The Philosophy of Spiritual Activity
GA 4
IV. The World as Perception
[ 1 ] Through thinking, concepts and ideas arise. What a concept is cannot be said in words. Words can only make the human being aware of the fact that he has concepts. When someone sees a tree, his thinking reacts to his observation; to the object there comes then an ideal counterpart, and he regards the object and ideal counterpart as belonging together. When the object disappears from his field of observation, there remains behind only its ideal counterpart. The latter is the concept of the object. The more our experience broadens, the greater the sum of our concepts becomes. The concepts however by no means stand there isolated. They join themselves together into a lawful whole. The concept “organism” joins itself, for example, to the others of “lawful development” and “growth.” Other concepts formed in connection with single things merge totally into one. All the concepts that I make for myself of lions merge together into the overall concept “lion.” In this way the individual concept join themselves into a united system of concepts within which every one has its particular place. Ideas are not qualitatively different from concepts. They are only concepts that are fuller in content, more saturated, and wider in scope. I must particularly emphasize that heed be taken at this point of the fact that I have indicated thinking as my starting point and not concepts and ideas, which are first gained through thinking. These already presuppose thinking. What I have said therefore about the self-sustaining and self-determined nature of thinking cannot simply be transferred to concepts. (I state this here expressly, because herein lies my difference with Hegel. He posits the concept as primary and original.)
[ 2 ] The concept cannot be gained from observation. This is already evident from the fact that the maturing human being only slowly and gradually forms his concepts for the objects which surround him. The concepts are added to the observation.
[ 3 ] A widely read philosopher of the present day, Herbert Spencer, describes the mental process we carry out with respect to an observation in the following way:
[ 4 ] “If, when walking through the fields some day in September you hear a rustle a few yards in advance, and, on observing the ditch-side where it occurs, see the herbage agitated, you will probably turn toward the spot to learn by what this sound and motion are produced. As you approach, there flutters into the ditch a partridge; on seeing which your curiosity is satisfied—you have what you call an explanation of the appearances. The explanation, mark, amounts to this: that whereas through life you have had countless experiences of disturbance among small stationary bodies, accompanying the movement of other bodies among them, and have generalized the relation between such disturbances and such movements, you consider this particular disturbance explained on finding it to present an instance of the like relation.”1First Principles, Part I, Par. 23. When viewed more closely the matter turns out to be completely different from what is described here. When I hear a sound, I seek first of all the concept corresponding to this observation. It is only this concept that first takes me beyond the sound. Whoever does not reflect further just hears the sound and is content with that. Through my reflection, however, it is clear to me that I have to comprehend a sound as an effect. Therefore, only when I join the concept effect with the perception of the sound, am I moved to go beyond the individual observation and seek the cause. The concept “effect” calls up the concept “cause,” and I then look for the causal object, which I find in the form of the partridge. These concepts, “cause” and “effect,” however, I can never gain through mere observation, no matter how many instances it may cover. Observation calls forth thinking, and this latter first shows me the way to join the single experience to another.
[ 5 ] If one demands of a “strictly objective science” that is take its content only from observation, one must demand at the same time that it renounce all thinking Because thinking by its very nature goes beyond what is observed.
[ 6 ] This is the place now to pass from thinking to the being who thinks. For, through him thinking is joined with observation. Human consciousness is the stage upon which concept and observation meet each other and where they become joined. But this (human) consciousness is thereby characterized at the same time. It is the mediator between thinking and observation. Insofar as the human being observes a thing, this thing appears to him as given; insofar as he thinks, he appears to himself as active. He considers the thing as object, himself as the thinking subject. Because he focuses his thinking upon the observation, he has consciousness of the objects; because he directs his thinking upon himself, he has consciousness of himself or self-consciousness. Human consciousness must necessarily be self-consciousness at the same time, because it is thinking consciousness. For then thinking directs its gaze upon its own activity, it then has its own inmost being, its subject, as object before it.
[ 7 ] But the fact must not be overlooked now that it is only with the help of thinking that we are able to designate ourselves as subject ad to set ourselves over against objects. Therefore thinking must never be considered to be a merely subjective activity. Thinking is beyond subject and object. It forms these two concepts just as much as all others. When we as thinking subject, therefore, relate the concept to an object, we must not, in so doing, consider this relationship to be something merely subjective. It is not the subject that brings about the relationship, but rather thinking. The subject does not think by virtue of being subject, but rather appears to itself as a subject because it is able to think. The activity which the human being as thinking entity, exercises is therefore no merely subjective one, but rather one that is neither subjective nor objective, one that goes beyond these two concepts. I must never say that my individual subject thinks; it is much more the case that my subject itself lives by the grace of thinking. Thinking is an element that leads me out of and above my self, and joins me with objects. But it separates me from them at the same time, inasmuch as it places me over against them a subject.
[ 8 ] This is the basis for the double nature of the human being: he thinks and thereby encompasses himself and the rest of the world; but he must, by means of thinking, at the same time designate himself as an individual that stands over and against the things.
[ 9 ] The next thing will now be to ask ourselves how the other element—which we have up to now merely called object of observation, and which encounters thinking within our consciousness—come into our consciousness?
[ 10 ] In order to answer this question we must exclude from our field of observation everything that has already been brought into it through thinking. For our content of consciousness at any given moment is already permeated with concepts in the most manifold way.
[ 11 ] We must picture to ourselves a being with fully developed human intelligence arising out of nothingness and approaching the world. What he would become aware of in it, before he brought his thinking into activity, is the pure content of observation. The world would then show this being only the bare aggregate, without interconnection of the objects of sensation: colors, tones, sensations of pressure, warmth, taste, and smell; then feelings of pleasure and displeasure. This aggregate is the content of pure observation without thoughts. Over against it stands thinking, which is ready to unfold its activity when a point of attack is found. Experience soon teaches us that a point is found. Thinking is capable of drawing threads from one element of observation to the other. Thinking connects definite concepts with these elements and brings them thereby into a relationship. We have already seen above, how a sound confronting us is joined with another observation through the fact that we designate the former as the effect of the latter.
[ 12 ] When we now recall that the activity of thinking is absolutely not to be taken as subjective, we will thus also not be tempted to believe that such connections, established through thinking, have a merely subjective validity.
[ 13 ] It will now be a matter, through thinking considerations of seeking the connection which the directly given content of observation described above has to our conscious subject.
[ 14 ] Because of the variability in the use of language it seems advisable for me to come to an understanding with my reader about the use of a word which I will have to employ in what follows. I will call the immediate objects of sensation enumerated above perceptions, insofar as the conscious subject takes cognizance of them through observation. I therefore use this word to indicate, not the process of observation, but rather the object of this observation.
[ 15 ] I do not choose the term sensation, because in physiology this has a definite meaning that is narrower than my concept of perception. An emotion within myself can certainly be called a perception, but not a sensation in the physiological sense. I come to know even my emotions through their becoming perceptions for me. And the way we come to know our thinking through observation is such, that we can also use the word perception for thinking as it first appears to our consciousness.
[ 16 ] The naive person considers his perceptions, in the way they immediately appear to him, as things having an existence completely independent of him. When he sees a tree, he believes right away that it is standing there in that spot toward which his gaze is directed, in the shape he sees, with the colors its parts have, etc. When the same person sees the sun appear in the morning as a disk on the horizon, and follows the course of this disk, he believes that all this exists and occurs in this way (in and for itself), just as he observes it to. He holds fast to his belief, until he meets other perceptions that contradict his former ones. The child, who does not yet have any experience of distance, reaches for the moon, and corrects the way he had first seen it to be only when a second perception is found to be in contradiction with the first. Every broadening of the circle of my perception obliges me to correct my picture of the world. This is evident in daily life just as much as in the spiritual development of mankind. The picture which the ancients made for themselves of the relationship of the earth to the sun and to the other heavenly bodies, had to be replaced by Copernicus with another one, because it did not accord with perceptions unknown to earlier times. A man born blind said, after Dr. Franz had operated on him, that before his operation he had formed a completely different picture of the size of objects through the perceptions of his sense of touch. He had to correct his perceptions of touch through his perceptions of sight.
[ 17 ] How is it that we are compelled to make such continuous corrections of our observations?
[ 18 ] A simple reflection brings the answer to this question. When I am standing at one end of an avenue of trees, the trees distant from me at the other end appear to me smaller and closer together than they do where I am standing. My perceptual picture becomes a different one when I change the place from which I make my observations. This picture, therefore, in the form in which it approaches me, is dependent upon a determining factor which is not due to the object, but which rather is attributable to me, the one doing the perceiving. For an avenue of trees it is a matter of complete indifference where I am standing. The picture, however, that I receive of it, is essentially dependent upon where I am standing. In the same way it is a matter of indifference to the sun and to the planetary system that human beings happen to view them from the earth. The perceptual picture, however, which presents itself to human beings is determined through this their dwelling place. This dependency of our perceptual picture upon our point of observation is the one that is easiest to recognize. The matter becomes more difficult, to be sure, when we learn to know the dependency of our perceptual world upon our bodily and spiritual organization. The physicist shows us that within the space in which we hear a sound, vibrations of the air take place, and that the body also, in which we seek the origin of the sound, exhibits a vibrating movement of its parts. We only perceive this movement as sound if we have a normally organized ear. Without such an ear the whole world would remain forever silent for us. Physiology teaches us that there are people who perceive nothing of the magnificent splendor of color that surrounds us. Their perceptual picture evinces only nuances of light and dark. Others do not perceive only one particular color, such as red, for example. This shade is missing from their world picture, which is therefore actually a different one than that of the average person. I would like to call the dependency of my perceptual picture upon my place of observation, “mathematical,” and the dependency upon my organization “qualitative.” Through the former, the size relationships and respective distances of my perceptions are determined; through the latter, the quality of my perceptions. That I see a red surface as red—this qualitative determination—depends upon the organization of my eye.
[ 19 ] My perceptual pictures are therefore at first subjective. Knowledge of the subjective character of our perceptions can easily lead to doubt as to whether anything objective underlies them at all. When we know that a perception—of a red color, for example, or of a particular tone—is not possible without a definite structure in our organism, one can arrive at the belief that this perception, apart from our subjective organism, has no reality, that the perception has no kind of existence without the act of perceiving, whose object it is. This view has found a classic proponent in George Berkeley, who was of the opinion that the human being, from the moment he has become conscious of the significance of the subject for the perception, can no longer believe in a world that is present without the conscious mind. He says, “Some truths there are, so near and obvious to the mind that man need only open his eyes to see them. Such I take this important one to be, to wit, that all the choir of heaven and furniture of the earth, in a word, all those bodies which compose the mighty frame of the world, have any subsistence without a mind, that their being is to be perceived or known; that, consequently, so long as they are not actually perceived by me, or do not exist in my mind or that of any other created spirit, they must either have no existence at all, or else subsist in the mind of some eternal spirit.”2Principles of Human Knowledge, Part I, Section 6 For this view, nothing more of the perception remains, if one disregards the fact of its being perceived. There is no color when none is seen, no tone when none is heard. Just as little as color and tone, do dimension, shape, and motion exist outside of the act of perception. We nowhere see bare dimension or shape, but always see them connected with color or with other characteristics which indisputably depend upon our subjectivity. If these latter characteristics disappear along with our perception, then that must also be the case for the elements of dimension or shape that are bound to them.
[ 20 ] An objection can be made that, even if figure, color, tone, etc. do have not existence other than within my act of perception, there must still be things which are there without my act of perception, there must still be things which are there without my consciousness and to which my conscious perceptual pictures are similar; to this objection the above view responds by saying that a color can only be similar to a color, a figure similar to a figure. Our perceptions can only be similar to our perceptions, but not to any other things. Even what we call an object is nothing other than a group of perceptions which are connected in a definite way. If I take away from a table its shape, dimensions, color, etc.—everything in short that is only my perception—then nothing more remains. This view, consistently pursued, leads to the opinion that the objects of my perceptions are present only through me, and indeed only insofar as, and as long as, I perceive them; they disappear along with my act of perceiving and have no meaning without it. Other than my perceptions I know of no objects, however, and can know of none.
[ 21 ] No objection can be brought against this opinion as long as I am merely bringing into consideration in a general way the fact that the perception is codetermined by the organization of my subject. The matter would present itself in an essentially different way, however, if we were able to say what the function of our perceiving is in the genesis of a perception. We would then know what is happening with the perception during the act of perceiving, and could also determine what about it would already have to exist, before it is perceived.
[ 22 ] With this, our consideration of the object of perception leads over to the subject of perception. I do not perceive other things only; I also perceive my self. The perception of my self has at first the content that I am what endures in the face of perceptual pictures that continually come and go. The perception of my “I” can always appear in my consciousness while I am having other perceptions. When I am absorbed in the perception of a given object, I have for the moment only a consciousness of it. To this can then come the perception of my self. I am from then on conscious not merely of the object, but also of my personality, which stands before the object and observes it. I do not merely see a tree, but I also know that it is I who see it. I recognize also that something is occurring within me while I observe the tree. When the tree disappears from my field of vision, something of this occurrence remains behind for my consciousness: a picture of the tree. During my observation this picture has connected itself with my self. My self has become richer; its content has acquired a new element. This element I call my mental picture3Vorstellung (often translated “representation”) of the tree. I would never be in a position to speak of mental pictures, if I did not experience them within the perception of my self. Perceptions would come and go; I would let them pass before me. Only because I perceive my self and notice that its content also changes with ever perception, do I see myself compelled to bring my observation of the object into relationship with my own change in condition, and to speak of my mental picture.
[ 23 ] I perceive the mental picture connected to my self in the same sense as I perceive color, tone, etc. connected to other objects. I can also now make the distinction of calling these other objects which come before me outer world, while I designate the content of my self-perception as inner world. Misconceptions about the relationship of mental picture and object have brought about the greatest misunderstandings in modern philosophy. The perception of a change in us, the modification that my self undergoes, was pushed into the foreground, and the object causing this modification was totally lost from view. One said that we do not perceive the objects, but only our mental pictures. I supposedly know nothing about the table-in-itself, which is the object of my observation, but only about the change which takes place with my self while I am perceiving the table. This view should not be confused with that of Berkeley mentioned before. Berkeley maintains the subjective nature of the content of my perception, but he does not say I can only know about my mental pictures. He limits my knowledge to my mental pictures, because he is of the opinion that there are no objects outside of mental picturing. What I look upon as a table is for Berkeley no longer present as soon as I no longer direct my gaze upon it. Therefore Berkeley lets my perception arise directly through the power of God. I see a table because God calls forth this perception within me. Berkeley thus knows no other real beings except God and human spirits. What we call world is present only within spirits. What the naive person calls outer world, physical nature, does not exist for Berkeley. Over against this view there stands the Kantian one now predominating, which limits our knowledge of the world to our mental pictures, not because it is convinced that there can be nothing apart from our mental pictures, but because it believes us to be so organized that we can experience only the changes of our own self and not the things-in-themselves which cause these changes. From the fact that I know only my mental pictures, this view concludes not that there is no existence independent of these mental pictures, but only that the subject cannot take up such an existence directly into itself; it can do nothing with it except through the “medium of his subjective thoughts, to imagine it, to suppose it, to think it, to know it, or perhaps also not to know is” (O. Liebmann, Contribution to the Analysis of Reality).4Zur Analysis der Wirklichkeit This view believes it is saying something absolutely certain, something directly obvious without any proof. “The first fundamental principle which the philosopher has to bring to distinct consciousness for himself consists in the recognition that our knowledge at first extends itself to nothing beyond our mental pictures. Our mental pictures are the only thing that we know directly, experience directly; and, just because we experience them directly, it is the case that even the most radical doubt cannot tear away from us our knowledge of our mental pictures. On the other hand, knowledge that goes beyond our mental picturing—whenever I use this expression I mean it in the widest sense, so that all psychic happenings come under it—is not secure from doubt. Therefore, at the beginning of any philosophizing, all knowledge which goes beyond our mental pictures must be expressly presented as doubtful”; thus Volkelt begins his book on Immanuel Kant's Epistemology. What is here presented in this way, as though it were an immediate and obvious truth, is in reality, however, the result of a thought-operation that runs as follows: The naive person believes that the objects, in the way he perceives them, are also present outside of his consciousness. Physics, physiology, and psychology seem to teach, however, that for our perceptions our organization is necessary, that we consequently can know about nothing except what our organization transmits to us from the things. Our perceptions are thus modifications of our organization, not things-in-themselves. Eduard von Hartmann has characterized the train of thought indicated here as in fact the one which must convince us of the principle that we can have a direct knowledge only of our mental pictures (see his Basic Problem of Epistemology).5Das Grundproblem der Erkenntnistheorie Because outside of our organism, we find vibrations of physical bodies and of the air which manifest to us as sound, it is concluded that what we call sound is nothing more than a subjective reaction of our organism to those motions in the outer world. In the same way one finds that color and warmth are only modifications of our organism. And one is in fact of the view that these two kinds of perceptions are called forth in us through the effect of occurrences in the outer world which are utterly different form what our warmth of color experience is. When such occurrences stimulate the nerves in my skin, I have the subjective perception of warmth; when such occurrences encounter the optic nerve, I perceive light and color. Light, color, and warmth, therefore, are that with which my sensory nerves respond to the stimuli from outside. Even my sense of touch transmits to me, not the objects of the outer world, but only my own states. In the sense of modern physics one could think, for example, that bodies consist of infinitely small particles, of molecules, and that these molecules do not border directly upon each other, but rather are at certain distances from each other. Between them, therefore, is empty space. Across these distances the molecules act upon each other by means of forces of attraction and repulsion. When I bring my hand toward a body, the molecules of my hand by no means directly touch those of the body, but rather there remains a certain distance between body and hand; and what I sense as the body's resistance is nothing more than the effect of the force of repulsion which its molecules exert upon my hand. I am altogether outside the body and only perceive its effect upon my organism.
[ 24 ] The doctrine put forward by J. Müller (1801–1858) about the so-called specific sense energies complements these reflections. It consists in declaring that each sense organ has the characteristic of responding to all outer stimuli in one specific way only. If the optic nerve is acted upon, a perception of light arises, no matter whether the stimulus occurs through what we call light, or whether a mechanical pressure or an electric current affects the nerve. Furthermore, different perceptions are called forth in the different sense organs by the same outer stimuli. This seems to indicate that our senses can transmit only what occurs within them, but nothing of the outer world. The senses, each according to its nature, determine the perceptions.
[ 25 ] Physiology shows that a direct knowledge of what the objects cause to happen within our sense organs is also out of the question. As the physiologist pursues the occurrences in our own body, he finds that, already in the sense organs, the effects of an outer motion are transformed in the most manifold way. We see that most distinctly with the eye and ear. Both are very complicated organs which essentially change the outer stimulus before they bring it to the corresponding nerve. From the peripheral end of the nerve, the already changed stimulus is now conducted further to the brain. Here first of all the central organs must be stimulated again. From this is inferred that the outer occurrence has undergone a series of transformations before it comes to consciousness. What takes place in the brain is connected with the outer occurrence through so many intermediary occurrences that any similarity between the two is inconceivable. What the brain finally communicates to the soul are neither outer occurrences nor occurrences in the sense organs, but only such as are in the brain. But the soul still does not perceive even these directly. What we finally have in our consciousness are not brain processes at all, but rather sensations. My sensation of red has absolutely no similarity to the process which takes place in my brain when I experience the red. The latter only appears again in the soul as an effect and is only caused by the brain process. Therefore Hartmann says (The Basic Problem of Epistemology), “What the subject perceives are therefore always only modifications of his own psychic states and nothing else.” When I have sensations thee are, however, still far from being grouped together into what I perceive as the things. Only single sensations, after all, can be communicated to me through the brain. The sensations of hard and soft are communicated to me through the sense of touch, sensations of color and light through the sense of sight. In spite of this the sensations find themselves united upon one and the same object. This union must therefore first be accomplished by the soul itself. This means that the soul assembles into physical objects the single sensations communicated through the brain. My brain transmits to me individually my sensations of sight, touch, and hearing—and does this, indeed, along entirely different paths—which my soul then assembles into the mental picture “trumpet.” It is this last part (mental picture of the trumpet) of a process that, for my consciousness, is given first of all. There is in this lat part nothing more to be found of what is outside me and originally made an impression on my senses. The external object, on its way to the brain, and through the brain to the soul, has been entirely lost.
[ 26 ] It would be difficult to find another edifice of thought in the history of the spiritual life of man which has been assembled with keener thought, and which nevertheless crumbles into nothingness upon closer examination. Let us take a closer look at the way it is built up. One starts first of all with what is given to naive consciousness, with the thing that is perceived. Then one shows that everything belonging to this thing would not be there for us if we had no senses. No eye: no color. Therefore the color is not yet present in that which works upon the eye. The color first arises through the interaction of the eye with the object. The latter is therefore colorless. But the color is also not present in the eye; for in it a chemical or physical process is present, which is first led to the brain through a nerve, and which there causes another process. Even this is not yet the color. The color is first called forth, through the brain process, within the soul. There the color still does not enter into my consciousness, but rather is first transferred outward by the soul onto a body. On this body I believe I finally perceive the color. We have made a complete circle. We become conscious of a colored body. That is first. Now the thought operation commences. If I had no eye, the body would be colorless for me. Thus, I cannot attribute the color to the body. I take up the search for the color. I look for it in the eye: in vain; in the nerve: in vain; in the brain: also in vain; in the soul: here I do find it, in fact, but not connected with the body. I find the colored body again only where I took my start. The circle is closed. I believe that I now recognize as a creation of my soul, what the naive person believes to be present outside of space.
[ 27 ] As long as one stops here, everything seems to be in excellent shape. But the matter must be taken up once more from the beginning. Until now I have been dealing with an object: with the outer perception about which earlier, as a naive person, I had a completely incorrect view. I was of the opinion that the perception had an objective existence, in the form that I perceive it. Now I notice that the perception disappears along with my mental picturing, that it is only a modification of my soul state. Now do I still have any right at all to start with the perception in my consideration? Can I say of the perception that it acts upon my soul? From now on I must treat the table, which I earlier believed acted upon me and brought forth a mental picture of itself in me, itself as a mental picture. But then my sense organs and the processes in them are also merely subjective. I have no right to speak of a real eye, but only of my mental picture of an eye. It is just the same with the nerves and the brain process, and no less so with the occurrence in the soul itself through which things are supposedly built up out of the chaos of manifold sensations. If, under the assumption of the correctness of the first circle of thought, I run through once more the parts of my act of knowledge, the latter shows itself to be a web of mental pictures that, as such, certainly cannot act upon each other. I cannot say that my mental picture of the object acts upon my mental picture of the eye and that out of this interaction emerges my mental picture of the color. But I also do not need to do this. For as soon as it is clear to me that my sense organs and their activity, my nerve and soul process, can also only be given me through perception, the train of thought described above reveals itself in its full impossibility. It is correct that for me there is no perception without the corresponding sense organ. But just as little is there a sense organ without perception. I can go over from my perception of the table to the eye that sees it, to the nerves of the hand which touch it; but what occurs within these I can again learn only from perception. And there I soon notice then that in the process which takes place in the eye, there is not a trace of similarity with what I perceive as color. I cannot do away with my perception of color just by showing the process in the eye that takes place in it during this perception. Just as little do I find the color again within the processes of the nerves and brain; I only connect new perceptions within my organism to the first ones which the native person places outside his organism. I only go from one perception to another.
[ 28 ] Moreover, there is a break in this whole line of reasoning. I am in a position to follow the occurrences in my organism up to the processes in my brain, even though my conclusions become every more hypothetical the more I approach the central occurrences of the brain. The path of external observation ends with the occurrences in my brain, with that occurrence, in fact, which I would perceive if I could study the brain with the help of physical and chemical means and methods. The path of inner observation begins with the sensation and extends to the construction of things out of the material of sensation. In the transition from brain process to sensation the path of observation is broken.
[ 29 ] The way of thinking characterized here, which calls itself “critical idealism” in contradistinction to the standpoint of the naive consciousness which calls itself “naive realism,” makes the mistake of characterizing the one perception as mental picture, while accepting the other in the very same sense as does the native realism which it seemingly had refuted. This way of thinking wants to prove that perceptions have the character of mental pictures, by accepting in naive fashion the perceptions made of one's own organism as objectively valid facts, and in all this still overlooking the fact that it is throwing together two realms of observation, between which it can find no mediation.
[ 30 ] Critical idealism can refute naive realism only if it itself accepts, in naive realistic fashion, that one's own organism exits objectively. The moment it becomes conscious of the total similarity in nature between the perceptions made of one's own organism and the perceptions accepted by native realism as existing objectively, it can no longer base itself upon the first kind of perceptions as though they afforded a sure foundation. It would also have to regard one's subjective organization as a mere complex of mental pictures. In so doing, however, it would lose the possibility of thinking that the content of the perceived world is caused by one's spiritual organization. One would have to assume that the mental picture “color” is only a modification of the mental picture “eye.” So-called critical idealism cannot be proven without borrowing from naive realism. The latter is only refuted through the fact that one accepts naive realism's own presuppositions as valid in another area, without examining them there.
[ 31 ] From all this, it is certain, at least that critical idealism cannot be proven through investigations within the realm of perception, and that thereby perception cannot be divested of its objective character.
[ 32 ] But even less can the thesis, “The perceived world is my mental picture,” be presented as obvious in itself and needing no proof. Schopenhauer begins his principal work, The World as Will and Mental Picture,6Die Welt als Wille und Vorstellung (usually translated The World as Will and Representation). with the word: “The world is my mental picture:—this is the truth which is valid with respect to every living and knowing being, even though man alone can bring it into reflective abstract consciousness; and if he really does this, then philosophical enlightenment has occurred for him. It will then become definite and certain for him that he knows no sun and no earth, but always only an eye that sees the sun, a hand that feels the earth; that the world which surrounds him is there only as mental picture, i.e., that it absolutely is there only in relationship to something else, to the one doing the mental picturing, which he himself is.—If ever a truth could be declared a priori, it is this one; for it is the expression of that form which every possible and imaginable experience has, that form which is more general than all others, such as time, space and causality; for all these already presuppose the first form ...” This whole thesis founders upon the fact I have already indicated above, that the eye and the hand are no less perceptions than the sun and the earth. And one could, in Schopenhauer's sense and in his own terms, confront his thesis with: My eye that sees the sun, and my hand that feels the earth are my mental pictures in just the same way as the sun and earth themselves are. That I thereby invalidate his thesis, however, is immediately clear. For only my real eye and my real hand could have, connected to them as their own modifications, the mental pictures sun and earth; my mental pictures of eye and hand could not however have these mental pictures. But only of these can critical idealism speak.
[ 33 ] Critical idealism is totally unfitted to gain a view of the relationship between perception and mental picture. To distinguish, as indicted on page 49, between what is happening with the perception during the act of perceiving, and what must already be there in the perception before it is perceived—this, critical idealism cannot undertake to do. In order to do this, therefore, another path must be taken.
IV. Die Welt als Wahrnehmung
[ 1 ] Durch das Denken entstehen Begriffe und Ideen. Was ein Begriff ist, kann nicht mit Worten gesagt werden. Worte können nur den Menschen darauf aufmerksam machen, daß er Begriffe habe. Wenn jemand einen Baum sieht, so reagiert sein Denken auf seineBeobachtung; zu demGegenstande tritt ein ideelles Gegenstück hinzu, und er betrachtet den Gegenstand und das ideelle Gegenstück als zusammengehörig.Wenn der Gegenstand aus seinem Beobachtungsfelde verschwindet, so bleibt nur das ideelle Gegenstück davon zurück. Das letztere ist der Begriff des Gegenstandes. Je mehr sich unsere Erfahrung erweitert, desto größer wird die Summe unserer Begriffe. Die Begriffe stehen aber durchaus nicht vereinzelt da. Sie schließen sich zu einem gesetzmäßigen Ganzen zusammen. Der Begriff «Organismus» schließt sich zum Beispiel an die andern: «gesetzmäßige Entwickelung, Wachstum» an. Andere an Einzeldingen gebildete Begriffe fallen völlig in eins zusammen. Alle Begriffe, die ich mir von Löwen bilde, fallen in den Gesamtbegriff «Löwe» zusammen. Auf diese Weise verbinden sich die einzelnen Begriffe zu einem geschlossenen Begriffssystem, in dem jeder seine besondere Stelle hat. Ideen sind qualitativ von Begriffen nicht verschieden. Sie sind nur inhaltsvollere, gesättigtere und umfangreichere Begriffe. Ich muß einen besonderen Wert darauf legen, daß hier an dieser Stelle beachtet werde, daß ich als meinen Ausgangspunkt das Denken bezeichnet habe und nicht Begriffe und Ideen, die erst durch das Denken gewonnen werden. Diese setzen das Denken bereits voraus. Es kann daher, was ich in bezug auf die in sich selbst ruhende, durch nichts bestimmte Natur des Denkens gesagt habe, nicht einfach auf die Begriffe übertragen werden. (Ich bemerke das hier ausdrücklich, weil hier meine Differenz mit Hegel liegt. Dieser setzt den Begriff als Erstes und Ursprüngliches.)
[ 2 ] Der Begriff kann nicht aus der Beobachtung gewonnen werden. Das geht schon aus dem Umstande hervor, daß der heranwachsende Mensch sich langsam und allmählich erst die Begriffe zu den Gegenständen bildet, die ihn umgeben. Die Begriffe werden zu der Beobachtung hinzugefügt.
[ 3 ] Ein vielgelesener Philosoph der Gegenwart, Herbert Spencer, schildert den geistigen Prozeß, den wir gegenüber der Beobachtung vollziehen, folgendermaßen:
[ 4 ] «Wenn wir an einem Septembertag durch die Felder wandelnd, wenige Schritte vor uns ein Geräusch hören und an der Seite des Grabens, von dem es herzukommen schien, das Gras in Bewegung sehen, so werden wir wahrscheinlich auf die Stelle losgehen, um zu erfahren, was das Geräusch und die Bewegung hervorbrachte. Bei unserer Annäherung flattert ein Rebhuhn in den Graben, und damit ist unsere Neugierde befriedigt: wir haben, was wir eine Erklärung der Erscheinungen nennen. Diese Erklärung läuft, wohlgemerkt, auf folgendes hinaus: weil wir im Leben unendlich oft erfahren haben, daß eine Störung der ruhigen Lage kleiner Körper die Bewegung anderer zwischen ihnen befindlicher Körper begleitet, und weil wir deshalb die Beziehungen zwischen solchen Störungen und solchen Bewegungen verallgemeinert haben, so halten wir diese besondere Störung für erklärt, sobald wir finden, daß sie ein Beispiel eben dieser Beziehung darbietet.» Genauer besehen stellt sich die Sache ganz anders dar, als sie hier beschrieben ist. Wenn ich ein Geräusch höre, so suche ich zunächst den Begriff für diese Beobachtung. Dieser Begriff erst weist mich über das Geräusch hinaus. Wer nicht weiter nachdenkt, der hört eben das Geräusch und gibt sich damit zufrieden. Durch mein Nachdenken aber ist mir klar, daß ich ein Geräusch als Wirkung aufzufassen habe. Also erst wenn ich den Begriff der Wirkung mit der Wahrnehmung des Geräusches verbinde, werde ich veranlaßt, über die Einzelbeobachtung hinauszugehen und nach der Ursache zu suchen. Der Begriff der Wirkung ruft den der Ursache hervor, und ich suche dann nach dem verursachenden Gegenstande, den ich in der Gestalt des Rebhuhns finde. Diese Begriffe, Ursache und Wirkung, kann ich aber niemals durch bloße Beobachtung, und erstrecke sie sich auf noch so viele Fälle, gewinnen. Die Beobachtung fordert das Denken heraus, und erst dieses ist es, das mir den Weg weist, das einzelne Erlebnis an ein anderes anzuschließen.
[ 5 ] Wenn man von einer «streng objektiven Wissenschaft» fordert, daß sie ihren Inhalt nur der Beobachtung entnehme, so muß man zugleich fordern, daß sie auf alles Denken verzichte. Denn dieses geht seiner Natur nach über das Beobachtete hinaus.
[ 6 ] Nun ist es am Platze, von dem Denken auf das denkende Wesen überzugehen. Denn durch dieses wird das Denken mit der Beobachtung verbunden. Das menschliche Bewußtsein ist der Schauplatz, wo Begriff und Beobachtung einander begegnen und wo sie miteinander verknüpft werden. Dadurch ist aber dieses (menschliche) Bewußtsein zugleich charakterisiert. Es ist der Vermittler zwischen Denken und Beobachtung. Insoferne der Mensch einen Gegenstand beobachtet, erscheint ihm dieser als gegeben, insoferne er denkt, erscheint er sich selbst als tätig. Er betrachtet den Gegenstand als Objekt, sich selbst als das denkende Subjekt. Weil er sein Denken auf die Beobachtung richtet, hat er Bewußtsein von den Objekten; weil er sein Denken auf sich richtet, hat er Bewußtsein seiner selbst oder Selbstbewußtsein. Das menschliche Bewußtsein muß notwendig zugleich Selbstbewußtsein sein, weil es denkendes Bewußtsein ist. Denn wenn das Denken den Blick auf seine eigene Tätigkeit richtet, dann hat es seine ureigene Wesenheit, also sein Subjekt, als Objekt zum Gegenstande.
[ 7 ] Nun darf aber nicht übersehen werden, daß wir uns nur mit Hilfe des Denkens als Subjekt bestimmen und uns den Objekten entgegensetzen können. Deshalb darf das Denken niemals als eine bloß subjektive Tätigkeit aufgefaßt werden. Das Denken ist jenseits von Subjekt und Objekt. Es bildet diese beiden Begriffe ebenso wie alle anderen. Wenn wir als denkendes Subjekt also den Begriff auf ein Objekt beziehen, so dürfen wir diese Beziehung nicht als etwas bloß Subjektives auffassen. Nicht das Subjekt ist es, welches die Beziehung herbeiführt, sondern das Denken. Das Subjekt denkt nicht deshalb, weil es Subjekt ist; sondern es erscheint sich als ein Subjekt, weil es zu denken vermag. Die Tätigkeit, die der Mensch als denkendes Wesen ausübt, ist also keine bloß subjektive, sondern eine solche, die weder subjektiv noch objektiv ist, eine über diese beiden Begriffe hinausgehende. Ich darf niemals sagen, daß mein individuelles Subjekt denkt; dieses lebt vielmehr selbst von des Denkens Gnaden. Das Denken ist somit ein Element, das mich über mein Selbst hinausführt und mit den Objekten verbindet. Aber es trennt mich zugleich von ihnen, indem es mich ihnen als Subjekt gegenüberstellt.
[ 8 ] Darauf beruht die Doppelnatur des Menschen: er denkt und umschließt damit sich selbst und die übrige Welt; aber er muß sich mittels des Denkens zugleich als ein den Dingen gegenüberstehendes Individuum bestimmen.
[ 9 ] Das nächste wird nun sein, uns zu fragen: Wie kommt das andere Element, das wir bisher bloß als Beobachtungsobjekt bezeichnet haben, und das sich mit dem Denken im Bewußtsein begegnet, in das letztere?
[ 10 ] Wir müssen, um diese Frage zu beantworten, aus unserem Beobachtungsfelde alles aussondern, was durch das Denken bereits in dasselbe hineingetragen worden ist. Denn unser jeweiliger Bewußtseinsinhalt ist immer schon mit Begriffen in der mannigfachsten Weise durchsetzt.
[ 11 ] Wir müssen uns vorstellen, daß ein Wesen mit vollkommen entwickelter menschlicher Intelligenz aus dem Nichts entstehe und der Welt gegenübertrete. Was es da gewahr würde, bevor es das Denken in Tätigkeit bringt, das ist der reine Beobachtungsinhalt. Die Welt zeigte dann diesem Wesen nur das bloße zusammenhanglose Aggregat von Empfindungsobjekten: Farben, Töne, Druck, Wärme, Geschmacks, und Geruchsempfindungen; dann Lust und Unlustgefühle. Dieses Aggregat ist der Inhalt der reinen, gedankenlosen Beobachtung. Ihm gegenüber steht das Denken, das bereit ist, seine Tätigkeit zu entfalten, wenn sich ein Angriffspunkt dazu findet. Die Erfahrung lehrt bald, daß er sich findet.DasDenken ist imstande, Fäden zu ziehen von einem Beobachtungselement zum andern. Es verknüpft mit diesen Elementen bestimmte Begriffe und bringt sie dadurch in ein Verhältnis. Wir haben oben bereits gesehen, wie ein uns begegnendes Geräusch mit einer anderen Beobachtung dadurch verbunden wird, daß wir das erstere als Wirkung der letzteren bezeichnen.
[ 12 ] Wenn wir uns nun daran erinnern, daß die Tätigkeit des Denkens durchaus nicht als eine subjektive aufzufassen ist, so werden wir auch nicht versucht sein zu glauben, daß solche Beziehungen, die durch das Denken hergestellt sind, bloß eine subjektive Geltung haben.
[ 13 ] Es wird sich jetzt darum handeln, durch denkende Überlegung die Beziehung zu suchen, die der oben angegebene unmittelbar gegebene Beobachtungsinhalt zu unserem bewußten Subjekt hat.
[ 14 ] Bei dem Schwanken des Sprachgebrauches erscheint es mir geboten, daß ich mich mit meinem Leser über den Gebrauch eines Wortes verständige, das ich im folgenden anwenden muß. Ich werde die unmittelbaren Empfindungsobjekte, die ich oben genannt habe, insoferne das bewußte Subjekt von ihnen durch Beobachtung Kenntnis nimmt, Wahrnehmungen nennen. Also nicht den Vorgang der Beobachtung, sondern das Objekt dieser Beobachtung bezeichne ich mit diesem Namen.
[ 15 ] Ich wähle den Ausdruck Empfindung nicht, weil dieser in der Physiologie eine bestimmte Bedeutung hat, die enger ist als die meines Begriffes von Wahrnehmung. Ein Gefühl in mir selbst kann ich wohl als Wahrnehmung, nicht aber als Empfindung im physiologischen Sinne bezeichnen. Auch von meinem Gefühle erhalte ich dadurch Kenntnis, daß es Wahrnehmung für mich wird. Und die Art, wie wir durch Beobachtung Kenntnis von unserem Denken erhalten, ist eine solche, daß wir auch das Denken in seinem ersten Auftreten für unser Bewußtsein Wahrnehmung nennen können.
[ 16 ] Der naive Mensch betrachtet seine Wahrnehmungen in dem Sinne, wie sie ihm unmittelbar erscheinen, als Dinge, die ein von ihm ganz unabhängiges Dasein haben. Wenn er einen Baum sieht, so glaubt er zunächst, daß dieser in der Gestalt, die er sieht, mit den Farben, die seine Teile haben usw., dort an dem Orte stehe, wohin der Blick gerichtet ist. Wenn derselbe Mensch morgens die Sonne als eine Scheibe am Horizonte erscheinen sieht und den Lauf dieser Scheibe verfolgt, so ist er der Meinung, daß das alles in dieser Weise (an sich) bestehe und vorgehe, wie er es beobachtet. Er hält so lange an diesem Glauben fest, bis er anderen Wahrnehmungen begegnet, die jenen widersprechen. Das Kind, das noch keine Erfahrungen über Entfernungen hat, greift nach dem Monde und stellt das, was es nach dem ersten Augenschein für wirklich gehalten hat, erst richtig, wenn eine zweite Wahrnehmung sich mit der ersten im Widerspruch befindet. Jede Erweiterung des Kreises meiner Wahrnehmungen nötigt mich, mein Bild der Welt zu berichtigen. Das zeigt sich im täglichen Leben ebenso wie in der Geistes-entwickelung der Menschheit. Das Bild, das sich die Alten von der Beziehung der Erde zu der Sonne und den andern Himmelskörpern machten, mußte von Kopernikus durch ein anderes ersetzt werden, weil es mit Wahrnehmungen, die früher unbekannt waren, nicht zusammenstimmte. Als Dr. Franz einen Blindgeborenen operierte, sagte dieser, daß er sich vor seiner Operation durch die Wahrnehmungen seines Tastsinnes ein ganz anderes Bild von der Größe der Gegenstände gemacht habe. Er mußte seine Tastwahrnehmungen durch seine Gesichtswahrnehmungen berichtigen.
[ 17 ] Woher kommt es, daß wir zu solchen fortwährenden Richtigstellungen unserer Beobachtungen gezwungen sind?
[ 18 ] Eine einfache Überlegung bringt die Antwort auf diese Frage. Wenn ich an dem einen Ende einer Allee stehe, so erscheinen mir die Bäume an dem andern, von mir entfernten Ende kleiner und näher aneinandergerückt als da, wo ich stehe. Mein Wahrnehmungsbild wird ein anderes, wenn ich den Ort ändere, von dem aus ich meine Beobachtungen mache. Es ist also in der Gestalt, in der es an mich herantritt, abhängig von einer Bestimmung, die nicht an dem Objekte hängt, sondern die mir, dem Wahrnehmenden, zukommt. Es ist für eine Allee ganz gleichgültig, wo ich stehe. Das Bild aber, das ich von ihr erhalte, ist wesentlich davon abhängig. Ebenso ist es für die Sonne und das Planetensystem gleichgültig, daß die Menschen sie gerade von der Erde aus ansehen. Das Wahrnehmungsbild aber, das sich diesen darbietet, ist durch diesen ihren Wohnsitz bestimmt. Diese Abhängigkeit des Wahrnehmungsbildes von unserem Beobachtungsorte ist diejenige, die am leichtesten zu durchschauen ist. Schwieriger wird die Sache schon, wenn wir die Abhängigkeit unserer Wahrnehmungswelt von unserer leiblichen und geistigen Organisation kennen lernen. Der Physiker zeigt uns, daß innerhalb des Raumes, in dem wir einen Schall hören, Schwingungen der Luft stattfinden, und daß auch der Körper, in dem wir den Ursprung des Schalles suchen, eine schwingende Bewegung seiner Teile aufweist. Wir nehmen diese Bewegung nur als Schall wahr, wenn wir ein normal organisiertes Ohr haben. Ohne ein solches bliebe uns die ganze Welt ewig stumm. Die Physiologie belehrt uns darüber, daß es Menschen gibt, die nichts wahrnehmen von der herrlichen Farbenpracht, die uns umgibt. Ihr Wahrnehmungsbild weist nur Nuancen von Hell und Dunkel auf. Andere nehmen nur eine bestimmte Farbe, zum Beispiel das Rot, nicht wahr. Ihrem Weltbilde fehlt dieser Farbenton, und es ist daher tatsächlich ein anderes als das eines Durchschnittsmenschen. Ich möchte die Abhängigkeit meines Wahrnehmungsbildes von meinem Beobachtungsorte eine mathematische, die von meiner Organisation eine qualitative nennen. Durch jene werden die Größenverhältnisse und gegenseitigen Entfernungen meiner Wahrnehmungen bestimmt, durch diese die Qualität derselben. Daß ich eine rote Fläche rot sehe — diese qualitative Bestimmung — hängt von der Organisation meines Auges ab.
[ 19 ] Meine Wahrnehmungsbilder sind also zunächst subjektiv. Die Erkenntnis von dem subjektiven Charakter unserer Wahrnehmungen kann leicht zu Zweifeln darüber führen, ob überhaupt etwas Objektives denselben zum Grunde liegt. Wenn wir wissen, daß eine Wahrnehmung, zum Beispiel die der roten Farbe, oder eines bestimmten Tones nicht möglich ist ohne eine bestimmte Einrichtung unseres Organismus, so kann man zu dem Glauben kommen, daß dieselbe, abgesehen von unserem subjektiven Organismus, keinen Bestand habe, daß sie ohne den Akt des Wahrnehmens, dessen Objekt sie ist, keine Art des Daseins hat. Diese Ansicht hat in George Berkeley einen klassischen Vertreter gefunden, der der Meinung war, daß der Mensch von dem Augenblicke an, wo er sich derBedeutung des Subjekts für dieWahrnehmung bewußt geworden ist, nicht mehr an eine ohne den bewußten Geist vorhandene Welt glauben könne. Er sagt: «Einige Wahrheiten liegen so nahe und sind so einleuchtend, daß man nur die Augen zu öffnen braucht, um sie zu sehen. Für eine solche halte ich den wichtigen Satz, daß der ganze Chor am Himmel und alles, was zur Erde gehört, mit einem Worte alle die Körper, die den gewaltigen Bau der Welt zusammensetzen, keine Subsistenz außerhalb des Geistes haben, daß ihr Sein in ihrem Wahrgenommen — oder Erkanntwerden besteht, daß sie folglich, solange sie nicht wirklich von mir wahrgenommen werden oder in meinem Bewußtsein oder dem eines anderen geschaffenen Geistes existieren, entweder überhaupt keine Existenz haben oder in dem Bewußtsein eines ewigen Geistes existieren.» Für diese Ansicht bleibt von der Wahrnehmung nichts mehr übrig, wenn man von dem Wahrgenommenwerden absieht. Es gibt keine Farbe, wenn keine gesehen, keinen Ton, wenn keiner gehört wird. Ebensowenig wie Farbe und Ton existieren Ausdehnung, Gestalt und Bewegung außerhalb des Wahrnehmungsaktes. Wir sehen nirgends bloße Ausdehnung oder Gestalt, sondern diese immer mit Farbe oder andern unbestreitbar von unserer Subjektivität abhängigen Eigenschaften verknüpft. Wenn die letzteren mit unserer Wahrnehmung verschwinden, so muß das auch bei den ersteren der Fall sein, die an sie gebunden sind.
[ 20 ] Dem Einwand, daß, wenn auch Figur, Farbe, Ton usw. keine andere Existenz als die innerhalb des Wahrnehmungsaktes haben, es doch Dinge geben müsse, die ohne das Bewußtsein da sind und denen die bewußten Wahrnehmungsbilder ähnlich seien, begegnet die geschilderte Ansicht damit, daß sie sagt: eine Farbe kann nur ähnlich einer Farbe, eine Figur ähnlich einer Figur sein. Unsere Wahrnehmungen können nur unseren Wahrnehmungen, aber keinerlei anderen Dingen ähnlich sein. Auch was wir einen Gegenstand nennen, ist nichts anderes als eine Gruppe von Wahrnehmungen, die in einer bestimmten Weise verbunden sind. Nehme ich von einem Tische Gestalt, Ausdehnung, Farbe usw., kurz alles, was nur meine Wahrnehmung ist, weg, so bleibt nichts mehr übrig. Diese Ansicht führt, konsequent verfolgt, zu der Behauptung: Die Objekte meiner Wahrnehmungen sind nur durch mich vorhanden, und zwar nur insoferne und solange ich sie wahrnehme; sie verschwinden mit dem Wahrnehmen und haben keinen Sinn ohne dieses. Außer meinen Wahrnehmungen weiß ich aber von keinen Gegenständen und kann von keinen wissen.
[ 21 ] Gegen diese Behauptung ist so lange nichts einzuwenden, als ich bloß im allgemeinen den Umstand in Betracht ziehe, daß die Wahrnehmung von der Organisation meines Subjektes mitbestimmt wird. Wesentlich anders stellte sich die Sache aber, wenn wir imstande wären, anzugeben, welches die Funktion unseres Wahrnehmens beim Zustandekommen einer Wahrnehmung ist. Wir wüßten dann, was an der Wahrnehmung während des Wahrnehmens geschieht, und könnten auch bestimmen, was an ihr schon sein muß, bevor sie wahrgenommen wird.
[ 22 ] Damit wird unsere Betrachtung von dem Objekt der Wahrnehmung auf das Subjekt derselben abgeleitet. Ich nehme nicht nur andere Dinge wahr, sondern ich nehme mich selbst wahr.. Die Wahrnehmung meiner selbst hat zunächst den Inhalt, daß ich das Bleibende bin gegenüber den immer kommenden und gehenden Wahrnehmungsbildern. Die Wahrnehmung des Ich kann in meinem Bewußtsein stets auftreten, während ich andere Wahrnehmungen habe. Wenn ich in die Wahrnehmung eines gegebenen Gegenstandes vertieft bin, so habe ich vorläufig nur von diesem ein Bewußtsein. Dazu kann dann die Wahrnehmung meines Selbst treten. Ich bin mir nunmehr nicht bloß des Gegenstandes bewußt, sondern auch meiner Persönlichkeit, die dem Gegenstand gegenüber steht und ihn beobachtet. Ich sehe nicht bloß einen Baum, sondern ich weiß auch, daß ich es bin, der ihn sieht. Ich erkenne auch, daß in mir etwas vorgeht, während ich den Baum beobachte. Wenn der Baum aus meinem Gesichtskreise verschwindet, bleibt für mein Bewußtsein ein Rückstand von diesem Vorgange: ein Bild des Baumes. Dieses Bild hat sich während meiner Beobachtung mit meinem Selbst verbunden. Mein Selbst hat sich bereichert; sein Inhalt hat ein neues Element in sich aufgenommen. Dieses Element nenne ich meine Vorstellung von dem Baume. Ich käme nie in die Lage, von Vorstellungen zu sprechen, wenn ich diese nicht in der Wahrnehmung meines Selbst erlebte. Wahrnehmungen würden kommen und gehen; ich ließe sie vorüberziehen. Nur dadurch, daß ich mein Selbst wahrnehme und merke, daß mit jeder Wahrnehmung sich auch dessen Inhalt ändert, sehe ich mich gezwungen, die Beobachtung des Gegenstandes mit meiner eigenen Zustandsveränderung in Zusammenhang zu bringen und von meiner Vorstellung zu sprechen.
[ 23 ] Die Vorstellung nehme ich an meinem Selbst wahr, in dem Sinne, wie Farbe, Ton usw. an andern Gegenständen. Ich kann jetzt auch den Unterschied machen, daß ich diese andern Gegenstände, die sich mir gegenüberstellen, Außenwelt nenne, während ich den Inhalt meiner Selbstwahrnehmung als Innenwelt bezeichne. Die Verkennung des Verhältnisses von Vorstellung und Gegenstand hat die größten Mißverständnisse in der neueren Philosophie herbeigeführt. Die Wahrnehmung einer Veränderung in uns, die Modifikation, die mein Selbst erfährt, wurde in den Vordergrund gedrängt und das diese Modifikation veranlassende Objekt ganz aus dem Auge verloren. Man hat gesagt: wir nehmen nicht die Gegenstände wahr, sondern nur unsere Vorstellungen. Ich soll nichts wissen von dem Tische an sich, der Gegenstand meiner Beobachtung ist, sondern nur von der Veränderung, die mit mir selbst vorgeht, während ich den Tisch wahrnehme. Diese Anschauung darf nicht mit der vorhin erwähnten Berkeleyschen verwechselt werden. Berkeley behauptet die subjektive Natur meines Wahrnehmungsinhaltes, aber er sagt nicht, daß ich nur von meinen Vorstellungen wissen kann. Er schränkt mein Wissen auf meine Vorstellungen ein, weil er der Meinung ist, daß es keine Gegenstände außerhalb des Vorstellens gibt. Was ich als Tisch ansehe, das ist im Sinne Berkeleys nicht mehr vorhanden, sobald ich meinen Blick nicht mehr darauf richte. Deshalb läßt Berkeley meine Wahrnehmungen unmittelbar durch die Macht Gottes entstehen. Ich sehe einen Tisch, weil Gott diese Wahrnehmung in mir hervorruft. Berkeley kennt daher keine anderen realen Wesen als Gott und die menschlichen Geister. Was wir Welt nennen, ist nur innerhalb der Geister vorhanden. Was der naive Mensch Außenwelt, körperliche Natur nennt, ist für Berkeley nicht vorhanden. Dieser Ansicht steht die jetzt herrschende Kantsche gegenüber, welche unsere Erkenntnis von der Welt nicht deshalb auf unsere Vorstellungen einschränkt, weil sie überzeugt ist, daß es außer diesen Vorstellungen keine Dinge geben kann, sondern weil sie uns so organisiert glaubt, daß wir nur von den Veränderungen unseres eigenen Selbst, nicht von den diese Veränderungen veranlassenden Dingen an sich erfahren können. Sie folgert aus dem Umstande, daß ich nur meine Vorstellungen kenne, nicht, daß es keine von diesen Vorstellungen unabhängige Existenz gibt, sondern nur, daß das Subjekt eine solche nicht unmittelbar in sich aufnehmen, sie nicht anders als durch das «Medium seiner subjektivenGedanken imaginieren, fingieren, denken, erkennen, vielleicht auch nicht erkennen kann» (O. Liebmann, Zur Analysis der Wirklichkeit, Seite 28). Diese Anschauung glaubt etwas unbedingt Gewisses zu sagen, etwas, was ohne alle Beweise unmittelbar einleuchtet. «Der erste Fundamentalsatz, den sich der Philosoph zu deutlichem Bewußtsein zu bringen hat, besteht in der Erkenntnis, daß unser Wissen sich zunächst auf nichts weiter als auf unsere Vorstellungen erstreckt. Unsere Vorstellungen sind das Einzige, was wir unmittelbar erfahren, unmittelbar erleben; und eben weil wir sie unmittelbar erfahren, deswegen vermag uns auch der radikalste Zweifel das Wissen von denselben nicht zu entreißen. Dagegen ist das Wissen, das über unser Vorstellen — ich nehme diesen Ausdruck hier überall im weitesten Sinne, so daß alles psychische Geschehen darunter fällt — hinausgeht, vor dem Zweifel nicht geschützt. Daher muß zu Beginn des Philosophierens alles über die Vorstellungen hinausgehende Wissen ausdrücklich als bezweifelbar hingestellt werden», so beginnt Volkelt sein Buch über «Immanuel Kants Erkenntnistheorie». Was hiermit so hingestellt wird, als ob es eine unmittelbare und selbstverständliche Wahrheit sei, ist aber in Wirklichkeit das Resultat einer Gedankenoperation, die folgendermaßen verläuft: Der naive Mensch glaubt, daß die Gegenstände, so wie er sie wahrnimmt, auch außerhalb seines Bewußtseins vorhanden sind. Die Physik, Physiologie und Psychologie scheinen aber zu lehren, daß zu unseren Wahrnehmungen unsere Organisation notwendig ist, daß wir folglich von nichts wissen können, als von dem, was unsere Organisation uns von den Dingen überliefert. Unsere Wahrnehmungen sind somit Modifikationen unserer Organisation, nicht Dinge an sich. Den hier angedeuteten Gedankengang hat Eduard von Hartmann in der Tat als denjenigen charakterisiert, der zur Überzeugung von dem Satze führen muß, daß wir ein direktes Wissen nur von unseren Vorstellungen haben können (vergleiche dessen «Grundproblem der Erkenntnistheorie», S. 16-40). Weil wir außerhalb unseres Organismus Schwingungen der Körper und der Luft finden, die sich uns als Schall darstellen, so wird gefolgert, daß das, was wir Schall nennen, nichts weiter sei als eine subjektive Reaktion unseres Organismus auf jene Bewegungen in der Außenwelt. In derselben Weise findet man, daß Farbe und Wärme nur Modifikationen unseres Organismus seien. Und zwar ist man der Ansicht, daß diese beiden Wahrnehmungsarten in uns hervorgerufen werden durch die Wirkung von Vorgängen in der Außenwelt, die von dem, was Wärmeerlebnis oder Farbenerlebnis ist, durchaus verschieden sind. Wenn solche Vorgänge die Hautnerven meines Körpers erregen, so habe ich die subjektive Wahrnehmung der Wärme, wenn solche Vorgänge den Sehnerv treffen, nehme ich Licht und Farbe wahr. Licht, Farbe und Wärme sind also das, womit meine Sinnesnerven auf den Reiz von außen antworten. Auch der Tastsinn liefert mir nicht die Gegenstände der Außenwelt, sondern nur meine eigenen Zustände. Im Sinne der modernen Physik könnte man etwa denken, daß die Körper aus unendlich kleinen Teilen, den Molekülen bestehen, und daß diese Moleküle nicht unmittelbar aneinandergrenzen, sondern gewisse Entfernungen voneinander haben. Es ist also zwischen ihnen der leere Raum. Durch diese wirken sie aufeinander mittelst anziehender und abstoßender Kräfte. Wenn ich meine Hand einem Körper nähere, so berühren die Moleküle meiner Hand keineswegs unmittelbar diejenigen des Körpers, sondern es bleibt eine gewisse Entfernung zwischen Körper und Hand, und was ich als Widerstand des Körpers empfinde, das ist nichts weiter als die Wirkung der abstoßenden Kraft, die seine Moleküle auf meine Hand ausüben. Ich bin schlechthin außerhalb des Körpers und nehme nur seine Wirkung auf meinen Organismus wahr.
[ 24 ] Ergänzend zu diesen Überlegungen tritt die Lehre von den sogenannten spezifischen Sinnesenergien, die J. Müller (1801-1858) aufgestellt hat. Sie besteht darin, daß jeder Sinn die Eigentümlichkeit hat, auf alle äußeren Reize nur in einer bestimmten Weise zu antworten. Wird auf den Sehnerv eine Wirkung ausgeübt, so entsteht Lichtwahrnehmung, gleichgültig ob die Erregung durch das geschieht, was wir Licht nennen, oder ob ein mechanischer Druck oder ein elektrischer Strom auf den Nerv einwirkt. Andrerseits werden in verschiedenen Sinnen durch die gleichen äußeren Reize verschiedene Wahrnehmungen hervorgerufen. Daraus scheint hervorzugehen, daß unsere Sinne nur das überliefern können, was in ihnen selbst vorgeht, nichts aber von der Außenwelt. Sie bestimmen die Wahrnehmungen je nach ihrer Natur.
[ 25 ] Die Physiologie zeigt, daß auch von einem direkten Wissen dessen keine Rede sein kann, was die Gegenstände in unseren Sinnesorganen bewirken. Indem der Physiologe die Vorgänge in unserem eigenen Leibe verfolgt, findet er, daß schon in den Sinnesorganen die Wirkungen der äußeren Bewegung in der mannigfaltigsten Weise umgeändert werden. Wir sehen das am deutlichsten an Auge und Ohr. Beide sind sehr komplizierte Organe, die den äußeren Reiz wesentlich verändern, ehe sie ihn zum entsprechenden Nerv bringen. Von dem peripherischen Ende des Nervs wird nun der schon veränderte Reiz weiter zum Gehirn geleitet. Hier erst müssen wieder die Zentralorgane erregt werden. Daraus wird geschlossen, daß der äußere Vorgang eine Reihe von Umwandlungen erfahren hat, ehe er zum Bewußtsein kommt. Was da im Gehirne sich abspielt, ist durch so viele Zwischenvorgänge mit dem äußeren Vorgang verbunden, daß an eine Ähnlichkeit mit demselben nicht mehr gedacht werden kann. Was das Gehirn der Seele zuletzt vermittelt, sind weder äußere Vorgänge, noch Vorgänge in den Sinnesorganen, sondern nur solche innerhalb des Gehirnes. Aber auch die letzteren nimmt die Seele noch nicht unmittelbar wahr. Was wir im Bewußtsein zuletzt haben, sind gar keine Gehirnvorgänge, sondern Empfindungen. Meine Empfindung des Rot hat gar keine Ähnlichkeit mit dem Vorgange, der sich im Gehirn abspielt, wenn ich das Rot empfinde. Das letztere tritt erst wieder als Wirkung in der Seele auf und wird nur verursacht durch den Hirnvorgang. Deshalb sagt Hartmann (Grundproblem der Erkenntnistheorie, S. 37): «Was das Subjekt wahrnimmt, sind also immer nur Modifikationen seiner eigenen psychischen Zustände und nichts anderes.» Wenn ich die Empfindungen habe, dann sind diese aber noch lange nicht zu dem gruppiert, was ich als Dinge wahrnehme. Es können mir ja nur einzelne Empfindungen durch das Gehirn vermittelt werden. Die Empfindungen der Härte und Weichheit werden mir durch den Tast, die Farben, und Lichtempfindungen durch den Gesichtssinn vermittelt. Doch finden sich dieselben an einem und demselben Gegenstande vereinigt. Diese Vereinigung muß also erst von der Seele selbst bewirkt werden. Das heißt, die Seele setzt die einzelnen durch das Gehirn vermittelten Empfindungen zu Körpern zusammen. Mein Gehirn überliefert mir einzeln die Gesichts, Tast, und Gehörempfindungen, und zwar auf ganz verschiedenen Wegen, die dann die Seele zu der Vorstellung Trompete zusammen setzt. Dieses Endglied (Vorstellung der Trompete) eines Prozesses ist es, was für mein Bewußtsein zu allererst gegeben ist. Es ist in demselben nichts mehr von dem zu finden, was außer mir ist und ursprünglich einen Eindruck auf meineSinnegemacht hat.Der äußereGegenstand ist auf dem Wege zum Gehirn und durch das Gehirn zur Seele vollständig verlorengegangen.
[ 26 ] Es wird schwer sein, ein zweites Gedankengebäude in der Geschichte des menschlichen Geisteslebens zu finden, das mit größerem Scharfsinn zusammengetragen ist, und das bei genauerer Prüfung doch in nichts zerfällt. Sehen wir einmal näher zu, wie es zustande kommt. Man geht zunächst von dem aus, was dem naiven Bewußtsein gegeben ist, von dem wahrgenommenen Dinge. Dann zeigt man, daß alles, was an diesem Dinge sich findet, für uns nicht da wäre, wenn wir keine Sinne hätten. Kein Auge: keine Farbe. Also ist die Farbe in dem noch nicht vorhanden, was auf das Auge wirkt. Sie entsteht erst durch die Wechselwirkung des Auges mit dem Gegenstande. Dieser ist also farblos. Aber auch im Auge ist die Farbe nicht vorhanden; denn da ist ein chemischer oder physikalischer Vorgang vorhanden, der erst durch den Nerv zum Gehirn geleitet wird, und da einen andern auslöst. Dieser ist noch immer nicht die Farbe. Sie wird erst durch den Hirnprozeß in der Seele hervorgerufen. Da tritt sie mir noch immer nicht ins Bewußtsein, sondern wird erst durch die Seele nach außen an einen Körper verlegt. An diesem glaube ich sie endlich wahrzunehmen. Wir haben einen vollständigen Kreisgang durchgemacht. Wir sind uns eines farbigen Körpers bewußt geworden. Das ist das Erste. Nun hebt die Gedankenoperation an. Wenn ich keine Augen hätte, wäre der Körper für mich farblos. Ich kann die Farbe also nicht in den Körper verlegen. Ich gehe auf die Suche nach ihr. Ich suche sie im Auge: vergebens; im Nerv: vergebens; im Gehirne: ebenso vergebens; in der Seele: hier finde ich sie zwar, aber nicht mit dem Körper verbunden. Den farbigen Körper finde ich erst wieder da, wo ich ausgegangen bin. Der Kreis ist geschlossen. Ich glaube das als Erzeugnis meiner Seele zu erkennen, was der naive Mensch sich als draußen im Raume vorhanden denkt.
[ 27 ] So lange man dabei stehen bleibt, scheint alles in schönster Ordnung. Aber die Sache muß noch einmal von vorne angefangen werden. Ich habe ja bis jetzt mit einem Dinge gewirtschaftet: mit der äußeren Wahrnehmung, von dem ich früher, als naiver Mensch, eine ganz falsche Ansicht gehabt habe. Ich war der Meinung: sie hätte so, wie ich sie wahrnehme, einen objektiven Bestand. Nun merke ich, daß sie mit meinem Vorstellen verschwindet, daß sie nur eine Modifikation meiner seelischen Zustände ist. Habe ich nun überhaupt noch ein Recht, in meinen Betrachtungen von ihr auszugehen? Kann ich von ihr sagen, daß sie auf meine Seele wirkt? Ich muß von jetzt ab den Tisch, von dem ich früher geglaubt habe, daß er auf mich wirkt und in mir eine Vorstellung von sich hervorbringt, selbst als Vorstellung behandeln. Konsequenterweise sind dann aber auch meine Sinnesorgane und die Vorgänge in ihnen bloß subjektiv. Ich habe kein Recht, von einem wirklichen Auge zu sprechen, sondern nur von meiner Vorstellung des Auges. Ebenso ist es mit der Nervenleitung und dem Gehirnprozeß und nicht weniger mit dem Vorgange in der Seele selbst, durch den aus dem Chaos der mannigfaltigen Empfindungen Dinge aufgebaut werden sollen. Durchlaufe ich unter Voraussetzung der Richtigkeit des ersten Gedankenkreisganges die Glieder meines Erkenntnisaktes nochmals, so zeigt sich der letztere als ein Gespinst von Vorstellungen, die doch als solche nicht aufeinander wirken können. Ich kann nicht sagen: meine Vorstellung des Gegenstandes wirkt auf meine Vorstellung des Auges, und aus dieser Wechselwirkung geht die Vorstellung der Farbe hervor. Aber ich habe es auch nicht nötig. Denn sobald mir klar ist, daß mir meine Sinnesorgane und deren Tätigkeiten, mein Nerven, und Seelenprozeß auch nur durch die Wahrnehmung gegeben werden können, zeigt sich der geschilderte Gedankengang in seiner vollen Unmöglichkeit. Es ist richtig: für mich ist keine Wahrnehmung ohne das entsprechende Sinnesorgan gegeben. Aber ebensowenig ein Sinnesorgan ohne Wahrnehmung. Ich kann von meiner Wahrnehmung des Tisches auf das Auge übergehen, das ihn sieht, auf die Hautnerven, die ihn tasten; aber was in diesen vorgeht, kann ich wieder nur aus der Wahrnehmung erfahren. Und da bemerke ich denn bald, daß in dem Prozeß, der sich im Auge vollzieht, nicht eine Spur von Ähnlichkeit ist mit dem, was ich als Farbe wahrnehme. Ich kann meine Farbenwahrnehmung nicht dadurch vernichten, daß ich den Prozeß im Auge aufzeige, der sich während dieser Wahrnehmung darin abspielt. Ebensowenig finde ich in den Nerven, und Gehirnprozessen die Farbe wieder; ich verbinde nur neue Wahrnehmungen innerhalb meines Organismus mit der ersten, die der naive Mensch außerhalb seines Organismus verlegt. Ich gehe nur von einer Wahrnehmung zur andern über.
[ 28 ] Außerdem enthält die ganze Schlußfolgerung einen Sprung. Ich bin in der Lage, die Vorgänge in meinem Organismus bis zu den Prozessen in meinem Gehirne zu verfolgen, wenn auch meine Annahmen immer hypothetischer werden, je mehr ich mich den zentralen Vorgängen des Gehirn es nähere. Der Weg der äußeren Beobachtung hört mit demVorgange in meinem Gehirne auf, und zwar mit jenem, den ich wahrnehmen würde, wenn ich mit physikalischen, chemischen usw. Hilfsmitteln und Methoden das Gehirn behandeln könnte. Der Weg der inneren Beobachtung fängt mit der Empfindung an und reicht bis zum Aufbau der Dinge aus dem Empfindungsmaterial. Beim Übergang von dem Hirnprozeß zur Empfindung ist der Beobachtungsweg unterbrochen.
[ 29 ] Die charakterisierte Denkart, die sich im Gegensatz zum Standpunkte des naiven Bewußtseins, den sie naiven Realismus nennt, als kritischen Idealismus bezeichnet, macht den Fehler, daß sie die eine Wahrnehmung als Vorstellung charakterisiert, aber die andere gerade in dem Sinne hinnimmt, wie es der von ihr scheinbar widerlegte naiveRealismus tut. Sie will den Vorstellungscharakter der Wahrnehmungen beweisen, indem sie in naiver Weise die Wahrnehmungen am eigenen Organismus als objektiv gültige Tatsachen hinnimmt und zu alledem noch übersieht, daß sie zwei Beobachtungsgebiete durcheinander wirft, zwischen denen sie keine Vermittlung finden kann.
[ 30 ] Der kritische Idealismus kann den naiven Realismus nur widerlegen, wenn er selbst in naiv-realistischer Weise seinen eigenen Organismus als objektiv existierend annimmt. In demselben Augenblicke, wo er sich der vollständigen Gleichartigkeit der Wahrnehmungen am eigenen Organismus mit den vom naiven Realismus als objektiv existierend angenommenen Wahrnehmungen bewußt wird, kann er sich nicht mehr auf die ersteren als auf eine sichere Grundlage stützen. Er müßte auch seine subjektive Organisation als bloßen Vorstellungskomplex ansehen. Damit geht aber die Möglichkeit verloren, den Inhalt der wahrgenommenen Welt durch die geistige Organisation bewirkt zu denken. Man müßte annehmen, daß die Vorstellung «Farbe» nur eine Modifikation der Vorstellung «Auge» sei. Der sogenannte kritische Idealismus kann nicht bewiesen werden, ohne eine Anleihe beim naiven Realismus zu machen. Der letztere wird nur dadurch widerlegt, daß man dessen eigene Voraussetzungen auf einem anderen Gebiete ungeprüft gelten läßt.
[ 31 ] Soviel ist hieraus gewiß: durch Untersuchungen innerhalb des Wahrnehmungsgebietes kann der kritische Idealismus nicht bewiesen, somit die Wahrnehmung ihres objektiven Charakters nicht entkleidet werden.
[ 32 ] Noch weniger aber darf der Satz: «Die wahrgenommene Welt ist meine Vorstellung» als durch sich selbst einleuchtend und keines Beweises bedürftig hingestellt werden. Schopenhauer beginnt sein Hauptwerk «Die Welt als Wille und Vorstellung» mit den Worten: «Die Welt ist meine Vorstellung: — dies ist die Wahrheit, welche in Beziehung auf jedes lebende und erkennende Wesen gilt; wiewohl der Mensch allein sie in das reflektierte abstrakte Bewußtsein bringen kann: und tut er dies wirklich, so ist die philosophische Besonnenheit bei ihm eingetreten. Es wird ihm dann deutlich und gewiß, daß er keine Sonne kennt und keine Erde; sondern immer nur ein Auge, das eine Sonne sieht, eine Hand, die eine Erde fühlt; daß die Welt, welche ihn umgibt, nur als Vorstellung da ist, das heißt durchweg nur in Beziehung auf ein Anderes, das Vorstehende, welches er selbst ist. — Wenn irgend eine Wahrheit a priori ausgesprochen werden kann, so ist es diese: denn sie ist die Aussage derjenigen Form aller möglichen und erdenklichen Erfahrung, welche allgemeiner als alle andern, als Zeit, Raum und Kausalität ist: denn alle diese setzen jene eben schon voraus ... » Der ganze Satz scheitert an dem oben bereits von mir angeführten Umstande, daß das Auge und die Hand nicht weniger Wahrnehmungen sind als die Sonne und die Erde. Und man könnte im Sinne Schopenhauers und mit Anlehnung an seine Ausdrucksweise seinen Sätzen entgegenhalten: Mein Auge, das die Sonne sieht, und meine Hand, die die Erde fühlt, sind meine Vorstellungen gerade so wie die Sonne und die Erde selbst. Daß ich damit aber den Satz wieder aufhebe, ist ohne weiteres klar. Denn nur mein wirkliches Auge und meine wirkliche Hand könnten die Vorstellungen Sonne und Erde als ihre Modifikationen an sich haben, nicht aber meine Vorstellungen Auge und Hand. Nur von diesen aber darf der kritische Idealismus sprechen.
[ 33 ] Der kritische Idealismus ist völlig ungeeignet, eine Ansicht über das Verhältnis von Wahrnehmung und Vorstellung zu gewinnen. Die auf Seite 67f. angedeutete Scheidung dessen, was an der Wahrnehmung während des Wahrnehmens geschieht und was an ihr schon sein muß, bevor sie wahrgenommen wird, kann er nicht vornehmen. Dazu muß also ein anderer Weg eingeschlagen werden.
IV. The world as perception
[ 1 ] Thinking gives rise to concepts and ideas. What a concept is cannot be said with words. Words can only make people aware that they have concepts. When someone sees a tree, his thinking reacts to his observation; an ideal counterpart is added to the object, and he regards the object and the ideal counterpart as belonging together; when the object disappears from his field of observation, only the ideal counterpart remains. The latter is the concept of the object. The more our experience expands, the greater the sum of our concepts becomes. However, the concepts are not isolated. They come together to form a lawful whole. The term "organism", for example, joins the others: "lawful development, growth". Other concepts formed from individual things merge completely into one. All the concepts that I form of lions coincide in the overall concept "lion". In this way, the individual concepts combine to form a closed conceptual system in which each has its own special place. Ideas are not qualitatively different from concepts. They are only more substantial, more saturated and more comprehensive concepts. I must place particular emphasis here on the fact that I have designated thinking as my starting point and not concepts and ideas, which are only gained through thinking. These already presuppose thinking. Therefore, what I have said with regard to the self-contained nature of thinking, which is not determined by anything, cannot simply be transferred to concepts. (I note this here explicitly because this is where my difference with Hegel lies. The latter places the concept as the first and original.)
[ 2 ] The concept cannot be derived from observation. This is already evident from the fact that the growing human being only slowly and gradually forms concepts about the objects that surround him. The concepts are added to the observation.
[ 3 ] A much-read contemporary philosopher, Herbert Spencer, describes the mental process that we carry out in relation to observation as follows:
[ 4 ] "If, walking through the fields on a September day, we hear a sound a few paces in front of us, and see the grass in motion on the side of the ditch from whence it seemed to come, we are likely to go to the spot to learn what produced the sound and the motion. As we approach, a partridge flutters into the ditch, and our curiosity is satisfied: we have what we call an explanation of the phenomena. This explanation, it should be noted, amounts to the following: because we have experienced infinitely often in life that a disturbance of the still position of small bodies accompanies the motion of other bodies situated between them, and because we have therefore generalized the relations between such disturbances and such motions, we consider this particular disturbance explained as soon as we find that it presents an example of this very relation." On closer inspection, the matter is quite different from what is described here. When I hear a sound, I first look for the term for this observation. Only this concept leads me beyond the sound. If you don't think about it any further, you just hear the sound and are satisfied with that. Through my thinking, however, it is clear to me that I have to understand a sound as an effect. So it is only when I connect the concept of effect with the perception of the sound that I am prompted to go beyond the individual observation and search for the cause. The concept of effect evokes that of cause, and I then search for the causative object, which I find in the shape of the partridge. However, I can never gain these concepts, cause and effect, through mere observation, no matter how many cases it extends to. Observation challenges thinking, and it is only this that shows me the way to connect the individual experience to another.
[ 5 ] If one demands of a "strictly objective science" that it takes its content only from observation, one must at the same time demand that it renounces all thinking. For this, by its very nature, goes beyond what is observed.
[ 6 ] Now it is time to move on from thinking to the thinking being. For through this, thinking is connected with observation. Human consciousness is the arena where concept and observation meet and where they are linked. But this (human) consciousness is characterized by this at the same time. It is the mediator between thinking and observation. Insofar as man observes an object, it appears to him as given; insofar as he thinks, he appears to himself as active. He regards the object as an object, himself as the thinking subject. Because he directs his thinking towards observation, he has consciousness of the objects; because he directs his thinking towards himself, he has consciousness of himself or self-consciousness. Human consciousness must necessarily be self-consciousness at the same time, because it is thinking consciousness. For when thinking focuses on its own activity, it has its very own essence, i.e. its subject, as its object.
[ 7 ] Now, however, it must not be overlooked that we can only define ourselves as subjects and oppose ourselves to objects with the help of thinking. Therefore, thinking must never be understood as a purely subjective activity. Thinking is beyond subject and object. It forms these two concepts as well as all others. So if we, as a thinking subject, relate the concept to an object, we must not understand this relationship as something merely subjective. It is not the subject that brings about the relationship, but thinking. The subject does not think because it is a subject; rather, it appears to be a subject because it is able to think. The activity that man performs as a thinking being is therefore not a merely subjective one, but one that is neither subjective nor objective, one that transcends these two concepts. I may never say that my individual subject thinks; rather, it lives by the grace of thinking itself. Thinking is thus an element that leads me beyond my self and connects me with the objects. But at the same time, it separates me from them by opposing me to them as a subject.
[ 8 ] This is the basis of man's dual nature: he thinks and thus encloses himself and the rest of the world; but by means of thinking he must at the same time define himself as an individual facing things.
[ 9 ] The next thing to ask ourselves is: How does the other element, which we have so far merely described as an object of observation and which meets with thought in consciousness, come into the latter?
[ 10 ] In order to answer this question, we must separate out from our field of observation everything that has already been brought into it by thinking. For our respective content of consciousness is always already interspersed with concepts in the most diverse ways.
[ 11 ] We must imagine that a being with fully developed human intelligence arises out of nothing and confronts the world. What it would become aware of there, before it brings its thinking into activity, is the pure content of observation. The world then showed this being only the mere incoherent aggregate of sensory objects: colors, sounds, pressure, warmth, taste, and olfactory sensations; then feelings of pleasure and displeasure. This aggregate is the content of pure, thoughtless observation. Opposite it is thinking, which is ready to develop its activity when a point of attack is found. Experience soon teaches that it will be found; thinking is capable of drawing threads from one element of observation to another. It links certain concepts with these elements and thereby brings them into a relationship. We have already seen above how a sound we encounter is linked to another observation by describing the former as the effect of the latter.
[ 12 ] If we now remember that the activity of thinking is not at all to be understood as a subjective one, we will not be tempted to believe that such relations, which are established through thinking, have merely a subjective validity.
[ 13 ] It will now be a matter of seeking, through thinking reflection, the relationship that the directly given observational content indicated above has to our conscious subject.
[ 14 ] In view of the fluctuation in the use of language, it seems necessary to me that I come to an understanding with my reader about the use of a word that I must apply in the following. I shall call the immediate objects of sensation which I have mentioned above, in so far as the conscious subject takes cognizance of them by observation, perceptions. So it is not the process of observation, but the object of this observation that I designate by this name.
[ 15 ] I do not choose the term sensation because it has a specific meaning in physiology that is narrower than that of my concept of perception. I can certainly describe a feeling in myself as perception, but not as sensation in the physiological sense. I also gain knowledge of my feeling by the fact that it becomes perception for me. And the way in which we obtain knowledge of our thinking through observation is such that we can also call thinking in its first appearance for our consciousness perception.
[ 16 ] The naive man regards his perceptions in the sense in which they appear to him immediately, as things that have an existence quite independent of him. When he sees a tree, he first believes that it is standing there in the place where his gaze is directed, in the shape he sees, with the colors its parts have, and so on. When the same person sees the sun appear as a disk on the horizon in the morning and follows the course of this disk, he believes that everything exists and happens in the way he observes it. He holds on to this belief until he encounters other perceptions that contradict it. The child, who has no experience of distances, reaches for the moon and only realizes what he thought was real at first sight when a second perception contradicts the first. Every widening of the circle of my perceptions forces me to correct my image of the world. This can be seen in daily life as well as in the spiritual development of mankind. The image that the ancients had of the relationship of the earth to the sun and the other celestial bodies had to be replaced by Copernicus because it did not agree with perceptions that were previously unknown. When Dr. Franz operated on a man born blind, he said that before his operation he had formed a completely different picture of the size of objects through the perceptions of his sense of touch. He had to correct his tactile perceptions with his visual perceptions.
[ 17 ] Where does it come from that we are forced to make such continual corrections to our observations?
[ 18 ] A simple consideration provides the answer to this question. If I am standing at one end of an avenue, the trees at the other end, farther away from me, appear smaller and closer together than where I am standing. My perceptual image changes when I change the place from which I am making my observations. The form in which it approaches me is therefore dependent on a purpose that does not depend on the object, but on me, the perceiver. It makes no difference to an avenue where I stand. But the image I get of it is essentially dependent on it. In the same way, it makes no difference to the sun and the planetary system that people are looking at them from the earth. But the perceptual image that presents itself to them is determined by their place of residence. This dependence of the perceptual image on our place of observation is the easiest to see through. The matter becomes more difficult when we get to know the dependence of our perceptual world on our physical and mental organization. The physicist shows us that within the space in which we hear a sound, vibrations of the air take place, and that the body in which we seek the origin of the sound also exhibits a vibrating movement of its parts. We only perceive this movement as sound if we have a normally organized ear. Without such an ear, the whole world would remain eternally mute to us. Physiology teaches us that there are people who perceive nothing of the glorious splendor of color that surrounds us. Their perceptual image only shows nuances of light and dark. Others do not perceive a certain color, for example red. Their view of the world lacks this shade of color and is therefore actually different from that of the average person. I would like to call the dependence of my perceptual image on my place of observation a mathematical one, and that of my organization a qualitative one. By the former the proportions and mutual distances of my perceptions are determined, by the latter the quality of them. The fact that I see a red surface as red - this qualitative determination - depends on the organization of my eye.
[ 19 ] My perceptual images are therefore initially subjective. The realization of the subjective character of our perceptions can easily lead to doubts as to whether they are based on anything objective at all. If we know that a perception, for example of the red color or of a certain sound, is not possible without a certain facility of our organism, we can come to the belief that the same, apart from our subjective organism, has no existence, that without the act of perception, of which it is the object, it has no kind of existence. This view has found a classical exponent in George Berkeley, who was of the opinion that from the moment man has become aware of the importance of the subject for perception, he can no longer believe in a world existing without the conscious mind. He says: "Some truths are so close and so obvious that one need only open one's eyes to see them. One such I consider to be the important proposition that the whole choir in the sky and everything that belongs to the earth, in a word all the bodies that compose the vast structure of the world, have no subsistence outside the mind, that their existence consists in their being perceived or recognized, that consequently, as long as they are not really perceived by me or exist in my consciousness or that of another created mind, they either have no existence at all or exist in the consciousness of an eternal mind." For this view, there is nothing left of perception apart from being perceived. There is no color if none is seen, no sound if none is heard. Just as little as color and sound do expansion, form and movement exist outside the act of perception. Nowhere do we see mere extension or shape, but these are always linked to color or other properties that are indisputably dependent on our subjectivity. If the latter disappear with our perception, then this must also be the case with the former, which are bound to them.
[ 20 ] The objection that, even if figure, color, sound, etc. have no other existence than that within the act of perception, there must nevertheless be things that exist without consciousness and to which the conscious perceptual images are similar, is countered by the view described above by saying that a color can only be similar to a color, a figure similar to a figure. Our perceptions can only be similar to our perceptions, but not to any other things. Even what we call an object is nothing other than a group of perceptions that are connected in a certain way. If I take away from a table shape, extension, color, etc., in short, everything that is only my perception, then nothing remains. This view, if pursued consistently, leads to the assertion that the objects of my perceptions exist only through me, and only insofar and as long as I perceive them; they disappear with the perception and have no meaning without it. Apart from my perceptions, however, I know of no objects and can know of none.
[ 21 ] There is no objection to this assertion as long as I merely take into account the fact that perception is co-determined by the organization of my subject. The matter would be considerably different, however, if we were able to indicate what the function of our perception is in the formation of a perception. We would then know what happens to the perception during perception and could also determine what must already be there before it is perceived.
[ 22 ] Thus, our consideration is derived from the object of perception to the subject of perception. I not only perceive other things, but I perceive myself. The perception of myself initially has the content that I am what remains in relation to the perceptual images that are always coming and going. The perception of the I can always appear in my consciousness while I have other perceptions. When I am absorbed in the perception of a given object, I am only conscious of it for the time being. The perception of my self can then be added to this. I am now not only aware of the object, but also of my personality, which stands opposite the object and observes it. I not only see a tree, but I also know that it is me who sees it. I also recognize that something is going on in me while I am observing the tree. When the tree disappears from my field of vision, a residue of this process remains for my consciousness: an image of the tree. This image has joined with my self during my observation. My self has been enriched; its content has absorbed a new element. I call this element my image of the tree. I would never be able to speak of perceptions if I did not experience them in the perception of my self. Perceptions would come and go; I would let them pass. Only by perceiving my self and realizing that its content also changes with each perception do I see myself compelled to connect the observation of the object with my own change of state and to speak of my imagination.
[ 23 ] I perceive the idea in my self, in the same sense that I perceive color, sound, etc. in other objects. I can now also make the distinction that I call these other objects, which confront me, the external world, while I call the content of my self-perception the internal world. The misunderstanding of the relationship between perception and object has led to the greatest misunderstandings in modern philosophy. The perception of a change in us, the modification that my self undergoes, has been pushed to the fore and the object that causes this modification has been completely lost sight of. It has been said that we do not perceive objects, but only our ideas. I should know nothing of the table itself, which is the object of my observation, but only of the change that takes place in myself while I perceive the table. This view must not be confused with Berkeley's view mentioned earlier. Berkeley asserts the subjective nature of my perceptual content, but he does not say that I can only know of my perceptions. He restricts my knowledge to my conceptions because he thinks that there are no objects outside of conception. What I see as a table is no longer there in Berkeley's sense as soon as I stop looking at it. Berkeley therefore allows my perceptions to arise directly through the power of God. I see a table because God produces this perception in me. Berkeley therefore knows of no real beings other than God and human spirits. What we call the world exists only within the spirits. What the naive person calls the outside world, physical nature, does not exist for Berkeley. This view is opposed to the Kantian view now prevailing, which restricts our knowledge of the world to our ideas, not because it is convinced that there can be no things apart from these ideas, but because it believes us to be so organized that we can only know of the changes of our own selves, not of the things in themselves which cause these changes. It does not conclude from the fact that I only know my ideas that there is no existence independent of these ideas, but only that the subject cannot directly take such an existence into himself, cannot imagine, invent, think, recognize, perhaps also not recognize it other than through the "medium of his subjective thoughts" (O. Liebmann, Zur Analysis der Wirklichkeit, page 28). This view believes to say something absolutely certain, something that is immediately obvious without any evidence. "The first fundamental proposition which the philosopher must bring to clear awareness consists in the realization that our knowledge extends first to nothing more than our conceptions. Our ideas are the only things that we experience directly, that we experience directly; and precisely because we experience them directly, even the most radical doubt cannot wrest knowledge of them from us. On the other hand, knowledge that goes beyond our imagination - I take this expression here everywhere in the broadest sense, so that all psychic events fall under it - is not protected from doubt. Therefore, at the beginning of philosophizing, all knowledge that goes beyond the imagination must be expressly posited as doubtful", is how Volkelt begins his book on "Immanuel Kant's Epistemology". What is here presented as if it were an immediate and self-evident truth is in reality the result of an operation of thought that proceeds as follows: The naive person believes that objects, as he perceives them, also exist outside his consciousness. Physics, physiology and psychology, however, seem to teach that our organization is necessary for our perceptions, that we can therefore know nothing but what our organization tells us about things. Our perceptions are thus modifications of our organization, not things in themselves. The train of thought indicated here has indeed been characterized by Eduard von Hartmann as the one that must lead to the conviction that we can only have direct knowledge of our perceptions (see his "Grundproblem der Erkenntnistheorie", pp. 16-40). Since we find vibrations of bodies and air outside our organism which present themselves to us as sound, it is concluded that what we call sound is nothing more than a subjective reaction of our organism to those movements in the external world. In the same way, we find that color and heat are only modifications of our organism. It is believed that these two types of perception are caused in us by the effect of processes in the external world that are quite different from the experience of warmth or color. When such processes excite the skin nerves of my body, I have the subjective perception of warmth; when such processes affect the optic nerve, I perceive light and color. So light, color and warmth are what my sensory nerves respond to the external stimulus with. The sense of touch does not provide me with the objects of the outside world either, but only my own states. In the sense of modern physics, one could think that bodies consist of infinitely small parts, the molecules, and that these molecules are not directly adjacent to each other, but have certain distances between them. There is therefore empty space between them. Through this they act on each other by means of attractive and repulsive forces. When I bring my hand close to a body, the molecules of my hand by no means touch those of the body directly, but a certain distance remains between body and hand, and what I perceive as the resistance of the body is nothing more than the effect of the repulsive force that its molecules exert on my hand. I am outside the body altogether and only perceive its effect on my organism.
[ 24 ] In addition to these considerations, there is the doctrine of the so-called specific sensory energies, which J. Müller (1801-1858) put forward. It consists in the fact that each sense has the peculiarity of responding to all external stimuli in only one specific way. If an effect is exerted on the optic nerve, light perception arises, regardless of whether the excitation is caused by what we call light or whether a mechanical pressure or an electric current acts on the nerve. On the other hand, different perceptions are evoked in different senses by the same external stimuli. From this it appears that our senses can only transmit what is going on within themselves, but nothing from the outside world. They determine the perceptions according to their nature.
[ 25 ] Physiology shows that there can be no question of a direct knowledge of what the objects in our sensory organs cause. By following the processes in our own bodies, the physiologist finds that the effects of external movement are already transformed in the most varied ways in the sensory organs. We see this most clearly in the eye and ear. Both are very complicated organs that substantially change the external stimulus before they bring it to the corresponding nerve. From the peripheral end of the nerve, the already altered stimulus is then transmitted to the brain. Only here must the central organs be excited again. From this it is concluded that the external process has undergone a series of transformations before it comes to consciousness. What takes place in the brain is connected with the external process by so many intermediate processes that a resemblance to it can no longer be thought of. What the brain ultimately conveys to the soul are neither external processes nor processes in the sense organs, but only those within the brain. But even the latter are not yet directly perceived by the soul. What we ultimately have in our consciousness are not brain processes at all, but perceptions. My sensation of red bears no resemblance at all to the process that takes place in the brain when I perceive red. The latter only occurs again as an effect in the soul and is only caused by the brain process. This is why Hartmann says (Grundproblem der Erkenntnistheorie, p. 37): "What the subject perceives are therefore always only modifications of his own mental states and nothing else." If I have sensations, then these are by no means grouped into what I perceive as things. Only individual sensations can be conveyed to me by the brain. The sensations of hardness and softness are conveyed to me through the sense of touch, the colors, and the sensations of light through the sense of sight. But they are united in one and the same object. This union must therefore first be brought about by the soul itself. That is to say, the soul assembles the individual sensations conveyed by the brain into bodies. My brain transmits to me individually the sensations of sight, touch and hearing, in quite different ways, which the soul then assembles into the idea of the trumpet. This final link (the idea of the trumpet) of a process is what is first of all given to my consciousness. There is nothing more to be found in it of what is outside me and originally made an impression on my senses; the external object has been completely lost on the way to the brain and through the brain to the soul.
[ 26 ] It will be difficult to find a second structure of thought in the history of human mental life that has been assembled with greater acumen and yet, on closer examination, falls apart into nothing. Let us take a closer look at how it comes about. First we start from what is given to the naive consciousness, from what is perceived. Then we show that everything that is found in this thing would not be there for us if we had no senses. No eye: no color. So color is not yet present in that which acts on the eye. It only arises through the interaction of the eye with the object. This is therefore colorless. But color is not present in the eye either, because a chemical or physical process is present there that is first transmitted to the brain through the nerve, where it triggers another process. This is still not the color. It is only caused in the soul by the brain process. There it still does not enter my consciousness, but is only transferred outwards through the soul to a body. In this body I believe I finally perceive it. We have gone through a complete cycle. We have become conscious of a colored body. That is the first thing. Now the thought operation begins. If I had no eyes, the body would be colorless for me. So I cannot transfer the color into the body. I go in search of it. I search for it in the eye: in vain; in the nerve: in vain; in the brain: also in vain; in the soul: here I find it, but not connected to the body. I only find the colored body again where I have gone out. The circle is complete. I believe that I recognize as the product of my soul what the naive person thinks of as existing outside in space.
[ 27 ] As long as you stand still, everything seems to be in perfect order. But the matter has to be started all over again. Up to now, I have managed with one thing: with external perception, of which I used to have a completely wrong view as a naive person. I was of the opinion that it had an objective existence as I perceived it. Now I realize that it disappears with my imagination, that it is only a modification of my mental states. Do I still have any right to start from it in my observations? Can I say of it that it has an effect on my soul? From now on I must treat the table, which I used to believe had an effect on me and produced an idea of itself in me, as an idea itself. Consequently, my sense organs and the processes in them are also merely subjective. I have no right to speak of a real eye, but only of my imagination of the eye. It is the same with nerve conduction and the brain process, and no less with the process in the soul itself, by which things are to be constructed out of the chaos of manifold sensations. If I go through the links of my act of cognition again, assuming that the first train of thought is correct, then the latter shows itself to be a web of ideas which, as such, cannot act on each other. I cannot say: my conception of the object acts on my conception of the eye, and from this interaction the conception of color emerges. But neither do I need to. For as soon as I realize that my sense organs and their activities, my nervous and mental processes, can only be given to me through perception, the train of thought described above shows itself to be completely impossible. It is true: for me there is no perception without the corresponding sense organ. But neither is there a sense organ without perception. I can pass from my perception of the table to the eye, which sees it, to the skin nerves, which feel it; but again, I can only experience what is going on in these from perception. And then I soon notice that in the process that takes place in the eye there is not a trace of similarity with what I perceive as color. I cannot destroy my perception of color by pointing out the process that takes place in the eye during this perception. Nor do I find the color again in the nerves and brain processes; I only connect new perceptions within my organism with the first, which the naive person relocates outside his organism. I only pass from one perception to another.
[ 28 ] In addition, the whole conclusion contains a leap. I am able to trace the processes in my organism to the processes in my brain, even if my assumptions become more and more hypothetical the closer I get to the central processes of the brain. The path of external observation ends with the process in my brain, namely with that which I would perceive if I were able to treat the brain with physical, chemical, etc. aids and methods. tools and methods to treat the brain. The path of internal observation begins with sensation and extends to the construction of things from the sensory material. At the transition from the brain process to sensation, the path of observation is interrupted.
[ 29 ] The characterized way of thinking, which in contrast to the standpoint of naive consciousness, which it calls naive realism, calls itself critical idealism, makes the mistake of characterizing one perception as perception, but accepts the other precisely in the sense that naive realism, which it apparently refutes, does. It wants to prove the imaginary character of perceptions by naively accepting the perceptions of one's own organism as objectively valid facts and, in addition, overlooking the fact that it confuses two areas of observation between which it can find no mediation.
[ 30 ] Critical idealism can only refute naïve realism if it itself accepts its own organism as objectively existing in a naïve-realistic manner. At the same moment that it becomes aware of the complete similarity of the perceptions of its own organism with the perceptions assumed by naive realism to exist objectively, it can no longer rely on the former as a secure foundation. He would also have to regard his subjective organization as a mere imaginary complex. With this, however, the possibility of thinking the content of the perceived world to be caused by the mental organization is lost. One would have to assume that the idea of "color" is only a modification of the idea of "eye". So-called critical idealism cannot be proved without borrowing from naive realism. The latter is only refuted by allowing its own presuppositions in another field to stand unchecked.
[ 31 ] So much is certain from this: critical idealism cannot be proven by investigations within the field of perception, and thus perception cannot be stripped of its objective character.
[ 32 ] However, the sentence: "The perceived world is my imagination" can be presented even less as self-evident and in need of no proof. Schopenhauer begins his main work "The World as Will and Representation" with the words: "The world is my representation: - this is the truth which holds good in relation to every living and cognizing being; although man alone can bring it into reflected abstract consciousness: and if he really does so, philosophical prudence has entered into him. It then becomes clear and certain to him that he knows no sun and no earth; but always only an eye that sees a sun, a hand that feels an earth; that the world which surrounds him is there only as a conception, that is, throughout only in relation to an Other, that which is above, which is himself. - If any truth can be stated a priori, it is this: for it is the statement of that form of all possible and conceivable experience which is more general than all others, than time, space, and causality: for all these presuppose that very one ... " The whole proposition fails because of the circumstance already mentioned by me above, that the eye and the hand are no less perceptions than the sun and the earth. And one could counter his sentences in the sense of Schopenhauer and with reference to his mode of expression: My eye, which sees the sun, and my hand, which feels the earth, are my perceptions just as much as the sun and the earth themselves. But it is quite clear that I am thereby canceling the sentence. For only my real eye and my real hand could have the ideas sun and earth as their modifications in themselves, but not my ideas eye and hand. But critical idealism may only speak of these.
[ 33 ] Critical idealism is completely unsuitable for gaining a view of the relationship between perception and imagination. It cannot make the distinction indicated on page 67f. between what happens to perception during perception and what must already be there before it is perceived. Another path must therefore be taken.