INTRODUCTION
Kant claimed that he was 'awakened from his dogmatic slumbers' by Hume's criticism of the concept of cause and effect. However, as Bertrand Russell points out, the awakening was only temporary, and he soon invented a soporific which enabled him to sleep again.
In Kant's view Pure Reason teaches that human knowledge is based on experience; but Practical Reason recognizes that there are a priori in the mind certain notions independent of experience and postulating the ideas of human liberty, God and immortality. So, while distinguishing the provinces of materialism and idealism, he attempted to find a bond of union between them.
Published in 1788, the Critique of Practical Reason forms the central focus of Kant's thinking. It stands midway between the Critique of Pure Reason and the Critique of Judgement. Here Kant figures as a vindicator of the truth of Christianity, approaching his proof by first establishing positive affirmations of the immortality of the soul and the existence of God. It includes an argument concerning the summum bonum of life, the special aim being to demonstrate that man should not simply seek to be happy, but should, by absolute obedience to the moral law, seek to become worthy of that happiness which God can bestow.

ABOUT THIS SQUASHED VERSION
The previous translators and editors of Kant's Pure Reason have been universally scathing of the style of this strong contender for the title of 'worst written book ever'. 'Wearisome' 'repetetive' 'clumsy' are among the kinder descriptions. JMD Mieklejohn explains how "He wearies by frequent repetition, and employs a great number of words to express, in the clumsiest way, what could have been enounced more clearly and distinctly with a few". It is that clear enouncement with a few words that is aimed for in this condensed version, largely based on the abridgement first published by Sir John Hammeron at the beginning of the twentieth century. It may well have succeeded, but, to be honest, Kant being Kant, it is rather difficult to tell.

The Critique of Pure Reason
by Immanuel Kant, 1781
This edition edited by Glyn Hughes © 2002

I--KNOWLEDGE TRANSCENDENTAL: AESTHETIC

EXPERIENCE is something of which we are conscious. It is the first result of our comprehension, but it is not the limit of our understanding, since it stimulates our faculty of reason, but does not satisfy its desire for knowledge.

While all our knowledge may begin with sensible impressions or experience there is an element in it which does not rise from this source, but transcends it. That knowledge is transcendental which is occupied not so much with mere outward objects as with our manner of knowing those objects, that is to say, with a priori concepts of them.

All our knowledge is either a priori or a posteriori. That is a posteriori knowledge which is derived from sensible experience as including sensible impressions or states; while a priori knowledge is that which is not thus gained, but consists of whatever is universal or necessary.

A complete Transcendental Philosophy would be a systematic exposition of all that is a priori in human knowledge, or of 'all the principles of pure reason.' But a Critique of Pure Reason cannot include all this. It can do little more than deal with the synthetic element or quality in a priori knowledge, as distinguished from the analytic elements.

We perceive objects through our sensibility which furnishes us, as our faculty of receptivity, with those intuitions that become translated into thought by means of the understanding. This is the origin of our conceptions, or ideas. I denominate as matter that which in a phenomenon corresponds to sensation; while I call form that quality of matter which presents it in a perceived order. Only matter is presented to our minds a posteriori; as to form, this must inevitably exist in the mind a priori, and therefore it can be considered apart from all sensation.

Pure representation, entirely apart from sensation, in a transcendental signification, forms the pure intuition of the mind, existing in it as a mere form of sensibility. 'Transcendental aesthetic' is the science of all the principles of sensibility. But transcendental logic is the science of the principles of pure thought. In studying the former we shall find that there are two pure forms of sensuous intuition, namely, space and time.

Are space and time actual entities? Or are they only relations of things? Space is simply the form of all the phenomena of external senses; that is, it is the subjective condition of the sensibility under which alone external intuition is possible. Thus the form of all phenomena may exist a priori in the soul as a pure intuition previous to all experience. So we can only speak of space and of extended objects from the standpoint of human reason. But when we have abstracted all the forms perceived by our sensibility, there remains a pure intuition which we call space. Therefore our discussion teaches us the objective validity of space with regard to all that can appear before us externally as an object; but equally the subjective ideality of space with regard to things if they are considered in themselves by our reason, that is, without taking into account the nature of our sensibility.

Time is not empirically conceived of; that is, it is not experimentally apprehended. Time is a necessary representation on which all intuitions are dependent, and the representation of time to the mind is thus given a priori. In it alone can phenomena be apprehended. These may vanish, but time cannot be put aside.

Time is not something existing by itself independently, but is the formal condition a priori of all phenomena. If we deduct our own peculiar sensibility, then the idea of time disappears indeed, because it is not inherent in any object, but only in the subject which perceives that object. Space and time are essential a priori ideas, and they are the necessary conditions of all particular perceptions. From the latter and their objects we can, in imagination without exception, abstract; from the former we cannot.

Space and time are therefore to be regarded as the necessary a priori pre- conditions of the possibility and reality of all phenomena. It is clear that 'transcendental aesthetic' can obtain only these two elements, space and time, because all other concepts belong to the senses and pre-suppose experience, and so imply something empirical. For example, the concept of motion pre-supposes something moving, but in space regarded alone there is nothing that moves; therefore, whatever moves must be recognized by experience, and is a purely empirical datum.

II--TRANSCENDENTAL LOGIC

OUR knowledge is derived from two fundamental sources of the consciousness. The first is the faculty of receptivity of impressions; the second, the faculty of cognition of an object by means of these impressions or representations, this second power being sometimes styled spontaneity of concepts. By the first, an object is given to us; by the second it is thought of in the mind. Thus intuition and concepts constitute the elements of our entire knowledge, for neither intuition without concepts, nor concepts without intuition can yield any knowledge whatever. Hence arise two branches of science, 'aesthetic' and logic, the former being the science of the rules of sensibility; the latter, the science of the rules of understanding.

Logic can be treated in two directions; either as logic of the general use of the understanding, or of some particular use of it. The former includes the rules of thought, without which there can be no use of the understanding; but it has no regard to the objects to which the understanding is applied. This is elementary logic. But logic of the understanding in some particular use includes rules of correct thought in relation to special classes of objects; and this latter logic is generally taught in schools as preliminary to the study of sciences.

Thus, general logic takes no account of any of the contents of knowledge, but is limited simply to the consideration of the forms of thought. But we are constrained by anticipation to form an idea of a logical science which has to deal not only with pure thought, but also has to determine the origin, validity and extent of the knowledge to which intuitions relate, and this might be styled transcendental logic.

In 'transcendental aesthetic' we isolated the faculty of sensibility. So in transcendental logic we isolate the understanding, concentrating our consideration on that element of thought which has its source simply in the understanding. But transcendental logic must be divided into transcendental analytic and transcendental dialectic. The former is a logic of truth, and is intended to furnish a canon of criticism. When logic is used to judge not analytically, but to judge synthetically of objects in general, it is called transcendental dialectic, which serves as a protection against sophistical fallacy.

Analytic of Pure Concepts

The understanding may be defined as the faculty of judging. The function of thought in a judgement can come under four heads, each with three subdivisions.

1 Quantity of judgements:
Universal, particular, singular.

4 Modality
Problematical, assertory, apodictic (above contradiction).

If we examine each of these forms of judgement we discover that in every one is involved some peculiar idea which is its essential characteristic. Thus, a singular judgement, in which the subject of discourse is a single object, involves obviously the special idea of oneness, or unity. A particular judgement, relating to several objects, implies the idea of plurality, and discriminates between the several objects. Now the whole list of these ideas will constitute the complete classification of the fundamental conceptions of the understanding, regarded as the faculty which judges, and these may be called categories.

TABLE OF THE CATEGORIES

3 Of Relation
Substance and accident
Cause and effect
Action and reaction.

4 Of Modality
Possibility – impossibility
Existence - non – existence
Necessity - contingence

These, then, are the fundamental, primary, or native conceptions of the understanding, which flow from, or constitute the mechanism of, its nature; are inseparable from its activity; and are hence for human thought, universal and necessary, or a priori. These categories are 'pure' conceptions of the understanding, inasmuch as they are independent of all that is contingent in sense.

Transcendental Dialectic

A distinction is usually made between what is immediately known and what is only inferred. In every syllogism is first a fundamental proposition; secondly, another deduced from it; and, thirdly, the consequence.

In the use of pure reason its concepts, or transcendental ideas aim at unity of all conditions of thought. So all transcendental ideas may be arranged in three classes; the first containing the unity of the thinking subject; the second, the unity of the conditions of phenomena observed; the third, the unity of the objective conditions of thought.

This classification becomes clear if we note that the thinking subject is the object-matter of psychology; while the system of all phenomena (the world) is the object-matter of cosmology; and the Being of all Beings (God) is the object- matter of theology.

Hence we perceive that pure reason supplies three transcendental ideas, namely, the idea of a transcendental science of the soul (psychologia rationalis); of a transcendental science of the world (cosmologia rationalis); and, lastly, of a transcendental science of God (theologia transcendentalis). It is the glory of transcendental idealism that by it the mind ascends in the series of conditions till it reaches the unconditioned, that is, the principles. We thus progress from our knowledge of self to a knowledge of the world, and through it to a knowledge of the Supreme Being.

III--THE ANTINOMIES OF PURE REASON

TRANSCENDENTAL reason attempts to reconcile conflicting assertions. There are four of these antinomies, or conflicts.

FIRST ANTINOMY.

SECOND ANTINOMY.

THIRD ANTINOMY.

FOURTH ANTINOMY.

The theses in these four antinomies constitute the teaching of philosophical dogmatism. The antitheses constitute doctrines of philosophical empiricism.

IV--CRITICISM OF THE CHIEF ARGUMENTS FOR THE EXISTENCE OF GOD

THE ontological argument aims at asserting the possibility of conceiving the idea of an ens realissimum, of being possessed of all reality. But the idea of existence and the fact of existence are two very different things. Whatever I conceive, or sensibly imagine, I necessarily conceive as though it were existing. Though my pocket be empty, I may conceive it to contain a 'hundred thalers.' If I conceive them there, I can only conceive them as actually existing there. But, alas, the fact that I am under this necessity of so conceiving by no means carries with it a necessity that the coins should really be in my pocket. That can only be determined by experience.

The cosmological argument contends that if anything exists, there must also exist an absolutely necessary being. Now, at least I myself exist. Hence there exists an absolutely necessary being. The argument coincides with that by which the thesis of the fourth antinomy is supposed. The objections to it are summed up in the proof of the antithesis of the fourth antinomy. As soon as we have recognized the true conception of causality, we have already transcended the sensible world.

The physico-theological or teleological argument is what is often styled the argument from design. It proceeds not from general, but particular experience. Nature discloses manifold signs of wise intention and harmonious order, and these are held to betoken a divine designer. This argument deserves always to be treated with respect. It is the oldest and clearest of all proofs, and best adapted to convince the reason of the mass of mankind. It animates us in our study of nature. And it were not only a cheerless, but an altogether vain task to attempt to detract from the persuasive authority of this proof. There is naught to urge against its rationality and its utility.

All arguments, however, to prove the existence of God must, in order to be theoretically valid, start from specifically and exclusively sensible or phenomenal data, must employ only the conceptions of pure physical science, and must end with demonstrating in sensible experience an object congruous with, or corresponding to, the idea of God. But this requirement cannot be met, for, scientifically speaking, the existence of an absolutely necessary God cannot be either proved or disproved. Hence room is left for faith in any moral proofs that may present themselves to us, apart from science. With this subject ethics, the science of practice or of practical reason, will have to deal.

The Critique of Practical Reason
by Immanuel Kant, 1788
Edited by Glyn Hughes © 2002

I--ANALYTIC OF PRACTICAL REASON

PRACTICAL principles are propositions containing a general determination of the will. They are maxims, or subjective propositions, when expressing the will of an individual; objective, when they are valid expressions of the will of rational beings generally.

Practical principles which presuppose an object of desire are empirical, or experimental, and supply no practical laws. Reason, in the scope of a practical law, influences the will not by the medium of pleasure or pain. All rational beings necessarily wish for happiness, but they are not all agreed either as to the means to attain it, or as to the objects of their enjoyment of it. To discover any law which would bring all men into harmony is absolutely impossible.

One of the problems of practical reason is to find the law which can necessarily determine the will, assuming that the will is free. The solution of this problem is to be found in action according to the moral law. We should so act that the maxim of our will can always be valid as a principle of universal legislation. Experience shows how the moral consciousness determines freedom of the will.

Suppose that someone affirms of his inclination for sensual pleasure that he cannot possibly resist temptation to indulgence. If a gallows were erected at the place where he is tempted on which he should be hanged immediately after satiating his passions, would he not be able to control his inclination? We need not long doubt what would be his answer.

But ask him, if his sovereign commanded him to bear false witness against an honourable man, under penalty of death, whether he would hold it possible to conquer his love of life. He might not venture to say what he would choose, but he would certainly admit that it is possible to make choice. Thus, he judges that he can choose to do a thing because he is conscious of moral obligation, and he thus recognizes for himself a freedom of will of which, but for the moral law, he would never have been conscious.

We obtain the exact opposite of the principle of morality if we adopt the principle of personal private happiness as the determining motive of the will. This contradiction is not only logical, but also practical. For morality would be totally destroyed were not the voice of reason as clear and penetrating in relation to the will, even to the most ordinary men.

If one of your friends, after bearing false witness against you, attempted to justify his base conduct by enumerating the advantages which he had thus secured for himself and by declaring that thus he performed a true human duty, you would either laugh him to scorn or turn from him in horror. And yet, if a man acts for his own selfish ends, you have not the slightest objection to such behaviour.

Morality and Happiness

THE maxim of self love simply advises; the law of morality commands. There is a vast difference between what we are advised and what we are obliged to do. No practical laws can be based on the principle of happiness, even on that of universal happiness, for the knowledge of this happiness rests on merely empirical or experimental data, every man's ideas of it being conditioned only on his individual opinion. Therefore, this principle of happiness cannot prescribe rules for all rational beings.

But the moral law demands prompt obedience from everyone, and thus even the most ordinary intelligence can discern what should be done. Everyone has power to comply with the dictates of morality, but even with regard to any single aim it is not easy to satisfy the vague precept of happiness. Nothing could be more absurd than a command that everyone should make himself happy, for one never commands anyone to do what he inevitably wishes to do. Finally, in the idea of our practical reason, there is something which accompanies the violation of a moral law--namely, its demerit, with the consciousness that punishment is a natural consequence. Therefore, punishment should be connected in the idea of practical reason with crime, by the principles of moral legislation.

Analysis of Principles

THE practical material principles of determination constituting the basis of morality may be thus classified.

1. SUBJECTIVE.--External: Education; the civil constitution. Internal: Physical feeling; moral feeling.
2. OBJECTIVE.--Internal: Perfection. External: Will of God.

The subjective elements are all experimental, or empirical, and cannot supply the universal principle of morality, though they are expounded in that sense by such writers as Montaigne, Mandeville, Epicurus and Hutcheson.

But the objective elements, as enunciated and expounded by Wolf and the Stoics, and by Crusius and other theological moralists, are founded on reason, for absolute perfection as a quality of things (that is, God Himself) can only be thought of by rational concepts.

The concept of perfection in a practical sense is the adequacy of a thing for various ends. As a human quality (and so internal) this is simply talent, and what completes it is skill. But supreme perfection in substance, that is, God Himself, and therefore external (considered practically), is the adequacy of this being for all purposes. All the principles above classified are material, and so can never furnish the supreme moral law. For even the Divine will can supply a motive in the human mind because of the expectation of happiness from it.

Therefore, the formal practical principle of the pure reason insists that the mere form of a universal legislation must constitute the ultimate determining principle of the will. Here is the only possible practical principle which is sufficient to furnish categorical imperatives, that is, practical laws which make action a duty.

It follows from this analytic that pure reason cannot be practical. It can determine the will independently of all merely experimental elements.

There is a remarkable contrast between the working of the pure speculative reason and that of the pure practical reason. In the former--as was shown in the treatise on that subject--a pure, sensible intuition of time and space made knowledge possible, though knowledge only of objects of the senses.

On the contrary, the moral law brings before us a fact absolutely inexplicable from any of the data of the world of sense. And the entire range of our theoretical use of reason indicates a pure world of understanding, which even positively determines it, and enables us to know something of it--namely, a law.

We must observe the distinction between the laws of a system of nature to which the will is subject, and of a system of nature which is subject to the will. In the former, the objects cause the ideas which determine the will; in the latter, the objects are caused by the will. Hence, causality of the will has its determining principle exclusively in the faculty of pure reason, which may, therefore, also be called a pure practical reason.

The moral law is a law of the causality through freedom, and therefore of the possibility of a super-sensible system of nature. It determines the will by imposing on its maxim the condition of a universal legislative form, and thus it is able for the first time to impart practical reality to reason, which otherwise would continue to be transcendent when seeking to proceed speculatively with its ideas.

Thus the moral law induces a stupendous change. It changes the transcendent use of reason into the immanent use. And in result reason itself becomes, by its ideas, an efficient cause in the field of experience.

Hume and Scepticism

IT may be said of David Hume that he initiated the attack on pure reason. My own labours in the investigation of this subject were occasioned by his sceptical teaching. He argued that without experience it is impossible to know the difference between one thing in itself and another; that is, we cannot know a priori, and, therefore, the notion of a cause is fictitious and illusory, arising only from the habit of observing certain things associated with each in a succession of connexions.

On such principles we can never come to any conclusion as to causes and effects. We can never predict a consequence from any of the known attributes of things. We can never say of any event that it must necessarily have followed from another; that is, that it must have had an antecedent cause. And we could never lay down a rule derived even from the greatest number of observations. Hence we must trust entirely to blind chance, abolishing all reason, and such a surrender establishes empiricism in an impregnable citadel.

Mathematics escaped Hume, because he considered that its propositions were analytical, proceeding from one determination to another, by reason of identity contained in each. But this is not really so, for, on the contrary, they are synthetical, the results depending ultimately on the assent of observers as witnesses to the universality of propositions.

My investigations led me to the conclusion that the objects with which we are familiar are by no means things in themselves, but are simply phenomena, connected in a certain way with experience. So that without contradiction they cannot be separated from that connexion. Only by that experience can they be recognized. I was able to prove the objective reality of the concept of cause in regard to objects of experience, and to demonstrate its origin from pure understanding, without experimental or empirical sources.

Thus, I first destroyed the source of scepticism, and then the resulting scepticism itself. And thus was subverted the thorough doubt as to whatever theoretic reason claims to perceive, as well as the claim of Hume that the concept of causality involved something absolutely unthinkable.

Good and Evil

BY a concept of practical reason, I understand the representation to the mind of an object as an effect possible to be produced through freedom. The only objects of practical reason are good and evil. For by 'good' we understand an object necessarily desired and by 'evil' one necessarily abhorred, reason actuating the mind in each case.

In the common use of language we uniformly distinguish between the 'good' and the 'pleasant,' the 'evil' and the 'unpleasant,' good and evil being judged by reason alone. The judgement on the relation of means to ends certainly belongs to reason. But 'good' or 'evil' always implies only a reference to the 'will,' as resolved by the law of reason, to make something its object.

Thus good and evil properly relate to actions, not to personal sensations. Hence, only the maxim of the will, and consequently the person himself, can be called good or evil, not the thing itself.

The Stoic was right, even though he might be laughed at, who during violent attacks of gout exclaimed, 'Pain, I will never admit that thou art an evil!' What he felt was indeed what we call a bad thing; but he had no reason to admit that any evil attached thereby to himself, for the pain did not in the least detract from his personal worth, but only from that of his condition. If a single lie had been on his conscience it would have humiliated his soul; but pain seemed only to elevate it, when he was not conscious of having deserved it as a punishment for any unjust deed.

The rule of judgement subject to the laws of pure practical reason is this: Ask yourself whether if the action you propose were to happen by a natural system of law, of which you were yourself a part, you could regard it as possible by your own will? In fact, everyone does decide by this rule whether actions are morally good or evil.

II--DIALECTIC OF PRACTICAL REASON

The Immortality of the Soul

PURE practical reason postulates the immortality of the soul, for reason in the pure and practical sense aims at the perfect good (summum bonum), and this perfect good is only possible on the supposition of the soul's immortality. It is the moral law which determines the will, and in his will the perfect harmony of the mind with the moral law is the supreme condition of the summum bonum.

The principle of the moral destination of our nature--that only by endless progress can we come into full harmony with the moral law--is of the greatest use, not only for fortifying the speculative reason, but also with respect to religion. In default of this, either the moral law is degraded from its holiness, being represented as indulging our convenience, or else men strain after an unattainable aim, hoping to gain absolute holiness of will, thus losing themselves in fanatical theosophic dreams utterly contradicting self-knowledge.

For a rational, but finite, being the only possibility is an endless progression from the lower to the higher degrees of perfection. The Infinite Being, to whom the time condition is nothing, sees in this endless succession the perfect harmony with the moral law.

The Existence of God

THE pure practical reason must also postulate the existence of God as the necessary condition of the attainment of the summum bonum. As the perfect good can only be promoted by accordance of the will with the moral law, so also this summum bonum is possible only through the supremacy of an Infinite Being possessed of causality harmonising with morality. But the postulate of the highest derived good (sometimes denominated the best world) coincides with the postulate of a highest original good, or of the existence of God.

We now perceive why the Greeks could never solve their problem of the possibility of the summum bonum, because they made the freedom of the human will the only and all-sufficient ground of happiness, imagining there was no need for the existence of God for that end. Christianity alone affords an idea of the summum bonum which answers fully to the requirement of practical reason. That idea is the Kingdom of God.

The holiness which the Christian law requires makes essential an infinite progress. But just for that very reason it justifies in man the hope of endless existence. And it is only from an Infinite Supreme Being, morally perfect, holy, good and with an omnipotent will, that we can hope, by accord with His will, to attain the summum bonum, which the moral law enjoins on us as our duty to seek ever to attain.

The moral law does not enjoin on us to render ourselves happy, but instructs us how to become worthy of happiness. Morality must never be regarded as a doctrine of happiness, or direction how to become happy, its province being to inculcate the rational condition of happiness, not the means of attaining it. God's design in creating the world is not primarily the happiness of the rational beings in it, but the summum bonum, which super-adds another condition to that desire of human beings, namely, the condition of deserving such happiness. That is to say, the morality of rational beings is a condition which alone includes the rule by observing which they can hope to participate in happiness at the hand of an all- wise Creator.

The highest happiness can only be conceived as possible under conditions harmonising with the divine holiness. Thus they are right who make the glory of God the chief end of creation. For beyond all else that can be conceived, that glorifies God which is the most estimable thing in the whole world, honour for His command and obedience to His law, when to this is added His glorious design to crown so beauteous an order of things with happiness corresponding.

Conclusion

TWO things fill the mind with ever new and increasing wonder--the starry heavens above me, and the moral law within me. I need not search for them, and vaguely guess concerning them, as if they were veiled in darkness or hidden in the infinite altitude. I see them before me, and link them immediately with the consciousness of my existence. The former begins from the spot I occupy in the outer world of sense, and enlarges my connexion with it to a boundless extent with worlds upon worlds and systems of systems.

The second begins with my invisible self, my personality, and places me in a truly infinite world traceable only by the understanding, with which I perceive I am in an universal and necessary connexion, as I am also thereby with all those visible worlds.

This view infinitely elevates my value as an intelligence by my personality, in which the moral law reveals to me a life independent of the animal and even the whole material world, and reaching by destiny into the infinite.

But though admiration may stimulate inquiry, it cannot compensate for the want of it. The contemplation of the world, beginning with the most magnificent spectacle possible, ended in astrology; and morality, beginning with the noblest attribute of human nature, ended in superstition. But after reason was applied to careful examination of the phenomena of nature a clear and unchangeable insight was secured into the system of the world. We may entertain the hope of a like good result in treating of the moral capacities of our nature by the help of the moral judgement of reason.

Immanuel Kant
1724-1804
Kant's grave in Kaliningrad Cemetery, Kaliningrad, Russia