Concluding Remark
The speculative employment of reason with respect to nature leads to the absolute necessity of some supreme cause of the world: the practical employment of reason with a view to freedom leads also to absolute necessity, but only of the laws of the actions of a rational being as such. Now it is an essential principle of reason, however employed, to push its knowledge to a consciousness of its necessity (without which it would not be rational knowledge). It is, however, an equally essential restriction of the same reason that it can neither discern the necessity of what is or what happens, nor of what ought to happen, unless a condition is supposed on which it is or happens or ought to happen. In this way, however, by the constant inquiry for the condition, the satisfaction of reason is only further and further postponed. Hence it unceasingly seeks the unconditionally necessary and finds itself forced to assume it, although without any means of making it comprehensible to itself, happy enough if only it can discover a conception which agrees with this assumption. It is therefore no fault in our deduction of the supreme principle of morality, but an objection that should be made to human reason in general, that it cannot enable us to conceive the absolute necessity of an unconditional practical law (such as the categorical imperative must be). It cannot be blamed for refusing to explain this necessity by a condition, that is to say, by means of some interest assumed as a basis, since the law would then cease to be a supreme law of reason. And thus while we do not comprehend the practical unconditional necessity of the moral imperative, we yet comprehend its incomprehensibility, and this is all that can be fairly demanded of a philosophy which strives to carry its principles up to the very limit of human reason.
17 I adopt this method of assuming freedom merely as an idea which rational beings suppose in their actions, in order to avoid the necessity of proving it in its theoretical aspect also. The former is sufficient for my purpose; for even though the speculative proof should not be made out, yet a being that cannot act except with the idea of freedom is bound by the same laws that would oblige a being who was actually free. Thus we can escape here from the onus which presses on the theory.
18 Interest is that by which reason becomes practical, i.e., a cause determining the will. Hence we say of rational beings only that they take an interest in a thing; irrational beings only feel sensual appetites. Reason takes a direct interest in action then only when the universal validity of its maxims is alone sufficient to determine the will. Such an interest alone is pure. But if it can determine the will only by means of another object of desire or on the suggestion of a particular feeling of the subject, then reason takes only an indirect interest in the action, and, as reason by itself without experience cannot discover either objects of the will or a special feeling actuating it, this latter interest would only be empirical and not a pure rational interest. The logical interest of reason (namely, to extend its insight) is never direct, but presupposes purposes for which reason is employed.
The Metaphysics of Morals
General Introduction to the Metaphysics of Morals
I. The Relation of the Faculties of the Human Mind to the Moral Laws
II. The Idea and Necessity of a Metaphysic of Morals
III. The Division of a Metaphysic of Morals
General Divisions of the Metaphysics of Morals
I. Division of the Metaphysic of Morals as a System of Duties generally
II. Division of the Metaphysic of Morals according to Relations of Obligation
III. Division of the Metaphysic of Morals
IV. General preliminary Conceptions defined and explained
' But next to a new History of Law, what we most require is a new Philosophy of Law.'—Sir Henry Sumner Maine.
Translator's preface
Kant's Science of Right [Rechtslehre] is a complete exposition of the Philosophy of Law, viewed as a rational investigation of the fundamental Principles of Jurisprudence. It was published in 1796,[1] as the First Part of his Metaphysic of Morals,[2] the promised sequel and completion of the Foundation for a Metaphysic of Morals,[3] published in 1785. The importance and value of the great thinker's exposition of the Science of Right, both as regards the fundamental Principles of his own Practical Philosophy and the general interest of the Philosophy of Law, were at once recognised. A second Edition, enlarged by an Appendix, containing Supplementary Explanations of the Principles of Right, appeared in 1798.[4] The work has since then been several times reproduced by itself, as well as incorporated in all the complete editions of Kant's Works. It was immediately rendered into Latin by Born[5] in 1798, and again by König[6] in 1800. It was translated into French by Professor Tissot in 1837,[7] of which translation a second revised Edition has appeared. It was again translated into French by M. Barni, preceded by an elaborate analytical introduction, in 1853.[8] With the exception of the Preface and Introductions,[9] the work now appears translated into English for the first time.
Kant's Science of Right was his last great work of an independent kind in the department of pure Philosophy, and with it he virtually brought his activity as a master of thought to a close.[10] It fittingly crowned the rich practical period of his later philosophical teaching, and he shed into it the last effort of his energy of thought. Full of years and honours he was then deliberately engaged, in the calm of undisturbed and unwearied reflection, in gathering the finally matured fruit of all the meditation and learning of his life. His three immortal Critiques of the Pure Reason[11] (1781), the Practical Reason[12] (1788), and the Judgment[13]