The Critique of Practical Reason by Immanuel Kant (best short books to read TXT) 📕

hold as a universal law of nature that statements should be allowed to have the force of proof and yet to be purposely untrue. Similarly, the maxim which I adopt with respect to disposing freely of my life is at once determined, when I ask myself what it should be, in order that a system, of which it is the law, should maintain itself. It is obvious that in such a system no one could arbitrarily put an end to his own life, for such an arrangement would not be a permanent order of things. And so in all similar cases. Now, in nature, as it actually is an object of experience, the free will is not of itself determined to maxims which could of themselves be the foundation of a natural system of universal laws, or which could even be adapted to a system so constituted; on the contrary, its maxims are private inclinations which constitute, indeed, a natural whole in conformity with pathological (physical) laws, but could not form part of a system of nature, which would only be possible through our will acting in accordance with pure practical laws. Yet we are, through reason, conscious of a law to which all our maxims are subject, as though a natural order must be originated from our will. This law, therefore, must be the idea of a natural system not given in experience, and yet possible through freedom; a system, therefore, which is supersensible, and to which we give objective reality, at least in a practical point of view, since we look on it as an object of our will as pure rational beings.

Hence the distinction between the laws of a natural system to which the will is subject, and of a natural system which is subject to a will (as far as its relation to its free actions is concerned), rests on this, that in the former the objects must be causes of the ideas which determine the will; whereas in the latter the will is the cause of the objects; so that its causality has its determining principle solely in the pure faculty of reason, which may therefore be called a pure practical reason.

There are therefore two very distinct problems: how, on the one side, pure reason can cognise objects a priori, and how on the other side it can be an immediate determining principle of the will, that is, of the causality of the rational being with respect to the reality of objects (through the mere thought of the universal validity of its own maxims as laws).

{BOOK_1|CHAPTER_1 ^paragraph 135}

The former, which belongs to the critique of the pure speculative reason, requires a previous explanation, how intuitions without which no object can be given, and, therefore, none known synthetically, are possible a priori; and its solution turns out to be that these are all only sensible and, therefore, do not render possible any speculative knowledge which goes further than possible experience reaches; and that therefore all the principles of that pure speculative reason avail only to make experience possible; either experience of given objects or of those that may be given ad infinitum, but never are completely given.

The latter, which belongs to the critique of practical reason, requires no explanation how the objects of the faculty of desire are possible, for that being a problem of the theoretical knowledge of nature is left to the critique of the speculative reason, but only how reason can determine the maxims of the will; whether this takes place only by means of empirical ideas as principles of determination, or whether pure reason can be practical and be the law of a possible order of nature, which is not empirically knowable. The possibility of such a supersensible system of nature, the conception of which can also be the ground of its reality through our own free will, does not require any a priori intuition (of an intelligible world) which, being in this case supersensible, would be impossible for us. For the question is only as to the determining principle of volition in its maxims, namely, whether it is empirical, or is a conception of the pure reason (having the legal character belonging to it in general), and how it can be the latter. It is left to the theoretic principles of reason to decide whether the causality of the will suffices for the realization of the objects or not, this being an inquiry into the possibility of the objects of the volition. Intuition of these objects is therefore of no importance to the practical problem. We are here concerned only with the determination of the will and the determining principles of its maxims as a free will, not at all with the result. For, provided only that the will conforms to the law of pure reason, then let its power in execution be what it may, whether according to these maxims of legislation of a possible system of nature any such system really results or not, this is no concern of the critique, which only inquires whether, and in what way, pure reason can be practical, that is directly determine the will.

In this inquiry criticism may and must begin with pure practical laws and their reality. But instead of intuition it takes as their foundation the conception of their existence in the intelligible world, namely, the concept of freedom. For this concept has no other meaning, and these laws are only possible in relation to freedom of the will; but freedom being supposed, they are necessary; or conversely freedom is necessary because those laws are necessary, being practical postulates. It cannot be further explained how this consciousness of the moral law, or, what is the same thing, of freedom, is possible; but that it is admissible is well established in the theoretical critique.

The exposition of the supreme principle of practical reason is now finished; that is to say, it has been- shown first, what it contains, that it subsists for itself quite a priori and independent of empirical principles; and next in what it is distinguished from all other practical principles. With the deduction, that is, the justification of its objective and universal validity, and the discernment of the possibility of such a synthetical proposition a priori, we cannot expect to succeed so well as in the case of the principles of pure theoretical reason. For these referred to objects of possible experience, namely, to phenomena, and we could prove that these phenomena could be known as objects of experience only by being brought under the categories in accordance with these laws; and consequently that all possible experience must conform to these laws. But I could not proceed in this way with the deduction of the moral law. For this does not concern the knowledge of the properties of objects, which may be given to the reason from some other source; but a knowledge which can itself be the ground of the existence of the objects, and by which reason in a rational being has causality, i.e., pure reason, which can be regarded as a faculty immediately determining the will.

Now all our human insight is at an end as soon as we have arrived at fundamental powers or faculties, for the possibility of these cannot be understood by any means, and just as little should it be arbitrarily invented and assumed. Therefore, in the theoretic use of reason, it is experience alone that can justify us in assuming them. But this expedient of adducing empirical proofs, instead of a deduction from a priori sources of knowledge, is denied us here in respect to the pure practical faculty of reason. For whatever requires to draw the proof of its reality from experience must depend for the grounds of its possibility on principles of experience; and pure, yet practical, reason by its very notion cannot be regarded as such. Further, the moral law is given as a fact of pure reason of which we are a priori conscious, and which is apodeictically certain, though it be granted that in experience no example of its exact fulfilment can be found. Hence, the objective reality of the moral law cannot be proved by any deduction by any efforts of theoretical reason, whether speculative or empirically supported, and therefore, even if we renounced its apodeictic certainty, it could not be proved a posteriori by experience, and yet it is firmly established of itself.

{BOOK_1|CHAPTER_1 ^paragraph 140}

But instead of this vainly sought deduction of the moral principle, something else is found which was quite unexpected, namely, that this moral principle serves conversely as the principle of the deduction of an inscrutable faculty which no experience could prove, but of which speculative reason was compelled at least to assume the possibility (in order to find amongst its cosmological ideas the unconditioned in the chain of causality, so as not to contradict itself)- I mean the faculty of freedom. The moral law, which itself does not require a justification, proves not merely the possibility of freedom, but that it really belongs to beings who recognize this law as binding on themselves. The moral law is in fact a law of the causality of free agents and, therefore, of the possibility of a supersensible system of nature, just as the metaphysical law of events in the world of sense was a law of causality of the sensible system of nature; and it therefore determines what speculative philosophy was compelled to leave undetermined, namely, the law for a causality, the concept of which in the latter was only negative; and therefore for the first time gives this concept objective reality.

This sort of credential of the moral law, viz., that it is set forth as a principle of the deduction of freedom, which is a causality of pure reason, is a sufficient substitute for all a priori justification, since theoretic reason was compelled to assume at least the possibility of freedom, in order to satisfy a want of its own. For the moral law proves its reality, so as even to satisfy the critique of the speculative reason, by the fact that it adds a positive definition to a causality previously conceived only negatively, the possibility of which was incomprehensible to speculative reason, which yet was compelled to suppose it. For it adds the notion of a reason that directly determines the will (by imposing on its maxims the condition of a universal legislative form); and thus it is able for the first time to give objective, though only practical, reality to reason, which always became transcendent when it sought to proceed speculatively with its ideas. It thus changes the transcendent use of reason into an immanent use (so that reason is itself, by means of ideas, an efficient cause in the field of experience).

The determination of the causality of beings in the world of sense, as such, can never be unconditioned; and yet for every series of conditions there must be something unconditioned, and therefore there must be a causality which is determined wholly by itself. Hence, the idea of freedom as a faculty of absolute spontaneity was not found to be a want but, as far as its possibility is concerned, an analytic principle of pure speculative reason. But as it is absolutely impossible to find in experience any example in accordance with this idea,