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The Philosophy of Spiritual Activity
GA 4

VII. Are There Limits to Knowing?

We have established that the elements needed for the explanation of reality are to be taken from the two spheres: perceiving and thinking. As we have seen, it is because of our organization that full, total reality, including our own subject, appears to us at first as a duality. The activity of knowing overcomes this duality inasmuch as, out of the two elements of reality — i.e., out of the perception and out of the concept produced by thinking — it joins together the complete thing. Let us call the way in which the world approaches us, before it has gained its rightful form through out knowing activity, “the world of appearance” in contrast to the entity composed, in a unified way, of perception and concept. Then we may say that the world is given us as a duality (dualistic), and our activity of knowing elaborates it into a unity (monistic.) A philosophy which takes its starting point from this basic principle may be designated as a monistic philosophy or monism. Confronting this view there stands the two-world theory or dualism. This latter assumes, not just two sides of one unified reality, merely kept part by our organization, but rather two worlds absolutely different from each other. It then seeks principles of explanation for one of these worlds within the other.

Dualism is based on an incorrect understanding of what we call knowledge. It separates the whole of existence into two regions, each of which has its own laws, and lets these regions stand over against one another outwardly.

Out of such a dualism has sprung the differentiation between the object of perception and the “thing-in-itself” which, through Kant, has been introduced into science and to the present day has not been expelled from it. According to our expositions, it lies in the nature of our spiritual organization that a particular thing can be given only as a perception. Our thinking then overcomes the separateness of the thing by assigning to each perception its lawful place within the world whole. As long as the separated parts of the world whole are designated as perceptions, we are simply following, in this separating out, a law of our subjectivity. But if we consider the sum total of all perceptions to be one part, and then place over against this part a second one in the “things-in-themselves,” we are philosophizing off into the blue. Then we are merely playing with concepts. We are constructing an artificial polarity, but cannot gain any content for the second part of it, because such a content for a particular thing can be drawn only from perception.

Any kind of existence which is assumed outside the region of perception and concept is to be assigned to the sphere of unjustified hypotheses. The “thing-in-itself” belongs in this category. It is of course completely natural that the dualistic thinker cannot find the connection between his hypothetically assumed world principle and what is given in an experienceable way. A content for his hypothetical world principle can be gained only if one borrows it from the world of experience and deceives oneself about so doing. Otherwise his hypothetical world principle remains a concept devoid of any content, a non-concept which only has the form of a concept. The dualistic thinker usually asserts then that the content of this concept is inaccessible to our knowledge; we can only know that such a content is present, not what is present. In both cases the overcoming of dualism is impossible. If one brings a few abstract elements from the world of experience into the concept of the thing-in-itself, it still remains impossible, in spite of this, to reduce the rich concrete life of experience down to a few characteristics which themselves are only taken from this perception. Du Bois-Reymond thinks that the unperceivable atoms of matter, through their position and motion, produce sensation and feeling, and then comes to the conclusion that we can never arrive at a satisfactory explanation as to how matter and motion produce sensation and feeling, for “it is, indeed, thoroughly and forever incomprehensible that it should not be a matter of indifference to a number of atoms of carbon, hydrogen, nitrogen, oxygen, etc. how they lie and move, how they lay and moved, how will lie and move. There is no way to understand how consciousness could arise out of their interaction.” This conclusion is characteristic for this whole trend of thought. Out of the rich world of perceptions are isolated: position and motion. These are carried over and applied to the imagined world of atoms. Then astonishment sets in about the fact that one cannot unfold concrete life out of his principle, which one has made oneself and which is borrowed from the world of perception.

That the dualist, working with a concept which is completely devoid of any content, of “in-itself,” can come to no elucidation of the world, follows already from the definition of his principle presented above.

In any case, the dualist sees himself compelled to set insurmountable barriers before our ability to know. The adherent of a monistic world view knows that everything he needs to explain any given phenomenon of the world must lie within the sphere of this phenomenon given him. What might hinder him from attaining this explanation can only be barrier or shortcomings of his organization which chance to be there because of his time or place. And these are, in fact, not barriers and shortcomings of the human organization in general, but only of his particular individual one.

It follows from the concept of the activity of knowing, as we have determined this concept to be, that limits to knowledge cannot be spoken of. The activity of knowing is not a general concern of the world, but rather is a business which the human being has to settle with himself. Things demand no explanation. They exist and affect each other according to the laws which are discoverable through thinking. They exist in inseparable oneness with these laws. Our selfhood approaches the things then, and at first grasps only that part of them which we have called perception. But within the inner being of this selfhood, the power is to be found with which to find also the other part of reality. Only when my selfhood has united, also for itself, the two elements of reality which in the world are inseparably joined, is the satisfaction of knowledge then present: the “I” has attained reality again.

The preconditions for the coming into existence of the activity of knowing are therefore through and for the “I.” The latter poses for itself the questions of knowing activity. And my “I” takes them, in fact, from the element of thinking, which is entirely clear and transparent in itself. If we pose ourselves questions which we cannot answer, then the content of the question must not be clear and definite in all its parts. It is not the world which poses us questions, but rather we ourselves who pose them.

I can imagine that I would lack any possibility of answering a question that I found written down somewhere, without knowing from which sphere the content of the question has been taken.

Our knowledge is concerned with questions that are posed us through the fact that, over against a sphere of perception which is determined by place, time, and my subjective organization, there stands a conceptual sphere which points to the totality of the world. My task consists in reconciling these two spheres, both well known to me, with each other. A limit to knowledge cannot be spoken of here. This or that can at some time or other remain unexplained because we are hindered by our place in life from perceiving the things that are at work there. What is not found today, however, can be found tomorrow. The barriers erected in this way are only transitory ones which, with the progress of perception and thinking, can be overcome.

Dualism makes the mistake of transferring the antithesis of object and subject, which has significance only within the realm of perception onto purely imaginary entities outside the realm of perception. But since the things, which are separated within the horizon of perception, are separate from each other only as long as the perceiving person refrains from thinking, which removes all separation and lets it be known as a merely subjectively determined one, the dualist transfers onto entities behind our perceptions characteristics which, even for these perceptions, have no absolute validity, but only a relative one. He thereby divides the two factors which come into consideration for the process of knowledge, perception and concept, into four: 1. the object-in-itself; 2. the perception which the subject has of the objects; 3, the subject; 4. the concept which relates the perception to the object-in-itself. The relation between the object and the subject is a real one; the subject is really (dynamically) influenced by the object. The real process is said not to fall within our consciousness. This real process, however, is said to evoke in the subject a counter-effect to the effect coming from the object. The result of this counter-effect is said to be the perception. This is what first falls within our consciousness. The object is said to have an objective reality (independent of the subject), the perception is subjective reality. This subjective reality is said to relate the subject to the object. This latter relation is said to be an ideal one. Dualism thus splits the process of knowledge into two parts. The one part, creation of the object of perception out of the “thing-in-itself,” dualism lets take place outside our consciousness; the other part, connection of the perception with the concept and the relation of the concept to the object, dualism lets take place inside our consciousness. With these presuppositions it is clear that the dualist believes he can gain in his concepts only subjective representations of what lies in front of his consciousness. The objectively real process in the subject, through which the perception comes about, and all the more so, the objective interrelationships of the “things-in-themselves,” remain unknowable in any direct way for such a dualist; in his opinion the human being can only create for himself conceptual representations of what is objectively real. The bond of unity among things, which joins these things with one another and objectively with our individual spirit (as “thing-in-itself”), lies beyond our consciousness in an existence-in-itself of which we would likewise only be able to have a conceptual representation within our consciousness.

Dualism believes it would rarify the whole world into an abstract conceptual pattern if it did not affirm, besides the conceptual relationships of objects, real relationships as well. In other words, the ideal principles to be found through thinking appear to the dualist to be too airy, and he seek in addition to them real principles by which they can be supported.

Let us take a closer look at these real principles. The naive person (naive realist) regards the objects of outer experiences are realities. The fact that he can grasp these things with his hands and see them with his eyes, is for him valid proof of their reality. “Nothing exists the one cannot perceive,” is to be regarded as precisely the first axiom of the naive person, and it is accepted just as much in its reverse form: “Everything that can be perceived, exists.” The best proof for this assertion is the naive person's believe in immortality and spirits. He pictures the soul to himself as fine physical matter, which under particular conditions can become visible, even to the ordinary person (naive belief in ghosts).

Compared to his real world, everything else for the naive realist, particularly the world of ideas, is unreal, “merely ideal.” What we bring to the objects in thinking, that is mere thought about things. Our thought adds nothing real to our perception.

However, not only with respect to the existence of things does the naive person consider sense perception to be the only testimony of reality, but also with respect to processes. A thing can, in his view, only work upon another when a force present to sense perception goes forth from the one thing that lays hold of the other. Earlier physics believed that extremely fine substances stream out of material bodies and penetrate through out sense organs into the soul. The actual seeing of these substances is impossible only because of the coarseness of our senses compared with the fineness of these substances. In principle one granted reality to these substances for the same reason one grants it to the objects of the sense world, namely, because of their form of existence which was thought to be analogous to that of sense-perceptible reality.

The self-sustained being of what is ideally experienceable is not regarded by the naive consciousness as real in the same sense as what is experienceable by the senses. An object grasped in a “mere idea” is regarded as a mere chimera until conviction as to its reality can be given through sense perception. The naive person demands, to put it briefly, in addition to the ideal testimony of his thinking, the real testimony of his senses as well. In this need of the naive person lies the basis for the rise of the primitive forms of belief in revelation. The God who is given through thinking remains, to the naive consciousness, always a God who is only “thought.” The naive consciousness demands a manifestation through means which are accessible to sense perception. God must appear in bodily form, and one wants to attach little value to the testimony of thinking but only to such things as proof of divinity through changing water into wine, which is verifiable by sense perception.

The naive person also pictures the activity of knowing as an occurrence analogous to the sense process. The things make an impression in the soul, or they send out pictures which penetrate through the senses, and so on.

That which the naive person can perceive with his senses, he regards as real, and that of which he has no perception (God, soul, knowing, etc.) he pictures to himself as analogous to what is perceived.

If naive realism wants to found a science, it can view such a science only as the exact description of the content of perception. Concepts are for it only means to an end. They are there in order to create ideal reflections of our perceptions. For the things themselves they mean nothing. Then naive realist regards as real only the individual tulips which are seen, or can be seen; he regards the one idea of tulip as an abstraction, as the unreal thought pictures which the soul has composed for itself out of the features which all tulips have in common.

Experience, which teaches us that the content of our perceptions is of a transitory nature, refutes naive realism and its basic principle that everything which is perceived is real. The tulip that I see is real today; in a year it will have vanished into nothingness. What has maintained itself is the species tulip. But this species, for naive realism is “only” an idea, not a reality. Thus this world view finds itself in the situation of seeing its realities come and then vanish, while what it holds to be unreal maintains itself in the face of what is real. Therefore the naive realist must also allow, besides his perceptions, something else of an ideal nature to play its part. He must take up into himself entities which he cannot perceive with his senses. He comes to terms with this in that he thinks the form of existence of these entities to be analogous to that of sense objects. Such hypothetically assumed realities are the invisible forces through which sense-perceptible things act upon each other. One such thing is heredity, which transcends the individual, and which is the reason why, out of one individual, a new one develops, similar to it, through which the species maintains itself. Another such thing is the life principle permeating the bodily organism; another is the soul, for which the person of naive consciousness always finds a concept analogous to sense realities; and still another, finally, is the Divine Being of the naive person. This Divine Being is thought to be active in a way that corresponds exactly to what can be perceived of how the human being himself is active; anthropomorphically.

Modern physics traces sense impressions back to processes of the smallest parts of bodies and of an infinitely fine substance, of ether, or to something similar. What we, for example, experience as warmth is the motion of a body's parts within the space taken up by the body causing the warmth. Here also something unperceivable is again thought of an analogous to what is perceivable. The sense-perceptible analogy to the concept “body” is in this sense something like the interior of space enclosed on all sides, within which elastic balls are moving in all direction, striking each other, bouncing on and off the walls and so on.

Without such assumptions the world would disintegrate for naive realism into an incoherent aggregate of perceptions without mutual relationships, that comes together in no kind of unity. It is clear, however, that naive realism can only come to this assumption through an inconsistency. If it wants to remain true to its basic principle that only what is perceived is real, then it ought not, after all, assume something real where it perceives nothing. The unperceivable forces which emanate from perceivable things are actually unjustified hypotheses from the standpoint of naive realism. And because it knows of no other realities, it endows its hypothetical forces with perceptible content. It therefore applies one form of being (that of perceptible existence) to a region where it lacks the means which alone has anything to say about this form of being: sense perception.

This self-contradictory world view leads to metaphysical realism. This constructs, besides perceivable reality, still another unperceivable one, which it thinks of as analogous to the first. Metaphysical realism is therefore necessarily dualism.

Wherever metaphysical realism notices a relationship between perceivable things (movement toward something, becoming aware of something objective, and so on), there it postulates a reality. But the relationship which it notices, it can express only through thinking; it cannot perceive the relationship. The ideal relationship is arbitrarily made into something similar to what is perceivable. So for this trend of thought, the real world is composed of the objects of perception, which are in eternal becoming, which come and then vanish, and of the unperceivable forces by which the objects of perception are brought forth and which are what endure.

Metaphysical realism is a contradictory mixture of naive realism and idealism. Its hypothetical forces are unperceivable entities with the qualities of perceptions. It has decided — besides the region of the world for whose form of existence it has a means of knowledge in perception — to allow yet another region to exist, where this means fails, and which can be discovered only by means of thinking. But metaphysical realism cannot at the same time bring itself also to acknowledge the form of being which thinking communicates to it, the concept (the idea), as an equally valid factor along with perception. If one wants to avoid the contradiction of the unperceivable perception, one must acknowledge that, for the relationship between perceptions which is communicated through thinking, there is no other form of existence for us than that of the concept. When one throws out the unjustified part of metaphysical realism, the world presents itself as the sum total of perceptions and their conceptual (ideal) relationships. Then metaphysical realism flows over into a world view which demands, for perception, the principle of perceivability, and for the interrelationships among perceptions, thinkability. This world view can grant no credibility to a third region of the world — besides the perceptual world and the conceptual one — for which both principles, the so-called real principle and the ideal principle, have validity at the same time.

When metaphysical realism asserts that, besides the ideal relationship between the object of perception and in perceiving subject, there must exist in addition a real relationship between the “thing-in-itself” of the perception and the “thing-in-itself” of the perceivable subject (of the so-called individual spirit), then this assertion rests upon the incorrect assumption of an unperceivable real process analogous to the processes of the sense world. When metaphysical realism states further that I come into a consciously ideal relationship with my world of perception, but that I can only come into a dynamic (force) relationship with the real world — then one commits no less the error already criticized. One can speak of a relationship between forces only within the world of perception (in the sphere of the sense of touch), but not outside it.

We shall call the world view characterized above, into which metaphysical realism finally flows when it strips of its contradictory elements, monism, because this world view joins one-sided realism with idealism into a higher unity.

For naive realism the real world is a sum of objects of perception; for metaphysical realism, reality is also ascribed to the unperceivable forces, as well as to perceptions; monism replace the forces with the ideal connections which it gains through thinking. Such connections, however, are the laws of nature. A law of nature is indeed nothing more than the conceptual expression for the connection between certain perceptions.

Monism is never put in the position of asking for other principles of explanation for reality besides perception and concept. It knows that within the entire domain of reality there is no cause to do so. It sees in the world of perception, as this is directly present to perception, something half real; in uniting the world of perception with the conceptual world it finds the full reality. The metaphysical realist may object to the adherent of monism: It might be the case that for your organization your knowledge is complete in itself, that no part is mission; but you do not know how the world is mirrored in an intelligence organized differently from yours. Monism's answer would be: If there are intelligences other than human ones, and if their perceptions have another form than ours do, then only that has significance for me which reaches me from them through perception and concept. Through my perception, and indeed through my specifically human perception, I am placed as subject over against the object. The connection of things is thereby broken. The subject re-establishes this connection through thinking. It has thereby united itself again with the world whole. Since it is only by our subject that this whole seems to be split at a place between our perception and our concept, so it is that in the reuniting of these two true knowledge is also given. For beings with a different world of perception (for example, with twice our number of sense organs) the connection would appear to be broken at a different place, and its re-establishment would accordingly also have to take a form specific to those beings. Only for naive and metaphysical realism, which both see in the content of the soul only an ideal representation of the world, does the question of a limit to knowledge arise. For them, what is outside the subject is something absolute, something self-contained, and the content of the subject is a picture of it and stands totally outside this absolute. The completeness of one's knowledge depends upon the greater or lesser similarity of one's picture to the absolute object. A being whose number of senses is smaller than man's will perceive less of the world; a being with a larger number, more of it. The former accordingly will have a less complete knowledge than the latter.

Monism sees the matter differently. Through the organization of the perceiving entity, the form is determined as to where the coherency of the world appears torn apart into subject and object. The object is not something absolute, but only something relative with respect to this particular subject. Therefore the bridging over of this antithesis can again only happen in the very specific way precisely characteristic of the human subject. As soon as the “I,” which is separated off from the world in perception, joins itself back into coherency with the world again in thinking contemplation, then all further questioning, which was only a consequence of the separation, ceases.

A differently constituted being would have a differently constituted knowledge. Our knowledge suffices to answer the questions posed by our own being.

Metaphysical realism must ask, by what means is what is given as perception given; by what means is the subject affected?

For monism, perception is determined through the subject. But at the same time, the subject has in thinking the means by which to dispel this self-evoked determination again.

Metaphysical realism confronts a further difficulty when it wants to explain the similarity of the world pictures of different human individuals. It must ask itself how it comes about that the picture of the world, which I construct out of my subjectively determined perception and my concepts, is equivalent to the picture which another individual constructs out of the same two subjective factors. How can I, out of my subjective world picture, draw any conclusions at all about that of another person? From the fact that people manage to deal with each other in actual practice, the metaphysical realist believes himself able to infer the similarity of their subjective pictures of the world. From the similarity of these world pictures he then goes on to infer the likeness existing between the individual spirits underlying the single human subjects of perception, or rather between the “I's-in-themselves” underlying the subjects.

This inference is therefore of a kind in which, from a sum of effects, the character of their underlying causes is inferred. We believe, from a sufficiently large number of instances, that we recognize the state of affairs well enough to know how the inferred causes will behave in other instances. We call such an inference an inductive inference. We will see ourselves obliged to modify the results of an inference, if a further observation yields something unexpected, because the character of the result is after all determined only by the individual form of the observations already made. The metaphysical realist claims, however, that this conditional knowledge of the causes is altogether sufficient for practical life.

The inductive inference is the methodological basis of modern metaphysical realism. There was a time when one believed one could unfold something out of concepts which was no longer a concept. One believed that, out of concepts, one could know the metaphysical real beings which metaphysical realism after all needs. This kind of philosophizing has been overcome and is obsolete today. Instead of this, however, one believes that one can infer, from a large enough number of perceptible facts, the character of the thing-in-itself which underlies these facts. Just as formerly from the concept, so today one seeks from our perceptions to be able to unfold the metaphysical. Since one has concepts before oneself in transparent clarity, one believed that one could also derive the metaphysical from them with absolute certainty. Perceptions do not lie before us with the same transparent clarity. Each successive one presents something different again from earlier ones of the same kind. Basically, therefore, what has been inferred from earlier perceptions is somewhat modified by each succeeding one. The form which one wins in this way for the metaphysical must therefore be called only a relatively true one; it is subject to correction through future instances. Eduard von Hartmann's metaphysics has a character determined by this basic, methodological principle; he set as motto on the title page of his first major work: “Speculative results arrived at by the inductive scientific method.”

The form which the metaphysical realist today gives to his things-in-themselves is won through inductive inferences. Through his deliberations on the process of knowledge he is convinced of the existence of an objective real coherency of the world alongside the “subjective” coherency knowable through perception and concept. He believes that he can determine, through inductive inferences drawn from his perceptions, how this objective reality is constituted.

Addendum to the Revised Edition of 1918


For the unprejudiced observation of our experience in perception and concept — the description of which has been attempted in the foregoing considerations — certain mental pictures that arise in the field of nature study will again and again be troublesome. One says to oneself, standing in this field, that colors in the light spectrum from red to violet are perceived through the eye. But beyond violet there lie forces within the spectrum's sphere of radiation for which there is no corresponding color perception of the eye, but for which there is definitely a corresponding chemical effect; in the same way, beyond the boundary of red effects, there lie radiations which have only warmth effects. Through consideration of this and similar phenomena, one comes to the view that the scope of the human world of perception is determined by the scope of the human senses, and that man would have a completely different world before him, if he had, in addition to his own senses, still others, or if he had altogether different ones. A person who likes to go off into extravagant fantasies (to which the brilliant discoveries of recent scientific research give a quite enticing stimulus) may very well conclude that into man's field of observation can come only what can act upon those senses which have emerged out of his organization. Man has no right to regard these perceptions, which are limited by his organization, as being in any way conclusive for reality. Every new sense would have to place him before a different picture of reality. — All this is, within appropriate bounds, an altogether justified opinion. But if someone allows this opinion to confuse him in his unprejudiced observation of the relationship between perception and concept which our expositions establish as valid, then he blocks his way to a knowledge of the world and of man that is rooted in reality. The experience of the being of thinking, that is, active working with the world of concepts, is something altogether different from the experience of what is perceivable through the senses. Whatever senses man might ever have in addition to his present ones, not one of them would give him a reality if he did not, in thinking, permeate with concepts the perceptions communicated by it; and every sense, whatever its nature, thus permeated, gives man the possibility of living within reality. Fantasies about the completely different perceptual picture possible with other senses have nothing to do with the question of how the human being stands within the real world. One has to recognize, in fact, that every perceptual picture receives its form from the organization of the perceiving entity, but that the perceptual picture, which is permeated by the experience of thinking contemplation, leads the human being into reality. Fantastic depictions of how differently a world would have to appear to other than human senses cannot motivate the human being to seek knowledge about his relationship to the world, but only the insight can do so, that each perception gives only a part of the reality contained within it, that it leads, therefore, away from its own reality. The other insight then takes its place beside the first, that thinking leads into that part of reality which is present in, but hidden by, the perception itself. It can also be disturbing for the unprejudiced observation of the relationship presented here between perception and concept worked out by thinking, when the necessity arises in the realm of physical experience of speaking, not at all about elements which are directly visible to perception, but rather about invisible magnitudes such as electrical or magnetic lines of forces, and so on. It can seem as though the elements of reality about which physics speaks had nothing to do either with what is perceivable, nor with the concept worked out in active thinking. But such an opinion would rest on a self-deception. In the first place it comes down to the fact that everything which is worked out by physics, insofar as it does not represent unjustified hypotheses which should be excluded, is won through perception and concept. What seems to be an invisible content is placed, by the physicist's correct instinct, for knowledge, totally into the realm in which perceptions lie, and is thought about in concepts with which one is active in this realm. The strengths of electrical and magnetic fields and so on are essentially not found through any process of knowledge other than that which occurs between perception and concept. — Increasing the number, or changing the form, of our human senses would result in a changed perceptual picture, in an enrichment or different form of human experience; but even with respect to this experience, a real knowledge would have to be attained through the interaction of concept and perception. Any deepening of knowledge depends upon the powers of intuition that live in thinking (see pages 71–72). This intuition can, within that experience which takes shape and is elaborated in thinking, delve down into greater or lesser depth of reality. The broadening of one's perceptual picture can be a stimulus to this delving down and in this way indirectly promote it. But this delving into the depths should never, in its attainment of reality, be confused with whether one stands before a broader or more narrow perceptual picture, in which always is present only half of reality because of conditions placed on it by the knowing organization. Whoever is not lost in abstractions will see how there is relevance for our knowledge of man's nature in the fact that physics must infer elements within the realm of perception, to which no sense is directly attuned the way there is to color or tone. The concrete nature of man is not only determined by what, through his organization, he places before himself as direct perception, but also through the exclusion of other things from this direct perception. Just as, besides our conscious waking state, the unconscious sleeping state is necessary to life, so, besides the circumference of our sense perception, there is necessary for man's experience of himself, a circumference — much greater in fact — of non-sense-perceptible elements within the realm from which our sense perceptions originate. All this has already been indirectly expressed in the original text of this book. The author adds these amplifications to the content of his book, because it has been his experience that many readers have not read carefully enough. — Attention should also be paid to the fact that the idea of perception, as developed in this book, should not be confused with the idea of outer sense perception, which is only a specific instance of the idea of perception. One will see, from the foregoing considerations, but even more from the following ones, that here, everything which approaches man sense-perceptibly and spiritually, is regarded as perception, before it is grasped by the actively elaborated concept. In order to have perceptions of a soul or spiritual nature, senses of the kind usually meant are not necessary. One might say that broadening our present use of language in this way is not permissible. But this broadening is absolutely necessary, if one does not want to be fettered in certain areas by just such current usage in broadening our knowledge. A person who speaks of perception only in the sense of sense perception will also fail to arrive at a concept, adequate for knowledge, concerning this sense perception. One must oftentimes broaden a concept so that, in a narrower realm, it will gain the meaning appropriate to it. One must also sometimes add something to what was at first meant by a certain concept so that what was thus meant finds its justification or even its correction. Thus, on page 96 of this book, one finds it stated that, “The mental picture is therefore an individualized concept.” The objection was made to me that this is an unusual use of language. But this use of language is necessary, if one wants to get behind what a mental picture really is. What would become of our progress in knowledge if the objection were made to everyone who is obliged to set a concept right, that: “That is an unusual use of language?”