Preface
Ancient Greek philosophy was divided into three sciences: physics, [387] ethics, and logic. This division is perfectly suitable to the nature of the subject, and the only improvement that can be made in it is perhaps only to supply its principle so that there will be a possibility on the one hand of insuring its completeness and on the other of correctly determining its necessary subdivisions.
All rational knowledge is either material and concerned with some object, or formal and concerned only with the form of understanding and of reason themselves and with the universal rules of thought in general without regard to differences of its objects. Formal philosophy is called logic. Material philosophy, however, has to do with determinate objects and with the laws to which these objects are subject; and such philosophy is divided into two parts, because these laws are either laws of nature or laws of freedom. The science of the former is called physics, while that of the latter is called ethics; they are also called doctrine of nature and doctrine of morals respectively.
Logic cannot have any empirical part, i.e., a part in which the universal and necessary laws of thought would be based on grounds taken from experience; for in that case it would not be logic, i.e., a canon for understanding and reason, which is valid for all thinking and which has to be demonstrated. Natural and moral philosophy, on the contrary, can each have an empirical part. The former has to because it must determine the laws of nature as an object of experience, and the latter because it must determine the will of man insofar as the will is affected by nature. The laws of the former are those according to which everything does happen, [388] while the laws of the latter are those according to which everything ought to happen, although these moral laws also consider the conditions under which what ought to happen frequently does not.
All philosophy insofar as it is founded on experience may be called empirical, while that which sets forth its doctrines as founded entirely on a priori principles may be called pure. The latter, when merely formal, is called logic; but when limited to determinate objects of the understanding, it is called metaphysics.
In this way there arises the idea of a twofold metaphysics: a metaphysics of nature and a metaphysics of morals. Physics will thus have its empirical part, but also a rational one. Ethics will too, though here the empirical part might more specifically be called practical anthropology, while the rational part might properly be called morals.
All industries, crafts, and arts have gained by the division of labor, viz., one man does not do everything, but each confines himself to a certain kind of work that is distinguished from all other kinds by the treatment it requires, so that the work may be done with the highest perfection and with greater ease. Where work is not so distinguished and divided, where everyone is a jack of all trades, there industry remains sunk in the greatest barbarism. Whether or not pure philosophy in all its parts requires its own special man might well be in itself a subject worthy of consideration. Would not the whole of this learned industry be better off if those who are accustomed, as the public taste demands, to purvey a mixture of the empirical with the rational in all sorts of proportions unknown even to themselves and who style themselves independent thinkers, while giving the name of hair-splitters to those who apply themselves to the purely rational part, were to be given warning about pursuing simultaneously two jobs which are quite different in their technique, and each of which perhaps requires a special talent that when combined with the other talent produces nothing but bungling? But I only ask here whether the nature of science does not require that the empirical part always be carefully separated from the rational part. Should not physics proper (i.e., empirical physics) be preceded by a metaphysics of nature, and practical anthropology by a metaphysics of morals? Both of these [389] metaphysics must be carefully purified of everything empirical in order to know how much pure reason can accomplish in each case and from what sources it draws its a priori teaching, whether such teaching be conducted by all moralists (whose name is legion) or only by some who feel a calling thereto.
Since I am here primarily concerned with moral philosophy, the foregoing question will be limited to a consideration of whether or not there is the utmost necessity for working out for once a pure moral philosophy that is wholly cleared of everything which can only be empirical and can only belong to anthropology. That there must be such a philosophy is evident from the common idea of duty and of moral laws. Everyone must admit that if a law is to be morally valid, i.e., is to be valid as a ground of obligation, then it must carry with it absolute necessity. He must admit that the command, “Thou shalt not lie,” does not hold only for men, as if other rational beings had no need to abide by it, and so with all the other moral laws properly so called. And he must concede that the ground of obligation here must therefore be sought not in the nature of man nor in the circumstances of the world in which man is placed, but must be sought a priori solely in the concepts of pure reason; he must grant that every other precept which is founded on principles of mere experience—even a precept that may in certain respects be universal—insofar as it rests in the least on empirical grounds—perhaps only in its motive—can indeed be called a practical rule, but never a moral law.
Thus not only are moral laws together with their principles essentially different from every kind of practical cognition in which there is anything empirical, but all moral philosophy rests entirely on its pure part. When applied to man, it does not in the least borrow from acquaintance with him (anthropology) but gives a priori laws to him as a rational being. To be sure, these laws require, furthermore, a power of judgment sharpened by experience, partly in order to distinguish in what cases they are applicable, and partly to gain for them access to the human will as well as influence for putting them into practice. For man is affected by so many inclinations that, even though he is indeed capable of the idea of a pure practical reason, he is not so easily able to make that idea effective in concreto in the conduct of his life.
A metaphysics of morals is thus indispensably necessary, not merely because of motives of speculation regarding the source of practical principles [390] which are present a priori in our reason, but because morals themselves are liable to all kinds of corruption as long as the guide and supreme norm for correctly estimating them are missing. For in the case of what is to be morally good, that it conforms to the moral law is not enough; it must also be done for the sake of the moral law. Otherwise that conformity is only very contingent and uncertain, since the non-moral ground may now and then produce actions that conform with the law but quite often produces actions that are contrary to the law. Now the moral law in its purity and genuineness (which is of the utmost concern in the practical realm) can be sought nowhere but in a pure philosophy. Therefore, pure philosophy (metaphysics) must precede; without it there can be no moral philosophy at all. That philosophy which mixes pure principles with empirical ones does not deserve the name of philosophy (for philosophy is distinguished from ordinary rational knowledge by its treatment in a separate science of what the latter comprehends only confusedly). Still less does it deserve the name of moral philosophy, since by this very confusion it spoils even the purity of morals and counteracts its own end.
There must be no thought that what is required here is already contained in the propaedeutic that precedes the celebrated Wolff’s moral philosophy, i.e., in what he calls Universal Practical Philosophy, and that hence there is no need to break entirely new ground. Just because his work was to be a universal practical philosophy, it has not taken into consideration any special kind of will, such as one determined solely by a priori principles without any empirical motives and which could be called a pure will, but has considered volition in general, together with all the actions and conditions belonging to it under this general signification. And thereby does his propaedeutic differ from a metaphysics of morals in the same way that general logic, which expounds the acts and rules of thinking in general, differs from transcendental philosophy, which treats merely of the particular acts and rules of pure thinking, i.e., of that thinking whereby objects are cognized completely a priori. For the metaphysics of morals has to investigate the idea and principles of a possible pure will and not the actions and conditions of human volition as such, which are [391] for the most part drawn from psychology. Moral laws and duty are discussed in this universal practical philosophy (though quite improperly), but this is no objection to what has been said about such philosophy. For the authors of this science remain true to their idea of it on the following point also: they do not distinguish the motives which, as such, are presented completely a priori by reason alone and are properly moral from the empirical motives which the understanding raises to general concepts merely by the comparison of experiences. Rather, they consider motives irrespective of any difference in their source; and inasmuch as they regard all motives as being homogeneous, they consider nothing but their relative strength or weakness. In this way they frame their concept of obligation, which is certainly not moral, but is all that can be expected from a philosophy which never decides regarding the origin of all possible practical concepts whether they are a priori or merely a posteriori.
I intend someday to publish a metaphysics of morals, but as a preliminary to that I now issue this Grounding [1785]. Indeed there is properly no other foundation for such a metaphysics than a critical examination of pure practical reason, just as there is properly no other foundation for a metaphysics [of nature] than the critical examination of pure speculative reason, which has already been published. But, in the first place, the former critique is not so absolutely necessary as the latter one, because human reason can, even in the most ordinary mind, be easily brought in moral matters to a high degree of correctness and precision, while on the other hand in its theoretical but pure use it is wholly dialectical. In the second place, if a critical examination of pure practical reason is to be complete, then there must, in my view, be the possibility at the same time of showing the unity of practical and speculative reason in a common principle; for in the final analysis there can be only one and the same reason, which is to be differentiated solely in its application. But there is no possibility here of bringing my work to such completeness, without introducing considerations of an entirely different kind and without thereby confusing the reader. Instead of calling the present work a Critique of Pure Practical Reason, I have, therefore, adopted the title Grounding for the Metaphysics of Morals [Grundlegung zur Metaphysik der Sitten.]
But, in the third place, since a metaphysics of morals, despite the forbidding title, is nevertheless capable of a high degree of popularity and adaptation to the ordinary understanding, I find it useful to separate from the aforementioned metaphysics this preliminary work on its foundation [Grundlage] in order later to have no need to introduce unavoidable [392] subtleties into doctrines that are easier to grasp.
The present Grounding [Grundlegung] is, however, intended for nothing more than seeking out and establishing the supreme principle of morality. This constitutes by itself a task which is complete in its purpose and should be kept separate from every other moral inquiry. The application of this supreme principle to the whole ethical system would, to be sure, shed much light on my conclusions regarding this central question, which is important but has not heretofore been at all satisfactorily discussed; and the adequacy manifested by the principle throughout such application would provide strong confirmation for the principle. Nevertheless, I must forego this advantage, which after all would be more gratifying for myself than helpful for others, since ease of use and apparent adequacy of a principle do not provide any certain proof of its soundness, but do awaken, rather, a certain bias which prevents any rigorous examination and estimation of it for itself without any regard to its consequences.
The method adopted in this work is, I believe, one that is most suitable if we proceed analytically from ordinary knowledge to a determination of the supreme principle and then back again synthetically from an examination of this principle and its sources to ordinary knowledge where its application is found. Therefore, the division turns out to be the following:
1. First Section. Transition from the Ordinary Rational Knowledge of Morality to the Philosophical
2. Second Section. Transition from Popular Moral Philosophy to a Metaphysics of Morals
3. Third Section. Final Step from a Metaphysics of Morals to a Critique of Pure Practical Reason.