perhaps nearer the truth than Kant.

Kant rejects speculative theology, but he substitutes for it “ethico-theology.” He is sufficiently akin to the deists and the defenders of a “natural religion” to renew their tenet, but he renews it on a new level and with superior means of thought. Rational religion is no longer permitted as the result of theoretical insights, nor as the product of an aesthetic or pseudo-aesthetic contemplation of the Universe, but it must be based upon moral reason; it is conceived as a religion of the moral will, as a strictly moral religion, or as a religion that has morality as its kernel. While the deists and rationalists of the eighteenth century had confused philosophic thought with religious faith, Kant reestablishes the stern meaning of faith as distinguished from all intellectual, aesthetic or mystical contemplation. He rediscovers the root of faith in the non-intellectual faculty of man's mind, but he still insists that a rational faculty, “pure practical reason” is the genuine and legitimate source of faith. Though not intellectual, religion at its best is a “pure rational faith.” This faith originates from the fact that practical reason is superior to the intellect and to theoretical reason with respect to the knowledge of God. Kant calls this superiority the primacy of practical reason.

As far as speculative elements are acknowledged in pure rational faith, they have no meaning of their own, no properly speculative, i.e., theoretical value; in other words, they do not pretend to express any truth concerning the nature of God; they have a practical meaning only, they concern man's moral relation to God. The existence of God cannot be proved by logical arguments, but it can be proved by moral reflections. Man is morally entitled and even required to believe in a moral Author of the world. Such a belief answers a rational and, therefore, not whimsical or merely subjective need. This rational propensity must be carefully distinguished from all other human wishes, inclinations, desires, interests, and so on. It is a need of pure practical reason itself. We, as human beings, are obliged to obey the moral law. Such an obedience would be deprived of its meaning, if the world in which we live and discharge our duties, were devoid of a moral purpose. As moral beings we belong at the same time to a natural and to a moral order. This duplicity is the source of the requirement of a moral belief in God not only as the Lawgiver but also as the first cause of nature.

Moral belief alone can assure us that obedience to the law and the pursuit of happiness are ultimately in harmony. We ourselves in obeying the moral law cannot bring about this harmony, since the supreme principle of morality excludes all merely utilitarian motives. Morality is not expediency. In man's life these can clash with each other. But it is just and therefore required by morality itself that man obtain happiness in adequate proportion to his moral conduct and value; to put it in another way: the good man should enjoy a good life. The highest good, consisting in such a state of balance between moral virtue and happiness, cannot be achieved without the help of a moral power which is at the same time a power over nature. This power must be absolute or unrestricted: it must command matter and form of the phenomenal world; and it must be the power of a morally unrestricted or perfect will, i.e., the omnipotent will of the moral Author of the world, or God. The belief in the existence of God is thus “postulated” by moral reason.

This is the “moral proof of the existence of God” which must supersede the rejected speculative proofs. “In this manner the moral laws lead through the conception of the summum bonum as the object and final end of pure practical reason to religion, that is, to the recognition of all duties as divine commands. They do this, not as sanctions, that is to say, arbitrary ordinances of a foreign will, contingent in themselves, but as essential laws of every free will in itself; but, nevertheless, they must be regarded as commands of the Supreme Being, because we can hope to attain the summum bonum which the moral law imposes upon us, only from a morally perfect (holy and good), and at the same time all-powerful, will, and consequently only through harmony with this will.”4 When we isolate the kernel of Kant's argument, it runs thus: The opposition between nature and morality, between the world of sense in space and time and the world of our duties, between the objective realm of things and processes and the subjective realm of persons and actions, or between the field in which the laws of nature are carried through by means of necessity and the field in which the laws of morality are to be carried through by means of freedom—this opposition cannot be ultimately valid. There must be an ultimate reality which is not affected by this duality; which is the unbroken whole of reality; which is subject to the laws of necessity and at the same time to the laws of freedom. This ultimate reality cannot be conceived of save as the Creation of the Creator-God.

This “proof” starts from the world of moral beings, and proceeds to God. It is a special kind of cosmological proof: an ethico-cosmological one. The spirit of this proof resembles the way in which Kant demonstrates the necessity of the transcendental ideal in the Critique of Pure Reason. There Kant demonstrates that the idea of an original unity of matter and form in an ens realissimum must be assumed. This idea represents the perfect truth of objective knowledge. Here Kant concludes that an original unity of nature (as matter) and morality (as form of the human will) is to be assumed. This idea represents the highest good as the goal of all human striving. In spite of this resemblance Kant insists that theoretical or speculative reason cannot demonstrate the existence of God, while pure practical reason can “postulate” this existence. There is an ambiguity in these expressions, because the word “God” does not mean the same thing in both cases. The existence of God cannot be demonstrated in the field of theoretical speculation, because the idea of God implies more than can be predicated by pure reason: it implies moral perfection or holiness. On the other hand, the existence of God, in so far as He is conceived as the ens realissimum, the being that contains logical perfection, is, if not demonstrated, nonetheless postulated by pure theoretical reason in much the same way as the existence of God, as the moral Author of the world is postulated by pure practical reason. Is the difference between demonstration and postulation to be maintained? And is it true that the practical phase of reason alone is capable of reaching God as God? These questions require cautious discussion.

First of all, it must be inquired whether the idea of God as the moral Author of the world is legitimately conceived. Is this idea a product of practical reason alone? Obviously not. Nor does Kant himself suggest it. On the contrary, he speaks “of the primacy of pure practical reason in its union with the speculative reason.” Indeed, practical reason alone is not able to reason about the feasibility of the summum bonum and about the possible and necessary presuppositions of its achievement. This reasoning transcends the bounds of the moral realm and moves toward a unification of theoretical and practical reason and their respective objects. Pure practical or moral reason alone does not “reason,” i.e., speculate, about our mental powers, nor about a possible unification of nature and morality. Pure practical reason thinks in terms of the moral law, of duties and obligations, of right and wrong, and so on; it reasons about the moral character of purposes and ends, of persons and acts. It philosophizes about all these terms and concepts in general. But it transcends the moral realm in the strict sense of this word and approaches the “metaphysical” or theological realm as soon as it philosophizes about the relationship between the totality of all natural objects (the ens realissimum) and the idea of the highest good and its possible achievement.

One cannot be quite sure whether Kant realized that the unification of practical and speculative reason is a kind of self-unification of the philosophizing reason or of the thinking mind functioning as a whole. It is the same thinking mind which speculates about the transcendental ideal and about the summum bonum, and achieves a measure of integrity in the union of speculative and moral reason. To speak precisely and accurately, it is not the union of speculative and moral reason that is required, but the speculative union of epistemology and of ethics. It is the same speculative reason in both fields. This reason aims at its union in the field of ethico-theology. And therefore it is not pure practical reason that proclaims the prerogative in its union with the speculative reason, but it is the speculative moral reason that proclaims the prerogative in its union with the likewise speculative theoretical reason. This statement perhaps sounds pedantic and formalistic; but it is important and of great consequence.

The primacy of the speculative practical reason means that the interest of morality is destined to prevail over the interest of scientific knowledge in the speculative field common to both. Kant argues that interest is always practical and that, therefore, the interest of the practical reason is the proper interest of reason. That is true; but it is also true that the interest of practical reason is practical and speculative as well. It is the interest of morality that is at stake; but it is this interest that seeks an alliance with and the help of speculation, not as Kant suggests the help of theoretical knowledge. As Kant does not discriminate sharply enough between scientific-theoretical and speculative-theoretical (epistemological) knowledge, it happens that he speaks of the union between practical and speculative reason as if the union between practical and scientific-theoretical knowledge were to be effected. Consequently he conceives of the unity between morality and nature as if the question of the cause of nature were to be answered. He thus applies the category of causality, which has its appropriate place in scientific knowledge and in the realm of empirical objects, for the purpose of unifying theoretical and practical reason in such a way that the cause of nature insures a harmony between happiness and morality.

Is this application of the category of causality justified? Is it necessary and possible to think of the harmony between nature and the ideal of the summum bonum in terms of “a cause of all nature, distinct from nature itself and containing the principle of this connexion”?5 In the Critique of Pure Reason Kant restricts the use of the categories to the realm of empirical objects, and he accordingly dismisses the possibility of applying the category of causality outside the field of objective experience. The cosmological antinomies show that both the thesis: “There belongs to the world, either as its part or as its cause, a being that is absolutely necessary,” and the antithesis: “An absolutely necessary being nowhere exists in the world, nor does it exist outside the world as its cause” can be demonstrated.6 This antinomy originates in the unrestricted use of the category. Is this unrestricted use of the category of causality permitted for the sake of the union of practical and theoretical reason?

Kant's answer is unequivocal. He says: yes, such unrestricted use is permitted for the sake of this union, but for a restricted purpose only, namely for a purely practical one. For this purpose the thesis alone is valid. There is a significant difference between thesis and antithesis according to Kant's Critique. The thesis concerns the problem of the relation between the phenomenal and the intelligible world, or between the realm of empirical objects in space and time and the thing in itself, or in other words the problem of the transcendental ideal or of the ens realissimum. The antithesis results from the standpoint of empirical knowledge only, or from the scientific empirical standpoint. Therefore, the thesis, says Kant, arouses “a certain practical interest in which every right thinking man \… heartily shares.” Further, “reason has a speculative interest on the side of the thesis.” “Thirdly, the thesis has also the advantage of popularity,” for “common understanding finds not the least difficulty in the idea of the unconditioned beginning of all synthesis.” The antithesis, on the other hand, represents the standpoint of empiricism and of natural science.7 But how can the interest of practical reason, the interest of speculation, and the advantage of popularity make valid what the Critique rejects? The Critique prepares the way for such a validation by saying that the thesis, though not conclusive, cannot be refuted by the antithesis, for the thesis concerns the ultimate condition of the existence of appearances altogether, while the antithesis does not refer to this problem in any way.

The mere statement that the thesis cannot be ultimately refuted obviously does not suffice to validate its assertion or to clarify its conception. It is the practical interest that achieves this validation according to Kant's teaching. But there is one point in this trend of Kant's thought which is noteworthy. When Kant shifts from the representation of the antinomies to their consideration and finally to their solution the word “cause” used in both the thesis and antithesis disappears and is replaced by the words “ground” or “condition.” And this is not only a linguistic alteration, nor is it accidental or superficial; it is founded on an alteration of thought also. The interest of speculation, as distinguished from the standpoint of the scientific, theoretical understanding, demands that the category of causality be no longer applied to express this relation, since it is in no way comparable with the relation of cause and effect in the empirical world. Explicitly in one passage Kant says, that “we are concerned here, not with unconditioned causality, but with the unconditioned existence of substance itself.”8 And in another passage he remarks: “This way of conceiving how an unconditioned being may serve as the ground [sic!] of appearance differs from that which we followed in the preceding section, in dealing with the empirically unconditioned causality of freedom. For there the thing itself was as cause (substantia phaenomenon) conceived to belong to the series of conditions, and only its causality was thought as intelligible. Here, on the other hand, the necessary being must be thought of as entirely outside the series of the sensible world (as ens extramundanum), and as purely intelligible. In no other way can it be secured against the law which renders all appearances contingent and dependent.”9

These quotations are very interesting. The second one refers to the problem of man's free will. Man considered as a moral being does not belong to the world of appearance only; he is not only an object of sensation and perception, of theoretical experience and scientific investigation; he is primarily a “thing-in-itself,” or something that does not only appear to our senses, but that really (“Existentially”) exists. Man as a moral being stands on the same level as the human understanding or as reason, but at the same time he belongs to the apparent world, he is an individual animal. This peculiar situation makes it possible and necessary to think of man as a creature acting in space and time, like other causal agents, but with the remarkable difference that he acts as a free will in so far as he acts as a morally responsible person. Here, therefore, the category of causality must be applied, although man as cause is not properly a cause, but rather an author of his actions. Being the author of his actions man is no longer necessitated to act by other causes, he himself is the only and ultimate cause of his actions, the first cause. As such a first cause man is not a phenomenal, but an “intelligible” being. But the effects of his action, nay, even his action itself as distinguished from him, belong to the phenomenal world of objects. Man, in other words, is an ens mundanum and extramundanum at the same time, whereas the suggested “cause” of nature is not an ens mundanum, but solely and exclusively an ens extramundanum. Man can be called a cause or an author, because he belongs to both worlds, the apparent or phenomenal and the intelligible or noumenal world. The transcendental ideal or the ens realissimum, on the contrary, does not belong to the phenomenal world at all but to the noumenal sphere alone. Therefore reason is not entitled to speak of it as a cause or an author, but as the supreme condition or ground of the possibility and the existence of all appearances only.

Despite these subtle but important distinctions made in the Critique of Pure Reason Kant speaks in the Critique of Practical Reason of the “cause of nature,” and justifies this conception by the additional restriction concerning the merely practical use of it. But can this restriction rehabilitate a concept annihilated by critical speculation? I think that reason, whether practical or theoretical, as long as it remains reason alone, unsupported by religious intuition and imagination, is not entitled, and not able, to postulate the existence of a cause of nature, not even when this cause is conceived of as the moral author of the world in which we, as moral beings, live. It is obvious that not pure practical reason alone, but the biblical image of the Creator led Kant to propose that reason postulates the existence of God as the Author of the world. Kant, I would suggest, is right in defending a certain correspondence of this biblical image with pure practical reason, but he is not right in asserting that reason alone can postulate and justify this image as a rational idea or as a concept which needs no imagination to be engendered. Whereas Kant in the Critique of Pure Reason does not fully appreciate the ability of reason to obtain positive results, in the Critique of Practical Reason he overrates the productive power of this same faculty.

Both the completely negative verdict about theology in the Critique of Pure Reason and the excessively positive verdict of the Critique of Practical Reason seem to be consistent with each other. In the former, Kant does not allow any theoretical theology at all, because there he has in mind only empirical knowledge; and in the latter, he allows merely practical knowledge of God, because he regards it as the only substitute for the previously criticised speculative theology. In both cases Kant is too little metaphysical (ontological). He denies the possibility of any rational or natural theology, because he, first of all, does not acknowledge the true character of speculation as being distinguished from theoretical knowledge of objects, and because, secondly, he does not acknowledge that ethical and ethico-theological speculation, though it be not theoretical in the sense of empirical sciences, nevertheless is theoretical in the sense of philosophical thought.

To be sure, Kant is right in a way, that man's adequate attitude toward God is not theoretical, but practical, and that, therefore, the knowledge of God has a practical, and not a merely theoretical function, or as Kant likes to say, “purpose.” But this important thesis also is not fully developed and clarified within the Kantian philosophy; and, therefore, its truth is not entirely clear. It remains obscure, because Kant is too rationalistic a thinker to descry the function of religious imagination. Kant approaches a right appreciation of the non-philosophical, non-speculative nature of religion, but he ruins his doctrine eventually by his conception of rational faith.

It is quite true, that in and by faith man's intellect and will are more deeply united than in any other region of his mind. But this unification is accomplished as little by practical as by theoretical reason. It is accomplished not by reason at all, but by imagination. Thus prophetic inspiration and divine revelation can be understood in their specific purport, whereas in the Kantian interpretation they lose their meaning and appear as obstacles of pure, rational faith. While Kant recognized clearly enough the superrational meaning of the beautiful and of creations in the realm of art, he did not succeed in rating the superrational in the realm of religion at its true value. He overcame rationalistic prejudices in analyzing the peculiar contribution of the man of genius, but he yielded to them in the case of the prophet. This is the deficiency of his philosophy seen by so many critics in the nineteenth and twentieth centuries; but none of these critics tried to supplement what is missing, and to supply philosophy with an appropriate theory of religious imagination and inspiration.

The deficiency of Kant's views is rooted in his concept of man as being composed of nature and reason. Thus the unity of mind, soul, and heart, the unity of the individual could not be rightly appraised and interpreted. Kant always fails to understand man when he meets this unity. In the field of aesthetics he attained more than anywhere else to a just comprehension because here the theoretical powers of sensation and intellect join each other and a new synthesis, not achieved in the theoretical sphere, is here produced. In the religious field the synthesis concerns not only the theoretical faculties, but intellect and will, theoretical and practical procedure. There Kant's moralism prevailed and made an alliance with his rationalism to defeat the supermoral and superrational powers operative in revelation and inspiration, in mystical intuition, and prophetic imagination. Thus spiritual values in their proper form remained hidden from him.

On the other hand, Kant underrated the speculative elements presented by his own ethico-theological theory. He did not realize that this theory represents a contribution to the despised and allegedly destroyed natural theology! The germ of such a theology appears in the transcendental ideal. But the idea of God is not confined to the idea of a perfect intellect that produces the content of its knowledge in a creative way; it is at once the idea of a perfect willy, only in this combination the idea of God is completed. Both the perfect intellect and the perfect will exceed the functions and the potentiality of human intellect and will. God is not only the consummation of knowledge, He is at the same time the ultimate goal of knowledge, i.e., absolute truth; and He is not only the perfect will, but also the ultimate goal of the will, i.e., the absolute good, the summum bonum. Thus the Aristotelian idea of God would have been reinterpreted by Kant.

But Kant misses the full reward of his critical inquiries, because he confuses natural theology and rational faith. He substitutes rational faith for natural theology. Instead of qualifying the nature of knowledge achieved by ontoand ethico-theological speculation Kant takes refuge in the device of a faith that is neither really rational nor a real faith, as Spinoza in a similar dialectical situation took refuge in the concept of an intellectual love that was neither really intellectual nor a real love. Kant was driven to this subterfuge because he rightly recognized the problematic character of the speculative idea of God, on the one hand, and, on the other, rightly felt that faith supplemented this problematic idea in a legitimate way. But he neither succeeded in granting to speculation what belongs to it, nor in recognizing the true nature of faith.

Natural theology, to be sure, must be restricted because the idea of God, even in the critical form of Kant's ethico-theology, contains insoluble problems that make the very concept problematic. An intellect that produces its own object is no longer an intellect; a will that produces its final purpose can no longer be conceived of as a will. In both cases the analogy breaks down. An analogical knowledge is not strictly knowledge; it resembles the imaginative knowledge of religious revelation without reaching its level. It lies between a legitimate conceptual and a legitimate imaginative knowledge. But the idea has, as Kant says, the function of a regulative principle. It indicates the direction in which we must seek ultimate truth without ever being enabled to find it. We need this idea as the point toward which all knowledge must move; but this point also signifies the definite end of all human intellectual endeavor. At the uttermost frontier of reason and speculation, unanswerable questions arise. Reason needs to be supplemented. This supplement is granted, not by postulates and rational belief, but by faith, in the genuine sense of the word.

I will conclude the discussion of Kant's doctrine by adding some remarks about the negative part of this statement. It is an illusion that we should attain to a rational content of faith. If no other way were open to faith in God, we could never reach it at all. Kant errs in thinking that the moral proof of the existence of God is more conclusive than the ontological and epistemological proofs; in assuming that the restrictive epithet “for the practical purpose” can excuse or improve the inherent frailty of the concepts used in the proof. He errs from the very outset in pronouncing that moral reason can postulate the existence of God.

The meaning of the term “postulate” is not quite clear in Kant's exposition, and this lack of clearness is significant. Kant uses the term in two different ways. He says that pure practical reason postulates the existence of God, but also that it postulates the belief in God. These different meanings should be carefully distinguished. Under the title: The Existence of God as a Postulate of Pure Practical Reason10 Kant explains the first meaning. A postulate, we learn, is a practical supposition or assumption. To postulate the existence of God is as much as to assert, that “it is morally necessary to assume the existence of God.”11 In this entire trend of thought the postulate is also called “rational faith.”12 It implies faith, because the necessity of the assumption is not theoretical, but practical. We are not entitled to state: “There is a God,” as if this statement were a sufficiently ascertained proposition; we are rather merely entitled (and even required morally) to say: “I believe that God exists.” The character of the certainty is not that of an assertion, but that of an assumption; and an assumption founded upon a moral interest and requirement does not express a mere hypothesis or an unverified probability, but it expresses rather a certainty “for practical purposes,” a practical belief in the truth of its content. The postulate itself is thus rational faith in God.

But this interpretation of Kant's famous doctrine is not the only one; there is a second meaning of the term “postulate,” suggesting that not the existence of God, but rather the belief in this existence, is the real content of the postulate; or that the necessity leading to the assumption of this existence is the necessity of the postulate. According to this version one division has the title: Of Belief from a Requirement of Pure Reason.13 If we follow this line of exposition, we must conclude that not the postulate, as such, but rather the postulated assumption or admission is the essence of rational faith.

Both interpretations of Kant's doctrine, however, are unsatisfactory and their very duality hints at an inner uncertainty and ambiguity of the entire theory. A postulate has not the true character of faith. Belief, in the religious sense, includes trust, fear, hope, longing, love, and similar affections, and they do not postulate but rather presuppose the existence of God. Faith, therefore, cannot be interpreted as postulation. It is a kind of devotion, of confidence, of loyalty, of reverence. Not (as Kant teaches) the postulation: “I will that there be a God \…” renders the true meaning of faith, but the prayer: “Not my will, but thine, be done.” On the other hand, belief itself cannot be postulated by reason either. To be sure, a certain agreement between morality and faith exists. Faith in God as the guarantor of a moral world order presupposes the validity of the moral law and is partly based on this validity. It is thus a reasonable faith; one might say, it is suggested by moral reason. But a suggestion is not a postulation. If anyone is able to postulate religious belief, not man and his moral reason, but God alone can do it.

There is no moral proof of the existence of God. Faith cannot be demonstrated, either as a postulate or as postulated. It is neither an act nor a product of reason. It transcends reason altogether, though it is in agreement with morality, and promotes morality. The content of faith may be reasonable, but it is certainly not rational. The idea of a moral Author of nature is not the result of merely ethical argumentations, not even of combined ethical and ontological considerations. This failure becomes even more obvious, when we pay attention to the problem of evil. It is not appropriate to say: “I will that there is a God,” even if we suppose (as Kant does) that it is a righteous man who speaks; it is certainly still less appropriate, if we take into consideration that man is never absolutely righteous. The sinner offends God by the very acts he performs. How can he venture to say: “I will that there is a God”? The principle of the primacy of practical reason cannot warrant the existence of a moral world order, much less the existence of a moral author of the world. Faith alone can assure this existence. Faith, not moral reason, ultimately has the primacy.

  • 1.

    Kant's Critique of Practical Reason, tr. by Th. K. Abbott, 3d ed., London, 1883, p. 200.

  • 2.

    l.c. p. 235.

  • 3.

    l.c. p. 241.

  • 4.

    l.c. p. 226 (translation slightly altered).

  • 5.

    l.c. p. 221.

  • 6.

    Cr. of P.R. B 480, 481.

  • 7.

    B 494 ff.

  • 8.

    B 587 (my italics).

  • 9.

    B 589 (Kant's italics).

  • 10.

    Book II, ch. II, division V; l.c. p. 220.

  • 11.

    l.c. p. 222.

  • 12.

    l.c. p. 223.

  • 13.

    Book II, ch. II, division VIII; l.c. p. 240.

From the book: