History Of Modern Philosophy by Richard Falckenberg (page 7)

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.

The _Prolegomena_ employs as a fifth proof for the intuitive character of space, an argument which had already appeared in the essay _On the Ultimate Ground of the Distinction of Positions in Space_. There are certain spatial distinctions which can be grasped by intuition alone, and which are absolutely incapable of comprehension through the understanding–for example, those of right and left, above and below, before and behind. No logical marks can be given for the distinction between the object and its image in the mirror, or between the right ear and the left. The complete description of a right hand must, in all respects (quality, proportionate position of parts, size of the whole), hold for the left as well; but, despite the complete similarity, the one hand cannot be exactly super-imposed on the other; the glove of the one cannot be worn on the other. This difference in direction, which has significance only when viewed from a definite point, and the impossibility mentioned of a congruence between an object (right hand) and its reflected image (left hand) can be understood only by intuition; they must be seen and felt, and cannot be made clear through concepts, and, consequently, can never be explained to a being which lacks the intuition of space.

In the “transcendental” exposition of space and time Kant follows this “metaphysical” exposition, which had to prove their non-empirical, and non-discursive, hence their _a priori_ and intuitive, character, with the proof that only such an explanation of space and time could make it conceivable how synthetic cognitions _a priori_ can arise from them. The principles of mathematics are of this kind. The synthetic character of geometrical truths is explained by the intuitive nature of space, their apodictic character by its apriority, and their objective reality or applicability to empirical objects by the fact that space is the condition of (external) perception. The like is true of arithmetic and time.

If space were a mere concept, no proposition could be derived from it which should go beyond the concept and extend our knowledge of its properties. The possibility of such extension or synthesis in mathematics depends on the fact that spatial concepts can always be presented or “constructed” in intuition. The geometrical axiom that in the triangle the sum of two sides is greater than the third is derived from intuition, by describing the triangle in imagination or, actually, on the board. Here the object is given through the cognition and not before it.–If space and time were empirical representations the knowledge obtained from them would lack necessity, which, as a matter of fact, it possesses in a marked degree. While experience teaches us only that something is thus or so, and not that it could not be otherwise, the axioms, (space has only three dimensions, time only one; only one straight line is possible between two points), nay, all the propositions of mathematics are strictly universal and apodictically certain: we are entirely relieved from the necessity of measuring all triangles in the world in order to find out whether the sum of their angles is equal to two right angles, and we do not need, as in the case of judgments of experience, to add the limitation, so far as it is yet known there are no exceptions to this rule. The apriority is the _ratio essendi_ of the strict necessity involved in the “it must be so” _(des Soseinmüssens_), while the latter is the _ratio cognoscendi_ of the former. Now since the necessity of mathematical judgments can only be explained through the ideality of space, this doctrine is perfectly certain, not merely a probable hypothesis.–The validity of mathematical principles for all objects of perception, finally, is based on the fact that they are rules under which alone experience is possible for us. It should be mentioned, further, that the conceptions of change and motion (change of place) are possible only through and in the representation of time. No concept could make intelligible the possibility of change, that is, of the connection of contradictory predicates in one and the same thing, but the intuition of succession easily succeeds in accomplishing it.

The argument is followed by conclusions and explanations based upon it; (1) Space is the form of the outer, time of the inner, sense. Through the outer sense external objects are given to us, and through the inner sense our own inner states. But since all representations, whether they have external things for their objects or not, belong in themselves, as mental determinations, to our inner state, time is the formal condition of all phenomena in general, directly of internal (psychical) phenomena, and, thereby, indirectly of external phenomena also. (2) The validity of the relations of space and time cognizable _a priori_ is established for all objects of possible experience, but is limited to these. They are valid for _all phenomena_ (for all things which at any time may be given to our senses), but only for these, not for things as they are _in themselves_. They have “empirical reality, but, at the same time, transcendental ideality.” As external phenomena all things are beside one another in space, and all phenomena whatever are in time and of necessity under temporal relations; in regard to all things which can occur in our experience, and in so far as they can occur, space and time are objectively, therefore empirically, real. But they do not possess absolute reality (neither subsistent reality nor the reality of inherence); for if we abstract from our sensuous intuition both vanish, and, apart from the subject (_N.B._, the transcendental subject, concerning which more below), they are naught. It is only from man’s point of view that we can speak of space, and of extended, moveable, changeable things; for we can know nothing concerning the intuitions of other thinking beings, we have no means of discovering whether they are bound by the same conditions which limit our intuitions, and which for us are universally valid. (3) Nothing which is intuited in space is a thing in itself. What we call external objects are nothing but mere representations of our sensibility, whose true correlative, the _thing in itself_, cannot be known by ever so deep penetration into the phenomenon; such properties as belong to things in themselves can never be given to us through the senses. Similarly nothing that is intuited in time is a thing in itself, so that we intuit ourselves only as we appear to ourselves, and not as we are.

The merely empirical reality of space and time, the limitation of their validity to phenomena, leaves the certainty of knowledge within the limits of experience intact; for we are equally certain of it, whether these forms necessarily belong to things in themselves, or only to our intuitions of things. The assertion of their absolute reality, on the other hand, involves us in sheer absurdities (that is, it necessitates the assumption of two infinite nonentities which exist, but without being anything real, merely in order to comprehend all reality, and on one of which even our own existence would be dependent), in view of which the origin of so peculiar a theory as the idealism of Berkeley appears intelligible. The critical theory of space and time is so far from being identical with, or akin to, the theory of Berkeley, that it furnishes the best and only defense against the latter. If anyone assumes the absolute or transcendental reality of these forms, it is impossible for him to prevent everything, including even our own existence, from being changed thereby into mere illusion. But the critical philosopher is far from degrading bodies to mere illusion; external phenomena are just as real for him as internal phenomena, though only as phenomena, it is true, as (possible) representations.

Phenomenon and illusion are not the same. The transcendental distinction between phenomena and things in themselves must not be confused with the distinction common to ordinary life and to physics, in accordance with which we call the rainbow a mere appearance (better, illusion), but the combination of sun and rain which gives rise to this illusion the thing in itself, as that which in universal experience and in all different positions with respect to the senses, is thus and not otherwise determined in intuition, or that which essentially belongs to the intuition of the object, and is valid for every human sensibility (in antithesis to that which only contingently belongs to it, and is valid only for a special position or organization of this or that sense). Similarly an object always appears to grow smaller as its distance increases, while in itself it is and remains of some fixed size. And this use of words is perfectly correct, in the _physical or empirical_ sense of “in itself”; but in the _transcendental_ sense the raindrops, also, together with their form and size, are themselves mere phenomena, the “in itself” of which remains entirely unknown to us. Kant, moreover, does not wish to see the subjectivity of the forms of intuition placed on a level with the subjectivity of sensations or explained by this, though he accepts it as a fact long established. The sensations of color, of tone, of temperature are, no doubt, like the representation of space in that they belong only to the subjective constitution of the sensibility, and can be attributed to objects only in relation to our senses. But the great difference between the two is that these sense qualities may be different in different persons (the color of the rose may seem different to each eye), or may fail to harmonize with any human sense; that they are not _a priori_ in the same strict sense as space and time, and consequently afford no knowledge of the objects of possible experience independently of perception; and that they are connected with the phenomenon only as the contingently added effects of a particular organization, while space, as the condition of external objects, necessarily belongs to the phenomenon or intuition of them. _It is through space alone that it is possible for things to be external objects for us_. The subjectivity of sensation is individual, while that of space and time is general or universal to mankind; the former is empirical, individually different, and contingent, the latter _a priori_ and necessary. Space alone, not sensation, is a _conditio sine qua non_ of external perception. Space and time are the sole _a priori_ elements of the sensibility; all other sensuous concepts, even motion and change, presuppose perception; the movable in space and the succession of properties in an existing thing are empirical data.

In confirmation of the theory that all objects of the senses are mere phenomena, the fact is adduced that (with the exception of the will and the feelings, which are not cognitions) nothing is given us through the senses but representations of relations, while a thing in itself cannot be known by mere relations. The phenomenon is a sum total of mere relations. In regard to matter we know only extension, motion, and the laws of this motion or forces (attraction, repulsion, impenetrability), but all these are merely relations of the thing to something, else, that is, external relations. Where is the inner side which underlies this exterior, and which belongs to the object in itself? This is never to be found in the phenomenon, and no matter how far the observation and analysis of nature may advance (a work with unlimited horizons!) they reach nothing but portions of space occupied by matter and effects which matter exercises, that is, nothing beyond that which is comparatively internal, and which, in its turn, consists of external relations. The absolutely inner side of matter is a mere fancy; and if the complaint that the “inner side” of things is concealed from us is to mean that we do not comprehend what the things which appear to us may be in themselves, it is unjust and irrational, for it demands that we should be able to intuit without senses, in other words, that we should be other than men. The transcendent questions concerning the noumenon of things are unanswerable; we know ourselves, even, only as phenomena! A phenomenon consists in nothing but the relation of something in general to the senses.

It is indubitable _that_ something corresponds to phenomena, which, by affecting our sensibility, occasions sensations in us, and thereby phenomena. The very word, the very concept, “phenomenon”, indicates a relation to something which is not phenomenon, to an object not dependent on the sensibility. _What_ this may be continues hidden from us, for knowledge is impossible without intuition. Things in themselves are unknowable. Nevertheless the idea (it must be confessed, the entirely empty idea) of this “transcendental object”, as an indeterminate somewhat = _x_ which underlies phenomena, is not only allowable, but, as a limiting concept, unavoidable in order to confine the pretensions of sense to the only field which is accessible to it, that is, to the field of phenomena.

The inference “space and time are nothing but representations and representations are in us, therefore space and time as well as all phenomena in them, bodies with their forces and motions, are in us,” does not accurately express Kant’s position, for he might justly reply that, according to him, bodies as phenomena are in different parts in space from that which we assign to ourselves, and thus without us; that space is the form of external intuition, and through it external objects arise for us from sensations; but that, in regard to the things in themselves which affect us, we are entirely ignorant whether they are within or without us.

It can easily be shown by literal quotations that there were distinct tendencies in Kant, especially in the first edition of his principal work, toward a radical idealism which doubts or denies not merely the cognizability, but also the existence of objects external to the subject and its representations, and which degrades the thing in itself to a mere thought in us, or completely does away with it (_e.g._, “The representation of an object as a thing in general is not only insufficient, but, … independently of empirical conditions, in itself contradictory “). But these expressions indicate only a momentary inclination toward such a view, not a binding avowal of it, and they are outweighed by those in which idealism is more or less energetically rejected. That which according to Kant _exists outside the representation of the individual_ is twofold: (1) the unknown things in themselves with their problematical characteristics, as the ground of phenomena; (2) the phenomena “themselves” with their knowable immanent laws, and their relations in space and time, as possible representations. When I turn my glance away from the rose its redness vanishes, since this predicate belongs to it only in so far and so long as it acts in the light on my visual apparatus. What, then, is left? That thing in itself, of course, which, when it appears to me, calls forth in me the intuition of the rose. But there is still something else remaining–the phenomenon of the rose, with its size, its form, and its motion in the wind. For these are predicates which must be attributed to the phenomenon itself as the object of my representation. If the rose, as determined in space and time, vanished when I turned my head away, it could not, unless intuited by a subject, experience or exert effects in space and time, could not lose its leaves in the wind and strew the ground with its petals. Perception and thought inform me not merely concerning events of which I am a witness, but also of others which have occurred, or which will occur, in my absence. The process of stripping the leaves from the rose has actually taken place as a phenomenon and does not first become real by my subsequent representation of it or inference to it. The things and events of the phenomenal world exist both before and after my perception, and are something distinct from my subjective and momentary representations of them. The space and time, however, in which they exist and happen are not furnished by the intuiting individual, but by the supra-individual, _transcendental consciousness_ or generic reason of the race. The phenomenon thus stands midway between its objective ground (the absolute thing in itself) and the subject, whose common product it is, as a relative thing in itself, as a reality which is independent of the contingent and changing representation of the individual, empirical subject, which is dependent for its form on the transcendental subject, and which is the only reality accessible to us, yet entirely valid for us. The phenomenal world is not a contingent and individual phenomenon, but one necessary for all beings organized as we are, a phenomenon for humanity. My representations are not the phenomena themselves, but images and signs through which I cognize phenomena, _i.e._, real things as they are for me and for every man (not as they are in themselves). The reality of phenomena consists in the fact that they can be perceived by men, and the objective validity of my knowledge of them in the fact that every man must agree in it. The laws which the understanding (not the individual understanding!) imposes upon nature hold for phenomena, because they hold for every man. Objectivity is universal validity. If the world of phenomena which is intuited and known by us wears a different appearance from the world of things in themselves, this does not justify us in declaring it to be mere seeming and dreaming; a dream which all dream together, and which all must dream, is not a dream, but reality. As we must represent the world> so it is, though for us, of course, and not in itself.

Many places in Kant’s works seem to argue against the intermediate position here ascribed to the world of phenomena–according to which it is less than things in themselves and more than subjective representation–which, since they explain the phenomenon as a mere representation, leave room for only two factors (on the one hand, the thing in itself = that in the thing which cannot be represented; on the other, the thing for me = my representation of the thing). In fact, the distinction between the phenomenon “itself” and the representation which the individual now has of it and now does not have, is far from being everywhere adhered to with desirable clearness; and wherever it is impossible to substitute that which has been represented and that which may be represented or possible intuitions for “mere representations in me,” we must acknowledge that there is a departure from the standpoint which is assumed in some places with the greatest distinctness. The latter finds unequivocal expression, among other places, in the “Analogies of Experience” and the “Deduction of the Pure Concepts of the Understanding,” § 2, No. 4 (first edition). The second of these passages speaks of one and the same universal experience, in which all perceptions are represented in thoroughgoing and regular connection, and of the thoroughgoing affinity of phenomena as the basis of the possibility of the association of representations. This affinity is ascribed to the objects of the senses, not to the representations, whose association is rather the result of the affinity, and not to the things in themselves, in regard to which the understanding has no legislative power.

The relation between the thing in itself and the phenomenon is also variable. Now they are regarded as entirely heterogeneous (that which can never be intuited exists in a mode opposed to that of the intuited and intuitable), and now as analogous to each other (non-intuitable properties of the thing in itself correspond to the intuitable characteristics of the phenomenon). The former is the case when it is said that phenomena are in space and time, while things in themselves are not; that in the first of these classes natural causation rules, and in the second freedom; that in the one-conditioned existence alone is found, in the other unconditioned.[1] But just as often things in themselves and phenomena are conceived as similar to one another, as two sides of the same object,[2] of which one, like the counter-earth of the Pythagoreans, always remains turned away from us, while the other is turned toward us, but does not reveal the true being of the object. According to this each particular thing, state, relation, and event in the world of phenomena would have its real counterpart in the noumenal sphere: un-extended roses in themselves would lie back of extended roses, certain non-temporal processes back of their growth and decay, intelligible relations back of their relations in space. This is approximately the relation of the two conceptions as in part taught by Lotze himself, in part represented by him as taught by Kant. Herbart’s principle, “So much seeming, so much indication of being” (_wie viel Schein so viel Hindeutung aufs Sein_), might also be cited in this connection. That which continually impelled Kant, in spite of his proclamation of the unknowableness of things in themselves, to form ideas about their character, was the moral interest, but this sometimes threw its influence in favor of their commensurability with phenomena and sometimes in the opposite scale. For in his ethics Kant needs the intelligible character or man as noumenon, and must assume as many men in themselves (to be consistent, then, in general, as many beings in themselves) as there are in the world of phenomena. But for practical reasons, again, the causality of the man in himself must be thought of as entirely different from, and opposed to, the mechanical causality of the sense world. Kant’s judgment is, also, no more stable concerning the value of the knowledge of the suprasensible, which is denied to us. “I do not _need_ to know what things in themselves may be, because a thing can never be presented to me otherwise than as a phenomenon.” And yet a natural and ineradicable need of the reason to obtain some conviction in regard to the other world is said to underlie the abortive attempts of metaphysics; and Kant himself uses all his efforts to secure to the practical reason the satisfaction of this need, though he has denied it to the speculative reason, and to make good the gap in knowledge by faith. From the theoretical standpoint an extension of knowledge beyond the limits of phenomena appears impossible, but unnecessary; from the practical standpoint it is, to a certain extent, possible and indispensable.

[Footnote 1: Kant’s conjectures concerning a common ground of material and mental phenomena, and those concerning the common root of sensibility and understanding, show the same tendency. On the one hand, duality, on the other, unity.]

[Footnote 2: “Phenomenon, which always has _two sides_, the one when the object in itself is considered (apart from the way in which it is intuited, and just because of which fact its character always remains problematical), the other when we regard the form of the intuition of this object, which must be sought not in the object in itself, but in the subject to whom the object appears, while it nevertheless actually and necessarily belongs to the phenomenon of _this object_.” “This predicate “–_sc_., spatial quality, extension–“is attributed to things only in so far as _they_ appear to us.”]

There is, then, a threefold distinction to be made: (1) _Things in themselves_, which can never be the object of our knowledge, because our forms of intuition are not valid for them. (2) _Phenomena_, things for us, nature or the totality of that which either is or, at least, may be the object of our knowledge (here belong the possible inhabitants of the moon, the magnetic matter which pervades all bodies, and the forces of attraction and repulsion, though the first have never been observed, and the second is not perceptible on account of the coarseness of our senses, and the last, because forces in general are not perceptible; nature comprehends everything whose existence “is connected with our perceptions in a possible experience”[1]). (3) _Our representations_ of phenomena, _i.e._, that of the latter which actually enters into the consciousness of the empirical individual. In the realm of things in themselves there is no motion whatever, but at most an intelligible correlate of this relation; in the world of phenomena, the world of physics, the earth moves around the sun; in the sphere of representation the sun moves around the earth. It is true, as has been said, that Kant sometimes ignores the distinction between phenomena as related to noumena and phenomena as related to representations; and, as a result of this, that the phenomenon is either completely volatilized into the representation[2] or split up into an objective half independent of us and a representative half dependent on us, of which the former falls into the thing in itself,[3] while the latter is resolved into subjective states of the ego.

[Footnote 1: “Nothing is actually given to us but the perception and the empirical progress from this to other possible perceptions.” “To call a phenomenon a real thing antecedent to perception, means … that in the _progress of experience_ we must meet with such a perception.”]

[Footnote 2: Phenomena “are altogether in me,” “exist only in our sensibility as a modification of it.” “There is nothing in space but that which is actually represented in it.” Phenomena are “mere representations, which, if they are not given in us (in perception) nowhere exist.”]

[Footnote 3: Here Kant is guilty of the fault which he himself has censured, of confusing the physical and transcendental meanings of “in itself.” He forgets that the thing, if it is momentarily not intuited or represented by me, and therefore is not immediately given for me as an individual, is nevertheless still present for me as man, is mediately given, that is, is discoverable by future search. That which is without my present consciousness is not for this reason without all human consciousness. In fact, Kant often overlooks the distinction between actual and possible intuition, so that for him the “objects” of the latter slip out of space and time and into the thing in itself. To the “transcendental object we may ascribe the extent and connection of our possible perceptions, and say that it is given in itself before all experience.” In it “the real things of the past are given.”]

After the possibility and the legitimacy of synthetic judgments _a priori_ have been proved for pure mathematics upon the basis of the pure intuitions, there emerges, in the second place, the problem of the possibility of _a priori_ syntheses in pure natural science, or the question, Do pure concepts exist? And after this has been answered in the affirmative, the further questions come up, Is the application of these, first, to phenomena, and second, to things in themselves, possible and legitimate, and how far?

%(b) The Concepts and Principles of the Pure Understanding (Transcendental Analytic).%–Sensations, in order to become “intuition” or the perception of a phenomenon, needed to be ordered in space and time; in order to become “experience” or a unified knowledge of objects, intuitions need a synthesis through concepts. In order to objective knowledge the manifold of intuition (already ordered by its arrangement in space and time) must be connected in the unity of the concept. Sensibility gives the manifold to be connected, the understanding the connecting unity. The former is able to intuit only, the latter only to think; knowledge can arise only as the result of their union. Intuitions depend on affections, concepts on functions, that is, on unifying acts of the understanding.

To discover the pure forms of thought it is necessary to isolate the understanding, just as an isolation of the sensibility was necessary above in order to the discovery of the pure forms of intuition. We obtain the elements of the pure knowledge of the understanding by rejecting all that is intuitive and empirical. These elements must be pure, must be concepts, further, not derivative or composite, but fundamental concepts, and their number must be complete. This completeness is guaranteed only when the pure concepts or _categories_ are sought according to some common principle, which assigns to each its position in the connection of the whole, and not (as with Aristotle) collected by occasional, unsystematic inquiries undertaken at random. The table of the forms of judgment will serve as a guide for the discovery of the categories. Thought is knowledge through concepts; the understanding can make no other use of concepts than to judge by means of them. Hence, since the understanding is the faculty of judging, the various kinds of connection in judgment must yield the various pure “connective-concepts” (_Verknüpfungsbegriffe_.–K. Fischer) or categories.

In regard to quantity, every judgment is universal, particular, or singular; in regard to quality, affirmative, negative, or infinite; in regard to relation, categorical, hypothetical, or disjunctive; and in regard to modality, problematical, assertory, or apodictic. To these twelve forms of judgment correspond as many categories, viz., I., Unity, Plurality, Totality; II., Reality, Negation, Limitation; III., Subsistence and Inherence (Substance and Accident), Causality and Dependence (Cause and Effect), Community (Reciprocity between the Active and the Passive); IV., Possibility–Impossibility, Existence–Non-existence, Necessity–Contingency.

The first six of these fundamental concepts, which have no correlatives, constitute the mathematical, the second six, which appear in pairs, the dynamical categories. The former relate to objects of (pure or of empirical) intuition, the latter to the existence of these objects (in relation to one another or to the understanding). Although all other _a priori_ division though concepts must be dichotomous, each of the four heads includes three categories, the third of which in each case arises from the combination of the second and first,[1] but, nevertheless, is an original (not a derivative) concept, since this combination requires a special _actus_ of the understanding. Universality or totality is plurality regarded as unity, limitation is reality combined with negation, community is the reciprocal causality of substances, and necessity is the actuality given by possibility itself. Kant omits, as unnecessary here, the useful, easy, and not unpleasant task of noting the great number of derivative concepts _a priori_ (predicables) which spring from the combination of these twelve original concepts (predicaments = categories) with one another, or with the modes of pure sensibility,–the concepts force, action, passion, would belong as subsumptions under causality, presence and resistance under community, origin, extinction, and change under modality,–since his object is not a system, but only the principles of one. His liking or even love for this division according to quantity, quality, relation, and modality, which he always has ready as though it were a universal key for philosophical problems, reveals a very strong architectonic impulse, against which even his ever active skeptical tendency is not able to keep up the battle.

[Footnote 1: Concerning this “neat observation,” Kant remarked that it might “perhaps have important consequences in regard to the scientific form of all knowledge of reason.” This prophecy was fulfilled, although in a different sense from that which floated before his mind. Fichte and Hegel composed their “thought-symphonies” in the three-four time given by Kant.]

In view of the derivation of the forms of thought from the forms of judgment Kant does not stop to give a detailed proof that the categories are concepts, and that they are pure. Their discursive (not intuitive) character is evident from the fact that their reference to the object is mediate only (and not, as in the case of intuition, immediate), and their _a priori_ origin, from the necessity which they carry with them, and which would be impossible if their origin were empirical. Here Kant starts from Hume’s criticism of the idea of cause. The Scottish skeptic had said that the necessary bond between cause and effect can neither be perceived nor logically demonstrated; that, therefore, the relation of causality is an idea which we–with what right?–add to perceived succession in time. This doubt (without the hasty conclusions), says Kant, must be generalized, must be extended to the category of substance (which had been already done by Hume, pp. 226-7, though the author of the Critique of Reason was not aware of the fact), and to all other pure concepts of the understanding. Then we may hope to kindle a torch at the spark which Hume struck out. The problem “It is impossible to see why, because something exists, something else must necessarily exist,” is the starting point alike of Hume’s skepticism and Kant’s criticism. The former recognized that the principle of causality is neither empirical nor analytic, and therefore concluded that it is an invention of reason, which confuses subjective with objective necessity. The latter shows that in spite of its subjective origin it has an objective value; that it is a truth which is independent of all experience, and yet valid for all who have experience, and for all that can be experienced.

Of the two questions, “How can the concepts which spring from our understanding possess objective validity?” and, “How (through what means or media) does their application to objects of experience take place?” the first is answered in the Deduction of the Pure Concepts of the Understanding, and the second in the chapter on their Schematism.

The _Deduction_, the most difficult portion of the Critique, shows that the objective validity of the categories, as concepts of objects in general, depends on the fact that _through them alone experience_ as far as regards the form of thought _is possible, _i.e._, it is only through them that any object whatever can be thought. All knowledge consists in judgments; all judgments contain a connection of representations; all connection–whether it be conscious or not, whether it relates to concepts or to pure or empirical intuitions–is an _act of the understanding_; it cannot be given by objects, but only spontaneously performed by the subject itself. We cannot represent anything as connected in the object unless we have ourselves first connected it. The connection includes three conceptions: that of the manifold to be connected (which is given by intuition), that of the act of synthesis, and that of the unity; this last is two-fold, an objective unity (the conception of an object in general in which the manifold is united), and a subjective unity (the unity of consciousness under which or, rather, through which the connection is effected). The categories represent the different kinds of combination, each one of these, again, being completed in three stages, which are termed the Synthesis of Apprehension in Intuition, the Synthesis of Reproduction in Imagination, and the Synthesis of Recognition in Concepts. If I wish to think the time from one noon to the next, I must (1) grasp (apprehend) the manifold representations (portions of time) in succession; (2) retain or renew (reproduce) in thought those which have preceded in passing to those which follow; (3) be conscious that that which is now thought is the same with that thought before, or know again (recognize) the reproduced representation as the one previously experienced. If the mind did not exercise such synthetic activity the manifold of representation would not constitute a whole, would lack the unity which consciousness alone can impart to it. Without this _one_ consciousness, concepts and knowledge of objects would be wholly impossible. The unity of pure self-consciousness or of “transcendental apperception” is the postulate of all use of the understanding. In the flux of internal phenomena there is no constant or abiding self, but the unchangeable consciousness here demanded is a precedent condition of all experience, and gives to phenomena a connection according to laws which determine an object for intuition, _i.e._, the conception of something in which they are necessarily connected.[1] Reference to an object is nothing other than the necessary unity of consciousness. The connective activity of the understanding, and with it experience, is possible only through “the synthetic unity of pure apperception,” the “I think,” which must be able to accompany all my representations, and through which they first become _mine_.

[Footnote 1: Object is “that which opposes the random or arbitrary determination of our cognitions,” and which causes “them to be determined in a certain way _a priori_.”]

Experience (in the strict sense) is distinguished from perception (experience in the wide sense) by its objectivity or universal validity. A judgment of perception (the sun shines upon the stone and the stone becomes warm) is only subjectively valid; while, on the other hand, a judgment of experience (the sun warms the stone) aims to be valid not only for me and my present condition, but always, for me and for everyone else. If the former is to become the latter, an _a priori_ concept must be added to the perception (in the above case, the concept of cause), under which the perception is subsumed. The category determines the perceptions in view of the form of the judgment, gives to the judgment its reference to an object, and thus gives to the percepts, or rather, concepts (sunshine and warmth), necessary and universally valid connection. The “reason why the judgments of others” must “agree with mine” is “the unity of the object to which they all relate, with which they agree, and hence must also all agree with one another.”

Though the categories take their origin in the nature of the subject, they are objective and valid for objects of experience, because experience is possible alone through them. They are not the product, but the ground of experience. The second difficulty concerns their applicability to phenomena, which are wholly disparate. By what means is the gulf between the categories, which are concepts and _a priori_, and perceptions, which are intuitous and empirical, bridged over? The connecting link is supplied by the imagination, as the faculty which mediates between sensibility and understanding to provide a concept with its image, and consists in the intuition of time, which, in common with the categories, has an _a priori_ character, and, in common with perceptions, an intuitive character, so that it is at once pure and sensuous. The subsumption of phenomena or empirical intuitions under the category is effected through the _Schemata_[1] of the concepts of the understanding, _i.e._, through _a priori_ determinations of time according to rules, which relate to time-_series_, time-_content_, time-_order_, and time-_comprehension_, and indicate whether I have to apply this or that category to a given object.

[Footnote 1: The schema is not an empirical image, but stands midway between this (the particular intuition of a definite triangle or dog) and the unintuitable concept, as a general intuition (of a triangle or a dog in general, which holds alike for right- and oblique-angled triangles, for poodles and pugs), or as a rule for determining our intuition in accordance with a concept.]

Each category has its own schema. The schema of quantity is number, as comprehending the successive addition of homogeneous parts. Filled time (being in time) is the schema of reality, empty time (not-being in time) the schema of negation, and more or less filled time (the intensity of sensation, indicating the degree of reality) the schema of limitation. Permanence in time is the sign for the application of the category of substance;[1] regular succession, for the application of the concept of cause; the coexistence of the determinations of one substance with those of another, the signal for their subsumption under the concept of reciprocity. The schemata of possibility, actuality, and necessity, finally, are existence at any time whatever (whensoever), existence at a definite time, and existence at all times. By such schematic syntheses the pure concept is brought near to the empirical intuition, and the way is prepared for an application of the former to the latter, or, what is the same thing, for the subsumption of the latter under the former.

[Footnote 1: This determination is important for psychology. Since the inner sense shows nothing constant, but everything in a continual flux,–for the permanent subject of our thoughts is an identical activity of the understanding, not an intuitable object,–the concept of substance is not applicable to psychical phenomena. Representations of a permanent (material substances) exist, indeed, but not permanent representations. The abiding self (ego, soul) which we posit back of internal phenomena is, as the Dialectic will show, a mere Idea, which, or, rather, the object of which, maybe “thought” as substance, it is true, but cannot be “given” in intuition, hence cannot be “known.”]

As a result of the fact that the schematism permits a presentation of the categories in time intuition antecedent to all experience, the possibility is given of synthetic judgments _a priori_ concerning objects of possible experience. Such judgments, in so far as they are not based on higher and more general cognitions, are termed “principles,” and the system of them–to be given, with the table of the categories as a guide, in the _Analytic of Principles_ or the Doctrine of the Faculty of Judgment–furnishes the outlines of “pure natural science.” When thus the rules of the subsumption to be effected have been found in the pure concepts, and the conditions and criteria of the subsumption in the schemata, it remains to indicate the principles which the understanding, through the aid of the schemata, actually produces _a priori_ from its concepts.

The principle of quantity is the _Axiom of Intuition_, the principle of quality the _Anticipation of Perception_; the principles of relation are termed _Analogies of Experience_, those of modality _Postulates of Empirical Thought in General_. The first runs, “All intuitions are extensive quantities”; the second, “In all phenomena sensation, and the real which corresponds to it in the object, has an intensive quantity, i.e., a degree.” The principle of the “Analogies” is, “All phenomena, as far as their existence is concerned, are subject _a priori_ to rules, determining their mutual relation in time” (in the second edition this is stated as follows: “Experience is possible only through the representation of a necessary connection of perceptions”). As there are three modes of time, there result three “Analogies,” the principles of permanence, of succession (production), and of coexistence. These are: (1) “In all changes of phenomena the substance is permanent, and its quantum is neither increased nor diminished in nature.” (2) “All changes take place according to the law of connection between cause and effect”; or, “Everything that happens (begins to be) presupposes something on which it follows according to a rule.” (3) “All substances, in so far as they are coexistent, stand in complete community, that is, reciprocity, one to another.” And, finally, the three “Postulates”: “That which agrees with the formal conditions of experience (in intuition and in concepts) is possible,” “That which is connected with the material conditions of experience (sensation) is actual” (perception is the only criterion of actuality). “That which, in its connection with the actual, is determined by universal conditions of experience, is (exists as) necessary.”

As the categories of substance and causality are specially preferred to the others by Kant and the Kantians, and are even proclaimed by some as the only fundamental concepts, so also the principles of relation have an established reputation for special importance. The leading ideas in the proofs of the “Analogies of Experience”–for in spite of their underivative character the principles require, and are capable of, proof–may next be noted.

The time determinations of phenomena, the knowledge of their duration, their succession, and their coexistence, form an indispensable part of our experience, not only of scientific experience, but of everyday experience as well. How is the objective time-determination of things and events possible? If the matter in hand is the determination of the particulars of a fight with a bloody ending, the witnesses are questioned and testify: We heard and saw how A began the quarrel by insulting B, and the latter answered the insult with a blow, whereupon A drew his knife and wounded his opponent. Here the succession of perceptions on the part of the persons present is accepted as a true reproduction of the succession of the actual events. But the succession of perceptions is not always the sure indication of an actual succession: the trees along an avenue are perceived one after the other, while they are in reality coexistent. We might now propose the following statement: The representation of the manifold of phenomena is always successive, I apprehend one part after another. I can decide whether these parts succeed one another in the object also, or whether they are coexistent, by the fact that, in the second case, the series of my perceptions is reversible, while in the first it is not. I can, if I choose, direct my glance along the avenue in such a way that I shall begin the second time with the tree at which I left off the first time; if I wish to assure myself that the parts of a house are coexistent, I cause my eye to wander from the upper to the lower portions, from the right side to the left, and then to perform the same motions in the opposite direction. On the other hand, it is not left to my choice to hear the thunder either before or after I see the lightning, or to see a passing wagon now here, now there, but in these cases I am bound in the succession of my sensuous representations. The possibility of interchange in the series of perceptions proves an objective coexistence, the impossibility of this, an objective succession. But this criterion is limited to the immediate present, and fails us when a time relation between unobserved phenomena is to be established. If I go at evening into the dining room and see a vessel of bubbling water, which is to be used in making tea, over a burning spirit lamp, whence do I derive the knowledge that the water began, and could begin, to boil only after the alcohol had been lighted, and not before? Because I have often seen the flame precede the boiling of the water, and in this the irreversibility of the two perceptions has guaranteed to me the succession of the events perceived? Then I may only assume that it is very probable, not that it is certain, that in this case also the order of the two events has been the same as I have observed several times before. As a matter of fact, however, we all assert that the water could not have come into a boiling condition unless the generation of heat had preceded; that in every case the fire must be there before the boiling of the water can commence. Whence do we derive this _must_? Simply and alone from the thought of a causal connection between the two events. Every phenomenon _must_ follow in time that phenomenon of which it is the effect, and must precede that of which it is the cause. It is through the relation of causality, and through this alone, that the objective time relation of phenomena is determined. If nothing preceded an event on which it must follow according to a rule,[1] then all succession in perception would be subjective merely, and nothing whatever would be objectively determined by it as to what was the antecedent and what the consequent in the phenomenon itself. We should then have a mere play of representations without significance for the real succession of events. Only the thought of a rule, according to which the antecedent state contains the necessary condition of the consequent state, justifies us in transferring the time order of our representations to phenomena.[2] Nay, even the distinction between the phenomenon itself, as the object of our representations, and our representations of it, is effected only by subjecting the phenomenon to this rule, which assigns to it its definite position in time after another phenomenon by which it is caused, and thus forbids the inversion of the perceptions. We can derive the rule of the understanding which produces the objective time order of the manifold from experience, only because we have put it into experience, and have first brought experience into being by means of the rule. We recapitulate in Kant’s own words: The objective (time) relation of phenomena remains undetermined by mere perception (the mere succession in my apprehension, if it is not determined by means of a rule in relation to an antecedent, does not guarantee any succession in the object). In order that this may be known as determined, the relation between the two states must be so conceived (through the understanding’s concept of causality) that it is thereby determined with necessity which of them must be taken as coming first, and which second, and not conversely. Thus it is only by subjecting the succession of phenomena to the law of causality that empirical knowledge of them is possible. Without the concept of cause no objective time determination, and hence, without it, no experience.

[Footnote 1: “A reality following on an empty time, that is, a beginning of existence preceded by no state of things, can as little be apprehended as empty time itself.”]

[Footnote 2: “If phenomena were things in themselves no one would be able, from the succession of the representations of their manifold, to tell how this is connected in the object.”]

That which the relation of cause and effect does for the succession[1] of phenomena, the relation of reciprocity does for their coexistence, and that of substance and accident for their duration. Since absolute time is not an object of perception, the position of phenomena in time cannot be directly determined, but only through a concept of the understanding. When I conclude that two objects (the earth and the moon) must be coexistent, because perceptions of them can follow upon one another in both ways, I do this on the presupposition that the objects themselves reciprocally determine their position in time, hence are not isolated, but stand in causal community or a relation of reciprocal influence. It is only on the condition of reciprocity between phenomena, through which they form a whole, that I can represent them as coexistent.

[Footnote 1: Against the objection that cause and effect are frequently, indeed in most cases, simultaneous (_e.g._ the heated stove and the warmth of the room), Kant remarks that the question concerns the order of time merely, and not the lapse of time. The ball lying on a soft cushion is simultaneous, it is true, with its effect, the depression in the cushion. “But I, nevertheless, distinguish the two by the time relation of dynamical connection. For if I place the ball on the cushion, its previously smooth surface is followed by a depression, but if there is a depression in the cushion (I know not whence) a leaden ball does not follow from it.”]

Coexistence and succession can be represented only in a permanent substratum; they are merely the modes in which the permanent exists. Since time (in which all change takes place, but which itself abides and does not change) in itself cannot be perceived, the substratum of simultaneity and succession must exist in phenomena themselves: the permanent in relation to which alone all the time relations of phenomena can be determined, is substance; that which alters is its determinations, accidents, or special modes of existing. Alteration, _i.e._, origin and extinction, is true of states only, which can begin and cease to be, and not of substances, which change (_sich verändern_), i.e., pass from one mode of existence into another, but do not alter (_wechseln_), i.e., pass from non-existence into existence, or the reverse. It is the permanent alone that changes, and its states alone that begin and cease to be. The origin and extinction of substances, or the increase and diminution of their quantum, would remove the sole condition of the empirical unity of time; for the time relations of the coexistent and the successive can be perceived only in an identical substratum, in a permanent, which exists always. The law “From nothing nothing comes, and nothing can return to nothing,” is everywhere assumed and has been frequently advanced, but never yet proved, for, indeed, it is impossible to prove it dogmatically. Here the only possible proof for it, the critical proof, is given: the principle of permanence is a necessary condition of experience. The same argument establishes the principle of sufficient reason, and the principle of the community of substances, together with the unity of the world to be inferred from this. The three Analogies together assert: “All phenomena exist in one nature and must so exist, because without such a unity _a priori_ no unity of experience, and therefore no determination of objects in experience, would be possible.”–In connection with the Postulates the same transcendental proof is given for a series of other laws of nature _a priori_, viz., that in the course of the changes in the world–for the causal principle holds only for effects in nature, not for the existence of things as substances–there can be neither blind chance nor a blind necessity (but only a conditional, hence an intelligible, necessity); and, further, that in the series of phenomena, there can be neither leap, nor gap, nor break, and hence no void–_in mundo non datur casus, non datur fatum, non datur saltus, non datur hiatus_.

While the dynamical principles have to do with the relation of phenomena, whether it be to one another (Analogies), or to our faculty of cognition (Postulates), the mathematical relate to the quantity of intuitions and sensations, and furnish the basis for the application of mathematics to natural science.[1] An extensive quantity is one in which the representation of the parts makes the representation of the whole possible, and so precedes it. I cannot represent a line without drawing it in thought, i.e., without producing all parts of it one after the other, starting from a point. All phenomena are intuited as aggregates or as collections of previously given parts. That which geometry asserts of pure intuition (i.e., the infinite divisibility of lines) holds also of empirical intuition. An intensive quantity is one which is apprehended only as unity, and in which plurality can be represented only by approximation to negation = 0. Every sensation, consequently every reality in phenomena, has a degree, which, however small it may be, is never the smallest, but can always be still more diminished; and between reality and negation there exists a continuous connection of possible smaller intermediate sensations, or an infinite series of ever decreasing degrees. The property of quantities, according to which no part in them is the smallest possible part, and no part is simple, is termed their continuity. All phenomena are continuous quantities, i.e., all their parts are in turn (further divisible) quantities. Hence it follows, first, that a proof for an empty space or empty time can never be drawn from experience, and secondly, that all change is also continuous. “It is remarkable,” so Kant ends his proof of the Anticipation, “that of quantities in general we can know one _quality_ only _a priori_, namely, their continuity, while with regard to quality (the real of phenomena) nothing is known to us _a priori_ but their intensive _quantity_, that is, that they must have a degree. Everything else is left to experience.”

[Footnote 1: In each particular science of nature, science proper (i.e., apodictically certain science) is found only to the extent in which mathematics can be applied therein. For this reason chemistry can never be anything more than a systematic art or experimental doctrine; and psychology not even this, but only a natural history of the inner sense or natural description of the soul. That which Kant’s _Metaphysical Elements of Natural Science_, 1786–in four chapters, Phoronomy, Dynamics, Mechanics, and Phenomenology–advances as pure physics or the metaphysics of corporeal nature, is a doctrine of motion. The fundamental determination of matter (of a somewhat which is to be the object of the external senses) is motion, for it is only through motion that these senses can be affected, and the understanding itself reduces all other predicates of matter to this. The second and most valuable part of the work defines matter as the movable, that which fills space by its moving force, and recognizes two original forces, repulsive, expansive superficial force or force of contact, by which a body resists the entrance of other bodies into its own space, and attractive, penetrative force or the force which works at a distance, in virtue of which all particles of matter attract one another. In order to a determinate filling of space the co-operation of both fundamental forces is required. In opposition to the mechanical theory of the atomists, which explains forces from matter and makes them inhere in it, Kant holds fast to the dynamical view which he had early adopted (cf. p. 324), according to which forces are the primary factor and matter is constituted by them.]

The outcome of the Analytic of Principles sounds bold enough. _The understanding is the lawgiver of nature_: “It does not draw its laws _a priori_ from nature, but prescribes them to it”; the principles of the pure understanding are the most universal laws of nature, the empirical laws of nature only particular determinations of these. All order and regularity take their origin in the spirit, and are put into objects by this. Universal and necessary knowledge remained inexplicable so long as it was assumed that the understanding must conform itself to objects; it is at once explained if, conversely, we make objects conform themselves to the understanding. This is a reversal of philosophical opinion which may justly be compared to the Copernican revolution in astronomy; it is just as paradoxical as the latter, but just as incontestably true, and just as rich in results. The sequel will show that this strangely sounding principle, that things conform themselves to our representations and the laws of nature are dependent on the understanding, is calculated to make us humble rather than proud. Our understanding is lawgiver within the limits of its knowledge, no doubt, but it knows only within the limits of its legislative authority; nature, to which it dictates laws, is nothing but a totality of phenomena; beyond the limits of the phenomenal, where its commands become of no effect, its wishes also find no hearing.

In the second edition the Analytic of Principles contains as a supplement a “Refutation of Idealism,” which, in opposition to Descartes’s position that the only immediate experience is inner experience, from which we reach outer experience by inference alone, argues that, conversely, it is only through outer experience, which is immediate experience proper, that inner experience–as the consciousness of my own existence in time–is possible. For all time determination presupposes something permanent in perception, and this permanent something cannot be in me (the mere representation of an external thing), but only actually existing things which I perceive without me. There is, further, a chapter on the “Ground of the Distinction of all Objects in general into Phenomena and Noumena,” with an appendix on the Amphiboly (ambiguity) of the Concepts of Reflection. The latter shows that the concepts of comparison: identity and difference, agreement and opposition, the internal and the external, matter and form, acquire entirely different meanings when they relate to phenomena and to things in themselves (in other words, to things in their relation to the sensibility, and in relation to the understanding merely); and further, in a criticism of the philosophy of Leibnitz, reproaches him with having intellectualized phenomena, while Locke is said to have sensationalized the concepts of the understanding.

The chapter on the distinction between phenomena and noumena very much lessens the hopes, aroused, perchance, by the establishment of the non-empirical origin of the categories, for an application of these not confined to any experience. Although the categories, that is, are in their origin entirely independent of all experience (so much so that they first make experience possible), they are yet confined in their application within the bounds of possible experience. They “serve only to spell phenomena, that we may be able to read them as experience,” and when applied to things in themselves lose all significance.[1] Similarly the principles which spring from them are “nothing more than principles of possible experience,” and can be referred to phenomena alone, beyond which they are arbitrary combinations without objective reality. Things in themselves may be thought, but they can never be known; for knowledge, besides the empty thought of an object, implies intuitions which must be subsumed under it or by which the object must be determined. In themselves the pure concepts relate to all that is thinkable, not merely to that which can be experienced, but the schemata, which assures their applicability in the field of experience, at the same time limit them to this sphere. The schematism makes the immanent use of the categories, and thus a metaphysics of phenomena, possible, but the transcendent use of them, and consequently the metaphysics of the suprasensible, impossible. The case would be different if our intuition were intellectual instead of sensuous, or, which is the same thing, if our understanding were intuitive instead of discursive; then the objects which we think would not need to be given us from another source (through sensuous intuition), but would be themselves produced in the act by which we thought them. The divine spirit may be such an archetypal, creative understanding (_intellectus archetypus_), which generates objects by its thought; the human spirit is not such, and therefore is confined, with its knowledge, within the circle of possible perception.–The conception of “intellectual intuition” leads to a distinction in regard to things in themselves: in its negative meaning noumenon denotes a thing in so far as it is _not_ the object of our _sensuous_ intuition, in its positive meaning a thing which is the object of a _non-sensuous_ intuition. The positive thing in itself is a problematical concept; its possibility depends on the existence of an intuitive understanding, something about which we are ignorant. The negative thing in itself cannot be known, indeed, but it can be thought; and the representation of it is a possible concept, one which is not self-contradictory[2] (a principle which is of great importance for practical philosophy). Still further, it is an indispensable concept, which shows that the boundary where our intuition ends is not the boundary of the thinkable as well; and even if it affords no positive extension of knowledge[3] it is, nevertheless, very useful, since it sets bounds to the use of the understanding, and thus, as it were, negatively extends our knowledge. That which lies beyond the boundary, the “how are they possible” _(Wiemöglichkeit)_ of things in themselves is shrouded in darkness, but the boundary itself, _i.e._, the “that they are possible” _(Dassmöglichkeit)_, of things in themselves, and the unknowableness of their nature, belongs to that which is within the boundary and lies in the light. In this way Kant believed that the categories of causality and substance might be applied to the relation of things in themselves to phenomena without offending against the prohibition of their transcendent use, since here the boundary appeared only to be touched, and not overstepped.

[Footnote 1: “A pure use of the categories is no doubt possible, that is, not self-contradictory, but it has no kind of objective validity, because it refers to no intuition to which it is meant to impart the unity of an object. The categories remain forever mere functions of thought by which no object can be given to me, but by which I can only think whatever may be given to me in intuition” (_Critique of Pure Reason_, Max Müller’s translation, vol. ii. p. 220). Without the condition of sensuous intuition, for which they supply the synthesis, the categories have no relation to any definite object; for without this condition they contain nothing but the logical function, or the form of the concept, by means of which alone nothing can be known and distinguished as to any object belonging to it (_Ibid_., pp. 213, 214).]

[Footnote 2: The thing in itself denotes the object in so far as it can be thought by us, but not intuited, and consequently not determined by intuitions, _i.e._, cannot be known. It is only through the schematism that the categories are limited to phenomena. O. Liebmann (_Kant und die Epigonen_, p. 27, and _passim_) overlooks or ignores this when he says: Kant here allows himself to “recognize an object emancipated from the forms of knowledge, therefore an irrational object, _i.e._, to represent something which is not representable–wooden iron.” The thing in itself is insensible, but not irrational, and the forms of intuition and forms of thought joined by Liebmann under the title forms of knowledge have in Kant a by no means equal rank.]

[Footnote 3: A category by itself, freed from all conditions of intuition (_e.g._, the representation of a substance which is thought without permanence in time, or of a cause which should not act in time), can yield no definite concept of an object.]

Though the concepts of the understanding possess a cognitive value in the sphere of phenomena alone, the hope still remains of gaining an entrance into the suprasensible sphere through the concepts of reason. It is indubitable that our spirit is conscious of a far higher need than that for the mere connection of phenomena into experience; it is that which cannot be experienced, the Ideas God, freedom, and immortality, which form the real end of its inquiry. Can this need be satisfied, and how? Can this end be attained, and reality be given to the Ideas? This is the third question of the Critique of Reason.

%(c) The Reason’s Ideas of the Unconditioned (Transcendental Dialectic).%–“All our knowledge begins with the senses, proceeds thence to the understanding, and ends with reason.” The understanding is the faculty of rules, reason the faculty of principles. The categories of the understanding are necessary concepts which make experience possible, and which, therefore, can always be given in experience; the Ideas of reason are necessary concepts to which no corresponding object can be given. Each of the Ideas gives expression to an unconditioned. How does the concept of the unconditioned arise, and what service does it perform for knowledge?

As perceptions are connected by the categories in the unity of the understanding, and thus are elevated into experience, so the manifold knowledge of experience needs a higher unity, the unity of reason, in order to form a connected system. This is supplied to it by the Ideas–which, consequently, do not relate directly to the objects of intuition, but only to the understanding and its judgments–in order, through the concept of the unconditioned, to give completion to the knowledge of the understanding, which always moves in the sphere of the conditioned, _i.e._, to give it the greatest possible unity together with the greatest possible extension. The concept of the absolute grows out of the logical task which is incumbent on reason, _i.e._, inference, and it may be best explained from this as a starting point. In the syllogism the judgment asserted in the conclusion is derived from a general rule, the major premise. The validity of this general proposition is, however, itself conditional, dependent on higher conditions. Then, as reason seeks the condition for each conditioned moment, and always commands a further advance in the series of conditions, it acts under the Idea of _the totality of conditions_, which, nevertheless, since it can never be given in experience, does not denote an object, but only an heuristic maxim for knowledge, the maxim, namely, never to stop with any one condition as ultimate, but always to continue the search further. The Idea of the unconditioned or of the completeness of conditions is a goal which we never attain, but which we are continually to approach. The categories and the principles of the understanding were _constitutive_ principles, the Ideas are _regulative_ merely; their function is to guide the understanding, to give it a direction helpful for the connection of knowledge, not to inform it concerning the actual character of things.

Since reason is the faculty of inference (as the understanding was found to be the faculty of judgment), the forms of the syllogism perform the same service for us in our search for the Ideas as the forms of judgment in the discovery of the categories. To the categorical, hypothetical, and disjunctive syllogisms correspond the three concepts of reason, the soul or the thinking subject, the world or the totality of phenomena, and God, the original being or the supreme condition of the possibility of all that can be thought. By means of these we refer all inner phenomena to the ego as their (unknown) common subject, think all beings and events in nature as ordered under the comprehensive system of the (never to be experienced) universe, and regard all things as the work of a supreme (unknowable) intelligence. These Ideas are necessary concepts; not accidental products nor mere fancies, but concepts sprung from the nature of reason; their use is legitimate so long as we remember that we can have a problematical concept of objects corresponding to them, but no knowledge of these; that they are problems and rules for knowledge, never objects and instruments of it. Nevertheless the temptation to regard these regulative principles as constitutive and these problems as knowable objects is almost irresistible; for the ground of the involuntary confusion of the required with the given absolute lies not so much in the carelessness of the individual as in the nature of our cognitive faculty. The Ideas carry with them an unavoidable illusion of objective reality, and the sophistical inferences which spring from them are not sophistications of men, but of pure reason itself, are natural misunderstandings from which even the wisest cannot free himself. At best we can succeed in avoiding the error, not in doing away with the transcendental illusion from which it proceeds. We can see through the illusion and avoid the erroneous conclusions built upon it, not shake off the illusion itself.

On this erroneous objective use of the Ideas three so-called sciences are based: speculative psychology, speculative cosmology, and speculative theology, which, together with ontology, constitute the stately structure of the (Wolffian) metaphysics. The Critique of Reason completes its work of destruction when, as Dialectic (Logic cf. Illusion), it follows the refutation of dogmatic ontology–developed in the Analytic–which believed that it knew things in themselves through the concepts of the understanding, with a refutation of rational psychology, rational cosmology, and rational theology. It shows that the first is founded on paralogisms, and the second entangled in irreconcilable contradictions, while the third makes vain efforts to prove the existence of the Supreme Being.

(i) _The Paralogisms of Rational Psychology_. The transcendental self-consciousness or pure ego which accompanies and connects all my representations, the subject of all judgments which I form, is, as the Analytic recognized, the presupposition of all knowing (pp. 358-359), but as such it can never become an object of knowledge. We must not make a given object out of the subject which never can be a predicate, nor substitute a real thinking substance for the logical subject of thought, nor revamp the unity of self-consciousness into the simplicity and identical personality of the soul. The rational psychology of the Wolffian school is guilty of this error, and whatever of proof it advances for the substantiality, simplicity, and personality of the soul, and, by way of deduction, for its immateriality and immortality as well as for its relation to the body, is based upon this substitution, this ambiguity of the middle term, and therefore upon a _quaternio terminorum_,–all its conclusions are fallacious. It is allowable and unavoidable to add in thought an absolute subject, the unity of the ego, to inner phenomena;[1] it is inadmissible to treat the Idea of the soul as a knowable thing. In order to be able to apply the category of substance to it, we would have to lay hold of a permanent in intuition such as cannot be found in the inner sense. Empirical psychology, then, alone remains for the extension of our knowledge of mental life, while rational psychology shrivels up from a doctrine into a mere discipline, which watches that the limits of experience are not overstepped. But even as a mere limiting determination it has great value. For, along with the hope of proving the immateriality and immortality of the soul, the fear of seeing them _disproved_ is also dissipated; materialism is just as unfounded as spiritualism, and if the conclusions of the latter concerning the soul as a simple, immaterial substance which survives the death of the body, cannot be proved, yet we need not, for that reason, regard them as erroneous, for the opposite is as little susceptible of demonstration. The whole question belongs not in the forum of knowledge, but in the forum of faith, and that which we gain by the proof that nothing can be determined concerning it by theoretical reasoning (viz., assurance against materialistic objections) is far more valuable than what we lose.

[Footnote 1: The rational concept of the soul as a simple, independent intelligence does not signify an actual being, but only expresses certain principles of systematic unity in the explanation of psychical phenomena, viz., “To regard all determinations as existing in one subject, all powers, as far as possible, as derived from, one fundamental power, all change as belonging to the states of one and the same permanent being, and to represent all phenomena in space as totally distinct from acts of thought.”]

(2) _The Antinomies of Rational Cosmology_. If in its endeavor to spin metaphysical knowledge concerning the nature of the spirit and the existence of the soul after death out of the concept of the thinking ego the reason falls into the snare of an ambiguous _terminus medius_, the difficulties which frustrate its attempts to use the Idea of the world in the extension of its knowledge _a priori_ are of quite a different character. Here the formal correctness of the method of inference is not open to attack. It may be proved with absolute strictness (and in the apagogical or indirect form, from the impossibility of the contrary) that the world has a beginning in time, and also that it is _limited_ in space; that every compound substance consists of _simple_ parts; that, besides the causality according to the laws of nature, there is a causality through _freedom_, and that an _absolutely necessary Being_ exists, either as a part of the world or as the cause of it. But the contrary may be proved with equal stringency (and indirectly, as before): The world is infinite in space and time; there is nothing simple in the world; there is no freedom, but everything in the world takes place entirely according to the laws of nature; and there exists no absolutely necessary Being either within the world or without it. This is the famous doctrine of the conflict of the four cosmological theses and antitheses or of the Antinomy of Pure Reason, the discovery of which indubitably exercised a determining influence upon the whole course of the Kantian Critique of Reason, and which forms one of its poles. The transcendental idealism, the distinction between phenomena and noumena, and the limitation of knowledge to phenomena, all receive significant confirmation from the Antithetic. Without the critical idealism (that which is intuited in space and time, and known through the categories, is merely the phenomenon of things, whose “in itself” is unknowable), the antinomies would be insoluble. How is reason to act in view of the conflict? The grounds for the antitheses are just as conclusive as those for the theses; on neither side is there a preponderance which could decide the result. Ought reason to agree with both parties or with neither?

The solution distinguishes the first two antinomies, as the mathematical, from the second two, as the dynamical antinomies; in the former, since it is a question of the composition and division of quanta, the conditions may be homogeneous with the conditioned, in the latter, heterogeneous. In the former, thesis and antithesis are alike _false_, since both start from the inadmissible assumption that the universe (the complete series of phenomena) is given, while in fact it is only required of us (is an Idea). The world does not exist in itself, but only in the empirical regress of phenomenal conditions, in which we never can reach infinity and never the limitation of the world by an empty space or an antecedent empty time, for infinite space, like empty space (and the same holds in regard to time), is not perceivable. Consequently the quantity of the world is neither finite nor infinite. The question of the quantity of the world is unanswerable, because the concept of a sense-world existing by itself _(before_ the regress) is self-contradictory. Similarly the problem whether the composite consists of simple elements is insoluble, because the assumption that the phenomenon of body is a thing in itself, which, antecedent to all experience, contains all the parts that can be reached in experience–in other words, that representations exist outside of the representative faculty–is absurd. Matter is infinitely divisible, no doubt, yet it does not consist of infinitely numerous parts, and just as little of a definite number of simple parts, but the parts exist merely in the representation of them, in the division (decomposition), and this goes as far as possible experience extends. The case is different with the dynamical antinomies, where thesis and antithesis can both be _true_, in so far as the former is referred to things in themselves and the latter to phenomena. The contradiction vanishes if we take that which the thesis asserts and the antithesis denies in different senses. The fact that in the world of phenomena the causal nexus proceeds without interruption and without end, so that there is no room in it either for an absolutely necessary Being or for freedom, does not conflict with this other, that beyond the world of sense there may exist an omnipotent, omniscient cause of the world, and an intelligible freedom as the ground of our empirically necessary actions. “May exist,” since for the critical philosopher, who has learned that every extension of knowledge beyond the limits of experience is impossible, the question can concern only the conceivability of the world-ground and of freedom. This possibility is amply sufficient to give a support for faith, as, on the other hand, it is indispensable in order to satisfy at once the demands of the understanding and of reason, especially to satisfy their practical interests. For if it were not possible to resolve the apparent contradiction, and to show its members capable of reconciliation, it would be all over either with the possibility of experiential knowledge or with the basis of ethics and religion. Without unbroken causal connection, no nature; without freedom, no morality; and without a Deity, no religion. Of special interest is the solution of the third antinomy, which is accomplished by means of the valuable (though in the form in which it is given by Kant, untenable) conception of the _intelligible character_.[1] Man is a citizen of two worlds. As a being of the senses (phenomenon) he is subject in his volition and action to the control of natural necessity, while as a being of reason (thing in itself) he is free. For science his acts are the inevitable results of precedent phenomena, which, in turn, are themselves empirically caused; nevertheless moral judgment holds him responsible for his acts. In the one case, they are referred to his empirical character, in the other, to his intelligible character. Man cannot act otherwise than he does act, if he be what he is, but he need not be as he is; the moral constitution of the intelligible character, which reflects itself in the empirical character, is his own work, and its radical transformation (moral regeneration) his duty, the fulfillment of which is demanded, and, hence, of necessity possible.

[Footnote 1: On the difficulties in the way of this theory and the possibility of their removal cf. R. Falckenberg, _Ueber den intelligiblen Character, zur Kritik der Kantischen Freiheitslehre_ (from the _Zeitschrift für Philosophie_, vol. lxxv.), Halle, 1879.]

(3) _Speculative Theology_. The principle of complete determination, according to which of all the possible predicates of things, as compared with their opposites, one must belong to each thing, relates the thing to be determined to the sum of all possible predicates or the _Idea of an ens realissimum_, which, since it is the representation of a single being, may be called the _Ideal_ of pure reason. From this prototype things, as its imperfect copies, derive the material of their possibility; all their manifold determinations are simply so many modes of limiting the concept of the highest reality, which is their common substratum, just as all figures are possible only as different ways of limiting infinite space. Or better: the derivative beings are not related to the ideal of the original Being as limitations to the sum of the highest reality (on which view the Supreme Being would be conceived as an aggregate consisting of the derivative beings, whereas these presuppose it, and hence cannot constitute it), but as consequences to a ground. But reason does not remain content with this entirely legitimate thought of the dependence of finite things on the ideal of the Being of all beings, as a relation of concepts to the Idea, but, dazzled by an irresistible illusion, proceeds to realize, to hypostatize, and to personify this ideal, and, since she herself is dimly conscious of the illegitimacy of such a transformation of the mere Idea into a given object, devises _arguments for the existence of God_. Reason, moreover, would scarcely be induced to regard a mere creation of its thought as a real being, if it were not compelled from another direction to seek a resting place somewhere in the regress of conditions, and to think the empirical reality of the contingent world as founded upon the rock of something absolutely necessary. There is no being, however, which appears more fit for the prerogative of absolute necessity than that one the concept of which contains the therefore to every wherefore, and is in no respect defective; in other words, rational theology joins the rational ideal of the most perfect Being with the fourth cosmological Idea of the absolutely necessary Being.

The proof of the existence of God may be attempted in three ways: we may argue the existence of a supreme cause either by starting from a definite experience (the special constitution and order of the sense-world, that is, its purposiveness), or from an indefinite experience (any existence whatever), or, finally, abstracting from all experience, from mere concepts _a priori_. But neither the empirical nor the transcendent nor the intermediate line of thought leads to the goal. The most impressive and popular of the proofs is the _physico-theological_ argument. But even if we gratuitously admit the analogy of natural products with the works of human art (for the argument is not able to prove that the purposive arrangement of the things in the world, which we observe with admiration, is contingent, and could only have been produced by an ordering, rational principle, not self-produced by their own nature according to general mechanical laws), this can yield an inference only to an intelligent author of the purposive form of the world, and not to an author of its matter, only, therefore, to a world-architect, not to a world-creator. Further, since the cause must be proportionate to the effect, this argument can prove only a very wise and wonderfully powerful, but not an omniscient and omnipotent, designer, and so cannot give any definite concept of the supreme cause of the world. In leaping from the contingency of the purposive order of the world to the existence of something absolutely necessary and thence to an all-comprehensive reality, the teleological argument abandons the ground of experience and passes over into the _cosmological argument_, which in its turn is merely a concealed ontological argument (these two differ only in the fact that the cosmological proof argues from the antecedently given absolute necessity of a being to its unlimited reality, and the ontological, conversely, from supreme reality to necessary existence). The weaknesses of the cosmological argument in its first half consist in the fact that, in the inference from the contingent to a cause for it, it oversteps the boundary of the sense-world, and, in the inference from the impossibility of an infinite series of conditions to a first cause, it employs the subjective principle of investigation–to assume hypothetically a necessary ultimate ground in behalf of the systematic unity of knowledge–as an objective principle applying to things in themselves. The _ontological argument_, finally, which the two nominally empirical arguments hoped to avoid, but in which in the end they were forced to take refuge, goes to wreck on the impossibility of dragging out of an idea the existence of the object corresponding to it. Existence denotes nothing further than the position of the subject with all the marks which are thought in its concept–that is, its relation to our knowledge, but does not itself belong to the predicates of the concept, and hence cannot be analytically derived from the latter. The content of the concept is not enriched by the addition of being; a hundred real dollars do not contain a penny more than a hundred conceived dollars. All existential propositions are synthetic; hence the existence of God cannot be demonstrated from the concept of God. It is a contradiction, to be sure, to say that God is not almighty, just as it is a contradiction to deny that a triangle has three angles: _if_ posit the concept I must not remove the predicate which necessarily belongs to it. If I remove the subject, however, together with its predicate (the almighty God is not), no contradiction arises, for in that case nothing remains to be contradicted.

Thus all the proofs for the existence of a necessary being are shown to be illusory, and the basis of speculative theology uncertain. Nevertheless the idea of God retains its validity, and the perception of the inability of reason to demonstrate its objective reality on theoretical grounds has great value. For though the existence of God cannot be proved, it is true, by way of recompense, that it cannot be disproved; the same grounds which show us that the assertion of his existence is based on a weak foundation suffice also to prove every contrary assertion unfounded. And should practical motives present themselves to turn the scale in favor of the assumption of a supreme and all-sufficient Being, reason would be obliged to take sides and to follow these grounds, which, it is true, are not objectively sufficient,[1] but still preponderant, and than which we know none better. After, however, the objective reality of the idea of God is guaranteed from the standpoint of ethics, there remains for transcendental theology the important negative duty (“censorship,” _Censor_) of exactly determining the concept of the most perfect Being (as a being which through understanding and freedom contains the first ground of all other things), of removing from it all impure elements, and of putting an end to all opposite assertions, whether atheistic, deistic (deism maintains the possibility of knowing the existence of an original being, but declares all further determination of this being impossible), or (in the dogmatic sense) anthropomorphic. Theism is entirely possible apart from a mistaken anthropomorphism, in so far as through the predicates which we take from inner experience (understanding and will) we do not determine the concept of God as he is in himself, but only _analogically_[2] in his relation to the world. That concept serves only to aid us in our contemplation of the world,[3] not as a means of knowing the Supreme Being himself. For speculative purposes it remains a mere ideal, yet a perfectly faultless one, which completes and crowns the whole of human knowledge.

[Footnote 1: “They need favor to supply their lack of legitimate claims.” Of themselves alone, therefore, they are unable to yield any theological knowledge, but they are fitted to prepare the understanding for it, and to give emphasis to other possible (moral) proofs.]

[Footnote 2: We halt _at_ the boundary of the legitimate use of reason, without overstepping it, when we limit our judgment to the relation of the world to the Supreme Being, and in this allow ourselves a symbolical anthropomorphism only, which in reality has reference to our language alone and not to the object.]

[Footnote 3: We are compelled to _look on_ the world _as if_ it were the work of a supreme intelligence and will. “We may confidently derive the phenomena of the world and their existence from other (phenomena), as if no necessary being existed, and yet unceasingly strive after completeness in the derivation, as though such a being were presupposed as a supreme ground.” In short, physical (mechanical) _explanation_, and a theistic point of view or teleological _judgment_.]

Thus the value of the Ideas is twofold. By showing the untenable ness of atheism, fatalism, and naturalism, they I clear the way for the objects of faith. By providing natural science with the standpoint of a systematical unity through teleological connection, they make an extension of the use of the understanding possible within the realm of experience,[1] though not beyond it. The systematic development of the Kantian teleology, which is here indicated in general outlines only, is found in the second part of the _Critique of Judgment_; while the practical philosophy, which furnishes the only possible proof, the moral proof, for the reality of the Ideas, erects on the site left free by the removal of the airy summer-houses of dogmatic metaphysics the solid mansion of critical metaphysics, that is, the metaphysics of duties and of hopes. “I was obliged to destroy knowledge in order to make room for faith.” The transition from the impossible theoretical or speculative knowledge of things in themselves to the possible “practical knowledge” of them (the belief that there is a God and a future world) is given in the _Doctrine of Method_, which is divided into four parts (the Discipline, the Canon, the Architectonic, and the History of Pure Reason), in its second chapter. There, in the ideal of the _Summum Bonum_, the proof is brought forward for the validity of the Ideas God, freedom, and immortality, as postulates inseparable from moral obligation; and by a cautious investigation of the three stages of assent (opinion, knowledge, and belief) both doctrinal and moral belief are assigned their places in the system of the kinds of knowledge.

[Footnote 1: The principle to regard all order in the world (_e.g._, the shape of the earth, mountains, and seas, the members of animal bodies) as if it proceeded from the design of a supreme reason leads the investigator on to various discoveries.]

We may now sum up the results of the three parts of Kant’s theoretical philosophy. The pure intuitions, the categories, and the Ideas are functions of the spirit, and afford non-empirical _(erfahrungsfreie)_ knowledge concerning the objects of possible experience (and concerning the possibility of knowledge). The first make universal and necessary knowledge possible in relation to the forms under which objects can be given to us; the second make a similarly apodictic knowledge possible in relation to the forms under which phenomena must be thought; the third make possible a judgment of phenomena differing from this knowledge, yet not in conflict with it. The categories and the Ideas, moreover, yield problematical concepts of objects which are not given to us in intuition, but which may exist outside of space and time: things in themselves cannot be known, it is true, but they can be thought, a fact of importance in case we should be assured of their existence in some other way than by sensuous intuition.

The determination of the limits of speculative reason is finished. All knowing and all demonstration is limited to phenomena or possible experience. But the boundary of that which can be experienced is not the boundary of that which is, still less of that which ought to be; the boundary of theoretical reason is not the boundary of practical reason. We _ought_ to act morally; in order to be able to do this we must ascribe to ourselves the power to initiate a series of events; and, in general, we are warranted in assuming everything the non-assumption of which makes moral action impossible. If we were merely theoretical, merely experiential beings, we should lack all occasion to suppose a second, intelligible world behind and above the world of phenomena; but we are volitional and active beings under laws of reason, and though we are unable to know things in themselves, yet we may and must _postulate_ them–our freedom, God, and immortality. For not only that which is a condition of experience is true and necessary, but that, also, which is a condition of morality. The discovery of the laws and conditions of morality is the mission of practical philosophy.

%2. Theory of Ethics.%

The investigation now turns from the laws of nature, which express a “must,” to the laws of will, in which an “ought” is expressed, and by which certain actions are not compelled, but prescribed. (If we were merely rational, and not at the same time sensuous beings, the moral law would determine the will in the form of a natural law; since, however, the constant possibility of deviation is given in the sensibility, or, rather, the moral standpoint can only be attained by conquering the sensuous impulses, therefore the moral law speaks to us in the form of an “ought,” of an imperative.) Among the laws of the will or imperatives, also, there are some which possess the character of absolute necessity and universality, and which, consequently, are _a priori_. As the understanding dictates laws to the phenomenal world, so practical reason gives a law to itself, is _autonomous_; and as the _a priori_ laws of nature relate only to the form of the objects of experience, so the moral law determines not the content, but only the form of volition: “Act only on that maxim whereby thou canst at the same time will that it should become a universal law.” The law of practical reason is a “categorical imperative.” What does this designation mean, and what is the basis of the formula of the moral law which has just been given?

Practical principles are either subjectively valid, in which case they are termed maxims (volitional principles of the individual), or objectively valid, when they are called imperatives or precepts. The latter are either valid under certain conditions (If you wish to become a clergyman you must study theology; he who would prosper as a merchant must not cheat his customers), or unconditionally valid (Thou shalt not lie). All prudential or technical rules are hypothetical imperatives, the moral law is a categorical imperative. The injunction to be truthful is not connected with the condition that we intend to act morally, but this general purpose, together with all the special purposes belonging to it, to avoid lying, etc., is demanded unconditionally and of everyone–as surely as we are rational beings we are under moral obligation, not in order to reputation here below and happiness above, but without all “ifs” and “in order to’s.” Thou shalt unconditionally, whatever be the outcome. And as the moral law is independent of every end to be attained, so it suffers neither increase nor diminution in its binding force, whether men obey it or not. It has absolute authority, no matter whether it is fulfilled frequently or seldom, nay, whether it is fulfilled anywhere or at any time whatsoever in the world!

There is an important difference between the good which we are under obligation to do and the evil which we are under obligation not to do, and the goods and ills which we seek and avoid. The goods are always relatively good only, _good for something_–as means to ends–and a bad use can be made of all that nature and fortune give us as well as a good one. That which duty commands is an end in itself, in itself good, absolutely worthful, and no misuse of it is possible. It might be supposed that pleasure, that happiness is an ultimate end. But men have very different opinions in regard to what is pleasant, one holding one thing pleasurable and another another. It is impossible to discover by empirical methods what duty demands of all men alike and under all circumstances; the appeal is to our reason, not to our sensibility. If happiness were the end of rational beings, then nature had endowed us but poorly for it, since instead of an unfailing instinct she has given us the weak and deceitful reason as a guide, which, with its train, culture, science, art, and luxury, has brought more trouble than satisfaction to mankind. Man has a destiny other than well-being, and a higher one–the formation of good dispositions: here we have the only thing in the whole world that can never be used for evil, the only thing that does not borrow its value from a higher end, but itself originally and inalienably contains it, and that gives value to all else that merits esteem. “Nothing can possibly be conceived in the world, or even out of it, which can be called good without qualification, except a _good will_.” Understanding, courage, moderation, and whatever other mental gifts or praiseworthy qualities of temperament may be cited, as also the gifts of fortune, “are undoubtedly good and desirable in many respects, but they may also become extremely evil and mischievous, if the will which is to make use of them is not good.” These are the classic words with which Kant commences the _Foundation of the Metaphysics of Ethics_.

When does the will deserve the predicate “good”? Let us listen to the popular moral consciousness, which distinguishes three grades of moral recognition. He who refrains from that which is contrary to duty, no matter from what motives–as, for example, the shopkeeper who does not cheat because he knows that honesty is the best policy–receives moderate praise for irreproachable outward behavior. We bestow warmer praise and encouragement on him whom ambition impels to industry, kind feeling to beneficence, and pity to render assistance. But he alone earns our esteem who does his duty for duty’s sake. Only in this third case, where not merely the external action, nor merely the impulse of a happy disposition, but the will itself, the maxim, is in harmony with the moral law, where the good is done for the sake of the good, do we find true morality, that unconditioned, self-grounded worth. The man who does that which is in accordance with duty out of reflection on its advantages, and he who does it from immediate–always unreliable–inclination, acts _legally_; he alone acts _morally_ who, without listening to advantage and inclination, takes up the law into his disposition, and does his duty because it is duty. The sole moral motive is the consciousness of duty, _respect for the moral lazy_[1]

[Footnote 1: The respect or reverence which the law, and, derivatively, the person in whom it is realized, compel from us, is, as self-produced through a concept of reason and as the only feeling which can be known _a priori_, specifically different from all feelings of inclination or fear awakened by sensuous influences. As it strengthens and raises our rational nature, the consciousness of our freedom and of our high destination, but, at the same time, humbles our sensibility, there is mingled with the joy of exaltation a certain pain, which permits no intimate affection for the stern and sublime law. It is not quite willingly that we pay our respect–just because of the depressing effect which this feeling exerts on our self-love.]

Here Kant is threatened by a danger which he does not succeed in escaping. The moral law demands perfect purity in our maxims; only the idea of duty, not an inclination, is to determine the will. Quite right. Further, the one judging is himself never absolutely certain, even when his own volition is concerned, that no motives of pleasure have mingled with the feeling of duty in contributing to the right action, unless that which was morally demanded has been contrary to all his inclinations. When a person who is not in need and who is free from cupidity leaves the money-box intrusted to his care untouched, or when a man who loves life overcomes thoughts of suicide, I may assume that the former was sufficiently protected against the temptation by his moderation, and the other by his cheerful disposition, and I rate their behavior as merely legal. When, on the other hand, an official inclined to extravagance faithfully manages the funds intrusted to him, or one who is oppressed by hopeless misery preserves his life, although he does not love it, then I may ascribe the abstinence from wrongdoing to moral principles. This, too, may be admitted. We are certain of the morality of a resolution only when it can be shown that no inclination was involved along with the maxim. The cases where the right action is performed in opposition to inclination are the only ones in which we may be certain that the moral quality of the action is unmixed–are they, then, the only ones in which a moral disposition is present? Kant rightly maintains that the admixture of egoistic motives beclouds the purity of the disposition, and consequently diminishes its moral worth. With equal correctness he draws attention to the possibility that, even when we believe that we are acting from pure principles, a hidden sensuous impulse may be involved. But he leaves unconsidered the possibility that, even when the inclinations are favorable to right action, the action may be performed, not from inclination, but because of the consciousness of duty. Given that a man is naturally industrious, does this happy predisposition protect him from fits of idleness? And if he resists them, must it always be his inclination to activity and never moral principle which overcomes the temptation? In yielding to the danger of confounding the limits of our certain knowledge of the purity of motives with the limits of moral action, and in admitting true morality only where action proceeds from principle in opposition to the inclinations, Kant really deserves the reproach of rigorism or exaggerated purism–sometimes groundlessly extended to the justifiable strictness of his views–and the ridicule of the well-known lines of Schiller (“Scruples of Conscience” and “Decision” at the conclusion of his distich-group “The Philosophers”):

“The friends whom I love I gladly would serve, but to this inclination incites me;
And so I am forced from virtue to swerve since my act, through affection, delights me.
The friends whom thou lovest thou must first seek to scorn, for to no other way can I guide thee;
‘Tis alone with disgust thou canst rightly perform the acts to which duty would lead thee.”

If we return from this necessary limitation of a groundless inference (that true morality is present only when duty is performed against our inclinations, when it is difficult for us, when a conflict with sensuous motives has preceded), to the development of the fundamental ethical conceptions, we find that important conclusions concerning the origin and content of the moral law result from the principle obtained by the analysis of moral judgment: this law commands with _unconditional authority_–for every rational being and under all circumstances–what has _unconditioned worth_–the disposition which corresponds to it. The universality and necessity (_unconditionalness_) of the categorical imperative proves that it springs from no other source than reason itself. Those who derive the moral law from the will of God subject it to a condition, viz., the immutability of the divine will. Those who find the source of moral legislation in the pursuit of happiness make rational will dependent on a natural law of the sensibility; it would be folly to enjoin by a moral law that which everyone does of himself, and does superabundantly. Moreover, the theories of the social inclinations and of moral sense fail of their purpose, since they base morality on the uncertain ground of feeling. Even the principle of perfection proves insufficient, inasmuch as it limits the individual to himself, and, in the end, like those which have preceded, amounts to a refined self-love. Theonomic ethics, egoistic ethics, the ethics of sympathy, and the ethics of perfection are all eudemonistic, and hence heteronomic. The practical reason[1] receives the law neither from the will of God nor from natural impulse, but draws it out of its own depths; it binds itself.

[Footnote 1: Will and practical reason are identical. The definition runs: Will is the faculty of acting in accordance with the representation of laws.]

The grounds which establish the derivation of the moral law from the will or reason itself exclude at the same time every material determination of it. If the categorical imperative posited definite ends for the will, if it prescribed a direction to definite objects, it could neither be known _a priori_ nor be valid for all rational beings: its apodictic character forbids the admission of empirical elements of every sort.[1] If we think away all content from the law we retain the form of universal legality,[2] and gain the formula: “Act so that the maxim of thy will can always at the same time hold good as a principle of universal legislation.” The possibility of conceiving the principle of volition as a universal law of nature is the criterion of morality. If you are in doubt concerning the moral character of an action or motive simply ask yourself the question, What would become of humanity if everyone were to act according to the same principle? If no one could trust the word of another, or count on aid from others, or be sure of his property and his life, then no social life would be possible. Even a band of robbers cannot exist unless certain laws are respected as inviolable duties.

[Footnote 1: The moral law, therefore, is independent of all experience in three respects, as to its origin, its content, and its validity. It springs from reason, it contains a formal precept only, and its validity is not concerned, whether it meets with obedience or not. It declares what ought to be done, even though this never should be done.]

[Footnote 2: The “formal principle” of the Kantian ethics has met very varied criticism. Among others Edmund Pfleiderer (_Kantischer Kritizismus und Englische Philosophie_, 1881) and Zeller express themselves unfavorably, Fortlage and Liebmann (_Zur Analysis der Wirklichkeit_, 2d ed., 1880, p. 671) favorably.]

It was indispensable to free the supreme formula of the moral law from all material determinations, _i.e._, limitations. This does not prevent us, however, from afterward giving the abstract outline a more concrete coloring. First of all, the concept of the dignity of persons in contrast to the utility of things offers itself as an aid to explanation and specialization. Things are means whose worth is always relative, consisting in the useful or pleasant effects which they exercise, in the satisfaction