CONCEPTS AND IDEAS arise through thinking. What a concept is cannot be stated in words. Words can do no more than draw attention to our concepts. When someone sees a tree, his thinking reacts to his observation, an ideal counterpart is added to the object, and he considers the object and the ideal counterpart as belonging together. When the object disappears from his field of observation, only the ideal counterpart of it remains. This latter is the concept of the object. The further our range of experience is widened, the greater becomes the sum of our concepts. But a concept is never found isolated. Concepts combine to form a totality built up according to inherent laws. The concept “organism” combines, for example, with those of “gradual development, growth.” Other concepts formed of single objects merge completely. All concepts that I form of lions, merge into the general concept “lion.” In this way the single concepts unite in an enclosed conceptual system, in which each concept has its special place. Ideas are not qualitatively different from concepts. They are but concepts that are richer in content, more saturated and comprehensive. At this particular point I must draw special attention to the fact that thinking is my point of departure, and not concepts and ideas which must first be gained by means of thinking. Concepts and ideas already presuppose thinking. Therefore, what I have said about the nature of thinking, that it exists through itself, that it is determined by nothing but itself, cannot simply be carried over and applied to concepts. (I mention this at this point explicitly because it is here that my difference with Hegel lies. For Hegel, the concept is the primary and original.)
The concept cannot be gained from observation. This can already be seen from the fact that the growing human being slowly and gradually forms concepts corresponding to the objects surrounding him. The concepts are added to observation.
A much-read contemporary philosopher, Herbert Spencer,  describes the mental process which we carry out in response to observation, in the following way:
“If, when walking through the fields one day in September, we hear a sound a few yards in advance, and, on observing the ditch-side where it occurs, see the grass move, we shall probably turn toward the spot to learn by what this sound and motion are produced. As we approach, a partridge flutters in the ditch; on seeing this our curiosity is satisfied; we have what we call an explanation of the phenomena. This explanation, please notice, amounts to this: Because we have experienced countless times in life that a disturbance of the stationary position of small bodies is accompanied by the movement of other bodies existing among them, and because we have therefore generalized the relation between such disturbances and such movements, we consider this particular disturbance explained as soon as we find it to be an example of just this relationship.” 
A closer examination gives a very different result from what is described above. When I hear a sound, the first thing I do is to find the concept that corresponds to this observation. It is this concept that takes me beyond the sound. Someone who did not reflect further would simply hear the sound and be content with that. But, because I reflect, it becomes clear to me that I have to understand the sound as an effect. It is therefore only when I connect the concept of effect with the perception of the sound that I am induced to go beyond the single observation and look for the cause. The concept of effect calls up that of cause; I then look for the object which is the cause, and in this case I find it to be the partridge. But these concepts, cause and effect, I can never gain by mere observation, however many instances I may have observed. Observation calls up thinking, and it is thinking that then shows me how to fit one individual occurrence to another.
If one demands of a “strictly objective science” that it must take its content from observation alone, then one must at the same time require that it is to desist from all thinking. For by its very nature, thinking goes beyond the observed object.
We must now pass from thinking itself to the being who thinks, for it is through the thinker that thinking is combined with observation. Human consciousness is the stage upon which concept and observation meet one another and become united. In saying this, we have at the same time characterized human consciousness. It is the mediator between thinking and observation. Insofar as the human being observes an object, it appears to him as given; insofar as he thinks, he appears to himself as active. He regards what comes to meet him as object, and himself as thinking subject. While he directs his thinking to the observation, he is conscious of the object; while he directs his thinking to himself he is conscious of himself, or is self-conscious. Human consciousness of necessity, must be self-conscious at the same time, because it is a thinking consciousness. For when thinking turns its attention to its own activity, then its own essential being, that is, its subject, is its object as well.
It must, however, not be overlooked that it is only with the help of thinking that we can define ourselves as subject and contrast ourselves with objects. For this reason, thinking must never be understood as a merely subjective activity. Thinking is beyond subject and object. It forms these two concepts, just as it forms all others. When therefore as thinking subject, we refer a concept to an object, we must not understand this reference as something merely subjective. It is not the subject that makes the reference, but thinking. The subject does not think because it is subject; rather it appears to itself as a subject because it is able to think. The activity carried out by man as a thinking being is, therefore, not a merely subjective activity. Rather it is neither subjective nor objective; it is an activity that goes beyond both these concepts. I ought never to say that my individual subject thinks; in fact, my subject exists by the very grace of thinking. Thinking, therefore, is an element that takes me beyond myself and unites me with the objects. Yet at the same time it separates me from them, inasmuch as it sets me, as subject, over against them.
Man's twofold nature is due to this: he thinks, and in so doing encompasses himself and the rest of the world; but at the same time, it is also by means of thinking that he defines himself as an individual who confronts the objects.
The next step is to ask ourselves: How does the other element, — that in consciousness meets with thinking — which we have so far simply called the object of observation, enter our consciousness?
In order to answer this question, we must separate from our field of observation all that has been brought into it by thinking. For the content of our consciousness at any moment is already permeated with concepts in the most varied ways.
We must imagine a being with fully developed human intelligence suddenly waking into existence out of nothing, and confronting the world. Everything of which it was aware before its thinking activity began, would be the pure content of observation. The world would then reveal to this being nothing but the mere disconnected aggregate of objects of sensation: colors, sounds, sensations of pressure, warmth, taste and smell, then feelings of pleasure and displeasure. This aggregate is the content of pure, unthinking observation. Over against it stands thinking, ready to unfold its activity if a point of attack can be found. Experience soon shows that it is found. Thinking is able to draw threads from one element of observation to another. It connects definite concepts with these elements and thereby brings about a relationship between them. We have already seen above how a sound that comes to meet us is connected with another observation by our identifying the former as the effect of the latter.
If we now remind ourselves that the activity of thinking is never to be understood as a subjective activity, then we shall not be tempted to believe that such relationships, established by thinking, have merely a subjective value.
Our next task is to discover by means of thinking reflection what relation the above-mentioned directly given content of observation has to our conscious subject.
The varied ways of using words make it necessary for me to come to an agreement with my readers concerning the use of a word which I shall have to employ in what follows. I shall use the word perceptions for the immediate objects of sensation enumerated above, insofar as the conscious subject becomes aware of them through observation. It is therefore not the process of observation, but the object of observation which I call perception. 
I do not choose the word sensation because in physiology this has a definite meaning which is narrower than that of my concept of perception. I can call a feeling in myself a perception, but not a sensation in the physiological sense. But I also become aware of my feelings by their becoming perceptions for me. And the way we become aware of our thinking through observation is such that we can also call thinking, as it first comes to the notice of our consciousness, a perception.
The naive man considers his perceptions, in the sense in which they directly seem to appear to him, as things having an existence completely independent of himself. When he sees a tree he believes, to begin with, that it stands in the form which he sees, with the colors of its various parts, etc., there on the spot toward which his gaze is directed. When in the morning he sees the sun appear as a disk on the horizon and follows the course of this disk, his opinion is that all this actually exists (by itself) and occurs just as he observes it. He clings to this belief until he meets with further perceptions which contradict those he first had. The child who has as yet no experience of distance grasps at the moon, and does not correct his first impression as to the real distance until a second perception contradicts the first. Every extension of the circle of my perceptions compels me to correct my picture of the world. We see this in everyday life, as well as in the intellectual development of mankind. That picture which the ancients made for themselves of the relation of the earth to the sun and to the other heavenly bodies had to be replaced through Copernicus by a different one, because theirs did not accord with perceptions which were unknown in those early times. A man who had been born blind said, when operated on by Dr. Franz, [25a] that the idea of the size of objects which he had formed by his sense of touch before his operation, was a very different one. He had to correct his tactual perceptions by his visual perceptions.
Why are we compelled to make these constant corrections of our observations?
A simple reflection will answer this question. When I stand at one end of an avenue, the trees at the far end seem smaller and nearer together than those where I stand. The picture of my perception changes when I change the place from which I am looking. The form in which it appears to me, therefore, is dependent on a condition which belongs not to the object, but to me, the perceiver. It is all the same to the avenue where I stand. But the picture of it which I receive depends essentially on the place where I stand.' In the same way, it is all the same to the sun and the planetary system that human beings happen to consider them from the earth; but the perception-picture of the heavens which human beings have is determined by the fact that they inhabit the earth. This dependence of our perception-picture upon our place of observation is the easiest one to grasp. Matters already become more difficult when we learn how our perceptions are dependent on our bodily and spiritual organization. The physicist shows us that within the space in which we hear a sound, vibrations of the air occur, and also that in the body in which we seek the origin of the sound, vibrating movements of its parts will be found. We perceive this movement as sound, but only if we have a normally constructed ear. Without this, the whole world would be forever silent for us. From physiology we know that there are people who perceive nothing of the splendor of color surrounding us. Their perception-picture shows only degrees of light and dark. Others are blind to one color, e.g., red. Their picture of the world lacks this shade of color, and therefore is actually a different one from that of the average person. I would call the dependence of my perception-picture on my place of observation, a mathematical one, and its dependence on my organization a qualitative one. The first determines the proportions of size and mutual distances of my perceptions, the second their quality. The fact that I see a red surface as red — this qualitative determination — depends on the organization of my eye.
My perception-pictures, then, are subjective to begin with. Knowledge of the subjective character of our perceptions may easily lead to doubt that there is any objective basis for them at all. If we know that a perception, for example, that of the color red or of a certain tone, is not possible without a specific structure of our organism, it is easy to believe that it has no existence at all apart from our subjective organization, that without the act of perceiving — the objective of which it is — it would have no kind of existence. This view found a classical exponent in George Berkeley.  His opinion was that man, from the moment he realizes the significance the subject has for perception, is no longer able to believe in the presence of a world without the conscious spirit. He said:
“Some truths there are so near and obvious to the mind that a man need only open his eyes to see them. Such I take this important one to be, viz., 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 not 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.”
According to this view, nothing remains of the perception, if one disregards the fact of its being perceived. There is no color when none is seen, no sound when none is heard. Apart from the act of perception, extension, form and motion exist as little as do color and sound. Nowhere do we see bare extension or form; these are always connected with color or some other quality unquestionably dependent on our subjectivity. If these latter disappear when our perception of them disappears, then the former, being bound up with them, must likewise disappear.
To the objection that even if figure, color, sound, etc., have no other existence than the one within the act of perception, yet there must be things that exist apart from consciousness and to which the conscious perception pictures are similar, the above view would answer that a color can be similar only to a color, a figure only to a figure. Our perceptions can be similar only to our perceptions, and to nothing else. What we call an object is also nothing but a collection of perceptions which are connected in a particular way. If I strip a table of its form, extension, color, etc., — in short, of all that is only my perception — then nothing else remains. If this view is followed to its logical conclusion, it leads to the assertion that the objects of my perceptions are present only through me and, indeed, only in as far as, and as long as I perceive them. They disappear with the act of perceiving them, and have no meaning apart from it. But apart from my perceptions I know of no objects and cannot know of any.
No objection can be made to this assertion as long as in general I merely take into account the fact that the perception is partially determined by the organization of my subject. It would be very different if we were able to estimate what function our perceiving has in bringing about a perception. We should then know what happens to the perception during the act of perceiving, and could also determine how much of it must already have existed before it was perceived.
This leads us to turn our consideration from the object of perception to its subject. I perceive not only other things; I also perceive myself. The immediate content of the perception of myself is the fact that I am the stable element in contrast to the continually coming and going perception-pictures. The perception of the I can always come up in my consciousness while I am having other perceptions. When I am absorbed in the perception of an object that is given, then, for the time being, I am conscious only of this object. To this, the perception of my self can come. I am then conscious, not only of the object, but also of my own personality, which confronts the object and observes it. I do not merely see a tree, but I also know that it is I who see it. I also realize that something takes place in me while I observe the tree. When the tree disappears from my field of vision, an after-effect of this process remains in my consciousness: an image of the tree. This image became united with my self during my observation. My self has become enriched; its content has taken a new element into itself. This element I call my representation of the tree. I should never be in a position to speak of representations if I did not experience them in the perception of my own self. Perceptions would come and go; I should let them slip by. Only because I perceive my self, and am aware that with each perception the content of my self also changes, do I find myself compelled to bring the observation of the object into connection with the changes in my own condition, and to speak of my representation.
I perceive the representation in my self in the same sense as I perceive color, sound, etc., in other objects. Now I am also able to make the distinction that I call those other objects that confront me, outer world, whereas the content of my self-perception I call inner world. Misunderstanding of the relationship between representation and object has led to the greatest mistakes in modern philosophy. The perception of a change in us, the modification experienced in the self, has been thrust into the foreground and the object which causes this modification is lost sight of altogether. It is said: We do not perceive the objects, but only our representations. I am supposed to know nothing of the table in itself, which is the object of my observation, but only of the changes which occur in my self while I perceive the table. This view should not be confused with that of Berkeley, mentioned above. Berkeley maintains the subjective nature of the content of perceptions, but he does not say that I can know only of my own representations. He limits man's knowledge to his representations because, in his opinion, there are no objects outside the act of representing. What I regard as a table is no longer present, according to Berkeley, when I cease to turn my gaze toward it. This is why Berkeley lets our perceptions arise directly out of the omnipotence of God. I see a table because God calls up this perception in me. For Berkeley, therefore, there are no real beings other than God and human spirits. What we call “world” is present only within spirits. For Berkeley, what the naive man calls outer world, or physical nature, is not there. This view is contrasted by the now predominant Kantian  view which limits our knowledge to our representation not because it is convinced that there cannot be things in existence besides these representations, but because it believes us to be so organized that we can experience only the modification in our own self, not the thing-in-itself that causes this modification. This conclusion arises from the view that I know only my representations, not that there is no existence apart from them, but only that the subject cannot take such an existence directly into itself; all it can do is merely through
“the medium of its subjective thoughts to imagine it, invent it, think it, cognize it, or perhaps also fail to cognize it.” 
This view believes it expresses something absolutely certain, something that is immediately obvious, in need of no proof.
“The first fundamental principle which the philosopher has to bring to clear consciousness consists in the recognition that our knowledge, to begin with, does not reach beyond our representations. Our representation is the only thing we experience and learn to know directly and, just because we have direct experience of it, even the most radical doubt cannot rob us of our knowledge. By contrast, the knowledge that goes beyond our representations — taking this expression here in the widest possible sense, so that all physical happenings are included in it — is open to doubt. Hence, at the very beginning of all philosophizing, all knowledge which goes beyond representations must explicitly be set down as being open to doubt.”
These are the opening sentences of Volkelt's book on Kant's Theory of Knowledge.  What is put forward here as an immediate and self-evident truth is in reality the result of a line of thought which runs as follows: The naive man believes that the objects, just as he perceives them, are also present outside his consciousness. Physics, physiology and psychology, however, seem to show that for our perceptions our organization is necessary and that, therefore, we cannot know about anything except what our organization transmits to us from the objects. Our perceptions therefore are modifications of our organization, not things-in-themselves. The train of thought here indicated has, in fact, been characterized by Eduard von Hartmann  as the one which must lead to the conviction that we can have a direct knowledge only of our own representations.  Outside our organisms we find vibrations of physical bodies and of air; these are sensed by us as sounds, and therefore it is concluded that what we call sound is nothing but a subjective reaction of our organisms to these movements in the external world. In the same way, color and warmth are found to be merely modifications of our organisms. And, indeed, the view is held that these two kinds of perceptions are called forth in us through effects or processes in the external world which are utterly different from the experiences we have of warmth or of color. If these processes stimulate the nerves in my skin, I have the subjective perception of warmth; if they happen to encounter the optic nerve, I perceive light and color. Light, color and warmth, then, are the responses of my sensory nerves to external stimuli. Even the sense of touch does not reveal to me the objects of the outer world, but only conditions in myself. In the sense of modern physics, one must imagine that bodies consist of infinitely small particles, molecules, and that these molecules are not in direct contact, but are at certain distances from one another. Between them, therefore, is empty space. Across this space they act on one another by attraction and repulsion. If I put my hand on a body, the molecules of my hand by no means touch those of the body directly, but there remains a certain distance between body and hand, and what I sense as the body's resistance is nothing other than the effect of the force of repulsion which its molecules exert on my hand. I am completely external to the body and perceive only its effects upon my organism.
These considerations have been supplemented by the theory of the so-called specific nervous energy, which has been advanced by J. Müller (1801-1858).  According to this theory, each sense has the peculiarity that it responds to all external stimuli in one definite way only. If the optic nerve is stimulated, perception of light results, irrespective of whether the nerve is stimulated by what we call light, or by a mechanical pressure, or an electric current. On the other hand, the same external stimulus applied to different senses gives rise to different perceptions. This appears to show that our sense-organs can transmit only what occurs in themselves, but nothing from the external world. They determine our perceptions, each according to its own nature.
Physiology also shows that there is no question of a direct knowledge of what the objects cause to take place in our sense-organs. When the physiologist traces the processes in our bodies, he discovers that already in the sense organs, the effects of the external vibrations are modified in the most manifold ways. This can be seen most clearly in the case of the eye and ear. Both are very complicated organs which modify the external stimulus considerably before they conduct it to the corresponding nerve. From the peripheral end of the nerve the already modified stimulus is then led further to the brain. Here at last the central organs are stimulated in their turn. From this the conclusion is drawn that the external process must have undergone a series of transformations before it reaches consciousness. What goes on in the brain is connected by so many intermediate processes with the external process, that any similarity to the latter is unthinkable. What the brain ultimately transmits to the soul is neither external processes nor processes in the sense-organs, but only such as occur in the brain. But even these are not directly perceived by the soul; what we finally have in consciousness are not brain processes at all, but sensations. My sensation of red has absolutely no similarity to the process which occurs in the brain when I sense the red. The red is caused by the processes in the brain and appears again only as an effect of this in the soul. This is why Hartmann says:  “What the subject perceives therefore is always only modifications of his own psychic states and nothing else.” When I have sensations, these are as yet far from being grouped into what I perceive as objects. For only single sensations can be transmitted to me by the brain. The sensations of hardness and softness are transmitted to me by the sense of touch, those of color and light by the sense of sight. Yet all these can be found united in one and the same object. The unification must, therefore, be caused by the soul itself; this means that the soul combines into bodies the separate sensations transmitted through the brain. My brain gives me separately and indeed along very different paths, the sensations of sight, touch and hearing, which the soul then combines into the representation “trumpet.” This last link (the representation of trumpet) is the very first process to enter my consciousness. In it can no longer be found anything of what is outside of me and originally made an impression on my senses. The external object has been entirely lost on the way to the brain and through the brain to the soul.
In the history of man's intellectual endeavor it would be hard to find another edifice of thought which has been put together with greater ingenuity and yet which, on closer analysis, collapses into nothing. Let us look a little closer at the way it has been built up. The starting point is taken from what is given in naive consciousness, that is, from things as perceived. Then it is shown that nothing of what belongs to these things would be present for us had we no senses. No eye: no color. Therefore, the color is not yet present in what affects the eye. It arises first through the interaction of the eye and the object. The latter must, therefore, be colorless. But neither is the color present in the eye, for what is present there is a chemical or physical process which first has to be led by the optic nerve to the brain, and there releases another process. This is not yet the color. The latter is only called up in the soul through the process in the brain. As yet it does not enter my consciousness, but is first placed by the soul on a body outside. Here, finally, I believe that I perceive it. We have completed a circle. We are conscious of a colored object. This is the starting point; here the building up of thoughts begins. If I had no eye, for me the object would be colorless. I cannot, therefore, place the color on the body. I start on a search for it. I look for it in the eye: in vain; in the nerve: in vain; in the brain: in vain once more; in the soul: here I find it indeed, but not attached to the body. I recover the colored body only there at the point from which I started. The circle is closed. I am confident that I recognize as a product of my soul what the naive man imagines to be present out there in space.
As long as one remains here, everything seems to fit beautifully. But we must start again from the beginning. Until now I have been dealing with the outer perception, of which earlier, as naive man, I had a completely wrong opinion. I believed that just as I perceive it, it had an objective existence. But now I have noticed that in the act of representing it, it disappears; that it is only a modification of my soul condition. Is there any justification for using it as a starting point in my consideration? Can I say of it that it affects my soul? From now on I have to treat the table, of which earlier I believed that it acted on me and brought about in me a representation of itself, as being itself a representation. From this it follows logically that my sense-organs and the processes in them are also mere subjective manifestations. I have no right to speak of a real eye, but only of my representation of eye. And the same holds good in regard to the nerves and the brain process, and no less in regard to what takes place in the soul itself, through which, out of the chaos of manifold sensations, objects are supposed to be built up. If I run through the steps of my act of cognition once more, presupposing the first line of thought to be correct, then the latter shows itself to be a web of representations which, as such, could not act upon one another. I cannot say: My representation of the object affects my representation of the eye, and from this interaction the representation of color comes about. Nor is there any need for saying this, for as soon as it is clear to me that my sense-organs and their activity, and my nerve and soul processes as well, can also be given only through perception, then the described line of thought shows itself in its full impossibility. It is true that I can have no perception without the corresponding sense organ, but neither can I have the sense-organ without perception. From my perception of the table I can go over to the eye which sees it, and to the nerves in the skin which touch it, but what takes place in these I can, again, leam only from perception. And there I soon notice that in the process which takes place in the eye there is no trace of similarity to what I perceive as color. I cannot deny the existence of my color perception by pointing to the process which takes place in the eye during this perception. And just as little can I find the color in the nerve and brain processes; all I do is only add new perceptions, within the organism, to the first perception, which the naive man placed outside his organism. I simply pass from one perception to another.
Apart from this there is an error in the whole conclusion of the line of thought. I am able to follow what takes place in my organism up to the processes in my brain, even though my assumptions become more and more hypothetical the nearer I get to the central processes in the brain. But the path of observation from outside ceases with what takes place in my brain, ceases, in fact, with what I should observe if I could treat the brain with the assistance and methods of physics and chemistry. The path of observation from within begins with the sensation and continues up to the building up of objects out of the material of sensation. In the transition from brain-process to sensation, there is a gap in the path of observation.
This characteristic way of thinking, which describes itself as critical idealism, in contrast to the standpoint of naive consciousness which it calls naive realism, makes the mistake of characterizing one perception as representation while taking another in the very same sense as does the naive realism which it apparently refutes. Critical idealism wants to prove that perceptions have the character of representations; in this attempt it accepts — in naive fashion — the perceptions belonging to the organism as objective, valid facts, and, what is more, fails to see that it mixes up two spheres of observation, between which it can find no mediation.
Critical idealism is able to refute naive realism only by itself assuming, in naive-realistic fashion, that one's own organism has objective existence. As soon as the critical idealist becomes conscious of the complete similarity between the perceptions connected with one's own organism and those which naive realism assumes to have objective existence, he can no longer rely on the perceptions of the organism as being a safe foundation. He would have to regard his own subjective organization also as a mere complex of representations. But then the possibility ceases of regarding the content of the perceived world as a product of man's spiritual organization. One would have to assume that the representation “color” was only a modification of the representation “eye.” So-called critical idealism cannot be proved without borrowing something from naive realism. Naive realism can only be refuted by accepting its assumptions — without testing them — in another sphere.
This much, then, is certain: Investigations within the sphere of perceptions cannot prove critical idealism, and consequently cannot strip perceptions of their objective character.
Still less can the principle, “The perceived world is my representation,” be stated as if it were obvious and in need of no proof. Schopenhauer  begins his principal work, Die Welt als Wille und Vorstellung, The World as Will and Representation, with the words:
“The world is my representation — this is a truth which holds good for every being that lives and cognizes, though man alone is able to bring it into reflective, abstract consciousness. If he really does this, then he has attained to philosophical selfconsciousness. It then becomes clear and certain to him that he does not know a sun or an earth, but always only an eye that sees a sun, a hand that feels an earth; that the world which surrounds him is only there as representation, that means throughout only in relation to something else, to the one who represents, that is, to himself. If ever a truth can be asserted a priori, this one can, for it expresses the form most general of all possible and thinkable experiences, more general than time, or space, or causality, for all these presuppose it ...”
The principle above: “The world is my representation,” on which this is based, is, however, wrecked by the fact, already mentioned, that the eye and the hand are perceptions in just the same sense as the sun and the earth. And if one used Schopenhauer's expressions in his own sense, one could object to his principle: My eye that sees the sun and my hand that feels the earth are my representations, just like the sun and the earth themselves. But that, with this, the principle is canceled out, is immediately obvious. For only my real eye and my real hand could have the representations “sun” and “earth” as their modifications; my representations “eye” and “hand” cannot have them. But critical idealism can speak of representations only.
It is impossible by means of critical idealism to gain insight into what relation perception has to representation. It is insensible to the distinction, mentioned on page 85, of what happens to the perception while perceiving takes place and what must be inherent in it before it is perceived. We must, therefore, attempt to gain this insight along another path.