History of Modern Philosophy · Chapter 23%part II. From Kant to the Present Time.% (2)
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[Footnote 1: There has been much discussion and much has been written concerning the relation of the two editions. In opposition to Schopenhauer and Kuno Fischer it must be maintained that the alterations in the second edition consist in giving greater prominence to realistic elements, which in the first edition remained in the background, though present even there.]
[Footnote 2: This publication was the occasion of a conflict between Kant and the censorship concerning the right of free religious inquiry; cf. Dilthey in the Archiv für Geschichte der Philosophie, vol. in. 1890, pp. 418-450.]
[Footnote 3: A. Krause: I. Kant wider K. Fischer, zum ersten Male mit Hülfe des verloren gewesenen Kantischen Hauptwerkes vertheidigt, 1884 (in reply, K. Fischer, Das Streber- und Gründerthum in der Litteratur, 1884); also, Das nachgelassene Werk I. Kants, mit Belegen populär-wissenschaftlich dargestellt, 1888.]
[Footnote 4: Besides this (centenary) translation the English reader may be referred to the earlier version of Meiklejohn in Bonn's Library; to the versions of the Prolegomena by Bax (also in Bonn's Library, and including the Metaphysical Elements of Natural Science), and Mahaffy and Bernard, new ed., 1889; to Abbot's Kant's Theory of Ethics, 4th ed., 1889, containing the Foundation of the Metaphysics of Ethics and the Critique of Practical Reason entire, with portions of the Metaphysics of Ethics and Religion within the Limits of Reason Only; to Bernard's translation of the Kritik of Judgment, 1892; and to Watson's Selections from Kant, 2d ed., 1888 (in Sneath's Modern Philosophers, 1892).—TR.]
The best complete edition of the works of Kant is the second edition of Hartenstein, in eight volumes, 1867-68, which is chronologically arranged and excellently gotten up. Simultaneously with the first edition of Hartenstein in ten volumes, in 1838 seq., appeared the edition in twelve volumes by K. Rosenkranz and F.W. Schubert (containing in the last volumes a biography of Kant by Schubert, and a history of the Kantian philosophy by Rosenkranz, 1842). Kehrbach's edition of the principal works in Reclam's Universal-Bibliothek, with the pagination of the original and collective editions (1877 seq.), is more valuable than Von Kirchmann's edition of the complete works in his Philosophische Bibliothek.
Among the works on Kant those of Kuno Fischer (vols. iii.-iv. of the Geschichte der neueren Philosophie, 3d ed., 1882; also Kant's Leben und die Grundlagen seiner Lehre, 1860) take the first place. The writings of Liebmann, Cohen, Stadler, Riehl, Volkelt, and others will be mentioned later, in connection with the neo-Kantian movement; here we may give some of the more important monographs and essays, selected from the enormously developed Kantian literature:
Ad. Böhringer, Kants erkenntnisstheoretischer Idealismus, 1888; K. Dieterich, Die Kantische Philosophie in ihrer inneren Entwickelungsgeschichte, 2 parts, 1885 (first published separately, Kant und Newton, 1877; Kant und Rousseau, 1878); W. Dilthey, Aus den Rostocker Kanthandschriften in the Archiv für Geschichte der Philosophie, vols. ii.-iii. 1889-90; M.W. Drobisch, Kants Ding an sich und sein Erfahrungsbegriff, 1885; B. Erdmann, Kants Kritizismus in der I. und II. Auflage der Kritik der reinen Vernunft, 1878; the same, Kants Prolegomena herausgegeben und erläutert, 1878, Introduction (in reply Emil Arnoldt, Kants Prolegomena nicht doppelt redigiert, 1879; cf. also H. Vaihinger, Die Erdmann-Arnoldtsche Kontroverse in the Philosophische Monatshefte, vol. xvi. 1880); Franz Erhardt, Kritik der Kantischen Antinomienlehre, 1888; R. Eucken, Ueber Bilder und Gleichnisse bei Kant, Zeitschrift für Philosophie, vol. lxxxiii, 1883, reprinted in his Beiträge zur Geschichte der neueren Philosophie, 1886; F. Frederichs, Der phänomenale Idealismus Berkeleys und Kants, 1871; the same, Kants Prinzip der Ethik, 1879; Ed. von Hartmann, Das Ding an sich und seine Beschaffenheit, 1871, in the 2d ed., 1875, and the 3d, 1885, entitled Kritische Grundlegung des transzendentalen Realismus; C. Hebler, Kantiana, in his Philosophische Aufsätze, 1869; Alfred Hegler, Die Psychologie in Kants Ethik, 1891; A. Hölder, Darstellung der Kantischen Erkenntnisstheorie, 1873 J. Jacobson, Die Auffindung des Apriori, 1876; the same, Ueber die Beziehungen zwischen Kategorien und Urtheilsformen, 1877; Wilhelm Koppelmann, Kants Lehre vom analytischen Urtheil, Philosoph. Monatshefte, vol. xxi, 1885; the same, Lotzes Stellung zu Kants Kritizismus, Zeitschrift für Philosophie, vol. lxxxviii, 1886; the same, Kants Lehre vom kategorischen Imperativ, 1888; the same, Kant und die Grundlagen der Christlichen Religion, 1890; E. Laas, Kants Analogien der Erfahrung, 1876; the same, Einige Bemerkungen zur Transzendentalphilosophie, Strassburg Abhandlungen, 1884; J. Mainzer, Die kritische Epoche in der Lehre von der Einbildungskraft, 1881; J.B. Meyer, Kants Psychologie, 1870; F. Paulsen, Was Kant uns sein kann, Vierteljahrsschrift für wissenschaftliche Philosophie, 1881; B. Pünjer, Die Religionslehre Kants, 1874; R. Quaebicker, Kants und Herbarts metaphysische Grundansichten über das Wesen der Seele, 1870; J. Rehmke, Physiologie und Kantianismus, address in Eisenach, 1883; Rud. Reicke, Lose Blätter aus Kants Nachlass, 1889 (on this H. Vaihinger in the Zeitschrift für Philosophie, vol. xcvi. 1889); O. Riedel, Die monadologischen Bestimmungen in Kants Lehre vom Ding an sich, dissertation at Kiel, 1884; O. Schneider, Die psychologische Entwickelung des Apriori, 1883; the same, Transzendentalpsychologie, 1891; F. Staudinger, Noumena, 1884; M. Steckelmacher, Die formale Logik Kants, Breslau Prize Essay, 1879; A. Stern, Die Beziehung Garves zu Kant, nebst ungedruckten Briefen, 1884; C. Stumpf, Psychologie und Erkenntnisstheorie, Abhandlungen der bayerischen Akademie der Wissenschaften, 1891; G. Thiele, Kants intellectuelle Anschauung als Grundbegriff seines Kritizismus, 1876; the same, Die Philosophie Kants nach ihrem systematischen Zusammenhange und ihrer logischhistorischen Entiwickelung, I. (1) Kants vorkritische Naturphilosophie, 1882; (2) Kants vorkritische Erkenntnisstheorie, 1887; Ad. Trendelenburg, Ueber eine Lücke in Kants Beweis von der ausschliessenden Subjectivität des Raumes and der Zeit in vol. iii. of his Historische Beiträge zur Philosophie, 1867; Ueberhorst, Kants Lehre von dem Verhältnisse der Kategorien zu der Erfahrung, 1878; H. Vaihinger, Eine Blattversetzung in Kants Prolegomena, Philosoph. Monatshefte, vol. xv. 1879; the same, Zu Kants Widerlegung des Idealismus, Strassburg Abhandlungen, 1884; J. Walter, Zum Gedächtniss Kants, Festrede, 1881; Th. Weber, Zur Kritik der Kantischen Erkenntnisstheorie (from the Zeitschrift für Philosophie), 1882; W. Windelband, Ueber die verschiedenen Phasen der Kantischen Lehre vom Ding an sich, Vierteljahrsschrift für wissenschaftliche Philosophie, 1877 (cf. the same author's Geschichte der neueren Philosophie, § 58); J. Witte, Beiträge zum Verständniss Kants, 1874; the same, Kantischer Kritizismus gegenüber unkritischem Dilettantismus (against A. Stöhr), 1885; Wohlrabe, Kants Lehre vom Gewissen, 1889; E. Zeller, Ueber das Kantische Moralprinzip, 1880; R. Zimmermann, Ueber Kants Widerlegung des Idealismus von Berkeley, 1871; the same, Ueber Kants mathematisches Vorurtheil und dessen Folgen, 1871.
Popular expositions have been given by the following: K. Fortlage (in his Philos. Vorträge, 1869); E. Last, Mehr Licht! Die Haupsätze Kants und Schopenhauers, 1879; the same, Die realistiche und die idealistische Anschauung entwickelt an Kants Idealität von Raum und Zeit, 1884; H. Romundt, Antaeus, neuer Aufbau der Lehre Kants über Seele, Freiheit, und Gott, 1882; the same, Grundlegung zur Reform der Philosophie, vereinfachte und erweiterte Darstellung von Kants Kritik der reinen Vernunft, 1885; the same, Die Vollendung des Socrates, Kants Grundlegung zur Reform der Sittenlehre; the same, Ein neuer Paulus, Kants Grundlegung zu einer sicheren Lehre von der Religion, 1886; the same, Die drei Fragen Kants, 1887; A. Krause, Populäre Darstellung von Kants Kritik der reinen Vernunft, 1881; K. Lasswitz, Die Lehre Kants von der Idealität des Raumes und der Zeit, 1883; Wilhelm Münz, Die Grundlagen der Kantischen Erkenntnisstheorie, 2d ed., 1885.
Among foreigners Villers, Cousin, Nolen, Desdouits, Cantoni, E. Caird [\A Critical Account of the Philosophy of Kant, 1877; The Critical Philosophy of Immanuel Kant, 2 vols., 1889], Adamson [On the Philosophy of Kant, 1879, and a valuable article in the Encyclopedia Britannica, 9th ed., vol. xiii.], Stirling [Text-book to Kant, 1881], [Watson, Kant and his English Critics, 1881], Morris Kant's Critique of Pure Reason, Griggs's Philosophical Classics, 1882, [Wallace, Kant, Blackwood's Philosophical Classics, 1882; Porter, Kant's Ethics, Griggs's Philosophical Classics, 1886; Green, Lectures, Works, vol. ii., 1886.—Tr.], have among others made contributions to Kantian literature. Of the older works we may mention the dictionaries of E. Schmid, 1788, and Mellin (in six volumes), 1797 seq., the critique of the Kantian philosophy in the first volume of Schopenhauer's chief work, 1819, and the essay of C.H. Weisse, In welchem Sinne hat sich die deutsche Philosophie jetzt wieder an Kant zu orientieren, 1847.
Kant's outward life was less eventful and less changeful than his philosophical development.[1] Born in Königsberg in 1724, the son of J.G. Cant, a saddler of Scottish descent, his home and school training were both strict and of a markedly religious type. He was educated at the university of his native city, and for nine years, from 1746 on, filled the place of a private tutor. In 1755 he became Docent, in 1770 ordinary professor in Königsberg, serving also for six years of this time as under-librarian. He seldom left his native city and never the province. The clearness which marked his extremely popular lectures on physical geography and anthropology was due to his diligent study of works of travel, and to an unusually acute gift of observation, which enabled him to draw from his surroundings a comprehensive knowledge of the world and of man. He ceased lecturing in 1797, and in 1804 old age ended a life which had always, even in minute detail, been governed by rule. A man of extreme devotion to duty, particularity, and love of truth, and an amiable, bright, and witty companion, Kant belongs to the acute rather than to the profound thinkers. Among his manifold endowments the tendency to combination and the faculty of intuition (as the Critique of Judgment especially shows) are present to a noticeable degree, yet not so markedly as the power of strict analysis and subtle discrimination. So that, although a mediating tendency is rightly regarded as the distinguishing characteristic of the Kantian thinking, it must also be remembered that synthesis is everywhere preceded by a mighty work of analysis, and that this still exerts its power even after the adjustment is complete. Thus Kant became the energetic defender of a qualitative view of the world in opposition to the quantitative view of Leibnitz, for which antitheses (e.g., sensation and thought, feeling and cognition, good and evil, duty and inclination) fade into mere differences of degree.
[Footnote 1: The following have done especially valuable service in the investigation of the development of Kant's doctrine: Paulsen (Versuch einer Entwickelungsgeschichte der Kantischen Erkenntnisstheorie, 1875), B. Erdmann, Vaihinger, and Windelband. Besides Hume and Leibnitz, Newton, Locke, Shaftesbury, Rousseau, and Wolff exercised an important influence on Kant.]
In the beginning of this chapter we have indicated how the new ideal of knowledge, under whose banner Kant brought about a reform of philosophy, grew out of the conflict between the rationalistic (dogmatic) and the empirical (skeptical) systems. This combines the Baconian ideal of the extension of knowledge with the Cartesian ideal of certainty in knowledge. It is synthetic judgments alone which extend knowledge, while analytic judgments are explicative merely.[1] A priori judgments alone are perfectly certain, absolutely universal, and necessarily valid; while a posteriori judgments are subjectively valid merely, lack necessity, and, at best, yield only relative universality.[2] All analytic judgments are a priori, all empirical or a posteriori judgments are synthetic. Between the two lies the object of Kant's search. Do synthetic judgments a priori exist, and how are they possible?
[Footnote 1: "All bodies are extended" is an analytic judgment; "all bodies possess weight," a synthetic judgment. The former explicates the concept of the subject by bringing into notice an idea already contained in it and belonging to the definition as a part thereof; it is based on the law of contradiction: an unextended body is a self-contradictory concept. The latter, on the contrary, goes beyond the concept of the subject and adds a predicate which had not been thought therein. It is experience which teaches us that weight is joined to matter, a fact which cannot be derived from the concept of matter. Almost all mathematical principles are synthetic, and here, as will be shown, it is not experience but "pure intuition" which permits us to go beyond the concept and add a new mark to it.]
[Footnote 2: The Scholastics applied the term a priori to knowledge from causes (from that which precedes), and a posteriori to knowledge from effects. Kant, following Leibnitz and Lambert, uses the terms to designate the antithesis, knowledge from reason and knowledge from experience. An a priori judgment is a judgment obtained without the aid of experience. When the principle from which it is derived is also independent of experience it is absolutely a priori, otherwise it is relatively a priori.]
Two sciences discuss the how, and a third the if of such judgments, which, at the same time, are ampliative and absolutely universal and necessary. The first two sciences are pure mathematics and pure natural science, of which the former is protected against doubt concerning its legitimacy by its evident character, and the latter, by the constant possibility of verification in experience; each, moreover, can point to the continuous course of its development. All this is absent in the third science, metaphysics, as science of the suprasensible, and to its great disadvantage. Experiential verification is in the nature of things denied to a presumptive knowledge of that which is beyond experience; it lacks evidence to such an extent that there is scarcely a principle to be found to which all metaphysicians assent, much less a metaphysical text-book to compare with Euclid; there is so little continuous advance that it is rather true that the later comers are likely to overthrow all that their predecessors have taught. In metaphysics, therefore, which, it must be confessed, is actual as a natural tendency, the question is not, as in the other two sciences, concerning the grounds of its legitimacy, but concerning this legitimacy itself. Mathematics and pure physics form synthetic judgments a priori, and metaphysics does the same. But the principles of the two former are unchallenged, while those of the third are not. In the former case the subject for investigation is, Whence this authority? in the latter case, Is she thus authorized?
Thus the main question, How are synthetic judgments a priori possible? divides into the subordinate questions, How is pure mathematics possible? How is pure natural science possible, and, How is metaphysics (in two senses: metaphysics in general, and metaphysics as science) possible? The Transcendental Aesthetic (the critique of sensibility or the faculty of intuition) answers the first of these questions; the Transcendental Analytic (the critique of the understanding), the second; and the Transcendental Dialectic (the critique of "reason" in the narrower sense) and the Transcendental Doctrine of Method (Methodenlehre), the third. The Analytic and the Dialectic are the two parts of the Transcendental "Logic" (critique of the faculty of thought), which, together with the Aesthetic, forms the Transcendental "Doctrine of Elements" (Elementarlehre), in contrast to the Doctrine of Method. The Critique of Pure Reason follows this scheme of subordinate division, while the Prolegomena co-ordinates all four parts in the manner first mentioned.
Let us anticipate the answers. Pure mathematics is possible, because there are pure or a priori intuitions (space and time), and pure natural science or the metaphysics of phenomena, because there are a priori concepts (categories) and principles of the pure understanding. Metaphysics as a presumptive science of the suprasensible has been possible in the form of unsuccessful attempts, because there are Ideas or concepts of reason which point beyond experience and look as though knowable objects were given through them; but as real science it is not possible, because the application of the categories is restricted to the limits of experience, while the objects thought through the Ideas cannot be sensuously given, and all assumed knowledge of them becomes involved in irresolvable contradictions (antinomies). On the other hand, a science is possible and necessary to teach the correct use of the categories, which may be applied to phenomena alone, and of the Ideas, which may be applied only to our knowledge of things (and our volition), and to determine the origin and the limits of our knowledge—that is to say, a transcendental philosophy. In regard to metaphysics (knowledge from pure reason), then, this is the conclusion reached: Rejection of transcendent metaphysics (that which goes beyond experience), recognition and development of immanent metaphysics (that which remains within the limits of possible experience). It is not possible as a metaphysic of things in themselves; it is possible as a metaphysic of nature (of the totality of phenomena), and as a metaphysic of knowledge (critique of reason).
The interests of the reason are not exhausted, however, by the question, What can we know? but include two further questions, What ought we to do? and, What may we hope? Thus to the metaphysics of nature there is added a metaphysics of morals, and to the critique of theoretical reason, a critique of practical reason or of the will, together with a critique of religious belief. For even if a "knowledge" of the suprasensible is denied to us, yet "practical" grounds are not wanting for a sufficiently certain "conviction" concerning God, freedom, and immortality.
After carrying the question of the possibility of synthetic judgments a priori from the knowledge of nature over to the knowledge of our duty, Kant raises it, in the third place, in regard to our judgment concerning the subjective and objective purposiveness of things, or concerning their beauty and their perfection, and adds to his critique of the intellect and the will a critique of the faculty of aesthetic and teleological judgment.
The Kantian philosophy accordingly falls into three parts, one theoretical, one practical (and religious), one aesthetic and teleological.
* * * * *
Before advancing to our account of the first of these parts, a few preliminary remarks are indispensable concerning the presuppositions involved in Kant's critical work and on the method which he pursues. The presuppositions are partly psychological, partly (as the classification of the forms of judgment and inference, and the twofold division of judgments) logical, either in the formal or the transcendental sense, and partly metaphysical (as the thing in itself). Kant takes the first of these from the psychology of his time, by combining the Wolffian classification of the faculties with that of Tetens, and thus obtains six different faculties: lower (sensuous) and higher (intellectual) faculties of cognition, of feeling, and of appetition; or sensibility (the capacity for receiving representations through the way in which we are affected by objects), understanding (the faculty of producing representations spontaneously and of connecting them); the sensuous feelings of pleasure and pain, taste; desire, and will. The understanding in the wide sense is equivalent to the higher faculty of cognition, and divides further into understanding in the stricter sense (faculty of concepts), judgment (faculty of judging), and reason (faculty of inference). Of these the first gives laws to the faculty of cognition or to nature, the second laws to taste, and the third laws to the will.
The most important of the fundamental assumptions concerns the relation, the nature, and the mission of the two faculties of cognition. These do not differ in degree, through the possession of greater or less distinctness—for there are sensuous representations which are distinct and intellectual ones which are not so—but specifically: Sensibility is the faculty of intuitions, understanding the faculty of concepts. Intuitions are particular, concepts general representations. The former relate to objects directly, the latter only indirectly (through the mediation of other representations). In intuition the mind is receptive, in conception it acts spontaneously. "Through intuitions objects are given to us; through concepts they are thought." It results from this that neither of the two faculties is of itself sufficient for the attainment of knowledge, for cognition is objective thinking, the determination of objects, the unifying combination or elaboration of a given manifold, the forming of a material content. Rationalists and empiricists alike have been deceived in regard to the necessity for co-operation between the senses and the understanding. Sensibility furnishes the material manifold, which of itself it is not able to form, while the understanding gives the unifying form, to which of itself it cannot furnish a content. "Intuitions without concepts are blind" (formless, unintelligible), "concepts without intuitions are empty" (without content). In the one case, form and order are wanting; in the other, the material to be formed. The two faculties are thrown back on each other, and knowledge can arise only from their union.
A certain degree of form is attained in sense, it is true, since the chaos of sensations is ordered under the "forms of intuition," space and time, which are an original possession of the intuiting subject, but this is not sufficient, without the aid of the understanding, for the genesis of knowledge. In view of the a priori nature of space and time, though without detraction from their intuitive character (they are immediate particular representations), we may assign pure sensibility to the higher faculty of cognition and speak of an intuiting reason.
The forms of intuition and of thought come from within, they lie ready in the mind a priori, though not as completed representations. They are functions, necessary actions of the soul, for the execution of which a stimulus from without, through sensations, is necessary, but which, when once this is given, the soul brings forth spontaneously. The external impulse merely gives the soul the occasion for such productive acts, while their grounds and laws are found in its own nature. In this sense Kant terms them "originally acquired," and in the Introduction to the Critique of Pure Reason declares that although it is indubitable that "all our knowledge begins with experience (impressions of sense), yet it does not all arise from experience." That a representation or cognition is a priori[1] does not mean that it precedes experience in time, but that (apart from the merely exciting, non-productive stimulation through impressions already mentioned) it is independent of all experience, that it is not derived or borrowed from experience.
[Footnote 1: The terms a priori representation and pure representation (concept, intuition) are equivalent; but in judgments, on the other hand, there is a distinction. A judgment is a priori when the connection takes place independently of experience, no matter whether the concepts connected are a priori or not. If the former is the case the a priori judgment is pure (mixed with nothing empirical); if the latter, it is mixed.]
The material of intuition and thought is given to the soul, received by it; it arises through the action of objects upon the senses, and is always empirical. Intuition is the only organ of reality; in sensation the presence of a real object as the cause of the sensation is directly revealed. When Kant's transcendental idealism was placed by a reviewer on a level with the empirical idealism of Berkeley, which denies the existence of the external world, he distinctly asserted that it had never entered his mind to question the reality of external things. Further, after the existence of real things affecting the senses had been transformed in his mind from a basis of the investigation into an object of inquiry, he endeavored to defend this assumption (which at first he had naïvely borrowed from the realism of pre-scientific thought) by arguments, but without any satisfactory result.[1]
[Footnote 1: The task of confirming the existence of things in themselves changes under his hands into another, that of proving the existence of external phenomena. "That external objects are real as representations" Berkeley had never disputed.]
On the basis of the inseparability of sensibility and understanding the ideal of knowledge—an extension of knowledge to be attained by a priori means (p. 333)—experiences a remarkable addition in the position that the rational synthesis thus obtained must be a knowledge of reality, must be applied to matter given in intuition. To the question, "How are synthetic judgments a priori possible?" is joined a second equally legitimate inquiry, "How do they become objectively valid, or applicable to objects of experience?" The principle from which their validity is proved—they are applicable to objects of experience because without them experience would not be possible, because they are conditions of experience—like the criterion of apriority (strict universality and necessity), is one of the noëtic assumptions of the critical theory.[1]
[Footnote 1: Cf. Vaihinger, Kommentar, i. pp. 425-430.]
Inasmuch as its investigation relates to the conditions of experience the Kantian criticism follows a method which it itself terms transcendental. Heretofore, when the metaphysical method had been adopted, the object had been the suprasensible; and when knowledge had been made the object of investigation, the method followed had been empirical, psychological. Kant had the right to consider himself the creator of noëtics, for he showed it the transcendental point of view. Knowledge is an object of experience, but its conditions are not. The object is to explain knowledge, not merely to describe it psychologically,—to establish a new science of knowledge from principles, from pure reason. That which lies beyond experience is sealed from our thought; that which lies on this side of it is still uninvestigated, though capable and worthy of investigation, and in extreme need thereof. Criticism forbids the transcendent use of reason (transcending experience); it permits, demands, and itself exercises the transcendental[1] use of it, which explains an experiential object, knowledge, from its conditions, which are not empirically given.
[Footnote A: Kant applies the term transcendental to the knowledge (the discovery, the proof) of the a priori factor and its relation to objects of experience. Unfortunately he often uses the same word not only to designate the a priori element itself, but also as a synonym for transcendent. In all three cases its opposite is empirical, namely, empirico-psychological investigation by observation in distinction from noëtical investigation from principles; empirical origin in distinction from an origin in pure reason, and empirical use in distinction from application beyond the limits of experience.]
There is, apparently, a contradiction between the empiristic result of the Critique of Reason (the limitation of knowledge to objects of experience) and its rationalistic proofs (which proceed metaphysically, not empirically), and, in fact, a considerable degree of opposition really exists. Kant argues in a metaphysical way that there can be no metaphysics. This contradiction is solved by the distinction which has been mentioned between that which is beyond, and that which lies within, the boundary of experience. That metaphysic is forbidden which on the objective side soars beyond experience, but that pure rational knowledge is permissible and necessary which develops from principles the grounds of experiential knowledge existing in the subject. In the Kantian school, however, these complementary elements,—empirical result, transcendental or metaphysical, properly speaking, pro-physical method,—were divorced, and the one emphasized, favored, and further developed at the expense of the other. The empiricists hold to the result, while they either weaken or completely misunderstand the rationalism of the method: the a priori factor, says Fries, was not reached by a priori, but by a posteriori, means, and there is no other way by which it could have been reached. The constructive thinkers, Fichte and his successors, adopt and continue the metaphysical method, but reject the empirical result. Fichte's aim is directed to a system of necessary, unconscious processes of reason, among which, rejecting the thing in itself, he includes sensation. According to Schelling nature itself is a priori, a condition of consciousness. This discrepancy between foundation and result continues in an altered form even among contemporary thinkers—as a discussion whether the "main purpose" of Criticism is to be found in the limitation of knowledge to possible experience, or the establishment of a priori elements—though many, in adherence to Kant's own view, maintain that the metaphysics of knowledge and of phenomena (immanent rationalism) is the only legitimate metaphysics.
%1. Theory of Knowledge.
(a) The Pure Intuitions (Transcendental Aesthetic).%—The first part of the Critique of Reason, the Transcendental Aesthetic, lays down the position that space and time are not independent existences, not real beings, and not properties or relations which would belong to things in themselves though they were not intuited, but forms of our intuition, which have their basis in the subjective constitution of our, the human, mind. If we separate from sensuous intuition all that the understanding thinks in it through its concepts, and all that belongs to sensation, these two forms of intuition remain, which may be termed pure intuitions, since they can be considered apart from all sensation. As subjective conditions (lying in the nature of the subject) through which alone a thing can become an object of intuition for us, they precede all empirical intuitions or are a priori.
Space and time are neither substantial receptacles which contain all that is real nor orders inhering in things in themselves, but forms of intuition. Now all our representations are either pure or empirical in their origin, and either intuitive or conceptual in character. Kant advances four proofs for the position that space and time are not empirical and not concepts, but pure intuitions: (1) Time is not an empirical concept which has been abstracted from experience. For the coexistence or succession of phenomena, i.e., their existence at the same time or at different times (from which, as many believe, the representation of time is abstracted), itself presupposes time—a coexistence or succession is possible only in time. It is no less false that space is abstracted from the empirical space relations of external phenomena, their existence outside and beside one another, or in different places, for it is impossible to represent relative situation except in space. Therefore experience does not make space and time possible; but space and time first of all make experience possible, the one outer, the other inner experience. They are postulates of perception, not abstractions from it. (2) Time is a necessary representation a priori. We can easily think all phenomena away from it, but we cannot remove time itself in view of phenomena in general; we can think time without phenomena, but not phenomena without time. The same is true of space in reference to external objects. Both are conditions of the possibility of phenomena. (3) Time is not a discursive or general concept. For there is but one time. And different times do not precede the one time as the constituent parts of which it is made up, but are mere limitations of it; the part is possible only through the whole. In the same way the various spaces are only parts of one and the same space, and can be thought in it alone. But a representation which can be given only by a single object is a particular representation or an intuition. Because, therefore, of the oneness of space and time, the representation of each is an intuition. The a priori, immediate intuition of the one space is entirely different from the empirical, general conception of space, which is abstracted from the various spaces. (4) Determinate periods of time arise by limitation of the one, fundamental time. Consequently this original time must be unlimited or infinite, and the representation of it must be an intuition, not a concept. Time contains in itself an endless number of representations (its parts, times), but this is never the case with a generic concept, which, indeed, is contained as a partial representation in an endless number of representations (those of the individuals having the same name), and, consequently, comprehends them all under itself, but which never contains them in itself. The general concept horse is contained in each particular representation of a horse as a general characteristic, and that of justice in each representation of a definite just act; time, however, is not contained in the different times, but they are contained in it. Similarly the relation of infinite space to the finite spaces is not the logical relation of a concept to examples of it, but the intuitive relation of an unlimited whole to its limited parts.