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History of Philosophy
German Philosophy: Kant
by Turner, William (S.T.D.)

Although the greater part of Kant's life lies within the eighteenth century, his philosophy belongs to the nineteenth. It is from the fundamental principles of his system of thought that the great speculative and practical tendencies of this third period spring. With Kant, therefore, begins the last period in the history of modern philosophy.


Life. Immanuel Kant was born at Königsberg in the year 1724. His parents were, according to family tradition, of Scotch descent. At the age of sixteen he entered the University of Königsberg, and there, for six years studied Wolff's philosophy and Newton's physics, having for teacher Martin Knutzen. On leaving the university he spent nine years as tutor in several distinguished families. He returned to Königsberg in 1755 to qualify himself for the position of licensed but unsalaried teacher (Privatdocent) at the university, a career in which he lingered for fifteen years. His first book, which was published in 1747, under the title Gedanken von der wahren Schätzung der lebendigen Kräfte, "Thoughts on the True Estimation of Living Forces," was followed by several others which treated of physical and metaphysical problems. Meantime he continued to lecture on Wolffian philosophy, employing the text-books then commonly in use, although it is evident from his written works and from the programme of his lectures that he had at this time begun to criticise both Wolff and Newton. The first outline of a definite independent system appears in the dissertation De Mundi Sensibilis atque Intelligibilis Formis et Principiis, which was published in 1770. In the same year Kant was appointed to the chair of philosophy at Königsberg, which he held until 1797. His epoch-making work, the Kritik der reinen Vernunft, appeared in 1781. This was followed by the Grundlegung zur Metaphysik der Sitten (1785), the Kritik der praktischen Vernunft (1788), the Kritik der Urtheilskraft (1790), and the Religion innerhalb der Grenzen der blossen Vernunft (1794). The last of these works provoked the hostility of the orthodox, and was the occasion of a reprimand from the government of East Prussia.

Kant spent the greater part of his life as professor at Königsberg. He never traveled, and had no appreciation of art; he was, however, thoroughly in sympathy with Nature in all her moods, professing unbounded admiration for "the starry sky above him and the moral law within him." He died in 1804.

Sources. The three Critiques -- the Critique of Pure Reason (the argument of which is presented in shorter and more readable form in the Prolegomena to any Future Metaphysic), the Critique of Practical Reason, and the Critique of the Faculty of Judgment -- form a trilogy of Kantian literature. Kant's complete works were published at various times, the best editions being Hartenstein's second edition, in eight volumes (Leipzig, 1867-1869), and Rosenkranz and Schubert's edition, in twelve volumes (Leipzig, 1838-1842). A new edition is being published by the Berlin Academy of Sciences. The Critique of Pure Reason was translated into English by Meiklejohn (London, 1854) and by Max Müller (London, 1881); the Prolegomena, by Mahaffy and Bernard (London, 1889); the Critique of Practical Reason, by Abbott (London, 1889); and the Critique of Judgment, by Bernard (London, 1892). To the list of secondary sources [2] must be added M. Ruyssen's Kant (Grands Philosophes series, Paris, 1900) and Paulsen's Kant (trans. by Creighton and Lefevre, New York, 1902). Wallace's Kant (Blackwood's Philosophical Classics, Edinburgh and Philadelphia, 1892) and E. Caird's Critical Philosophy of Kant (London, 1889) are the best English presentations of Kant's system. [3]
[2] Cf. Falckenberg's list, op. cit., p. 269 (English trans., p. 330). The works of Adickes, B. Erdmann, and Vaihinger are of specral importance.

[3] Consult also T. H. Green, Lectures on the Philosophy of Kant (in Works, Vol. II); Adamson, The Philosophy of Kant (Edinburgh, 1879); Watson, Kant and his English Critics (London, 1888); article on Kant in Encyc. Brit., etc.

General Standpoint and Aim. In the introduction to the Prolegomena, Kant informs us of the origin and aim of his philosophical investigations. "It was," he observes, "the suggestion of David Hume which first interrupted my dogmatic slumber and gave my investigations in the field of speculative philosophy quite a new direction. I first tried whether Hume's objection could not be put into a general form, and soon found that the concept of the connexion of cause and effect was by no means the only one by which the understanding thinks the connexion of things a priori. I sought to make certain of the number of such connexions, and when I had succeeded in this, by starting from a single principle, I proceeded to the deduction of these concepts which I was now certain were not deduced from experience, as Hume had apprehended, but sprang from the pure understanding." [4] If, therefore, we divide systems of philosophy into rational and empirical, according as they lay stress on the a priori concepts and principles of the pure understanding, or on the a posteriori impressions and associations of the empirical faculties, we may describe Kant as dissatisfied with the rational philosophy because it exaggerated the a priori, and with the empirical philosophy because it exaggerated the a posteriori elements of knowledge. Consequently he sets himself the task of examining or criticising all knowledge for the purpose of determining or, as he says, "deducing," the a priori concepts or forms of thought. And if it is the task of philosophy to answer the questions, What can I know? What ought I to do? What may I hope for? Kant considers that the answers to the second and third questions depend on the answer given to the first. His philosophy is, therefore, a transcendental criticism, [5] that is, an examination of knowledge for the purpose of determining the a priori elements, which are the conditions of knowledge, and which we cannot know by mere experience.
[4] Mahaffy's translation, p. 7.

[5] Falckenberg, op. cit., p. 277 (English trans., p. 340), explains that, although Kant at different times attaches different meanings to the word transcendental, he always uses it as opposed to empirical. cf. Dictionary of Philosophy and Psychology (ed. Baldwin), article, "Kant's Terminology," Nos. 12 and 13.
Division of Philosophy. Kant, as is well known, first devoted his attention to the transcendental criticism of pure reason, and afterwards took up the transcendental criticism of practical reason. In the first part of the Critique of Pure Reason he distinguishes the transcendental aesthetic and the transcendental logic, and subdivides the latter into transcendental analytic and transcendental dialectic.

Transcendental AEsthetic is defined as the "science of all the principles of sensibility a priori," [6] or the inquiry into the a priori conditions of sensation. Now, our external senses represent their objects as extended in space, and our internal senses represent our conscious states as succeeding each other in time. Space and time are the a priori conditions of external and internal sensation, -- conditions or forms which make sensation possible. They are, therefore, anterior to all experience. Space and time are not, as is commonly supposed, empirical concepts derived from experience; their a priori character appears from the very fact that knowledge based on the nature of space and time (mathematical knowledge) is necessary and universal; for it is a primary postulate of all Kant's transcendental inquiry that nothing which is necessary and universal can come from experience. Space and time are not properties of things; they belong to the subject, inhere in the subject, and are, so to speak, part of the subjective world. Tbeir rôle is to reduce the multiplicity of the object to that unity which is an essential condition of being perceived by the subject, which is one. They are the conditions of sensitive intuition, and have no objective reality, except in so far as they are applied to real things in the act of perception. "Space and time are the pure forms of our intuition, while sensation forms its matter." [7]
[6] Critigue of Pure Reason, p. 17. References are to Max Müller's translation.

[7] Op. cit., p. 34.
Transcendental Logic. General logic treats either of the pure forms of thought, or of these forms in their relation to concrete experience (applied logic). Transcendental logic treats of the origin, extent, and validity of concepts, which are neither of empirical nor of aesthetic origin, but are a priori. It is divided into transcendental analytic and transcendental dialectic: the first treats of the forms of the pure understanding (judgment), while the second treats of the elements of that knowledge which is pure understanding applied to objects given in intuition; and as this application is made by the reason, we may describe transcendental dialectic as the criticism of reason in the stricter sense of the word. [8]
[8] Cf. op. cit., pp. 42-50.
A. Transcendental Analytic. The a priori forms of the pure understanding are the categories, which stand to intellectual knowledge in the relation in which space and time stand to sense-knowledge. It will be well to consider: (a) the existence of the categories; (b) the construction of the table of categories; (c) the nature of the categories; and (d) the objective value of the categories.

a. The existence of the categories. All intuitions being sensuous, and the understanding being a supersensible faculty, it is evident that the concepts which belong to the understanding are not immediately referred to an object, but to some other representation, that is, to an intuition or to another concept. All the acts of the understanding may therefore be reduced to judgments. [9] Now there are judgments which are merely contingent and particular, as, "This table is square"; and there are judgments which are necessary and universal, as, "The sides of a square are equal to one another." But (and this is the fundamental assumption in Kant's Critique) wkat is necessary and universal in our knowledge is a priori. "Therefore, there is in our knowledge of necessary and universal propositions an a priori element, and this is the form, or category.
[9] Op. cit., p. 56.
b. Construction of the table of categories. Kant considers that Aristotle failed to draw up a complete and scientific table of the highest genera because that "acute thinker" did not realize that the right method to be pursued is not the analysis of being, but the analysis of thought. Now, according to Kant, to think is to judge, and to judge is to synthesize, or unite, two representations, namely subject and predicate. But since we are inquiring into the a priori elements of thought we must empty the subject and predicate of all their empirical and intuitional content, and consider merely their relations to each other. On the different kinds of relation which exist between subject and predicate we shall base our construction of the table of categories. These relations Kant reduces to twelve, to which, therefore, correspond the twelve categories:

Kinds of JudgmentCategories
I. Quantity:
II. Quality:
III. Relation:
CategoricalSubsistence and Inherence
HypotheticalCausality and Dependence
DisjunctiveReciprocity (Active and Passive)
IV. Modality:
ProblematicalPossibility -- Impossibility
AssertoryExistence -- Non-Existence
ApodeicticNecessity -- Contingency

It may be observed, in criticism of this system of categories, that an analysis of judgment is not a complete analysis of thought; for the ideas of which the judgment is composed are themselves capable of analysis. Indeed, while the analysis of judgment may be made the basis of a system of predicables, it is on an analysis of ideas that a system of categories must be based. Moreover, it is evident that in the Kantian table of categories, correctness of analysis is sacrificed. to symmetry of arrangement.

c. The nature of the categories. Kant's a priori forms, or categories, are not mere subjective dispositions, mere tendencies such as Leibniz attributed to the psychic monad, -- capabilities to be evolved into actuality in the process of ideation. Nor are they full-fledged ideas such as Plato attributed to the soul in its prenatal existence. they are the empty forms of intellectual knowledge, all the contents of intellectual knowledge being derived from experience.

The nature of the categories is best understood by a study of their function. All knowledge, whether sensuous or intellectual, is conditioned by unity, and is effected by a synthesis of the manifold of representations (sense impressions, etc.). Now, "How," Kant asks, "should we, a priori, have arrived at such a synthetical unity if the subjective grounds of such unity were not contained a priori in the original sources of all our knowledge ? " [10] We have seen that the a priori forms which effect the requisite unity in the case of sense-knowledge are space and time. The function of the categories is entirely similar: to effect the requisite unity in the case of intellectual knowledge, -- to synthesize the manifold of experience. But how is the application of the form to the contents brought about? The a priori forms must be brought down to the empirical contents anteriorly to experience; for they render empirical knowledge possible. Kant is therefore obliged to have recourse to the doctrine of schematism. The schemata are the work of the synthetic imagination, and mediate between the a priori form and the manifold of experience. Thus "the transcendental determination of time (which is the principal schema) is so far homogeneous with the category that it is general and founded on a rule a priori; and it is, on the other hand, so far homogeneous with the phenomenon that time must be contained in every empirical representation of the manifold." [11] From the fundamental schema, which is time, are derived as many schemata as there are categories.
[10] Op. cit., p. 102.

[11] Op. cit., p. 113.
The mental field thickens with the multitude of media through which and by means of which the process of intellectual knowledge takes place. We have, first, the manifold representations of sense-impression; then the application of the forms of space and time resulting in sense-intuition; next, we have the schema, and last of all the a priori form. And yet all this multiplicity is introduced in order to effect the synthetic unity without which knowledge is impossible. The representations are unified by the application of the a priori forms of space and time; the intuitions resulting from this application are in turn unified by the determining schema, which gives reality to the highest unifying form, namely the category. Finally, above all these is the unity of consciousness.

The doctrine of the function of the categories is well summed up in the formula, representations without the categories are blind, the categories without representative or other empirical content are empty. With regard to the schematism of our understanding applied to phenomena and their mere form, it were well, perhaps, to content ourselves with Kant's saying that such schematism is "an art hidden in the depth of the human soul, the true sense of which we shall hardly ever be able to understand." [12]
[12] Op. cit., p. 116.
d. The objective value of the categories. The value of the categories lies in this, that they render synthetic a priori judgments possible and thus make intellectual knowledge possible. In judgments which are merely analytical we remain within the given concept, while predicating something of it; but in judgments which are synthetic we go beyond the concept, in order to bring something together with it which is wholly different from what is contained in it. [13] It is therefore by means of synthetic a priori judgments that we make progress in our intellectual knowledge of reality, and since the categories are the a priori elements of such judgments, -- the elements which confer necessity and universality on them, thereby making them to be scientific, -- it is evident that it is the categories that render intellectual knowledge possible. Without the categories the objects of intellectual knowledge would be given in experience, but not known.
[13] Op. cit., p. 126.
Although the categories are a priori, that is, independent of sensation, they do not extend our knowledge beyond phenomena; they do not lead us to a noumenal knowledge of that which is given in sensation. Of themselves they are empty; in order to be valid they must be filled by experience, and all the content which experience can put into them is phenomenal. "The understanding a priori can never do more than anticipate the form of a possible experience; and, as nothing can be an object of experience except the phenomenon, it follows that the understanding can never go beyond the limits of sensibility. As phenomena are nothing but representations, the understanding refers them to a something as the object of our sensuous intuition. This means a something equal to x, of which we do not, nay, with the present constitution of our understanding can not, know anything." [14] This something is the noumenon, the transcendental object, the thing-in-itself (Ding an sich).
[14] Op. cit., pp. 201 and 204.
B. Transcendental Dialectic, which is the third portion of the Critique of Pure Reason, has for its object the examination or criticism of the ideas. These are forms less general than the categories, elements of reasoning rather than of judgment, serving to unify the manifold of intellectual experience, just as the categories and space and time serve to unify the manifold of sense-representation and impression. Consequently they do not refer immediately to the objects of intuition, but only to the understanding and its judgments. Now, just as the forms of judgment furnished us with a basis for the system of categories, so the forms of inference serve as a basis for the enumeration of ideas. To the three forms of syllogistic reasoning, namely categorical, hypothetical, and disjunctive, correspond the three ideas of the reasoning faculty, namely the idea of the soul, or thinking subject, the idea of matter, or the totality of phenomena, and the idea of God, the supreme condition of all possibility. [15] Reason being immanent, that is, having no direct relation to objects, these three ideas, the psychological, the cosmological, and the theological, should remain immanent. The attempt to establish them as existing outside the mind must necessarily lead to an entanglement of contradictions, and it is the aim of the transcendental dialectic to expose these contradictions and so dispel the transcendental illusion, which has vitiated every system of psychology, cosmology, and theology.
[15] Op. cit., pp. 140 ff.
a. Psychological idea. Kant rejects the rational psychology which attributes to the soul identity, substantiality, immateriality, and immortality. The whole Wolffian and Cartesian system of psychology he considers to be false in its starting point, -- the assumption, namely, that we have an intuitive knowledge of the understanding. We have, he contends, no such intuition. Thought is a succession of unifications, or syntheses: at the apex of the pyramid, the base of which is the manifold representation, stands the conscious principle; but as the conscious principle is devoid of empirical content, it is, like the noumenon, an x, an unknown quantity. Descartes says "I think," but what, Kant asks, is the I? It is the emptiest of all forms, a psychological subject of conscious states, which never can become the logical subject of a predicate referring to these states or to anything else. Empirical psychology, which alone can extend our knowledge of mental life, does not aim at telling us anything about the ego; rational psychology, which does aim at establishing truths concerning the ego, is wrong in its very starting point and is full of contradictions in the course of its development.

Kant, of course, does not deny the unity, substantiality, etc., of the soul; for he contends that reason is as far from being able to disprove as it is from being able to prove these truths, which, as the Critique of Practical Reason will demonstrate, rest ultimately on man's moral consciousness.

b. Cosmological idea. The totality of phenomena, or the world of which the cosmologists speak, presents, according to Kant, difficulties similar to those presented by the psychological idea. To every thesis which is formulated concerning the ultimate nature of matter, may be opposed an equally plausible antithesis. The antinomies, however, as these apparent contradictions are called, do not disprove the formal correctness of the inferential process employed in rational cosmology; they merely show that the cosmical concepts -- matter, cause, etc. -- extend beyond the limits of empirical knowledge and rational experience. The antinomies are four, corresponding to the four classes of categories:
alpha. Thesis: The world must have a beginning in time and be inclosed
in finite space. Antithesis: The world is eternal and infinite. 

beta. Thesis: Matter is ultimately divisible into simple parts (atoms
or monads) incapable of further division. Antithesis. Every material
thing is divisible; there exists nowhere in the world anything simple. 

gamma. Thesis: Besides the causality which is according to the laws of
nature and, therefore, necessary, there is causality which is free.
Antithesis: There is no freedom; everything in the world takes place
entirely according to the laws of nature. 

delta. Thesis: There exists an absolutely necessary Being belonging to
the world, either as a part or as a cause of it. Antithesis. There
nowhere exists an absolutely necessary Being, either within or without
the world.
It is only in the case of the first two antinomies that Kant considers both the thesis and antithesis to be false.

c. Theological idea. The idea of God is, according to Kant, the ideal of reason, that is, the expression of the need which reason has of coming to a perfect unity. Kant nowhere denies the objective validity of this idea; he contends, however, as we shall see, that it rests on the moral consciousness, not on any speculative basis. The criticism of the theological idea is, therefore, confined to an examination of the ontological, cosmological, and physico-theological proofs which natural theology brings forward to establish the thesis that God exists.

The ontological proof, which was formulated successively by St. Anselm, Descartes, and Leibniz, deduces the existence of God from the concept which we are able to form of Him. Kant points out the impossibility of arguing from the idea of a thing to the existence of that thing. Existence, he observes, is not a quality or attribute of the same nature as goodness or greatness: it adds nothing to the content of the idea. "A hundred real thalers contain no more, as to concept, than a hundred possible ones." Besides, all existential propositions are synthetical, because existence is not a quality of an idea, but a relation between the idea and experience. Therefore an existential proposition cannot be demonstrated from a concept without reference to experience.

The cosmological proof argues from the existence of contingent being to the existence of necessary Being. Kant criticises the argument from the view point of his own theory of cognition. Since the axiom of causality, on which the argument rests, is a synthetic judgment, it cannot be applied beyond the limits of experience. "The principle of causality has no meaning and no criterion for its use beyond the world of sense, while here it is meant to help us beyond the world of sense." [16]
[16] Op. cit., p. 491.
The physico-theological argument is that which is commonly called the argument from the purposiveness or design which is evident in the order of nature. Now, order and design "may prove the contingency of the form but not of the matter"; they may prove that there is a designer, but not that there is a creator, of the universe. Kant wishes to "commend and encourage" the use of such a line of reasoning, but he maintains that "it cannot by itself alone establish the existence of a Supreme Being." [17]
[17] Op. cit., p. 503.
The conclusion of the transcendental dialectic is, therefore, that the ideas do not add to our experience. Speculative philosophy does not add to our knowledge of the soul, the world, and God. Nevertheless, these ideas, although they do not constitute experience, regulate it, so that we cannot better order the faculties of the soul than by acting as if there were a soul; neither can we better order our experience of the external world than by representing it as made up of a multiplicity of created things, each of which stands to the rest of reality in reciprocal relation necessitated by law, and all of which spring from a common ground of unity and are ruled by the same guiding principle. Moreover, the criticism of the ideas shows that, while speculative philosophy is unable to establish the existence of God, the immortality of the soul, and the freedom of the will, materialism, fatalism, and atheism are equally unable to overthrow our belief in the truth of these doctrines. The ideas therefore clear the way for a rational faith founded on the moral consciousness.

Before we come to the constructive portion of Kant's philosophy as contained in the Critique of Practical Reason, we may here sum up the results of his destructive criticism of speculative philosophy and of theoretical knowledge in general. There is no transcendent knowledge, -- no knowledge beyond the limits of experience. In our knowledge of the empirical world there is, however, a transcendental element, -- the a priori forms of sensation, the categories and the regulative ideas, which make empirical knowledge possible, although they do not add to it either in content or in extension. The moral consciousness alone takes us beyond experience to the immutable, eternal, and universally valid ground on which all higher truth rests.

Critique of Practical Reason. When we pass from the Critique of Pure Reason to the Critique of Practical Reason, from the study of what is, or must be, to the study of what ought to be, from the inquiry into the conditions of possible theoretical experience to the inquiry into the conditions of actual moral experience, from the analysis of thought to the analysis of action, we find ourselves in an altogether new atmosphere. The second Critique discovers in the obligation of the moral law the aliquid inconcussibile, which, as the first Critique taught us, is not to be found in rational speculation; and thus are restored the existence of God, the immortality of the soul, and the freedom of the will, which in the first Critique were relegated to the rank of mere regulative formulas.

Kant's emphatic assertion of the supremacy of the moral law is well known. The starry heaven above us and the moral law within us are, he was accustomed to say, the only objects worthy of supreme admiration. But on what is the moral law founded? Consciousness tells me that I ought to perform certain actions, and a little thought suffices to convince me that the oughtness is universal and necessary. If I analyze, for example, the sense of obligation in the negative principle, Lie not, I find that, apart from the question of motive or utility, which are contingent determinants, it is a principle valid throughout all time and space. Now it is these properties, necessity and universality, that will enable us to answer the question, On what is the moral law founded?

It is necessary, however, to remark that, according to Kant, the universality and necessity affect the form, not the contents, of the moral law, so that in the example just mentioned the universality of the prohibition, Lie not, is derived from the general formula, into which all obligation is translatable, -- So act that you can will that the maxim on which your conduct rests should become a universal law. [18] More simply, the maxim on which your conduct rests must be fit to be an element of universal legislation.
[18] Grundlegung zur Metaphysik der Sitten, 2. Abschn., Werke (ed. Kirchmann), III, 44; also Kritik der Praktiscken Vernunft, No. 7, Werke, II, 35.
The moral law is not founded on pleasure; for nothing is more unstable than feeling, which is the determinant of pleasure, whereas the moral law, because of its universality and necessity, must rest on an unchangeable foundation. It is not founded on happiness; for the essential characteristic of the moral law is its obligatoriness, and no one is obliged to be happy. It is not founded on a moral sense; for mere sense cannot represent obligation as necessary and universal. Finally, it is not founded on perfection of self; for perfection is, in final analysis, reducible to pleasure or happiness.

The moral law is its own foundation; it is autonomous, being neither imposed by any external motive, nor deduced by the purely speculative reason from theoretical principles, but being impressed on the will by the practical reason [19] and revealed to us by immediate consciousness. Thus it stands on a basis firmer than that which theoretical knowledge can furnish, and it remains unaffected by the contention and clamor of metaphysical discussion.
[19] Falckenberg, op. cit., p. 316 (English trans., p. 388), calls attention to Kant's identification of will with practical reason.
The moral law is imperative: consciousness reveals it to us as commanding, not merely as persuading or advising. Its command may be categorical, as, Thou shalt not lie! or hypothetical, as, If you wish to become a clergyman you must study theology. The categorical imperative is, however, the characteristic expression of the moral law, and it is only in the authoritative though "hollow" voice of the universal categorical imperative, So act, etc., that the moral law speaks with all the authority of a universal and necessary moral determinant.

The moral law is the form which imparts to the contents of an action its goodness. The contents may be good relatively; the will, which is the form, is an absolute good. "Nothing," Kant observes, "can be called good without qualification except a good will." Effects and circumstances are not, therefore, of themselves, determinants of moral value: the sense of duty is alone praiseworthy. The only moral motive is respect for the moral law. Thus does Kant carry his reverence for the moral law to the extreme of purism, -- the exclusion of all egotistic motive as derogatory to the moral worth of actions.

The moral law is unconditional; in the form of the categorical imperative, its voice is unconditionally authoritative and its command is unconditionally a law of human conduct. It speaks to us immediately, for we are conscious of its commands. Here, then, we have found something which metaphysicians have sought in vain, -- an incontrovertible truth on which the freedom of the will, the existence of God, and the immortality of the soul may be made to rest.

First, the will is free; for the moral law, in saying Thou oughtest, implies that Thou canst. We have no immediate consciousness of freedom, but we have immediate consciousness of the moral law which implies freedom. I can because I ought, and I know that I can because I know that I ought. Freedom is, therefore, the ratio essendi of the moral law, and the moral law is the ratio cognoscendi of freedom. [20]
[20] Cf. Kritik d. Prakt. Vernunft, Werke, II, 132 ff.
Secondly, the moral law postulates the existence of God; for the imperative nature of the moral law implies that there exists somewhere a good which is not only supreme but complete (consummatum), an embodiment, so to speak, of that perfect holiness which is the sum of all the conditions implied in the moral order. Thus, while theonomic ethics supposes the existence of God, autonomic morality proves His existence. [21]
[21] Op. cit., II, 249 ff.
Thirdly, the moral law postulates the immortality of the soul. Theoretical reason, as we have seen, fails to determine in any manner the noumenal reality of the subject of our conscious states; but surely the practical reason, which imposes its law so imperiously, is a noumenal reality, of which its every action is a determination. Thus, the soul is immortal because immortal duration is alone sufficient for the complete fulfillment of the moral law. The highest perfection that we can attain in this life is virtue, and virtue is essentially incomplete: it is a striving towards holiness, with a residual inclination towards unholiness. Since the moral law will always continue with the same unrelenting imperativeness to urge the soul towards holiness, and since the inclination towards unholiness will never be completely overcome, the struggle between the desire to obey and the impulse to transgress the law must continue forever. [22]
[22] Op. cit., II, 146 ff.
The three postulates of the moral law restore, therefore, freedom, immortality, and theistic belief, which find no justifiable basis in the speculative reason. But which are we to believe, the theoretical or the practical reason? Kant does not hesitate to reply: we are to believe the practical reason, for it is supreme. Faith is a rational conviction based on the sense of duty, and is not less but rather more valid than the conviction based on theoretical knowledge.

This is not the place to take up Kant's theory of natural religion. It is sufficient to note that, as the principle enunciated at the end of the preceding paragraph implies, religion, according to Kant, is based on ethics. We come, then, to the third of Kant's philosophical critiques.

Critique of the Faculty of Judgment. The understanding (pure reason) is the faculty of a priori forms and principles of knowledge. Practical reason is the faculty of a priori principles of action. Mediating, as it were, between these is judgment (in the stricter sense of the word), which is the faculty of the a priori forms and principles of aesthetic feeling. In other words, the beautiful, or purposive, which is the object of judgment, is intermediate between the true and the good, which are the objects of pure reason and practical reason respectively. Judgment may be defined as the faculty by which we subsume the particular under the universal (law), or find the universal under which the particular is to be arranged. It refers the manifold to the one, the sensible order to the supersensible principle of design, and since all actualization of design produces in us the sentiment of the beautiful, the faculty of judgment is also concerned with the aesthetic aspect of nature and art. We have, then, as divisions of the critique of judgment, (I) critique of the teleological judgment, and (2) critique of the aesthetic judgment.

A. Critique of the Teleological Judgment. The analytic of the teleological judgment has for its scope to determine the different kinds of adaptation. These, Kant observes, are two, external and internal. External adaptation, such as that of the pine to the soil on which it grows, may be explained by mechanical causes; but internal adaptation, which is found in organic structure and function, cannot be explained by mechanical causes alone. There is in the organism a relation of part to part and of part to the whole, but no causal relation to anything outside the organism; so that the organism is at once cause and effect. We cannot explain organic activity in terms of mechanical causality; we can understand it only on the supposition that organisms act as though they were produced by a cause which had a purpose in view. The teleological concept is, therefore, regulative of our experience.

That the teleological concept is merely regulative, not constitutive, of experience appears from the antinomy, of which Kant treats in the dialectic of the teleological judgment. The antinomy is as follows: Thesis: All productions of material things and their forms may be explained by mechanical causes. Antithesis: Some products of material nature cannot be judged possible unless we suppose a final cause. Now, as doctrines, mechanism (as opposed to teleology) and teleology are irreconcilable; but as rules or maxims regulative of our experience, one is supplementary of the other. [23]
[23] Op. cit., II, 262.
B. Critique of the Aesthetic Judgment. The name judgment applied to the aesthetic faculty is evidence of the purpose of this portion of Kant's philosophy, the purpose, namely, to mediate between the sensationalists, who reduced beauty to mere feeling, and the rationalists, who removed all feeling from the faculty of aesthetic appreciation.

a. In his analytic of the aesthetic judgment, Kant determines that, as to quality, the beautiful is the object of disinterested satisfaction (wherein it differs from the agreeable and the good); with regard to quantity, it pleases universally (wherein it differs from the agreeable) ; with regard to relation, it is not based on concepts (wherein it differs from the good, that being beautiful in which we find the form or design without representing to ourselves any particular design); finally, with regard to modality, its pleases necessarily (wherein again it differs from the agreeable). That, then, is beautiful, which universally and necessarily gives disinterested pleasure without the concept of definite design. The satisfaction which we find in what is perfect is intellectual or conceptual; the satisfaction which the beautiful affords is emotional or aesthetic. [24]
[24] Kritik der Urtheilshraft, Werke, II, 41 ff.
The sublime is that which is great beyond all comparison; it gives satisfaction by its boundless and formless greatness, as the beautiful does by its definiteness of form. This greatness is either extensive in space or time or intensive in force or power. The great produces, it is true, a "humiliating" impression; but it is the sensitive nature that is humiliated, while at the same time the spiritual nature is exalted and carried out towards the idea of the Infinite, which the sublime always suggests. [25]
[25] Op. cit., II, 92ff.
b. In the dialectic of the aesthetic faculty, Kant insists that the highest use of the sublime and beautiful is their use as a symbol of moral good. For the aesthetic feeling is akin to the moral faculty, as indeed the teleological judgment also is. The question of the objective value of one or other of these faculties leads ultimately to the assertion that there is hidden in nature a principle of beauty and purpose and goodness which the speculative reason cannot formulate. [26]
[26] Cf. B. Erdmann, Die Stellung des Dinges an sich in Kant's AEsthetik und Analytik (Berlin, 2873).
Historical Position. Kant's influence on the development of thought in the nineteenth century can hardly be overestimated. His philosophy is, as it were, the watershed from which streams of thought flow down in various courses into modern idealism, agnosticism, and even materialism. To this source may also be traced some of the most noteworthy currents of contemporary religious thought, especially the movement towards nondogmatic Christianity; for it is not difficult to see in Kant's assertion of the supremacy of the moral law the origin of the tendency to regard Christianity more as a system of ethics and less as a system of dogmatic truth. Kant influenced not only the literature of his own country, to an extent unequaled perhaps in the history of that literature, but also, through his English exponents, of whom Coleridge was the chief, the literature of the English-speaking world.

Philosophy owes to Kant the energetic assertion of the grandeur of the moral law as the foundation of ethics, and the scarcely less energetic assertion of the essential unity of consciousness, as a point of view for the critical analysis of mental processes. Whether or not we admit with McCosh that "Kant was distinguished more as a logical thinker and systematizer than as a careful observer of what actually takes place in the mind," [27] or with Huxley that "his baggage train is bigger than his army, and the student who attacks him is too often led to suspect that he has won a position when he has only captured a mob of useless camp-followers," [28] we cannot deny that Kant revolutionized the world of speculative and practical thought by introducing a new point of view for the study of mental phenomena, and that, to this extent at least, he is, as he himself claimed to he, the Copernicus of mental science.
[27] Realistic Philosophy, II, 297.

[28] Hume, p. 80.
Kant inaugurated transcendental criticism. Now, criticism in the sense of a critical examination of experience, or the analysis of common consciousness, is undoubtedly the beginning of philosophical inquiry, and the critical investigation of knowledge is a starting point which philosophic method approves. But philosophic method cannot approve the attempt to criticise all knowledge without the aid of principles or standards of criticism, and such principles or standards Kant does not pretend to adopt. We cannot regard as a canon of criticism the assumption that what is necessary and universal in our knowledge must be a priori, -- an assumption which is untrue as to content. Yet it is to this assumption that Kant constantly recurs in his doctrine of categories, in his classification of certain judgments as synthetic and a priori, etc. It is only in the practical order, in the realm of moral consciousness, that Kant finds refuge from the pan-phenomenalism which he wishes to avoid; for the thing-in-itself, the subject, and God, though existing, are unknown and unknowable, as far as the speculative reason is concerned. Kant, whose express purpose was to deliver philosophy from scepticism, might well look back at Hume, the sceptic, and exclaim, "There, but for the categorical imperative, goes Immanuel Kant!"


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