Preface

Ancient Greek philosophy was divided into three sciences: physics, ethics, and logic. This division is perfectly suitable to the nature of the thing; and the only improvement that can be made in it is to add the principle on which it is based, so that we may both satisfy ourselves of its completeness, and also be able to determine correctly the necessary subdivisions.

Ancient Greek philosophy was divided into three sciences: physics, ethics, and logic. This division fits the subject perfectly. The only possible improvement is to state the principle behind the division. Stating this principle would let us confirm that the division is complete and correctly identify the necessary subdivisions.

All rational knowledge is either material or formal: the former considers some object, the latter is concerned only with the form of the understanding and of the reason itself, and with the universal laws of thought in general without distinction of its objects. Formal philosophy is called logic. Material philosophy, however, which has to do with determinate objects and the laws to which they are subject, is again twofold; for these laws are either laws of nature or of freedom. The science of the former is physics, that of the latter, ethics; they are also called natural philosophy and moral philosophy respectively.

All rational knowledge is either material or formal. Material knowledge considers some object. Formal knowledge concerns only the form of understanding and reason themselves, and the universal laws of thought in general. It makes no distinction between the objects of thought. Formal philosophy is called logic. Material philosophy, however, deals with specific objects and the laws governing them. It has two branches because these laws are either laws of nature or laws of freedom. The science of the laws of nature is physics. The science of the laws of freedom is ethics. These sciences are also called natural philosophy and moral philosophy, respectively.

Logic cannot have any empirical part; that is, a part in which the universal and necessary laws of thought should rest on grounds taken from experience; otherwise it would not be logic, i.e., a canon for the understanding or the reason, valid for all thought, and capable of demonstration. Natural and moral philosophy, on the contrary, can each have their empirical part, since the former has to determine the laws of nature as an object of experience; the latter the laws of the human will, so far as it is affected by nature: the former, however, being laws according to which everything does happen; the latter, laws according to which everything ought to happen. Ethics, however, must also consider the conditions under which what ought to happen frequently does not.

Logic cannot have any part based on experience. In other words, the universal and necessary laws of thought cannot rest on evidence drawn from experience. Otherwise, logic would not be a system of rules for understanding or reason, valid for all thought and demonstrably true. Natural and moral philosophy, by contrast, can each have a part based on experience. Natural philosophy must determine the laws of nature as an object of experience. Moral philosophy must determine the laws of the human will insofar as nature affects the will. But the laws of nature describe how everything does happen. The laws of the will describe how everything ought to happen. Ethics, however, must also consider the conditions under which what ought to happen frequently does not.

We may call all philosophy empirical, so far as it is based on grounds of experience: on the other hand, that which delivers its doctrines from a priori principles alone we may call pure philosophy. When the latter is merely formal it is logic; if it is restricted to definite objects of the understanding it is metaphysic.

We may call all philosophy empirical insofar as it is based on experience. By contrast, we may call philosophy pure when its teachings come from a priori principles alone. When pure philosophy deals only with form, it is logic. If pure philosophy is limited to specific objects of the understanding, it is metaphysics.

In this way there arises the idea of a twofold metaphysic—a metaphysic of nature and a metaphysic of morals. Physics will thus have an empirical and also a rational part. It is the same with Ethics; but here the empirical part might have the special name of practical anthropology, the name morality being appropriated to the rational part.

This leads to the idea of two kinds of metaphysics: a metaphysics of nature and a metaphysics of morals. Physics will therefore have both an empirical part and a rational part. The same applies to ethics. But in ethics, the empirical part might be given the special name of practical anthropology. The name morality would be reserved for the rational part.

All trades, arts, and handiworks have gained by division of labour, namely, when, instead of one man doing everything, each confines himself to a certain kind of work distinct from others in the treatment it requires, so as to be able to perform it with greater facility and in the greatest perfection. Where the different kinds of work are not distinguished and divided, where everyone is a jack-of-all-trades, there manufactures remain still in the greatest barbarism. It might deserve to be considered whether pure philosophy in all its parts does not require a man specially devoted to it, and whether it would not be better for the whole business of science if those who, to please the tastes of the public, are wont to blend the rational and empirical elements together, mixed in all sorts of proportions unknown to themselves, and who call themselves independent thinkers, giving the name of minute philosophers to those who apply themselves to the rational part only- if these, I say, were warned not to carry on two employments together which differ widely in the treatment they demand, for each of which perhaps a special talent is required, and the combination of which in one person only produces bunglers. But I only ask here whether the nature of science does not require that we should always carefully separate the empirical from the rational part, and prefix to Physics proper (or empirical physics) a metaphysic of nature, and to practical anthropology a metaphysic of morals, which must be carefully cleared of everything empirical, so that we may know how much can be accomplished by pure reason in both cases, and from what sources it draws this its a priori teaching, and that whether the latter inquiry is conducted by all moralists (whose name is legion), or only by some who feel a calling thereto.

All trades, arts, and crafts have benefited from the division of labor. Instead of doing everything, each person specializes in work that requires a different approach from other kinds of work. This specialization allows each person to work more easily and achieve the highest quality. Where different kinds of work are not distinguished and divided, everyone is a jack-of-all-trades. In such places, manufacturing remains in its most primitive state. Perhaps we should consider whether every branch of pure philosophy also requires someone devoted specifically to it. Would science as a whole benefit if certain thinkers were warned against combining two very different kinds of work? These thinkers mix rational and empirical elements to please public tastes, in proportions they themselves do not understand. They call themselves independent thinkers and dismiss those who study only the rational part as narrow philosophers. Yet the two kinds of work require very different approaches. Perhaps each requires a special talent, and combining both in one person produces only bunglers. But here I ask only whether the nature of science requires us always to separate empirical and rational elements carefully. Should we place a metaphysics of nature before Physics proper (or empirical physics), and a metaphysics of morals before practical anthropology? These metaphysical studies must be carefully stripped of everything empirical. We could then know how much pure reason can accomplish in both fields. We could also know the sources from which pure reason draws its a priori teachings, independently of experience. This requirement holds whether all moralists undertake the latter inquiry (and their numbers are legion), or only some who feel called to it.

As my concern here is with moral philosophy, I limit the question suggested to this: Whether it is not of the utmost necessity to construct a pure thing which is only empirical and which belongs to anthropology? for that such a philosophy must be possible is evident from the common idea of duty and of the moral laws. Everyone must admit that if a law is to have moral force, i.e., to be the basis of an obligation, it must carry with it absolute necessity; that, for example, the precept, "Thou shalt not lie," is not valid for men alone, as if other rational beings had no need to observe it; and so with all the other moral laws properly so called; that, therefore, the basis of obligation must not be sought in the nature of man, or in the circumstances in the world in which he is placed, but a priori simply in the conception of pure reason; and although any other precept which is founded on principles of mere experience may be in certain respects universal, yet in as far as it rests even in the least degree on an empirical basis, perhaps only as to a motive, such a precept, while it may be a practical rule, can never be called a moral law.

Since my concern here is moral philosophy, I will limit the question to the following. Is it not absolutely necessary to develop something pure that is based only on experience and belongs to anthropology? Such a philosophy must be possible, as the ordinary idea of duty and moral laws makes clear. Everyone must admit that a law must carry absolute necessity if it is to have moral force. In other words, absolute necessity is required if a law is to serve as the basis of an obligation. For example, the command, "You must not lie," does not apply to human beings alone. We cannot treat other rational beings as if they had no need to obey it. The same holds for all other moral laws properly so called. Therefore, the basis of obligation must not be sought in human nature or in the circumstances of human life. Instead, that basis must be sought a priori, through pure reason alone, independently of experience. Other commands founded solely on experience may be universal in certain respects. But any command that rests even slightly on experience, perhaps only in its motive, can never be called a moral law. Such a command may still be a practical rule.

Thus not only are moral laws with their principles essentially distinguished from every other kind of practical knowledge in which there is anything empirical, but all moral philosophy rests wholly on its pure part. When applied to man, it does not borrow the least thing from the knowledge of man himself (anthropology), but gives laws a priori to him as a rational being. No doubt these laws require a judgement sharpened by experience, in order on the one hand to distinguish in what cases they are applicable, and on the other to procure for them access to the will of the man and effectual influence on conduct; since man is acted on by so many inclinations that, though capable of the idea of a practical pure reason, he is not so easily able to make it effective in concreto in his life.

Thus moral laws and their principles differ fundamentally from every other kind of practical knowledge containing anything drawn from experience. Moreover, all moral philosophy rests entirely on its pure part, independent of experience. When applied to human beings, moral philosophy borrows nothing at all from the study of human beings (anthropology). Instead, it gives them laws a priori, independently of experience, as rational beings. These laws do, of course, require judgment sharpened by experience. Such judgment is needed both to identify the cases where the laws apply and to bring them to bear on the human will. It is also needed to give these laws an effective influence on conduct. This is because human beings are subject to so many inclinations. Although they can grasp the idea of pure practical reason, they cannot so easily make it effective in their actual lives.

A metaphysic of morals is therefore indispensably necessary, not merely for speculative reasons, in order to investigate the sources of the practical principles which are to be found a priori in our reason, but also because morals themselves are liable to all sorts of corruption, as long as we are without that clue and supreme canon by which to estimate them correctly. For in order that an action should be morally good, it is not enough that it conform to the moral law, but it must also be done for the sake of the law, otherwise that conformity is only very contingent and uncertain; since a principle which is not moral, although it may now and then produce actions conformable to the law, will also often produce actions which contradict it. Now it is only in a pure philosophy that we can look for the moral law in its purity and genuineness (and, in a practical matter, this is of the utmost consequence): we must, therefore, begin with pure philosophy (metaphysic), and without it there cannot be any moral philosophy at all. That which mingles these pure principles with the empirical does not deserve the name of philosophy (for what distinguishes philosophy from common rational knowledge is that it treats in separate sciences what the latter only comprehends confusedly); much less does it deserve that of moral philosophy, since by this confusion it even spoils the purity of morals themselves, and counteracts its own end.

A metaphysics of morals is therefore absolutely necessary. We need it not only for theoretical reasons, to investigate the sources of practical principles found in reason a priori. We also need it because morality is open to all kinds of corruption without such a guide and supreme standard. Only with this guide and standard can we judge morality correctly. For an action to be morally good, following the moral law is not enough. The action must also be done for the sake of the law. Otherwise, its agreement with the law is merely a matter of chance and cannot be relied on. A principle that is not moral may sometimes produce actions that follow the law. But such a principle will also often produce actions that contradict the law. Only in pure philosophy can we hope to find the moral law in its pure and genuine form. In a practical matter, this purity is of the greatest importance. We must therefore begin with pure philosophy (metaphysics). Without metaphysics, there can be no moral philosophy at all. Any approach that mixes these pure principles with principles drawn from experience does not deserve the name of philosophy. For philosophy differs from ordinary rational knowledge by treating in separate fields what ordinary knowledge grasps only in a confused way. Such a mixed approach deserves the name of moral philosophy even less. By confusing these principles, it corrupts the purity of morality itself and works against its own purpose.

Let it not be thought, however, that what is here demanded is already extant in the propaedeutic prefixed by the celebrated Wolf to his moral philosophy, namely, his so-called general practical philosophy, and that, therefore, we have not to strike into an entirely new field. Just because it was to be a general practical philosophy, it has not taken into consideration a will of any particular kind- say one which should be determined solely from a priori principles without any empirical motives, and which we might call a pure will, but volition in general, with all the actions and conditions which belong to it in this general signification. By this it is distinguished from a metaphysic of morals, just as general logic, which treats of the acts and canons of thought in general, is distinguished from transcendental philosophy, which treats of the particular acts and canons of pure thought, i.e., that whose cognitions are altogether a priori. For the metaphysic of morals has to examine the idea and the principles of a possible pure will, and not the acts and conditions of human volition generally, which for the most part are drawn from psychology. It is true that moral laws and duty are spoken of in the general moral philosophy (contrary indeed to all fitness). But this is no objection, for in this respect also the authors of that science remain true to their idea of it; they do not distinguish the motives which are prescribed as such by reason alone altogether a priori, and which are properly moral, from the empirical motives which the understanding raises to general conceptions merely by comparison of experiences; but, without noticing the difference of their sources, and looking on them all as homogeneous, they consider only their greater or less amount. It is in this way they frame their notion of obligation, which, though anything but moral, is all that can be attained in a philosophy which passes no judgement at all on the origin of all possible practical concepts, whether they are a priori, or only a posteriori.

Do not assume, however, that the work demanded here already exists in the introduction to the celebrated Wolf’s moral philosophy. That introduction is his so-called general practical philosophy. Nor should we assume, therefore, that we have no entirely new ground to explore. Precisely because Wolf intended a general practical philosophy, he did not consider any particular kind of will. Such a will might, for example, be determined solely by a priori principles, without any motives drawn from experience. We might call such a will a pure will. Instead, Wolf considered willing in general, with all the actions and conditions that belong to willing in this broad sense. This focus distinguishes general practical philosophy from a metaphysics of morals, just as general logic differs from transcendental philosophy. General logic studies the operations and rules of thought in general. Transcendental philosophy studies the particular operations and rules of pure thought, whose knowledge is entirely a priori. For a metaphysics of morals must examine the idea and principles of a possible pure will. It must not examine the acts and conditions of human willing in general, which are mostly drawn from psychology. General moral philosophy does, admittedly, discuss moral laws and duty, although such discussion is entirely out of place there. But that discussion is no objection, because the authors remain faithful to their conception of general moral philosophy. They do not distinguish properly moral motives from empirical motives. Properly moral motives are prescribed by reason alone, entirely a priori. Empirical motives are raised by the understanding into general concepts merely through comparisons of experiences. But these authors overlook the different sources of these motives and treat them all as the same kind. They consider only their greater or lesser amounts. In this way, they form their concept of obligation, which is anything but moral. Yet no more can be achieved by a philosophy that makes no judgment about the origin of all possible practical concepts. Such a philosophy does not judge whether these concepts are a priori or only a posteriori.

Intending to publish hereafter a metaphysic of morals, I issue in the first instance these fundamental principles. Indeed there is properly no other foundation for it than the critical examination of a pure practical reason; just as that of metaphysics is the critical examination of the pure speculative reason, already published. But in the first place the former is not so absolutely necessary as the latter, because in moral concerns human reason can easily be brought to a high degree of correctness and completeness, even in the commonest understanding, while on the contrary in its theoretic but pure use it is wholly dialectical; and in the second place if the critique of a pure practical Reason is to be complete, it must be possible at the same time to show its identity with the speculative reason in a common principle, for it can ultimately be only one and the same reason which has to be distinguished merely in its application. I could not, however, bring it to such completeness here, without introducing considerations of a wholly different kind, which would be perplexing to the reader. On this account I have adopted the title of Fundamental Principles of the Metaphysic of Morals instead of that of a Critical Examination of the pure practical reason.

I plan to publish a metaphysics of morals later, so I begin here with its fundamental principles. Strictly speaking, its only foundation is a critical examination of pure practical reason. Likewise, metaphysics rests on the critical examination of pure speculative reason, which I have already published. But first, examining practical reason is not as absolutely necessary as examining speculative reason. In moral matters, even the most ordinary human understanding can easily reach a high degree of accuracy and completeness. By contrast, in its pure theoretical use, human reason is entirely caught up in dialectical arguments. Second, a complete critique of pure practical reason must also show its unity with speculative reason through a common principle. Ultimately, practical and speculative reason can only be one and the same reason, distinguished merely by how reason is applied. But I could not make the examination complete here without introducing entirely different considerations that would confuse the reader. For this reason, I have chosen the title Fundamental Principles of the Metaphysic of Morals. I have used this title instead of A Critical Examination of Pure Practical Reason.

But in the third place, since a metaphysic of morals, in spite of the discouraging title, is yet capable of being presented in popular form, and one adapted to the common understanding, I find it useful to separate from it this preliminary treatise on its fundamental principles, in order that I may not hereafter have need to introduce these necessarily subtle discussions into a book of a more simple character.

But third, despite its intimidating title, a metaphysics of morals can be presented for a general audience in understandable terms. So I find it useful to separate this preliminary study of its basic principles from that more accessible work. This separation will spare me from having to include these necessarily subtle discussions later in a simpler book.

The present treatise is, however, nothing more than the investigation and establishment of the supreme principle of morality, and this alone constitutes a study complete in itself and one which ought to be kept apart from every other moral investigation. No doubt my conclusions on this weighty question, which has hitherto been very unsatisfactorily examined, would receive much light from the application of the same principle to the whole system, and would be greatly confirmed by the adequacy which it exhibits throughout; but I must forego this advantage, which indeed would be after all more gratifying than useful, since the easy applicability of a principle and its apparent adequacy give no very certain proof of its soundness, but rather inspire a certain partiality, which prevents us from examining and estimating it strictly in itself and without regard to consequences.

This work, however, does no more than investigate and establish the supreme principle of morality. That task alone forms a complete study and should remain separate from every other inquiry into morality. This important question has so far been examined very unsatisfactorily. No doubt, applying the same principle to the whole moral system would shed much light on my conclusions. My conclusions would also gain strong support from the principle’s adequacy throughout that system. But I must give up this advantage, which would, after all, be more gratifying than useful. A principle’s ease of application and apparent adequacy offer no very certain proof that the principle is sound. Instead, they encourage a bias in its favor. That bias prevents us from rigorously examining and judging the principle itself, without regard to its consequences.

I have adopted in this work the method which I think most suitable, proceeding analytically from common knowledge to the determination of its ultimate principle, and again descending synthetically from the examination of this principle and its sources to the common knowledge in which we find it employed. The division will, therefore, be as follows:

In this work, I have used the method I think most suitable. I begin analytically, moving from common knowledge to identifying its ultimate principle. Then I examine this principle and its sources and work back synthetically to common knowledge, where we find the principle applied. The work will therefore be divided as follows:

1 FIRST SECTION. Transition from the common rational knowledge of morality to the philosophical.

1 FIRST SECTION. Moving from ordinary rational knowledge of morality to philosophical knowledge.

2 SECOND SECTION. Transition from popular moral philosophy to the metaphysic of morals.

2 SECOND SECTION. Moving from popular moral philosophy to the metaphysics of morals.

3 THIRD SECTION. Final step from the metaphysic of morals to the critique of the pure practical reason.

3 THIRD SECTION. Final step from the metaphysics of morals to the critique of pure practical reason.