From the foregoing considerations it follows that it is impossible to prove, by analysis of the content of our perceptions, that our percepts are ideas. This is supposed to be proved by showing that, if the process of perceiving takes place in the way in which we conceive it in accordance with the naÏve-realistic assumptions concerning the psychological and physiological constitution of human individuals, then we have to do, not with things themselves, but merely with our ideas of things. Now, if NaÏve Realism, when consistently thought out, leads to results which directly contradict its presuppositions, then these presuppositions must be discarded as unsuitable for the foundation of a theory of the world. In any case, it is inadmissible to reject the presuppositions and yet accept the consequences, as the Critical Idealist does who bases his assertion that the world is my idea on the line of argument indicated above. (Eduard von Hartmann gives in his work Das Grundproblem der Erkenntnistheorie a full account of this line of argument.)

The truth of Critical Idealism is one thing, the persuasiveness of its proofs another. How it stands with the former, will appear later in the course of our argument, but the persuasiveness of its proofs is nil. If one builds a house, and the ground floor collapses whilst the first floor is being built, then the first floor collapses too. NaÏve Realism and Critical Idealism are related to one another like the ground floor to the first floor in this simile.

For one who holds that the whole perceptual world is only an ideal world, and, moreover, the effect of things unknown to him acting on his soul, the real problem of knowledge is naturally concerned, not with the ideas present only in the soul, but with the things which lie outside his consciousness, and which are independent of him. He asks, How much can we learn about them indirectly, seeing that we cannot observe them directly? From this point of view, he is concerned, not with the connection of his conscious percepts with one another, but with their causes which transcend his consciousness and exist independently of him, whereas the percepts, on his view, disappear as soon as he turns his sense-organs away from the things themselves. Our consciousness, on this view, works like a mirror from which the pictures of definite things disappear the very moment its reflecting surface is not turned towards them. If, now, we do not see the things themselves, but only their reflections, we must obtain knowledge of the nature of the former indirectly by drawing conclusions from the character of the latter. The whole of modern science adopts this point of view, when it uses percepts only as a means of obtaining information about the motions of matter which lie behind them, and which alone really “are.” If the philosopher, as Critical Idealist, admits real existence at all, then his sole aim is to gain knowledge of this real existence indirectly by means of his ideas. His interest ignores the subjective world of ideas, and pursues instead the causes of these ideas.

The Critical Idealist can, however, go even further and say, I am confined to the world of my own ideas and cannot escape from it. If I conceive a thing beyond my ideas, this concept, once more, is nothing but my idea. An Idealist of this type will either deny the thing-in-itself entirely or, at any rate, assert that it has no significance for human minds, i.e., that it is as good as non-existent since we can know nothing of it.

To this kind of Critical Idealist the whole world seems a chaotic dream, in the face of which all striving for knowledge is simply meaningless. For him there can be only two sorts of men: (1) victims of the illusion that the dreams they have woven themselves are real things, and (2) wise men who see through the nothingness of this dream world, and who gradually lose all desire to trouble themselves further about it. From this point of view, even one’s own personality may become a mere dream phantom. Just as during sleep there appears among my dream-images an image of myself, so in waking consciousness the idea of my own Self is added to the idea of the outer world. I have then given to me in consciousness, not my real Self, but only my idea of my Self. Whoever denies that things exist, or, at least, that we can know anything of them, must also deny the existence, respectively the knowledge, of one’s own personality. This is how the Critical Idealist comes to maintain that “All reality transforms itself into a wonderful dream, without a life which is the object of the dream, and without a mind which has the dream; into a dream which is nothing but a dream of itself.” (Cp. Fichte, Die Bestimmung des Menschen.)

Whether he who believes that he recognises immediate experience to be a dream, postulates nothing behind this dream, or whether he relates his ideas to actual things, is immaterial. In both cases life itself must lose all scientific interest for him. However, whereas for those who believe that the whole of accessible reality is exhausted in dreams, all science is an absurdity, for those who feel compelled to argue from ideas to things, science consists in studying these things-in-themselves. The first of these theories of the world may be called Absolute Illusionism, the second is called Transcendental Realism1 by its most rigorously logical exponent, Eduard von Hartmann.

These two points of view have this in common with NaÏve Realism, that they seek to gain a footing in the world by means of an analysis of percepts. Within this sphere, however, they are unable to find any stable point.

One of the most important questions for an adherent of Transcendental Realism would have to be, how the Ego constructs the world of ideas out of itself. A world of ideas which was given to us, and which disappeared as soon as we shut our senses to the external world, might provoke an earnest desire for knowledge, in so far as it was a means for investigating indirectly the world of the self-existing Self. If the things of our experience were “ideas,” then our everyday life would be like a dream, and the discovery of the true facts like waking. Even our dream-images interest us as long as we dream and, consequently, do not detect their dream character. But as soon as we wake, we no longer look for the connections of our dream-images among themselves, but rather for the physical, physiological, and psychological processes which underlie them. In the same way, a philosopher who holds the world to be his idea, cannot be interested in the reciprocal relations of the details within the world. If he admits the existence of a real Ego at all, then his question will be, not how one of his ideas is associated with another, but what takes place in the Soul which is independent of these ideas, while a certain train of ideas passes through his consciousness. If I dream that I am drinking wine which makes my throat burn, and then wake up with a fit of coughing (cp. Weygandt, Entstehung der TrÄume, 1893) I cease, the moment I wake, to be interested in the dream-experience for its own sake. My attention is now concerned only with the physiological and psychological processes by means of which the irritation which causes me to cough, comes to be symbolically expressed in the dream. Similarly, once the philosopher is convinced that the given world consists of nothing but ideas, his interest is bound to switch from them at once to the soul which is the reality lying behind them. The matter is more serious, however, for the Illusionist who denies the existence of an Ego behind the “ideas,” or at least holds this Ego to be unknowable. We might very easily be led to such a view by the reflection that, in contrast to dreaming, there is the waking state in which we have the opportunity to detect our dreams, and to realise the real relations of things, but that there is no state of the self which is related similarly to our waking conscious life. Every adherent of this view fails entirely to see that there is, in fact, something which is to mere perception what our waking experience to our dreams. This something is thought.

The naÏve man cannot be charged with failure to perceive this. He accepts life as it is, and regards things as real just as they present themselves to him in experience. The first step, however, which we take beyond this standpoint can be only this, that we ask how thought is related to perception. It makes no difference whether or no the percept, as given to me, has a continuous existence before and after I perceive it. If I want to assert anything whatever about it, I can do so only with the help of thought. When I assert that the world is my idea, I have enunciated the result of an act of thought, and if my thought is not applicable to the world, then my result is false. Between a percept and every kind of judgment about it there intervenes thought.

The reason why, in our discussion about things, we generally overlook the part played by thought, has already been given above (p. 31). It lies in the fact that our attention is concentrated only on the object about which we think, but not at the same time on the thinking itself. The naÏve mind, therefore, treats thought as something which has nothing to do with things, but stands altogether aloof from them and makes its theories about them. The theory which the thinker constructs concerning the phenomena of the world is regarded, not as part of the real things, but as existing only in men’s heads. The world is complete in itself even without this theory. It is all ready-made and finished with all its substances and forces, and of this ready-made world man makes himself a picture. Whoever thinks thus need only be asked one question. What right have you to declare the world to be complete without thought? Does not the world cause thoughts in the minds of men with the same necessity as it causes the blossoms on plants? Plant a seed in the earth. It puts forth roots and stem, it unfolds into leaves and blossoms. Set the plant before yourselves. It connects itself, in your minds, with a definite concept. Why should this concept belong any less to the whole plant than leaf and blossom? You say the leaves and blossoms exist quite apart from an experiencing subject. The concept appears only when a human being makes an object of the plant. Quite so. But leaves and blossoms also appear on the plant only if there is soil in which the seed can be planted, and light and air in which the blossoms and leaves can unfold. Just so the concept of a plant arises when a thinking being comes into contact with the plant.

It is quite arbitrary to regard the sum of what we experience of a thing through bare perception as a totality, a whole, while that which thought reveals in it is regarded as a mere accretion which has nothing to do with the thing itself. If I am given a rosebud to-day, the percept that offers itself to me is complete only for the moment. If I put the bud into water, I shall to-morrow get a very different picture of my object. If I watch the rosebud without interruption, I shall see to-day’s state gradually change into to-morrow’s through an infinite number of intermediate stages. The picture which presents itself to me at any one moment is only a chance section out of the continuous process of growth in which the object is engaged. If I do not put the bud into water, a whole series of states, the possibility of which lay in the bud, will not be realised. Similarly, I may be prevented to-morrow from watching the blossom further, and thus carry away an incomplete picture of it.

It would be a quite unscientific and arbitrary judgment which declared of any haphazard appearance of a thing, this is the thing.

To regard the sum of perceptual appearances as the thing is no more legitimate. It might be quite possible for a mind to receive the concept at the same time as, and together with, the percept. To such a mind it would never occur that the concept did not belong to the thing. It would have to ascribe to the concept an existence indivisibly bound up with the thing.

Let me make myself clearer by another example. If I throw a stone horizontally through the air, I perceive it in different places at different times. I connect these places so as to form a line. Mathematics teaches me to distinguish various kinds of lines, one of which is the parabola. I know a parabola to be a line which is produced by a point moving according to a certain well-defined law. If I analyse the conditions under which the stone thrown by me moves, I find that the line of its flight is identical with the line I know as a parabola. That the stone moves exactly in a parabola is a result of the given conditions and follows necessarily from them. The form of the parabola belongs to the whole phenomenon as much as any other feature of it. The hypothetical mind described above which has no need of the roundabout way of thought, would find itself presented, not only with a sequence of visual percepts at different points, but, as part and parcel of these phenomena, also with the parabolic form of the line of flight, which we can add to the phenomenon only by an act of thought.

It is not due to the real objects that they appear to us at first without their conceptual sides, but to our mental organisation. Our whole organisation functions in such a way that in the apprehension of every real thing the relevant elements come to us from two sources, viz., from perception and from thought.

The nature of things is indifferent to the way I am organised for apprehending them. The breach between perception and thought exists only from the moment that I confront objects as spectator. But which elements do, and which do not, belong to the objects, cannot depend on the manner in which I obtain my knowledge of them.

Man is a being with many limitations. First of all, he is a thing among other things. His existence is in space and time. Hence but a limited portion of the total universe can ever be given to him. This limited portion, however, is linked up with other parts on every side both in time and in space. If our existence were so linked with things that every process in the object world were also a process in us, there would be no difference between us and things. Neither would there be any individual objects for us. All processes and events would then pass continuously one into the other. The cosmos would be a unity and a whole complete in itself. The stream of events would nowhere be interrupted. But owing to our limitations we perceive as an individual object what, in truth, is not an individual object at all. Nowhere, e.g., is the particular quality “red” to be found by itself in abstraction. It is surrounded on all sides by other qualities to which it belongs, and without which it could not subsist. For us, however, it is necessary to isolate certain sections of the world and to consider them by themselves. Our eye can seize only single colours one after another out of a manifold colour-complex, our understanding only single concepts out of a connected conceptual system. This isolation is a subjective act, which is due to the fact that we are not identical with the world-process, but are only things among other things.

It is of the greatest importance for us to determine the relation of ourselves, as things, to all other things. The determining of this relation must be distinguished from merely becoming conscious of ourselves. For this self-awareness we depend on perception just as we do for our awareness of any other thing. The perception of myself reveals to me a number of qualities which I combine into an apprehension of my personality as a whole, just as I combine the qualities, yellow, metallic, hard, etc., in the unity “gold.” This kind of self-consciousness does not take me beyond the sphere of what belongs to me. Hence it must be distinguished from the determination of myself by thought. Just as I determine by thought the place of any single percept of the external world in the whole cosmic system, so I fit by an act of thought what I perceive in myself into the order of the world-process. My self-observation restricts me within definite limits, but my thought has nothing to do with these limits. In this sense I am a two-sided being. I am contained within the sphere which I apprehend as that of my personality, but I am also the possessor of an activity which, from a higher standpoint, determines my finite existence. Thought is not individual like sensation and feeling; it is universal. It receives an individual stamp in each separate human being only because it comes to be related to his individual feelings and sensations. By means of these particular colourings of the universal thought, individual men are distinguished from one another. There is only one single concept of “triangle.” It is quite immaterial for the content of this concept whether it is in A’s consciousness or in B’s. It will, however, be grasped by each of the two minds in its own individual way.

This thought conflicts with a common prejudice which is very hard to overcome. The victims of this prejudice are unable to see that the concept of a triangle which my mind grasps is the same as the concept which my neighbour’s mind grasps. The naÏve man believes himself to be the creator of his concepts. Hence he believes that each person has his private concepts. One of the first things which philosophic thought requires of us is to overcome this prejudice. The one single concept of “triangle” does not split up into many concepts because it is thought by many minds. For the thought of the many is itself a unity.

In thought we have the element which welds each man’s special individuality into one whole with the cosmos. In so far as we sense and feel (perceive), we are isolated individuals; in so far as we think, we are the All-One Being which pervades everything. This is the deeper meaning of our two-sided nature. We are conscious of an absolute principle revealing itself in us, a principle which is universal. But we experience it, not as it issues from the centre of the world, but rather at a point on the periphery. Were the former the case, we should know, as soon as ever we became conscious, the solution of the whole world problem. But since we stand at a point on the periphery, and find that our own being is confined within definite limits, we must explore the region which lies beyond our own being with the help of thought, which is the universal cosmic principle manifesting itself in our minds.

The fact that thought, in us, reaches out beyond our separate existence and relates itself to the universal world-order, gives rise to the desire for knowledge in us. Beings without thought do not experience this desire. When they come in contact with other things no questions arise for them. These other things remain external to such beings. But in thinking beings the concept confronts the external thing. It is that part of the thing which we receive not from without, but from within. To assimilate, to unite, the two elements, the inner and the outer, that is the function of knowledge.

The percept, thus, is not something finished and self-contained, but one side only of the total reality. The other side is the concept. The act of cognition is the synthesis of percept and concept. And it is only the union of percept and concept which constitutes the whole thing.

The preceding discussion shows clearly that it is futile to seek for any other common element in the separate things of the world than the ideal content which thinking supplies. All attempts to discover any other principle of unity in the world than this internally coherent ideal content, which we gain for ourselves by the conceptual analysis of our percepts, are bound to fail. Neither a personal God, nor force, nor matter, nor the blind will (of Schopenhauer and Hartmann), can be accepted by us as the universal principle of unity in the world. These principles all belong only to a limited sphere of our experience. Personality we experience only in ourselves, force and matter only in external things. The will, again, can be regarded only as the expression of the activity of our finite personalities. Schopenhauer wants to avoid making “abstract” thought the principle of unity in the world, and seeks instead something which presents itself to him immediately as real. This philosopher holds that we can never solve the riddle of the world so long as we regard it as an “external” world. “In fact, the meaning for which we seek of that world which is present to us only as our idea, or the transition from the world as mere idea of the knowing subject to whatever it may be besides this, would never be found if the investigator himself were nothing more than the pure knowing subject (a winged cherub without a body). But he himself is rooted in that world: he finds himself in it as an individual, that is to say, his knowledge, which is the necessary supporter of the whole world as idea, is yet always given through the medium of a body, whose affections are, as we have shown, the starting-point for the understanding in the perception of that world. His body is, for the pure knowing subject, an idea like every other idea, an object among objects. Its movements and actions are so far known to him in precisely the same way as the changes of all other perceived objects, and would be just as strange and incomprehensible to him if their meaning were not explained for him in an entirely different way …. The body is given in two entirely different ways to the subject of knowledge, who becomes an individual only through his identity with it. It is given as an idea in intelligent perception, as an object among objects and subject to the laws of objects. And it is also given in quite a different way as that which is immediately known to every one, and is signified by the word ‘will.’ Every true act of his will is also at once and without exception a movement of his body. The act of will and the movement of the body are not two different things objectively known, which the bond of causality unites; they do not stand in the relation of cause and effect; they are one and the same, but they are given in entirely different ways—immediately, and again in perception for the understanding.” (The World as Will and Idea, Book 2, § 18.) Schopenhauer considers himself entitled by these arguments to hold that the will becomes objectified in the human body. He believes that in the activities of the body he has an immediate experience of reality, of the thing-in-itself in the concrete. Against these arguments we must urge that the activities of our body become known to us only through self-observation, and that, as such, they are in no way superior to other percepts. If we want to know their real nature, we can do so only by means of thought, i.e., by fitting them into the ideal system of our concepts and ideas.

One of the most deeply rooted prejudices of the naÏve mind is the opinion that thinking is abstract and empty of any concrete content. At best, we are told, it supplies but an “ideal” counterpart of the unity of the world, but never that unity itself. Whoever holds this view has never made clear to himself what a percept apart from concepts really is. Let us see what this world of bare percepts is. A mere juxtaposition in space, a mere succession in time, a chaos of disconnected particulars—that is what it is. None of these things which come and go on the stage of perception has any connection with any other. The world is a multiplicity of objects without distinctions of value. None plays any greater part in the nexus of the world than any other. In order to realise that this or that fact has a greater importance than another we must go to thought. As long as we do not think, the rudimentary organ of an animal which has no significance in its life, appears equal in value to its more important limbs. The particular facts reveal their meaning, in themselves and in their relations with other parts of the world, only when thought spins its threads from thing to thing. This activity of thinking has always a content. For it is only through a perfectly definite concrete content that I can know why the snail belongs to a lower type of organisation than the lion. The mere appearance, the percept, gives me no content which could inform me as to the degree of perfection of the organisation.

Thought contributes this content to the percept from the world of concepts and ideas. In contrast with the content of perception which is given to us from without, the content of thought appears within our minds. The form in which thought first appears in consciousness we will call “intuition.” Intuition is to thoughts what observation is to percepts. Intuition and observation are the sources of our knowledge. An external object which we observe remains unintelligible to us, until the corresponding intuition arises within us which adds to the reality those sides of it which are lacking in the percept. To anyone who is incapable of supplying the relevant intuitions, the full nature of the real remains a sealed book. Just as the colour-blind person sees only differences of brightness without any colour qualities, so the mind which lacks intuition sees only disconnected fragments of percepts.

To explain a thing, to make it intelligible, means nothing else than to place it in the context from which it has been torn by the peculiar organisation of our minds, described above. Nothing can possibly exist cut off from the universe. Hence all isolation of objects has only subjective validity for minds organised like ours. For us the universe is split up into above and below, before and after, cause and effect, object and idea, matter and force, object and subject, etc. The objects which, in observation, appear to us as separate, become combined, bit by bit, through the coherent, unified system of our intuitions. By thought we fuse again into one whole all that perception has separated.

An object presents riddles to our understanding so long as it exists in isolation. But this is an abstraction of our own making and can be unmade again in the world of concepts.

Except through thought and perception nothing is given to us directly. The question now arises as to the interpretation of percepts on our theory. We have learnt that the proof which Critical Idealism offers for the subjective nature of percepts collapses. But the exhibition of the falsity of the proof is not, by itself, sufficient to show that the doctrine itself is an error. Critical Idealism does not base its proof on the absolute nature of thought, but relies on the argument that NaÏve Realism, when followed to its logical conclusion, contradicts itself. How does the matter appear when we recognise the absoluteness of thought?

Let us assume that a certain percept, e.g., red, appears in consciousness. To continued observation, the percept shows itself to be connected with other percepts, e.g., a certain figure, temperature, and touch-qualities. This complex of percepts I call an object in the world of sense. I can now ask myself: Over and above the percepts just mentioned, what else is there in the section of space in which they are? I shall then find mechanical, chemical, and other processes in that section of space. I next go further and study the processes which take place between the object and my sense-organs. I shall find oscillations in an elastic medium, the character of which has not the least in common with the percepts from which I started. I get the same result if I trace further the connection between sense-organs and brain. In each of these inquiries I gather new percepts, but the connecting thread which binds all these spatially and temporally separated percepts into one whole, is thought. The air vibrations which carry sound are given to me as percepts just like the sound. Thought alone links all these percepts one to the other and exhibits them in their reciprocal relations. We have no right to say that over and above our immediate percepts there is anything except the ideal nexus of precepts (which thought has to reveal). The relation of the object perceived to the perceiving subject, which relation transcends the bare percept, is therefore purely ideal, i.e., capable of being expressed only through concepts. Only if it were possible to perceive how the object of perception affects the perceiving subject, or, alternatively, only if I could watch the construction of the perceptual complex through the subject, could we speak as modern Physiology, and the Critical Idealism which is based on it, speak. Their theory confuses an ideal relation (that of the object to the subject) with a process of which we could speak only if it were possible to perceive it. The proposition, “No colour without a colour-sensing eye,” cannot be taken to mean that the eye produces the colour, but only that an ideal relation, recognisable by thought, subsists between the percept “colour” and the percept “eye.”

To empirical science belongs the task of ascertaining how the properties of the eye and those of the colours are related to one another; by means of what structures the organ of sight makes possible the perception of colours, etc. I can trace how one percept succeeds another and how one is related to others in space, and I can formulate these relations in conceptual terms, but I can never perceive how a percept originates out of the non-perceptible. All attempts to seek any relations between percepts other than conceptual relations must of necessity fail.

What then is a percept? This question, asked in this general way, is absurd. A percept appears always as a perfectly determinate, concrete content. This content is immediately given and is completely contained in the given. The only question one can ask concerning the given content is, what it is apart from perception, that is, what it is for thought. The question concerning the “what” of a percept can, therefore, only refer to the conceptual intuition which corresponds to the percept. From this point of view, the problem of the subjectivity of percepts, in the sense in which the Critical Idealists debate it, cannot be raised at all. Only that which is experienced as belonging to the subject can be termed “subjective.” To form a link between subject and object is impossible for any real process, in the naÏve sense of the word “real,” in which it means a process which can be perceived. That is possible only for thought. For us, then, “objective” means that which, for perception, presents itself as external to the perceiving subject. As subject of perception I remain perceptible to myself after the table which now stands before me has disappeared from my field of observation. The perception of the table has produced a modification in me which persists like myself. I preserve an image of the table which now forms part of my Self. Modern Psychology terms this image a “memory-idea.” Now this is the only thing which has any right to be called the idea of the table. For it is the perceptible modification of my own mental state through the presence of the table in my visual field. Moreover, it does not mean a modification in some “Ego-in-itself” behind the perceiving subject, but the modification of the perceiving subject itself. The idea is, therefore, a subjective percept, in contrast with the objective percept which occurs when the object is present in the perceptual field. The false identification of the subjective with this objective percept leads to the misunderstanding of Idealism: The world is my idea.

Our next task must be to define the concept of “idea” more nearly. What we have said about it so far does not give us the concept, but only shows us where in the perceptual field ideas are to be found. The exact concept of “idea” will also make it possible for us to obtain a satisfactory understanding of the relation of idea and object. This will then lead us over the border-line, where the relation of subject to object is brought down from the purely conceptual field of knowledge into concrete individual life. Once we know how we are to conceive the world, it will be an easy task to adapt ourselves to it. Only when we know to what object we are to devote our activity can we put our whole energy into our actions.