The Boundaries of Natural Science

I

The theme of this cycle of lectures was not chosen because it is traditional within academic or philosophical disciplines, as though we thought epistemology or the like should appear within our courses. Rather, it was chosen as the result of what I believe to be an open-minded consideration of the needs and demands of our time. The further evolution of humanity demands new concepts, new notions, and new impulses for social life generally: we need ideas which, when realized, can create social conditions offering to human beings of all stations and classes an existence that seems to them humane. Already, to be sure, it is being said in the widest circles that social renewal must begin with a renewal of our thinking. [ 1 ] Yet not everyone in these widest circles imagines something clear and distinct when speaking in this way. One does not ask: whence shall come the ideas upon which one might found a social economy offering man a humane existence? That portion of humanity which has received an education in the last three to four centuries, but particularly since the nineteenth century, has been raised with certain ideas that are outgrowths of the scientific world view or entirely schooled in it. This is particularly true of those who have undergone some academic training. Only those working in fields other than the sciences believe that natural science has had little influence on their pursuits. Yet it is easy to demonstrate that even in the newer, more progressive theology, in history and in jurisprudence — everywhere can be found scientific concepts such as those that arose from the scientific experiments of the last centuries, so that traditional concepts have in a certain way been altered to conform to the new. One need only allow the progress of the new theological developments in the nineteenth century to pass before the mind's eye. One sees, for example, how Protestant theology has arrived at its views concerning the man, Jesus, and the nature of Christ, because at every turn it had in mind certain scientific conceptions that it wanted to satisfy, against which it did not want to sin. At the same time, the old, instinctive ties within the social order began to slacken: they gradually ceased to hold human life together. In the course of the nineteenth century it became increasingly necessary to replace the instincts according to which one class subordinated itself to another, the instincts out of which the new parliamentary institutions, with all their consequences, have come with more-or-less conscious concepts. Not only in Marxism but in many other movements as well there has come about what one might call a transformation of the old social instincts into conscious concepts.

But what was this new element that had entered into social science, into this favorite son of modern thought? It was the conceptions, the new mode of thinking that had been developed in the pursuit of natural science. And today we are faced with the important question: how far shall we be able to progress within a web of social forces woven from such concepts? If we listen to the world's rumbling, if we consider all the hopeless prospects that result from the attempts that are made on the basis of these conceptions, we are confronted with a dismal picture indeed. One is then faced with the portentous question: how does it stand with those very concepts that we have acquired from natural science and now wish to apply to our lives, concepts that — this has become clearly evident in many areas already — are actually rejected by life itself? This vital question, this burning question with which our age confronts us, was the occasion of my choosing the theme, “The Boundaries of Natural Science.” Just this question requires that I treat the theme in such a way that we receive an overview of what natural science can and cannot contribute to an appropriate social order and an idea of the kind of scientific research, the kind of world view to which one would have to turn in order to confront seriously the demands made upon us by our time.

What is it we see if we consider the method according to which one thinks in scientific circles and how others have been influenced in their thinking by those circles? What do we see? We see first of all that an attempt is made to acquire data and to order it in a lucid system with the help of clear concepts. We see how an attempt is made to order the data gathered from inanimate nature by means of the various sciences — mechanics, physics, chemistry, etc. — to order them in a systematic manner but also to permeate the data with certain concepts so that they become intelligible. With regard to inanimate nature, one strives for the greatest possible clarity, for crystal-clear concepts. And a consequence of this striving for lucid concepts is that one seeks, if it is at all possible, to permeate everything that one finds in one's environment with mathematical formulae. One wants to translate data gathered from nature into clear mathematical formulae, into the transparent language of mathematics.

In the last third of the nineteenth century, scientists already believed themselves very close to being able to give a mathematical-mechanical explanation of natural phenomena that would be thoroughly transparent. It remained for them only to explain the little matter of the atom. They wanted to reduce it to a point-force [Kraftpunkt] in order to be able to express its position and momenta in mathematical formulae. They believed they would then be justified in saying: I contemplate nature, and what I contemplate there is in reality a network of interrelated forces and movements wholly intelligible in terms of mathematics. Hence there arose the ideal of the so-called “astronomical explanation of nature,” which states in essence: just as one brings to expression the relationships between the various heavenly bodies in mathematical formulae, so too should one be able to compute everything within this smallest realm, within the “little cosmos” of atoms and molecules, in terms of lucid mathematics. This was a striving that climaxed in the last third of the nineteenth century: it is now on the decline again. Over against this striving for a crystal-clear, mathematical view of the world, however, there stands something entirely different, something that is called forth the moment one tries to extend this striving into realms other than that of inanimate nature. You know that in the course of the nineteenth century the attempt was made to carry this point of view, at least to some extent, into the life sciences. And though Kant had said that a second Newton would never be found who could explain living organisms according to a causal principle similar to that used to explain inorganic nature, Haeckel could nevertheless claim that this second Newton had been found in Darwin, that Darwin had actually tried, by means of the principle of natural selection, to explain how organisms evolve in the same “transparent” terms. And one began to aim for just such a clarity, a clarity at least approaching that of mathematics, in all explanations, proceeding all the way up to the explanation of man himself. Something thereby was fulfilled which certain scientists explained by saying that man's need to understand the causes of phenomena is satisfied only when he arrives at such a transparent, lucid view of the world.

And yet over against this there stands something entirely different. One comes to see that theory upon theory has been contrived in order to construct a view of the world such as I have just described, and ever and again those who strove for such a view of the world called forth — often immediately — their own opposition. There always arose the other party, which demonstrated that such a view of the world could never produce valid explanations, that such a view of the world could never ultimately satisfy man's need to know. On the one hand it was argued how necessary it is to keep one's world view within the lucid realm of mathematics, while on the other hand it was shown that such a world view would, for example, remain entirely incapable of constructing even the simplest living organism in thought of mathematical clarity or, indeed, even of constructing a comprehensible model of organic substance. It was as though the one party continually wove a tissue of ideas in order to explain nature, and the other party — sometimes the same party — continually unraveled it.

It has been possible to follow this spectacle — for it seems just that to anyone who is able to view it with an unprejudiced eye — within the scientific work and striving of the last fifty years especially. If one has sensed the full gravity of the situation, that with regard to this important question nothing but a weaving and unraveling of theories has taken place, one can pose the question: is not the continual striving for such a conceptual explanation of phenomena perhaps superfluous? Is not the proper answer to any question that arises when one confronts phenomena perhaps that one should simply allow the facts to speak for themselves, that one should describe what occurs in nature and forgo any more detailed accounting? Is it not possible that all such explanations show only that humanity is still tied to its mother's apron strings, that humanity in its infancy sought a kind of luxury? Would not humanity, come of age, have to say to itself: we must not strive at all for such explanation; we get nowhere in that way and must simply extirpate the need to know? Why not? As we become older we outgrow the need to play; why, if we were justified in doing so, should we not simply outgrow the need for explanations?

Just such a question could already emerge in the most extraordinarily significant way when, on August 14, 1872, du Bois-Reymond stood before the Second General Meeting of the Association of German Scientists and Physicians to deliver his famous address, “The Boundaries of Natural Science” [“Grenzen des Naturerkennens”], an address still worthy of consideration today. Yet despite the amount that has been written about this address by the important physiologist, du Bois-Reymond, many still do not realize that it represents one of the important junctures in the evolution of the modern world view.

In medieval Scholasticism all of man's thinking, all of his notional activity, was determined by the view that one could explain the broad realms of nature in terms of certain concepts but that one had to draw the line upon reaching the super-sensible. The super-sensible had to be the object of revelation. They felt that man should stand in a relation to the super-sensible in such a way that he would not even wish to penetrate it with the same concepts he formed concerning the realms of nature and external human existence. A limit was set to knowledge on the side of the super-sensible, and it was strongly emphasized that such a limit had to exist, that it simply lay within human nature and the order of the universe that such a limit be recognized. This placement of a limit to knowledge was then renewed from an entirely different side by thinkers and researchers such as du Bois-Reymond. They were no longer Schoolmen, no longer theologians, but just as the medieval theologian, proceeding according to his own mode of thinking, had set a limit to knowledge at the super-sensible, so these thinkers and researchers set a limit at the sensible. The limit was meant to apply above all to the realm of external sensory data.

There were two concepts in particular that du Bois-Reymond had in mind, which to him established the limits natural science could reach but beyond which it could not proceed. Later he increased that number by five in his lecture, “The Seven Enigmas of the World,” but in the first lecture he spoke of the two concepts, “matter” and “consciousness.” He said that when contemplating nature we are forced, in thinking systematically, to apply concepts in such a way that we eventually arrive at the notion of matter. Just what this mysterious entity in space we call “matter” is, however, we can never in any way resolve. We must simply assume the concept “matter,” though it is opaque. If only we assume this opaque concept “matter,” we can apply our mathematical formulae and calculate the movements of matter in terms of the formulae. The realm of natural phenomena becomes comprehensible if only we can posit this “opaque” little point millions upon millions of times. Yet surely we must also assume that it is this same material world that first builds up our bodies and unfolds its own activity within them, so that there rises up within us, by virtue of this corporeal activity, what eventually becomes sensation and consciousness. On the one hand we confront a world of natural phenomena requiring that we construct a concept of “matter,” while on the other hand we confront ourselves, experience the fact of consciousness, observe its phenomena, and surmise that whatever it is we assume to be matter must also lie at the foundation of consciousness. But how, out of these movements of matter, out of inanimate, dead movement, there arises consciousness, or even simple sensation, is a mystery that we cannot possibly fathom. This is the other pole of all the uncertainties, all the limits to knowledge: how can we explain consciousness, or even the simplest sensation?

With regard to these two questions, then — What is matter? How does consciousness arise out of material processes? — du Bois-Reymond maintains that as researchers we must confess: ignorabimus, we shall never know. That is the modern counterpart to medieval Scholasticism. Medieval Scholasticism stood at the limit of the super-sensible world. Modern natural science stands at the limit delineated in essence by two concepts: “matter,” which is everywhere assumed within the sensory realm but nowhere to be found, and “consciousness,” which is assumed to originate within the sense world, although one can never comprehend how.

If one considers this development of modern scientific thought, must one not then say to oneself that scientific research is entangling itself in a kind of web, and only outside of this web can one find the world? For in the final analysis it is there, where matter haunts space, that the external world lies. If this is the one place into which one cannot penetrate, one has no way in which to come to terms with life. Within man one finds the fact of consciousness. Does one come at all near to it with explanations conceived in observing external nature? If in one's search for explanations one pulls up short at human life, how, then, can one arrive at notions of how to live in a way worthy of a human being? How, if one cannot understand the existence or the essence of man according to the assumptions one makes concerning that existence?

As this course of lectures progresses it shall, I believe, become evident beyond any doubt that it is the impotence of the modern scientific method that has made us so impotent in our thinking about social questions. Many today still do not perceive what an important and essential connection exists between the two. Many today still do not perceive that when in Leipzig on August 14, 1872 du Bois-Reymond spoke his ignorabimus, this same ignorabimus was spoken also with regard to all social thought. What this ignorabimus actually meant was: we stand helpless in the face of real life; we have only shadowy concepts; we have no concepts with which to grasp reality. And now, almost fifty years later, the world demands just such concepts of us. We must have them. Such concepts, such impulses, cannot come out of lecture-halls still laboring in the shadow of this ignorabimus. That is the great tragedy of our time. Here lie questions that must be answered.

We want to proceed from fundamental principles to such an answer and above all to consider the question: is there not perhaps something more intelligent that we as human beings could do than what we have done for the last fifty years, namely tried to explain nature after the fashion of ancient Penelope, by weaving theories with one hand and unraveling them with the other? Ah yes, if only we could, if only we could stand before nature entirely without thoughts! But we cannot: to the extent that we are human beings and wish to remain human beings we cannot. If we wish to comprehend nature, we must permeate it with concepts and ideas. Why must we do that?

We must do that, ladies and gentlemen, because only thereby does consciousness awake, because only thereby do we become conscious human beings. Just as each morning upon opening our eyes we achieve consciousness in our interaction with the external world, so essentially did consciousness awake within the evolution of humanity. Consciousness, as it is now, was first kindled through the interaction of the senses and thinking with the outer world. We can watch the historical development of consciousness in the interaction of man's senses with outer nature. In this process consciousness gradually was kindled out of the dull, sleepy cultural life of primordial times. Yet one must only consider with an open mind this fact of consciousness, this interaction between the senses and nature, in order to observe something extraordinary transpiring within man. We must look into our soul to see what is there, either by remaining awhile before fully awakening within that dull and dreamy consciousness or by looking back into the almost dreamlike consciousness of primordial times. If we look within our soul at what lies submerged beneath the surface consciousness arising in the interaction between senses and the outer world, we find a world of representations, faint, diluted to dream-pictures with hazy contours, each image fading into the other. Unprejudiced observation establishes this. The faintness of the representations, the haziness of the contours, the fading of one representation into another: none of this can cease unless we awake to a full interaction with external nature. In order to come to this awakening which is tantamount to becoming fully human — our senses must awake every morning to contact with nature. It was also necessary, however, for humanity as a whole to awake out of a dull, dreamlike vision of primordial worlds within the soul to achieve the present clear representations.

In this way we achieve the clarity of representation and the sharply delineated concepts that we need in order to remain awake, to remain aware of our environment with a waking soul. We need all this in order to remain human in the fullest sense of the word. But we cannot simply conjure it all up out of ourselves. We achieve it only when our senses come into contact with nature: only then do we achieve clear, sharply delineated concepts. We thereby develop something that man must develop for his own sake — otherwise consciousness would not awake. It is thus not an abstract “need for explanations,” not what du Bois-Reymond and other men like him call “the need to know the causes of things,” that drives us to seek explanations but the need to become human in the fullest sense through observing nature. We thus may not say that we can outgrow the need to explain like any other child's play, for that would mean that we would not want to become human in the fullest sense of the word — that is to say, not want to awake in the way we must awake.

Something else happens in this process, however. In coming to such concepts as we achieve in contemplating nature, we at the same time impoverish our inner conceptual life. Our concepts become clear, but their compass becomes diminished, and if we consider exactly what it is we have achieved by means of these concepts, we see that it is an external, mathematical-mechanical lucidity. Within that lucidity, however, we find nothing that allows us to comprehend life. We have, as it were, stepped out into the light but lost the very ground beneath our feet. We find no concepts that allow us to typify life, or even consciousness, in any way. In exchange for the clarity we must seek for the sake of our humanity, we have lost the content of that for which we have striven. And then we contemplate nature around us with our concepts. We formulate such complex ideas as the theory of evolution and the like. We strive for clarity. Out of this clarity we formulate a world view, but within this world view it is impossible to find ourselves, to find man. With our concepts we have moved out to the surface, where we come into contact with nature. We have achieved clarity, but along the way we have lost man. We move through nature, apply a mathematical-mechanical explanation, apply the theory of evolution, formulate all kinds of biological laws; we explain nature; we formulate a view of nature — within which man cannot be found. The abundance of content that we once had has been lost, and we are confronted with a concept that can be formed only with the clearest but at the same time most desiccated and lifeless thinking: the concept of matter. And an ignorabimus in the face of the concept of matter is essentially the confession: I have achieved clarity; I have struggled through to an awakening of full consciousness, but thereby I have lost the essence of man in my thinking, in my explanations, in my comprehension.

And now we turn to look within. We turn away from matter to consider the inner realm of consciousness. We see how within this inner realm of consciousness representations pass in review, feelings come and go, impulses of will flash through us. We observe all this and notice that when we attempt to bring the inner realm into the same kind of focus that we achieved with regard to the external world, it is impossible. We seem to swim in an element that we cannot bring into sharp contours, that continually fades in and out of focus. The clarity for which we strive with regard to outer nature simply cannot be achieved within. In the most recent attempts to understand this inner realm, in the Anglo-American psychology of association, we see how, following the example of Hume, Mill, James, and others, the attempt was made to impose the clarity attained in observation of external nature upon inner sensations and feelings. One attempts to impose clarity upon sensation, and this is impossible. It is as though one wanted to apply the laws of flight to swimming. One does not come to terms at all with the element within which one has to move. The psychology of association never achieves sharpness of contour or clarity regarding the phenomenon of consciousness. And even if one attempts with a certain sobriety, as Herbart has done, to apply mathematical computation to human mental activity [das Vorstellen], to the human soul, one finds it possible, but the computations hover in the air. There is no place to gain a foothold, because the mathematical formulae simply cannot comprehend what is actually occurring within the soul. While one loses man in coming to clarity regarding the external world, one finds man, to be sure — it goes without saying that one finds man when one delves into consciousness — but there is no hope of achieving clarity, for one swims about, borne hither and thither in an insubstantial realm. One finds man, but one cannot find a valid image of man.

It was this that du Bois-Reymond felt very clearly but was able to express only much less clearly — only as a kind of vague feeling about scientific research on the whole — when in August 1872 he spoke his ignorabimus. What this ignorabimus wants to say in essence is that on the one hand, we have in the historical evolution of humanity arrived at clarity regarding nature and have constructed the concept of matter. In this view of nature we have lost man — that is, ourselves. On the other hand we look down into consciousness. To this realm we want to apply that which has been most important in arriving at the contemporary explanation of nature. Consciousness rejects this lucidity. This mathematical clarity is entirely out of place. To be sure, we find man in a sense, but our consciousness is not yet strong enough, not yet intensive enough to comprehend man fully.

Again, one is tempted to answer with an ignorabimus, but that cannot be, for we need something more than an ignorabimus in order to meet the social demands of the modern world. The limit that du Bois-Reymond had come up against when he spoke [about] his ignorabimus on August 14, 1872 lies not within the human condition as such but only within its present stage of historical human evolution. How are we to transcend this ignorabimus? That is the burning question.