by Will Durant
Kant tried to counter Hume’s skepticism of causation by making the cause-and-effect relation not an objective reality but an intrinsic form of thought; as such it is independent of experience, and is not subject to the uncertainty of empirical ideas. Yet it is a necessary part of all experience, since we cannot understand experience without it. Hence “the concept of cause involves the character of necessity, which no experience can yield.”22 Kant supposed that by this léger-de-plume he had saved science from that humiliating limitation to probability to which Hume had condemned it. Indeed, he argued, it is the human mind, and not nature, that establishes the universal “laws of nature,” by endowing some of our generalizations—like those of mathematics—with qualities of universality and necessity not objectively perceived. “We ourselves introduce that order and regularity in the appearance which we entitle ‘nature.’ We could never find them in appearances had we not ourselves, by the nature of our own mind, originally set them there.”23 The “laws of nature” are not objective entities but mental constructs useful in handling experience.
All knowledge takes the form of ideas. In this sense the idealist is right: the world, for us, is merely our ideas. Since we know matter only as and through ideas, materialism is logically impossible, for it attempts to reduce the directly known (ideas) to the unknown or indirectly known. But the idealist is wrong if he believes that nothing exists except our ideas; for we know that ideas can be produced by sensations, and we cannot explain all sensations without assuming, for many of them, an external cause. As our knowledge is limited to phenomena or appearances—i.e., to the form the external cause takes after being molded by our modes of perception and conception—we can never know the objective nature of that external cause;24 it must remain for us a mysterious Ding-an-sich, a thing-in-itself, a “noumenon” conceived but never perceived. The external world exists, but in its ultimate reality it is unknowable.25
The soul too is real but unknowable. We never perceive it as an entity additional to the mental states that we perceive; it too is a noumenon, necessarily conceived as the reality behind the individual self, the moral sense, and the forms and processes of the mind. The sense of self mingles with every mental state, and provides continuity and personal identity. The consciousness of self (“apperception”) is the most intimate of all our experiences; and by no feat of the imagination can we conceive it as material.26 It seems impossible that an immaterial soul should act upon—and be acted upon by—a material body; but we may believe that the unknowable reality behind matter “may not, after all, be so different in character” from that inner thing-in-itself which is the soul.27
We cannot prove by pure or theoretical reason (as Wolff tried to do) that the individual soul is immortal, or that the will is free, or that God exists; but neither can we by pure reason disprove these beliefs (as some skeptics thought to do). Reason and the categories are equipped to deal only with phenomena or appearances, external or internal; we cannot apply them to the thing-in-itself—the reality behind sensations or the soul behind ideas. When we try to prove or disprove the dogmas of faith we fall into “paralogisms” (fallacies) or “antinomies”—inherent contradictions. We end in equal absurdities if we hold that the world had or had not a beginning; that the will is or is not free; or that a necessary or supreme being does or does not exist. Kant expressed with unwonted eloquence the argument from design,28 but he concluded that “the utmost that the argument can prove is an architect … who is always very much hampered by the adaptability of the material in which he works, not a creator … to whose idea everything is subject.”29
And yet how can we rest content with so baffling a conclusion—that free will, immortality, and God can be neither proved nor disproved by pure reason? There is (Kant urges) something in us deeper than reason, and that is our irrefutable consciousness that consciousness, mind, and soul are not material, and that the will is in some measure, however mysteriously and illogically, free; and we cannot be long content to think of the world as a senseless sequence of evolution and dissolution without moral significance or inherent mind. How can we justify our will to believe? Partly (says Kant) by the intellectual usefulness of belief—by its offering us some guidance in the interpretation of phenomena, as well as some philosophical sanity and religious peace.
The things of the world must be viewed as if they received their existence from a highest intelligence. The idea [of God] is thus really a heuristic, not an ostensive, concept [it is an assumption helpful to discovery and understanding, but it is not a demonstration].... In the domain of theology we must view everything as if the sum of all appearances (the sensible world itself) had a single, highest, and all-sufficient ground beyond itself—namely, a self-subsistent, original, creative reason. For it is in the light of this idea of a creative reason that we so guide the empirical employment of our reason as to secure its greatest possible extension. … The only determinate concept which the purely speculative reason gives us of God is, in the strictest sense, deistic; that is, reason does not determine the objective validity of such a concept, but yields only the idea of something which is the ground of the highest and necessary unit of all empirical reality.30
But a more imperative reason for religious belief, in Kant’s view, is that such belief is indispensable to morality. “If there is no primordial being distinct from the world, if the world is … without an Author, if our will is not free, if the soul is … perishable like matter, then moral ideas and principles lose all validity.”31 If moral character and social order are not to depend entirely on fear of the law, we must support religious belief, if only as a regulative principle; we must act as if we knew that there is a God, that our souls are immortal, that our wills are free.32 Moreover, as an aid to thought and morals, “we are justified in representing the cause of the world in terms of a subtle anthropomorphism (without which we could not think anything whatever in regard to it), namely, as a being that has understanding, feelings of pleasure and displeasure, and desires and volitions corresponding to these.”33
So the famous Critique concludes, leaving opposite schools of thought comforted and displeased. The skeptics could argue that Kant had justified agnosticism, and could scorn his reinstatement of God as a supplement to the police. The buffeted theologians reproached him for admitting so much to the infidels, and rejoiced that religion had apparently survived its perilous passage through Kant’s labyrinthine mind. In 1786 Karl Reinhold described the turmoil:
The Critique of Pure Reason has been proclaimed by the dogmatists as the attempt of a skeptic who undermines the certainty of all knowledge; by the skeptics as a piece of arrogant presumption that undertakes to erect a new form of dogmatism upon the ruins of previous systems; by the supernaturalists as a subtly plotted artifice to displace the historical foundations of religion, and to establish naturalism without polemic; by the naturalists as a new prop for the dying philosophy of faith; by the materialists as an idealistic contradiction of the reality of matter; by the spiritualists as an unjustifiable limitation of all knowledge to the corporeal world, concealed under the name of the domain of experience . . .34
Almost all these schools of thought attacked the book, giving it fame if only as a succès de scandale. Even its difficulty exalted it, making it a challenge that every up-to-date mind had to meet. Soon the sesquipedalia verba of Kant were in every learned mouth.
He could not understand why his critics could not understand him. Had he not defined every basic term over and over again? (Yes, and how variously!) In 1783 he answered the attacks by rephrasing the Critique in what he thought was a simpler form; and he defiantly entitled his rejoinder Prolegomena to Every Future Metaphysic That Will Be Able to Appear as Science. Before his Critique, he claimed, there had been no real metaphysics at all, for no system had prefaced itself with a critical scrutiny of its instrument—reason. If some readers could not understand the Kritik, that might be because they were not quite up to it; “in such a case one should apply one�
�s mental gifts to another object”; after all, “there is no need for everybody to study metaphysics.”35 The old professor had humor and pride, and temper too. As it proceeded, the Prolegomena became as difficult as the Critique.
The controversy continued under the tolerant regime of Frederick the Great. Kant had written in the Critique some eloquent passages on the nobility of reason, and its right to freedom of expression.36 In 1784, still relying on protection by Frederick and Zedlitz, he published an essay entitled Wasist Aufklärung? He defined the Enlightenment as freedom and independence of thought, and took as his motto and counsel Sapere aude— “Dare to know.” He regretted that intellectual liberation was so retarded by the conservatism of the majority. “If we ask whether we live in an enlightened [aufgeklärt] age, the answer is no”; we live only “in an age of enlightening” (Aufklärung) . He hailed Frederick as the embodiment and protector of the German Enlightenment, as the one monarch who had told his subjects, “Reason as you will.”37
This may have been written in the hope that Frederick’s successor would keep to the policy of toleration. But Frederick William II (1786-97) was more interested in the power of the state than in the freedom of the mind. When a second edition of the Critique of Pure Reason was prepared (1787) Kant modified some passages, and tried to soften his heresies with an apologetic preface: “I have found it necessary to deny knowledge [of things in themselves] in order to make room for faith. … Criticism alone can sever the root of materialism, fatalism, atheism, freethinking, fanaticism, and superstition.”38 He had reason for caution. On July 9, 1788, Johann Christian von Wöllner, “minister for the Lutheran Department,” issued a Religionsedikt which explicitly rejected religious toleration as responsible for the loosening of morals, and threatened with expulsion from their pulpits or chairs all preachers or teachers who deviated from orthodox Christianity. It was in this atmosphere of reaction that Kant published his second Critique.
III. CRITIQUE OF PRACTICAL REASON, 1788
Since the first Critique had argued that pure reason could not prove the freedom of the will, and since, in Kant’s view, morality required such freedom, the operations of reason seemed to have left morality, like theology, without a rational basis. Worse yet, the Enlightenment had sapped the religious foundation of morals by questioning the existence of a rewarding and punishing God. How could civilization survive if these traditional supports of morality collapsed? Kant felt that he himself, as an avowed disciple of the Aufklärung, was obligated to find some rational ground for a moral code. In a preliminary essay, Fundamental Principles of the Metaphysics of Morals (Grundlegung zur Metaphysik der Sitten, 1785), he rejected the attempt of freethinkers to base morality upon the experience of the individual or the race; such an a posteriori derivation would deprive moral principles of that universality and absoluteness which, in his judgment, a sound ethic required. With characteristic self-confidence he announced: “It is clear that all moral conceptions have their seat and origin completely a priori in the reason.”39 His second major work, Kritik der praktischen Vernunft, proposed to find and elucidate that seat and origin. It would analyze the a priori elements in morality as the first Critique had analyzed the a priori elements in knowledge.
Every individual (Kant argues) has a conscience, a sense of duty, a consciousness of a commanding moral law. “Two things fill the mind with ever new and increasing admiration and awe … : the starry heavens above, and the moral law within.”40 This moral consciousness often conflicts with our sensual desires, but we recognize that it is a higher element in us than the pursuit of pleasure. It is not the product of experience, it is a part of our inherent psychological structure, like the categories; it is an internal tribunal present in every person in every race.41 And it is absolute; it commands us unconditionally, without exception or excuse, to do the right for its own sake, as an end in itself, not as a means to happiness or reward or some other good. Its imperative is categorical.
That categorical imperative takes two forms. “Act so that the maxim of thy will can always hold good as a principle of universal legislation”; act in such a way that if all others should act like you, everything would be well; this [variation of the Golden Rule] is the “fundamental law of the pure practical reason,”42 and is “the formula of an absolutely good will.”43 In a second formulation, “So act as to treat humanity, whether in thine own person or in that of any other, in every case as an end, never only as a means,”44 Kant proclaimed a principle more revolutionary than anything in the American or French declaration of the rights of man.
The sense of moral obligation is additional evidence for some freedom of the will. How could we have this consciousness of duty if we were not free to do or not to do, if our actions were merely links in an unbreakable chain of mechanical cause and effect? Without free will personality is meaningless; if personality is meaningless, so is life; and if life is meaningless, so is the universe.45 Kant recognizes the apparently inescapable logic of determinism; and how can a free choice intervene in an objective world which (he confesses) is apparently governed by mechanical laws?46 His reply is a masterpiece of obscurity. Mechanical law, he reminds us, is a mental construct, a scheme which the mind, through its category of causality, imposes upon the world of space and time as a device for dealing with it consistently. Since we have limited the categories to the world of phenomena, and since we have admitted that we do not know the nature of the noumenal world—the thing-in-itself behind the phenomena—we cannot assume that the laws which we construct for the phenomena hold also for the ultimate reality. And as we have admitted that we know, in ourselves, only the phenomenal self—only the world of perceptions and ideas—and do not know the nature of the inner and noumenal soul, we cannot assume that the laws of cause and effect that seem to govern the actions of our bodies (including our brains) apply also to the volitions of the ultimate spiritual reality behind our mental processes. Behind the mechanisms of the phenomenal world of space and of ideas in time there may be freedom in the spaceless and timeless noumenal world of ultimate outer or inner reality. Our actions and ideas are determined once they enter the world of perceivable physical or mental events; they may still be free in their origin in the unperceivable soul; “in this way freedom and nature … can exist together.”47 We cannot prove this, but we may legitimately assume it as implied by the imperative character of our moral sense; our moral life would die without it.
After all (says Kant), why should we not give primacy to the practical over the speculative reason? Science, which seems to reduce us to automata, is ultimately a speculation—a gamble on the permanent validity of conclusions and methods that are always changing. We are justified in feeling that the will in man is more basic than the intellect; the intellect is an instrument forged by the will for dealing with the external and mechanical world; it should not be the master of the personality that uses it.48
But if the moral sense warrants us in assuming a measure of free will, it also warrants us in believing in the immortality of the soul. For our moral sense urges us on to a perfection that is repeatedly frustrated by our sensual impulses; we cannot achieve this perfection in our short earthly life; we must assume, if there is any justice in the world, that we shall be granted, for our moral fulfillment, a continued life after death. If this also assumes that a just God exists, this too is warranted by practical reason. Earthly happiness does not always accord with virtue; we feel that somewhere the balance between virtue and happiness will be restored; and this is possible only by supposing that there is a deity who will effect this reconciliation. “Accordingly the existence of a cause of all nature, distinct from nature itself, and containing the principle of … the exact harmony of happiness with morality, is also postulated” by the practical reason.49
Kant inverted the usual procedure: instead of deriving the moral sense and code from God (as the theologians had done), he deduced God from the moral sense. We must conceive our duties not as “arbitrary ordinances of a foreign
will, but as essential laws of every free will in itself”; however, since that will and God both belong to the noumenal world, we should accept these duties as divine commands. “We shall not look upon [moral] actions as obligatory because they are commands of God, but we shall regard them as divine commands because we have an inward obligation to them.”50
If all this will-ful thinking is slightly obscure, it may be because Kant was not very enthusiastic about his attempt to reconcile Voltaire with Rousseau. The Critique of Pure Reason had gone even further than Voltaire in confessing that pure reason cannot prove free will, immortality, or God. But Kant had found in Rousseau’s doctrines—of the weakness of reason, the primacy of feeling, and the derivation of religion from man’s moral sense—a possible escape from agnosticism, moral disintegration, and Wollner’s police. He thought that Rousseau had awakened him from “dogmatic slumber” in ethics as Flume had done in metaphysics.51 The first Critique belonged to the Aufklärung; the second belonged to the Romantic movement; the attempt to combine both was one of the subtlest performances in the history of philosophy. Heine credited the attempt to solicitude for popular needs: the professor saw his faithful servant Lampe weeping over the death of God; “then Immanuel Kant had compassion, and showed himself not only a great philosopher but also a good man, and half kindly, half ironically he said: ‘Old Lampe must have a God, or he cannot be happy; … for my part the practical reason may, then, guarantee the existence of God.’”52