It has been recognized that our knowledge of external reality, including the laws which the natural sciences discover and which technical inventions seem to prove beyond dispute, is dependent on the laws of our thinking and that, therefore all such knowledge represents an indirect and relative knowledge and does not give us direct access to the absolute nature of reality This fundamental thesis was firmly established by Kant and held by many philosophers before and after; moreover, it has found support from the most unexpected quarter; the recent developments in physics have shaken belief in the unlimited validity of the law of causality and thus in an absolute external necessity within the very branch of the natural sciences which seemed to guarantee the greatest possible certainty. in fact, these recent developments confirm what Kant has taught. (This will be discussed in detail. See Chapter 5, Section 2, paragraphs 18-20.)
Yet in spite of such strong support; this thesis has had very little influence. Firm belief in all external knowledge in general and in the natural sciences in particular, though robbed of its basis, has hardly been shaken. We no longer try, as in the nineteenth century, to find the final cause with the help of these sciences, nor do many people consider one of the concepts used by them as the absolute principle which explains everything. We hardly hope for such final explanations; but as we rely entirely on the unitary way of thinking which the sciences seem to make possible, their methods and results form, whether or not we are conscious of it, the body of knowledge which satisfies us as completely as the belief in some absolute principle did. Any other knowledge, though accepted by many individuals, is neglected and powerless in comparison. Every one of us, even if he accepts the teaching that external knowledge has to be considered as relative, will find it difficult to shake his own belief in external reality and in the natural sciences, and to trust things which cannot be seen, touched, measured or, at least, scientifically explained.
There seem to be two reasons which mainly explain this failure. On the one hand, the theory of knowledge rarely offers an alternative. It has become a special branch of knowledge, developed by specialists who only show that the foundations in which we believe are not the right ones, without showing what kind of belief would be right. The scientist is hardly influenced by these epistemological investigations; it does not matter to him whether his theories are based on absolute truth or on relative assumptions; it is even better, as we have seen, if he treats all his discoveries as mere hypotheses. (See Chapter 2, section 3, paragraphs 26-27.) As the theory of knowledge does not force him to take another kind of knowledge into account, he can go on as if this theory did not exist, and so the general public, not familiar with the teachings of the specialists, accepts his findings as if these other teachings did not exist. External knowledge remains the only knowledge upon which we can rely, the only one which seems to offer some satisfaction for our craving for certainty.
On the other hand, even if the theory of knowledge offers an alternative, which in some cases it does, the gulf between the sciences and morals or religion remains so deep that this does not alter the position, for the one cannot influence the other. We have seen that Kant offers such an alternative; his belief in the moral world is so strong as to make him believe that it is even 'a device of nature' to deprive us of any absolute knowledge in the realm of external reality, in order to force us to look for this knowledge for which we crave in the realm of morals. We believe that his teaching is true; it corresponds to our distinction between external and internal reality. But in his teaching, too, these two spheres exist as completely separated spheres which have no connection with one another; we must behave in one sphere as scientists and in the other as moral beings, without being shown how these two necessities are to be reconciled in our real lives. His teaching has been developed by both philosophers and theologians, but the gulf has only grown wider and the two spheres still exist side by side without influencing each other. If one meets and adherent of one of them, one hardly guesses the existence of the other.
If we now try to show that all our knowledge is based on opposites, we hope that this will bridge the gap and give to the important results of the theory of knowledge the influence which they so badly need, and this we hope for the following reasons.
(1) The necessity of applying opposites shows that the same principle is involved in all our thinking and that the one kind of knowledge cannot, therefore, be more or less valid than the other. The fact that all knowledge is dependent on the same laws of thinking destroys the exclusive claims usually made in favour of external knowledge. Thoughts referring to internal reality can neither be regarded as mere personal prejudice nor disregarded because this reality cannot be touched nor seen nor grasped with the help of science. They must be judged on their own merits, for the knowledge based on sense-experiences as well as the highest achievements of the sciences also depend on the correct application of opposites.
(2) As we have to make use of different kinds of opposites, the necessity of applying them also shows that any thought which is founded upon one kind alone must be incomplete. If we want to achieve comprehensive knowledge, therefore, we are forced to consider the whole realm of our knowledge and to pay attention to both realities. Any other claim is revealed as one-sided.
(3) Moreover, we cannot concentrate on external opposites alone, because the seemingly exclusive validity of external knowledge is made possible, as we shall see in greater detail in this chapter, by unconsciously introducing internal opposites. To make our outlook consistent, we are forced to introduce judgments of value without realizing that we do so, for we can ignore other aspects of experience, which clearly exist, only by judging them to be of no values. Even for the correct apprehension of external reality, therefore, the knowledge of internal reality is indispensable, for only if we apply the internal opposites consciously and correctly can we know that our knowledge of external reality is correct and remains unimpaired.
(4) Nor can we concentrate on internal reality alone, for the confusing of external and internal opposites must have very misleading consequences here too. If internal opposites are mistaken for statements about external facts, all our knowledge is fundamentally distorted. (see Chapter 1, Section 1, paragraphs 16 and 17; and Chapter 3, Section 3.) This, again, makes it indispensable to distinguish between external and internal opposites, which can only be done if we know both.
(5) The danger which is greatest to-day—that of overlooking completely the existence of internal reality when dealing with external facts—is eliminated by the necessity of transferring concepts from one reality to the other. As the concepts on which our knowledge of external reality is based—cause and effect, force, necessity—are transferred from internal reality, they cannot be understood in external reality at all; if we know that we think in opposites, however, this will no longer puzzle us, for we also know that we have to look for their meaning in internal reality from which they have been transferred. Thus external knowledge even points towards internal reality, for we are bound to try to understand the meaning of the concepts which we apply.
(6) But again, this important and necessary emphasis upon the knowledge of internal reality does not lead to the temptation o concentrating on this reality alone (which may become the danger of tomorrow). As we need external forms to grasp internal reality, we must acquire a clear knowledge of external reality as well. The emphasis upon internal reality does not allow us, therefore, to renounce the correct application of external opposites; it does not even allow us, as we have seen, to renounce the development of the natural sciences. (This does not mean, however, that a better knowledge of internal reality should not influence the sciences; it may prove very helpful in relating them again to human experience and moral principles.)
Thus, if we recognize the necessity of applying opposites, we can no longer confine ourselves to one way of thinking. The importance of internal reality becomes obvious even when we try to understand external reality, and the knowledge of internal reality needs the external opposites in order to become reliable and to lead to full knowledge. At the same time, the different kinds of knowledge are so closely interconnected that no gulf remains which might encourage us to restrict our thoughts to one reality alone.
(7) Finally, the necessity of applying opposites will also make us see that what matters most is to understand the division into two realities. Thus we are driven onwards until we reach the interconnected opposites, and these presuppose and test the correct application of all the different kinds of opposites. This will be discussed later.
The fact, however, that the knowledge of external reality has been overdeveloped and overestimated for a long time shows the line which we have to follow in our investigation of external opposites. When investigating internal opposites, we shall have to try to build up the knowledge of internal reality, for this knowledge has almost been lost. The knowledge of external reality does not require any such help; on th contrary it has to be prevented from invading other spheres. Here it is our main task, therefore, to prove that all our external knowledge is based on opposites, for this will enable us to confine this knowledge to its legitimate sphere and to make room for internal reality. In this way we shall also get to know the external opposites well enough to avoid any confusion of them with the other kinds of opposites. For, in spite of the general belief in a unitary external knowledge, these opposites can easily be recognized.
External things and events are correctly apprehended, according to our definition, when we perceive them as being independent of their relation to the person observing them; they have to exist in space and time; and they must be describable in terms of general validity, so that, if they are correctly described, everybody can recognize them. (See Chapter 2, Section 3, paragraph 5.)
The external opposites which help in the apprehension of this reality have to conform to these requirements. They seem, therefore, to be derived directly from external facts; they always refer to something which exists in space and time; they appear at first sight as a mere selection from facts which we find in external reality. (Language, however, encourages us once more in our investigation. The word 'fact' is derived from the Latin facere, to do; we must do something to create facts. The German word Tatsache makes this even clearer; it indicates that the matter (Sache) is dependent on our deed (Tat)). Their independence of the observer, moreover, finds its expression in their being independent of each other; each of the two parts of the opposites can be used by itself and seems to exist separately. If one part is taken away the other remains unimpaired. We can isolate the quality 'dark' as well as the quality 'light'; we can observe 'movement' without thinking consciously of 'rest'; we can concentrate on necessity and forget freedom. This independence of each other seems most strongly to confirm their external existence and their independence of the observer.
Nor can we alter arbitrarily the relationship between the two parts of the opposites; the light object is and always must be light in comparison with the dark object. The quality may appear different in different pairs of opposites; the light object may seem dark when compared with a lighter object; but such a change never takes place within the same pair of opposites; and within the new opposition the relationship is once more fixed. It is this impossibility of interchanging the parts at will which enable us to give a description of general validity.
The independence and the fixed relationship between these pairs of opposites makes it all too easy to overlook the part played by our thinking in external knowledge, and to consider this knowledge as a unitary system of thought. As the concepts forming the opposites seem to refer to something which has an independent existence of its own, they must create the impression that we apprehend this reality without forming special opposites. Yet it can easily be shown that there is no external knowledge whatever which is not based on opposites, and that this application of opposites is enforced by the laws of thinking.
We have already shown that our conception of qualities is dependent on opposites; the opposites 'light' and 'dark' have helped us to recognize that it is only by means of opposites that these and similar qualities can be apprehended at all. (See especially Chapter 1, Section 2, paragraphs 2-4; and Chapter 4, Section 1, paragraph 10.) To form any such concept we must look at the object solely from one point of view and exclude all other observations and considerations; to see it as bright, we must neglect its heaviness, size, coldness, and so on, and this isolation of one quality to the exclusion of all others and also of the object itself can be achieved only with the help of the opposite 'dark'. It is thus that we are enabled to concentrate on one quality alone.
This applies to qualities in general, but there seems to be one very striking exception. Yet this apparent exception, in fact, confirms most conclusively the necessity of applying opposites.
This exception is our apprehension of colours. It is not necessary, indeed it is hardly possible, to think of an opposite if we apprehend, for instance, red or green. (I say 'hardly possible' and not 'impossible' because painters, who have a more strongly developed sense of colours, experience and use them as opposites.) These concepts apply directly to a sense-impression which seems to be given without any opposition; we cannot explain the concept 'red' by calling 'green' its opposite; we can only explain it by pointing at something which is red. While in such cases as 'light' and 'dark' the opposite helps us to form the concept, it seems that, with colours, opposites enter our thought only when we proceed to their abstract explanation and base them on the number and length of light wares, thus creating a scale of degrees which implies opposites. But this explanation is quite obviously a later abstraction; it has nothing to do with our knowledge of the colours themselves which we apprehend independently of any such theory. The two rather exclude each other; we either see colours or observe wave motions. (See W. Heisenberg, Wandlungen in den Grundlagen der Naturwissenschaft, p. 36. This book confirms most of the conclusions of this chapter from the point of view of the physicist.)
This exception, however, is due to the fact that the eye is the most highly developed organ we possess. We have already mentioned some characteristics of this high development when comparing it with other senses, and we have seen that it can by itself oppose light to outward darkness. (See Chapter 1, Section 2, paragraphs 3-5.) Owing to this high development, opposites are used by the eye when it creates the sense-impressions of colours. Every colour has a corresponding complementary colour which forms its opposite, and it is only because this opposition is brought about by the eye itself that we hardly consider it as a n opposition at all and need not apply it in our thinking. In exceptional circumstances the opposition becomes obvious; if we are dazzled by a strong red light and close our eyes, we shall see the complementary colour green. The complementary colour also becomes visible when we compare different shadows, a shadow cast by candlelight, for instance, and that cast simultaneously by daylight, for the first appears blue and the second yellow—a phenomenon which cannot be explained by wavelengths at all, but only by these opposites. (See J. S. Haldane, The Philosophical Basis of Biology, pp. 90-1.) It is also characteristic, moreover, that we cannot see both the shortest and the longest rays—ultra-violet and infra-red. This indicates that our faculty of seeing is limited by the ability of the eye to make use of opposites; it cannot embrace opposites which lie too far apart, and thus visibility ceases. Only abstract thought, using opposites of its own, can go beyond.
Colours are usually considered as 'secondary qualities'—that is, it has been recognized that they are as closely connected with our ways of apprehending them as with the objects themselves. People who are colour-blind see a different scale of colours, and other living beings, as far as we can say, may see in quite different ways, or even react to the light-waves as if they were radio-waves. Nevertheless, colours are the most general attribute of external reality as we perceive it; we do not see anything colourless, our whole world is completely steeped in colours. This shows once again the great importance of the high development of the eye, and thus the fact that its activity is based on the application of opposites is also one of the best proofs that the need for opposites is fundamental and comprehensive. (Something similar may apply to sound as well, for we never hear pure sounds, but always their overtones too. Music uses opposites to a very great extent.)
When we proceed to the objects themselves, we must , as we have seen, apply opposites to apprehend and describe them. (See Chapter 1, Section 2, paragraphs 6 and 7.) Apart from their qualities, we need the opposition between the filled space and the empty space; we find out the boundaries of the object by contrasting it with its surroundings. We must oppose the form to the content, and we ascertain and describe the different materials with the help of different scales of degrees. But there seems to be once more and important exception—the fact that objects can be made known with the help of names.
There are unique objects and persons, countries and places, whose names do not imply any opposite at all. The name 'sun', for instance, undoubtedly applies directly to this single object; none of the abstractions which are based on opposites are required to form the name 'sun'. There are, of course, opposites which help to create our sense-impression, and we need these when we try to imagine or to describe the sun; but we leave them behind when we thank of the name itself; the sun has no opposite. It is only a later discovery that it is a star, and only then do opposites enter our thinking once more; yet knowledge of the sun is quite independent of this discovery.
This fact would be a difficulty only if we assumed that our thinking created reality, and we have never doubted that reality has to make an impression upon us before we are able to think about it. It does not seem surprising that an impression can be given a name. But at the same time it is highly characteristic that we need opposites, so to speak, on both sides of the name. On the one hand, we need them to have a clear sense-impression; the senses must isolate the object with the help of opposites before we are able to fix it by a name. This can be seen when we try to describe the object; we must describe the sun by its qualities such as bright, round, hot, thus making use of opposites, and we can hardly imagine it without opposing it to the surrounding sky. On the other hand, the name remains independent of opposites only so long as we do not know the nature of the object; as soon as we discover that the sun is a star, opposites are needed to give form to and to explain this abstraction—in this case, at least, the opposition between form and content and that between movement and rest. All such names indicate, therefore, that our thinking, though able to apprehend and to describe these objects, cannot proceed further; we do not know why there is, for us, only one such object as the sun. The point where the application of opposites becomes impossible or superfluous shows exactly where our thinking is forced to stop.
The same applies to the more general names. It is true that, to form them, we need many abstractions which require the help of opposites. To obtain the general name applying to every tree, for instance, we have to eliminate all those characteristics which belong to individual trees, which we do by opposing different trees to one another, thus gradually discovering what is essential and what accidental. This we can do, because the opposition between form and content enables us to recognize the different forms as accidental and to separate them from the general concept. Nevertheless, all such general names contain an element of uniqueness which cannot be further broken down or explained but must be taken for granted. Neither the tree nor the star have a direct opposite, and their further explanation which needs opposites does not dispense with these names altogether. But this does not mean that we are able to think without opposites; it show, on the contrary, the boundaries of our thinking. It confirms that our thinking depends on the impression evoked by external reality and that we cannot consider thought as the creator of the world. Yet the activity of thinking as such depends on the application of opposites.
The contrary difficulty arises when reality itself seems to provide us with opposites, for then they appear no longer as laws of our thinking—as, for instance, in the case of men and women. But even there thinking plays a most important part in forming and applying the opposites. Both men and women are human beings; they have many characteristics in common; they are members of families and nations; they have each, moreover, individual characteristics which are independent of their being men and women. But we must forget all that and concentrate exclusively on those qualities which enable us to bring them into clear opposition; we must isolate these qualities like all others as soon as we want to use these concepts with precision. It may or may not be surprising that nature contains such opposites; this question does not concern us here; (It would be fascinating—but a rather doubtful speculation—to follow up the principle of opposition in nature itself. However, as this is a metaphysical question, it does not come within the scope of this investigation.) but, even if such opposites occur in external reality, thinking has to transform them so thoroughly that, in our final usage of the terms, they are not different from those external opposites which spring from thinking alone.
There are also, to take another example, positive and negative electrons, but here the case is simpler; we know so little about them that this abstract description which uses the opposites created by thinking seems to be sufficient. If we knew more we should no doubt soon discover how one-sided this view of them is and how little justice it does to the electrons so described. (The fact that more and more kinds of electrons are being discovered seems to confirm this view.)
The more we proceed into the realm of abstraction, the more the opposites which we usually apply disappear; but it is easy to detect that the part which we usually apply disappear; but it is easy to detect that the part which the thinking in opposites plays becomes even more important. Abstract thinking gradually breaks down the world as we know it through our senses. The table and the air, for instance, so completely opposed to each other in our actual perception, become different kinds of matter, different combinations of atoms and electrons; the stone which we see fall does so because of the power of attraction of the earth which we do not see; sun and earth become stars among the other stars with which originally we would hardly compare them. Abstract thinking creates a world of its own which cuts right across the world which we see and touch. This different world, however, can be created only because it is kept together by the laws of our thinking—that is, by concepts which are made real by their opposites. It is only because we can always fall back on an opposite that in the void with which abstraction confronts us, we can find a basis which gradually enables us to become more and more independent of our senses. (The void to which abstraction leads—formal mathematical calculations leading beyond the sphere of imagination—has become visible in modern physics. It hovers above a bottomless abyss. See W. Heisenberg, Wandlungen in den Grundlagen der Naturwissenschaft, p. 95.)
The abstract world depends mainly on our faculty of establishing between the phenomena connections which are different from those which we immediately perceive. We must see everything within space and time which, though conditions of our perception, are not directly grasped, as Kant has shown, but mere forms added to it. (This will be considered later. See Chapter 11, Section 1.) We must bring into opposition different objects, such as the falling stone and the earth, and this opposition must be explained in terms of cause and effect. We must test the objects by the opposites of form and content, and the causal connections by the opposition between necessity and accident, so as to be able to decide what is merely accidental and what can include other objects or events as well. We must see the whole of external reality as a multiplicity of single units, so that we can see the single objects of events as instances of general laws which nay be applied to many such units. All this can be done because, form the very beginning of our perception, we find the world of the senses organized by the constructive concepts and thus can simply shift the emphasis from our sense-impressions to such opposites as space and time, cause and effect, matter and energy, form and content, the One and the Many—in short, to the concepts upon which the abstract world rests.
But does not, in the end, this progressive abstraction and the process of breaking down the seen reality also dissolve the constructive concepts themselves and base all knowledge on a single unitary principle of explanation? In modern physics, we hardly need any longer to differentiate between matter and energy, nor between space and time, and the more the different natural sciences advance, the more they are being unified, as happened for instance with physics and chemistry. Are we not able to think of a single natural science which would create an abstract world governed by one unitary principle, independent of all the opposites which we have mentioned?
We have already had several opportunities of pointing out that the advance of the sciences does not make them independent of opposites. On the contrary, the more they advance, the clearer their dependence on them becomes; it is when we renounce sensual apprehension completely that we come nearest to a pure and unmitigated application of opposites. It is clear, for instance, that the sciences are forced to use merely the bare opposites if the universe has to be considered as being infinite and yet limited, or if light has to be explained by the two contradictory assumptions that it consists both of pure waves which do not contain any matter and of material particles moving in a straight line across space. It is no accident that the electrons themselves have now to be considered in a similar way. That these contradictory assumptions, though they cannot be reconciled, have both to be accepted and both to be made the basis of calculation certainly shows clearly that we must conform to the requirements of our thinking. Similarly, the opposites come to the fore when matter is being broken down with the help of electrons into pure energy, for this energy has to be gathered again into quanta and fields. (See also Chapter 1, Section 2, paragraphs 8-10, Chapter 2, Section 3, paragraph 23, and Chapter 3, Section 2, paragraphs 5-11.)
The opposites we normally use are reconciled, because they refer to the unitary impression of reality which is merely made accessible by them; these theories, however, are satisfied with the opposites as such. They are so difficult to understand just because most of them do not even attempt to overcome the opposites, thus renouncing all relationship to the things we know and are able to imagine.
The most abstract theories, moreover, must start form the normal apprehension of reality and be tested by producing within it the effects desired, so that they can never free themselves completely from the opposites implied in our original perception. Their consequences only become discernible in the realms of the infinitely large or the infinitely small—of the stars or electrons; the world we live in remains a special case to which simpler theories apply, theories which are still based on the opposites used in perception, especially on the necessity of causal connections. As all theories have to start form this world and to return to it, no theory can escape entirely form the opposites which it seems to eliminate. Even if causality is no longer recognized as valid within the framework of the theory itself, the causal law has to guarantee a reliable relationship between the object under observation and the observed result, for otherwise experiments would be impossible. The same is true of measurements and technical application of scientific knowledge. (See W. Heisenberg, Wandlungen in den Grundlagen der Naturwissenschaft, p. 17.) The new discoveries, far indeed from contradicting Kant's teaching that causality is merely a category of thinking, thus confirm it; they show that it belongs, not to reality as such, for the deeper we understand it the less we can adhere to a strict causality, but to the laws of our thinking, for despite all such theoretical knowledge the application of causality remains indispensable.
The abstract theories are usually founded upon higher mathematics and it is very difficult, therefore, to follow them in those spheres which transcend the world we know. Nor is this necessary for our purpose, for the mere fact that they need mathematics shows that the opposites are not being overcome even there and that the emphasis is once more only being shifted from our sense-impressions to abstract opposites and constructive concepts. We have mentioned before that Kant proved beyond doubt that numbers cannot be won by abstraction alone, his proof being so conclusive that there is no need to repeat it here. He proved that same for mathematical axioms and all 'synthetical' mathematical laws; none of them represent pure abstractions form reality, because all their basic elements, such as numbers, straight line regular triangles and spheres have to be constructed first before one can begin to base abstractions on them. (See Chapter 3, Section 3, paragraph 12.) Opposites must help us to arrive at a regularity which can never be found complete in reality itself, for they are needed to exclude all accidental deviations, and constructive concepts must show that these deviations are accidental and must make it possible to apply the laws thus recognized to a reality which, without them, would not be accessible to such generalizations.
In particular there is, in the last resort, no escape from the opposition between the One and the Many. Although we are unable to eliminate the forms of space and time form our perception, we may be able to abolish them, at least apparently, in certain mathematical calculations. (Time is being considered as a fourth dimension, but as more and completely abstract dimensions have to be assumed as well, this transformation has little to do with the time which we experience.) We may also be able, in general, to make the distinction between form and content seem unimportant when we replace that between matter and energy by mathematical formulae. The calculus of probability may help us to bridge the gap between our practical dependence on the necessary working of causality or the necessity implied in mathematical laws on the one hand, and the recognition that such a causal necessity cannot be characteristic of primary reality on the other hand. But no scientific advance can ever free us from the opposition between the One and the Many, for all mathematics rests upon it, and no law, derived from a special case, could ever be applied to similar cases or to the whole of reality without it. Our knowledge would be reduced to single names, applying to unique things, if we were not able to establish this relationship within reality, and only so far as we are able to establish it are we able to get beyond the realm of mere impressions. This forms a last barrier which no science can possibly surmount.
But there is also another consideration which shows conclusively that the sciences cannot finally overcome the opposites on which all our knowledge is based. We have mentioned, so far, only the results of modern physics, because this science has made the greatest advances into the realm of the hitherto unknown, and because any complete unification of the different natural sciences would have to accept these most revealing discoveries as its final foundation. Such a unification would also be one of the conditions of any really unitary system; but this unification, too, cannot possibly succeed completely.
We have tried to stress before that external and internal reality do not represent different parts of reality, but that both include the whole of reality, which is seen each time from a different point of view. (See Chapter 2, Section 2, paragraphs 2-14.) The same is true, though perhaps to a lesser extent, of the different branches of the natural sciences; all of them investigate almost the whole of reality from their special point of view. Physics includes man and living beings so far as they are matter and solid objects; in many respects, as with weight for instance, physical considerations are very important for us, though we are living beings. Biology has to include the whole environment of living beings; it has to deal with their physical surroundings and dwellings, with the chemical analysis of their food, with the climate and even the sun, but it must look at all these from the biological point of view. All these elements are also important for psychology, which in its turn has to deal with the whole environment of man, although only so far as it produces psychological effects. It is true that physics will hardly deal with purely biological or psychological phenomena, though the boundaries between molecules and cells have become doubtful and though attempts are being made to explain thoughts by movements of particles in the brain, and it is also true that biology or psychology will hardly deal with the stars and galaxies, though astrology seems to satisfy a deep seated longing of mankind. Nevertheless, the phenomena which form the common subject of all the sciences and which have to be considered from different points of view, thus excluding complete unification, undoubtedly cover the greater part of external reality. (This has been thoroughly elaborated in J. S. Haldane, The Philosophical Basis of Biology.)
This overlapping of the sciences cannot possibly be overcome by their unification. Any unification rests on an advance in abstraction and has to be based on the most abstract theories; this, however, leaves some spheres completely untouched, and to these different methods have to be applied. The old differentiation between the sciences is, therefore, preserved. Even in the very realm of physics we still need a description of the different stars, and have to try to discover their history which, as it represents something which cannot be repeated, can never be replaced by purely abstract theory. Chemistry has been based on physical laws, but no abstract observation can make superfluous the observation of chemical processes by chemical methods. The lack of advance in our knowledge of colours is most probably due to the fact that no attention has been paid to the necessity for applying different principles to this sphere, for abstract knowledge, as we have just said, cannot help us to know the colors as such. (See this chapter, Section 2, paragraphs 7 and 8.) The same is true of biology, where no theories will ever abolish botany or zoology or physiology, and psychology will have to describe our actual thoughts and feelings whether or not science succeeds in explaining them by purely mechanical processes in the nerve-system. It would be an immense impoverishment of our knowledge if a super-science tried to destroy all these old-established branches of the sciences.
All this shows once more that no advance in science can ever free us from the opposites which are the condition of our natural perception. We may advance still farther than seems possible to-day; we shall still have to pay attention to the stones and the trees, to the stars and the countries; to flowers and animals and men, if we want to have knowledge of them at all. The renunciation of opposites means loss of knowledge.
The advance of the sciences, moreover, though it seems to enable us to dream of their final unification, has in fact led to an ever increasing specialization. While the unification seems to come within reach, scientific work has to be split up into more and more special branches. This indicates that we cannot even reduce the number of opposites. As soon as some oppositions give way to a unitary principle, new oppositions and differentiations spring into being; the differences between physics and chemistry, between animate and inanimate matter, may disappear, but each of the different kinds of molecules and atoms, of electrons and rays requires a different approach and technique and thus a new special branch within the unified science. (See W. Heisenberg, Wandlungen in den Grundlagen der Naturwissenschaft, p. 22.) It is true that this specialization rests on a far greater unity of method than the different older branches of the sciences. But this unity does not alter the position, for wherever unity could be strengthened, the impoverishment we have just had to mention took place, and only so far as new differentiations and oppositions were established has our knowledge been enriched. Nuclear physics, for instance, has enlarged our field of understanding, but we had to renounce the hope of understanding the qualities themselves, if the quicker or slower movement of the atom produces warmth, it cannot itself be warm, and the atom-theory cannot deal with warmth as such. (See W. Heisenberg, Wandlungen in den Grundlagen der Naturwissenschaft, pp. 24, 27.)
Again, it would certainly be very difficult to follow up this specialization and to investigate in every case whether mere differences or the familiar opposites are being stressed, or whether new opposites are being created. But there can hardly be any doubt that such an investigation would disclose the application of the familiar opposites and the creation of new ones. In any case, it would confirm what has been said before. Any isolation of a group of phenomena requires the help of opposites, all experiments must make use of the opposites of our normal perception, and specializations also increase the importance of mathematics, thus pointing to the final barrier of opposites which no abstraction can surmount.
The difficulty lies rather in another direction; to investigate specialization, the philosopher himself would have to become a specialist in all sciences and thus cease to be a philosopher. Each of the special different departments of science presents so many difficulties that it is hardly possible to change over from one to the other, and the mass of special knowledge has grown so large that no single mind can hope any longer to grasp even the bare results of all the sciences, in spite of the considerable unity of method and of all prospects of a final unification. So far as thinking is concerned, we are not really overpowering external reality, but being overpowered by it; as we are unable to grasp it as a whole, we are lost in a maze of unconnected and meaningless details. If specialization had to be taken into account, therefore, philosophy would cease to be possible.
Yet this difficulty is hardly important, because such an investigation would not serve an important purpose. The fundamental facts are what matters; philosophy is not called on to follow the details of the natural sciences, but to disclose their nature, so as to be able to show their significance and their right place in the general ordering of human life. That philosophy has lost its influence to such a degree seems mainly due to the fact that it has been overwhelmed by the natural sciences and given way to specialization, instead of dealing with the sciences from a philosophical point of view. It is the fundamental facts which must help us to decide how far science can reveal truth.
These fundamental facts have been established. There is no knowledge of external reality which is not based on external opposites, and the sciences are unable to break them down, for they cannot get away form the original opposites of our perceptions, nor can mathematics, which ever the greatest abstractions must us dispense with all the constructive concepts. All this is confirmed when the striving for unification, instead of leading to unity, brings about specialization.
The constructive concepts, however, by defining the boundaries of external knowledge, show us that we must apply internal opposites, too, if we want to do justice to our experience.
One of the most important factors in scientific thinking is the boundaries of the subject which is to be investigated. So long as men thought that there was an edge to the earth, the sky remained a half-sphere and the sun a flat disk. It was only when it had been discovered that the earth is a ball—that is, when its real boundaries became known—that the heavens could be transformed into a universe and that the shape and movements of the celestial bodies could be described correctly. Recent progress in physics has been possible because the boundaries of the physical world have once more been shifted and the infinitely large and the infinitely small have gradually been more and more include in its scope. The knowledge of life has similarly been dependent on the length of time taken into consideration; so long as thinking was confined to the present, single species existed without any connection with each other; the theory of evolution presupposed the braking down of these time-limits and became possible only after the past had been made accessible as well.
The erecting of correct boundaries becomes even more important when we consider external reality as a whole.
So long as a stroke of lightning was considered as an evil demon or as divine judgment, it was impossible to gain knowledge which could protect man against nature; yet, at the same time, morality remained dependent on reward and punishment, instead of being based on the good as such. So long as it was considered essential for the Christian belief that the earth should be the centre of the world, all progress in the realm of the natural sciences was impossible; yet, at the same time, religion seemed to be dependent on an assumption which has no bearing upon true faith, a dependence which had fateful consequences when knowledge finally developed. To-day we are no longer in danger of personifying natural forces or events, but rather in the opposite danger of excluding from serious consideration everything which cannot be explained mechanically, and of believing the working of man's mind to be a purely mechanical process. The consequences are even more dangerous; because internal reality is being completely suppressed, man can no longer counterbalance this scientific development, and now it is this development itself which threatens him with destruction.
It is possible, of course, that the individual person experiences the consequences of a stroke of lightning as divine judgment, but this is an inner experience and dowes not give us any knowledge of external reality. Similarly some mechanical explanations of human behaviour may be of importance for certain impersonal aspects of our lives, but they provide no knowledge of internal reality. We can include, as we have seen, any part of reality either in external or internal reality, but we must not try to explain the one by the other. It is just in such cases as these where the object referred to seems to belong, not to the reality which is actually being considered, but to the other—lightning to external, psychological processes to internal reality—that the drawing of the right boundaries is of the utmost importance. We must clearly recognize what our conclusions mean; otherwise knowledge of both realities is destroyed.
The erecting of wrong boundaries creates this danger because it allows arbitrariness. We can test our knowledge of reality only by finding out whether the laws of thinking have been applied correctly, and test these laws by finding out whether the results correspond to our real experience. (See Chapter 2, note at end of Section 1.) The proof that the test has been successful consists in the establishing of a necessary relationship between the two. If, however, we extend the realm of internal reality into external reality, or that of external into internal reality, no such certainty can be achieved. The possible personal interpretations of a stroke of lightning are as many as the possible scientific explanations of the sub-conscious elements in psychology. No interpretations of this kind can ever be proved beyond doubt; it will always be possible to replace them by others, according to the intentions or opinions of the different interpreters. Our knowledge remains insecure and open to distortions.
The task of setting boundaries is that of the constructive concepts. Our knowledge of each reality needs elements form the other, and only these concepts transfer them is such a way that the character of external or internal reality is not impaired. If we now consider only the external reality with which we are concerned here—all such concepts as cause, force, time, freedom, though belonging to internal reality, are transferred as purely formal concepts which do not disclose the content as such, but give only its abstraction, thus enabling us to gain that formal knowledge which is adequate for external reality. By giving a firm foundation to their opposites which are the main characteristics of external reality—to effect, matter, space, necessity—they enable us to concentrate on external reality itself without any further reference to internal reality. These concepts, therefore, represent boundaries, for, by the way in which the transferring is done, they force our attention in one direction only. We have seen that they have to be used in quite a different way when referring to internal reality; we have to start form them, as from any other boundary, in two different directions if we want to enter either the one or the other realm.
The urge for unity must sweep across these boundaries because they would exclude a large part of primary reality from external reality, and thus this urge is mainly directed against the application of constructive concepts. We have just said that the modern development of science transcends some of them; though it cannot succeed in eliminating all, a great deal of confusion is brought about by wrong generalizations, based on theories which have been partially successful in this respect. (See this chapter, Section 2, paragraphs 16-20.) These conclusions seem to have a certain justification, because the constructive concepts are being replaced by negations, matter does not exist, causality is negated; and, above all, inner processes are eliminated by being reduced to material ones. There seems to be nothing left outside the sphere of these theories upon which we could base any objections to them, and it is this very fact which creates the confusion.
The part which negation plays in external reality has already been explained. The negative as such has been recognized as meaningless in it, for we know this reality only so far as we know something. External negation, therefore, must remain a purely formal principle, helping us to deny errors, to limit special spheres in external reality and to focus attention upon them. Its most important task consists in making abstraction possible; if we progress, for instance, from the concept of a beech-tree to that of a tree, and then further to such concepts as plant, organism, wood, matter, we have always to use negation to eliminate some particular characteristic which belong only to the more concrete concepts and no longer to the more abstract ones. But we have also seen that the constructive concepts cannot be derived in this way; no abstraction from external reality could ever lead to such concepts as cause and effect. They are based on abstractions from internal reality and have to be added to external reality to enable us to grasp it. They are not part of the external reality which we apprehend, but presuppositions of our apprehension. Hence negation must not interfere with them; as it has a purely logical function, it can make possible abstractions within external reality, but must not be allowed to effect changes in the premises themselves, which it would do if it touched these concepts. Negation must be halted before it affects the constructive concepts, for otherwise it would rob external reality of its foundations. (For this and the following, see Chapter 3, Section 2, paragraphs 21-23; Chapter 3, Section 3, paragraphs 3-12; and Chapter 4, Section 2, paragraphs 18-20 [point 5(a)].)
We have had to mention before that we ought to see this difference in the process of abstraction. Negation only makes the importance of this difference more obvious. So long as it makes possible those abstractions which can be derived from external reality, as for instance, when we proceed from 'tree' to 'matter', only particular characteristics are gradually excluded, but the connection with reality is never lost; we can go back even from the most abstract concept to reality and point at things which represent matter. This, therefore, is the legitimate use of negation, for here it has purely logical functions; it creates simpler concepts which allow us to deal with external reality more easily. Yet if we negate such concepts as 'cause' and 'effect', they are eliminated altogether; there is either causality or no causality. We do not create a new and simpler concept, but effect changes in the fundamental structure, thus transcending the legitimate sphere of negation. As nothingness has no meaning in external reality, this kind of negation is pure destruction and we must beware of it. It is justified so far as errors have to be destroyed, but not in the process of abstraction.
If negation transcends these limits and is used to satisfy the urge for unity, correct thinking is inevitably falsified in at least four ways.
(1) Abstraction from the constructive concepts confronts us with that nothingness which has no meaning in external reality and thus really destroys it. Recent developments in physics, for instance, by depriving space and time of all those characteristics which make them different, exclude the world of our perception from scientific theory; by negating causality, they leave the world of our actual experience behind; the only things which have remained intact are mathematical formulae, because the One and the Many are the only constructive concepts which have not been negated.
(2) Our thinking is necessarily falsified, because it is this very nothingness which is required to make the knowledge of external reality our only and comprehensive knowledge. The negative as such must show that there is nothing beyond external reality which asks for further investigation and thereby contradicts unity. The claim that scientific knowledge can explain the whole of reality implies that everything which has to be grasped by other methods is either not real or not true—that is, that it is nothing at all. The elimination of contradictory elements such as values, feelings, meaning and inner experiences, does not rest upon a thorough investigation, for science cannot grasp them; it rests on pure negation, for the claim that nothing can possibly escape scientific investigation can only be upheld when all those things which actually do escape are negated, so as to appear as nothing. Naturally, the results of such a method of thinking must be distorted.
(3) Negation, thus employed, is also bound to falsify the opposites upon which our thinking rests. The claim that external reality is all-inclusive only appears convincing because a real opposition seems to be established, an opposition which adds to the many other opposites a last and fundamental one—external reality, representing everything, is confronted with complete nothingness. But from all we have said it is already clear that negation cannot create a real opposite to external reality. The main characteristic of all fruitful opposites is that both parts are in some sense positive; they allow us to understand reality because both parts refer to it. Nothingness, however, does not exist; it comes into being only by the denial of elements of reality which do exist. The opposition is wrong, because its negative part represents only a negation of positive elements of reality. The thinking in opposites, therefore, is not applied, but misused; it lends the appearance of truth to an opposition which does not consist of real opposites.
(4) In fact—and this is the most dangerous falsification—this meaningless and wrong opposition is only accepted because the two realities have been mixed up and unacknowledged value-judgments have been introduced into external reality. We have seen that negation has a meaning in internal reality and that positive and negative values are both positive, in so far as they both refer to a real experience; it is only because a negative value can be attached to everything outside the scope of scientific investigation that the crude negation of existing elements of reality becomes acceptable. The statement that nothing can escape such an investigation means, in fact, that all other experiences and all other knowledge are of no value for our knowledge of reality; their apparently complete negation represents nothing but a negation of their value. They are not really considered as non-existent, but as worthless or wrong. A value-judgment, meaningless in external reality, borrows meaning from internal reality in order to give and appearance of meaning to nothingness which otherwise would have no meaning in external reality.
Thus, however, negation interferes with the fundamental conditions of our thinking which we have stated. It becomes impossible to fulfil the two main conditions of a correct division into two realities—namely, that they have to be completely separated and yet to be taken into account simultaneously. The separation is destroyed, and as the participation of internal reality is not even acknowledged, it can no longer be taken into account. But in this way we see that negation confirms most strikingly the need to insist on the fulfilment of these conditions, for now indeed all possibility of correct thinking vanishes. Supported by such a method, arbitrariness reigns supreme. Unacknowledged value-judgments enable the modern scientific mind, alive in all of us, to attack everything which threatens to disturb unitary scientific thinking.
This arbitrariness becomes particularly obvious when science tries to deal with internal reality, as in psychology ad sociology. There results are so insecure that, if one wants to accept one of the systems of theories which exist side by side, there is no way but arbitrary choice. Moreover, as the inner phenomena can be considered only in their external aspects and thus not fully understood, there is always a tendency to attack—more directly and violently than in other sciences—anyone who believes in the existence of an internal reality.
Finally—and this is by far the most important distortion—the meaning of all inner experiences, of the absolute values, of belief can no longer be understood. As unconscious value-judgments are used to exclude conscious valuation, the values as such disappear, and even the occasional discovery of such an illegitimate value-judgment only adds to their bad reputation. Negation, freed from all necessary limitations, drives abstraction into the regions of nothingness, and human life, deprived of its values, becomes abstract too, which makes man the more willing to support this development with perverted value-judgments. They do not succeed in giving meaning to external nothingness, but they do succeed, to a most dangerous degree, in supplying negation with human energy. Nothingness finally seems to acquire meaning, because it becomes real as an inner void in man, and because this void, by creating intense dissatisfaction, turns as a destructive force against all reality.
Conscious thinking in opposites could do a great deal to counter these disastrous consequences of wrong thinking. It is the urge for unity which drives us onwards into more and more abstract regions and makes us overlook the obvious consequences of an unrestricted negation. Truth seems to lie in this direction alone. If we knew from the beginning that we could never get away from the opposites altogether and that their final exclusion could only lead to a complete void, we could prevent ourselves from supporting science by a false nothingness which alone creates the appearance of a unitary method of thinking. As we always need opposites, truth must be different form the knowledge of external reality, for the mere fact that we must apply opposites forces upon us conclusions of a different kind. The constructive concepts in particular, applying to both realities, but with a different meaning in each, can best enable us to understand the significance of external reality and of scientific knowledge and to see their relationship to other kinds of knowing.