If it is a sign of the philosophical genius that he creates and establishes new notions, concepts, and ideas in the traditional philosophy of his time, then Husserl was, without doubt, a great philosopher: During his whole career as philosopher, he introduced many new notions, beginning with the verb “kolligieren” in his first book The Philosophy of Arithmetic and ending with the concept of the Lebenswelt, or life-world, in The Crisis of European Sciences and Transcendental Phenomenology, his last major work, first published in 1936 in the journal Philosophia. But things are often not as simple as they seem at first glance. The notion of the Lebenswelt is simple and difficult at the same time; it depends on how one understands it—as a commonsense notion or as a philosophical concept or as both, as Husserl seems to do; he is at least in this respect quite consistent.
In this chapter I will investigate the origin and significance of Husserl’s notion of the Lebenswelt. I will not, however, begin with this delicate task before having clarified one point of possible misunderstanding. As many readers likely know, the book version of The Crisis of European Sciences emerged from a lecture that Husserl had presented in Vienna and Prague in 1935 (The Vienna Lecture), and which was later published in the Husserliana edition. Toward the end of this piece, he gives a short summary of his diagnosis of the crisis and its possible solutions from which I will quote some central remarks.
The crisis of European Existence, talked about so much today and documented in innumerable symptoms of the breakdown of life, is not an obscure fate, an impenetrable destiny; rather it becomes understandable and transparent against the background of the teleology of European history that can be discovered philosophically. The condition for this understanding, however, is that the phenomenon Europe be grasped in its central, essential nucleus. In order to be able to comprehend the disarray of the present crisis, we had to work out the concept of Europe as the historical teleology of the infinite goals of reason; we had to show how the European world was born out of ideas of reason, i.e., out of the spirit of philosophy. The crisis could then become distinguishable as the apparent failure of rationalism. The reason for the failure of a rational culture, however, as we said, lies not in the essence of rationalism itself but solely in its being rendered superficial, in its entanglement with naturalism and objectivism.
There are only two escapes from the crisis of European existence: the downfall of Europe in its estrangement from its own rational sense of life, its fall into hostility toward the spirit and into barbarity; or the rebirth of Europe from the spirit of philosophy through a heroism of reason that overcomes naturalism once and for all. (The Vienna Lecture, p. 299)
Now I must confess that the antiscientific attitude underlying Husserl’s talk and his diagnosis of the crisis and its desired cure by overcoming the naturalism and objectivism of the natural sciences (including mathematics) is, from my point of view, highly problematic, if not simply mistaken. But this does not imply that something very interesting and highly valuable could not be found in Husserl’s late work. On the contrary, I am convinced that Husserl’s invention of the concept of the Lebenswelt as an “irreducible” ingredient of all sciences is a very important discovery—not only from a philosophical but also from a scientific point of view. Consequently, it is my main task (1) to separate what seems to me right and what seems to me wrong in Husserl’s diagnosis of the crisis and (2) to explain in what sense Husserl’s analysis of the situation should be taken seriously. But the question immediately arises: By whom should it be taken seriously? By the philosopher, by the scientist, or by both? Here we encounter a first difficulty, and it is by no means the only one. There are similar difficulties regarding the notions of naturalism and objectivism. Do they denote a philosophical position, or do they refer to certain aspects of science that Husserl believes to lie at the root of its crisis?
In spite of these difficulties, and in light of Husserl’s notoriously cryptic and long-winded style of writing, it seems to me advisable to analyze Husserl’s concept of the Lebenswelt in a somewhat unusual manner. Instead of presenting an immanent interpretation of his late writings, I will approach them from an “external” point of view. I will compare what Husserl has to say on The Crisis of European Sciences with the utterances of some prominent scientists who have dealt—implicitly or explicitly—with similar questions and problems regarding the methodological foundations as well as the epistemological limits of science. I have in mind above all Weyl and Hilbert, who both stood in more or less close scientific contact with Husserl during different periods of their lives. After a brief review of Husserl’s considerations with respect to the indispensable role of the Lebenswelt in science, I will turn first to Weyl and discuss his conception of “Science as a Symbolic Construction of Man,” the title of an important essay in which Weyl criticizes a certain view of science as “ridiculously circular.” Next, I will turn to Hilbert and explain the sense in which he regards the Lebenswelt as an irreducible presupposition of all sciences, geometry and mathematics included. (Although Hilbert does not use the term Lebenswelt, he speaks of the geometry of “everyday life” and similar expressions.) Finally, I return to Husserl and his diagnosis of the crisis and try to separate what seems to me a justified critique of the positivistic worldview of science and what has to be rejected as misguided or even absurd. The essential result will be that the natural sciences and their foundations are not fixed and finished but are still open to supplementation and fundamental revision in the future.
The ambiguity in the title of this section is quite deliberate. In fact, it has been noticed by some authors that Husserl’s book The Crisis of European Sciences is itself the result of a kind of crisis in Husserl’s own thinking. It has been argued, for instance by Lothar Eley, that Husserl in the Crisis became aware that he had left unsolved a fundamental problem in his very first book The Philosophy of Arithmetic, namely the role and legitimation of the actual infinite in his genetic approach to arithmetic. Let me quote from Eley’s Introduction to that book:
To the true philosophy of the calculus also belong investigations of his late work The Crisis of European Sciences. This late work refers back in a remarkable manner to his early work [The Philosophy of Arithmetic] as we will see in a moment. According to this [genetic] program, the paradise of the actual infinite would have been dispelled from mathematics. Therefore, it comes as a surprise to rediscover this paradise in the late work The Crisis of European Sciences. (Philosophie der Arithmetik, Husserliana XII, p. xiii)
I will not now decide whether Eley is correct, whether Husserl really solved the old problem of the role of the actual infinite in mathematics in his late work. Instead I want to point out that the title of The Crisis of European Sciences and Transcendental Phenomenology contains a word that seems rather strange and out of place in this context. Why does Husserl not simply say “The Crisis of Sciences” instead of speaking explicitly of “The Crisis of EuropeanSciences”? There must be a reason for this, and, in fact, the reason is not difficult to come by: It is connected with the circumstance that the sciences, as we know them today (mathematics included), had their first origin in Greece and their rebirth during the Renaissance in Italy, after many centuries of deep sleep, and from there spread over Europe and the rest of the world. Now this story is such a commonplace that it alone cannot be the point of Husserl’s considerations. And indeed, if we look more closely at Husserl’s text, we recognize another strand. It is the cultural history of “European mankind,” of which the natural sciences form only a part, that is at the focus of Husserl’s concerns. Unfortunately the term cultural history is still somewhat too broad to characterize precisely what Husserl had in mind. For it is not, of course, the cultural history of European mankind as seen by a normal historian or a sociologist or one or another scientist, but, unsurprisingly, as seen by a philosopher. He, the philosopher, has a special interest in the contributions of philosophers to the cultural history of mankind, and this means the cultural history of European mankind, because it was in Europe that philosophy became the leader in the cultural evolution of mankind. This (and the next point, to which I will come in a moment) is much clearer in the short lecture held in Vienna than in the long book.
In this lecture I shall venture the attempt to find new interest in the frequently treated themes of the European crisis by developing the philosophical-historical idea (or the teleological sense) of European humanity. As I exhibit, in the process, the essential function that philosophy and its branches, our sciences, have to exercise within that sense, the European crisis will receive a new elucidation. (The Vienna Lecture, p. 269)
But what is the “function” or role of philosophy and its branches in this historical sense, and what is the European crisis of which Husserl speaks in the beginning and which later—after the elucidation—turns out to be the crisis of European sciences? In order to make a very long story short, I will condense the answer into six propositions:
Although these statements are my own formulations, it should be clear that they do not express my own opinion. I wanted only to capture Husserl’s convictions as outlined in the Vienna lecture and later elaborated at great length in The Crisis of European Sciences. From now on, I will keep a more critical distance from Husserl’s point of view. My first critical point is the following:
My sketch of Husserl’s Crisis (and even more, of course, the book itself) can give the impression that Husserl had written a history of philosophy enriched by some very interesting subchapters on the history of modern science. But this, I think, is a mistake. The history that Husserl tells in the first chapters is much too sloppy and, what is more important, far too permeated with common prejudices and trivial errors for it to count as a serious attempt to write a book on the history of philosophy, not to mention of science—at least it fails to meet my standards in these matters. I would not only demand more historical precision but also expect a deeper and more concrete understanding of what was going on intellectually in a given historical development. Instead, I think, Husserl’s intention was a completely different one: He wanted to put certain philosophical ideas (regarding his theory of mind and intentions) into a “historical dressing” so that it seemed to the reader as if he had only to strip the ideas of their historical clothing in order to get a clear and genuine view of them.
Now this already sounds more critical than I wanted, but I have, at least for the first part of my thesis, some good corroboration in the Vienna lecture. Not only is the entire line of this lecture more theoretical than genuinely historical, but Husserl also makes clear that history has an only instrumental character for him.
The foregoing considerations on the philosophy of the spirit provide us with the proper attitude for grasping and dealing with our subject of spiritual Europe as a problem purely within the humanistic disciplines [ein rein geisteswissenschaftliches Problem], and first of all in the manner of spiritual history. As already indicated in our introductory statements, a remarkable teleology, inborn, as it were, only in our Europe, will become visible in this way, one which is quite intimately involved with the outbreak or irruption of philosophy and its branches, the sciences, in the ancient Greek spirit. We can foresee that this will involve a clarification of the deepest reasons for the origin of the portentous naturalism, or, what will prove to be equivalent, of modern dualism in the interpretation of the world. Finally this will bring to light the actual sense of the crisis of European humanity. (The Vienna Lecture, p. 273)
Now the passage just quoted cries out for clarification. What does “purely humanistic” (rein geisteswissenschaftlich) mean? Does Husserl intend a “science of mind” in distinction and opposition to the natural sciences? If the answer is yes, as I suspect, then it is highly problematic, because it sets up a wrong opposition. What does “naturalism” mean, and why is it fatal? And why is the so-called modern dualism equivalent to naturalism and therefore equally fatal? These are all legitimate questions, but I will not go into them now. I only want to show that Husserl is not doing “real” history of philosophy or of science, as the historian understands this task, but instead tries to advance an idea of mind, which he projects backward into the history of mankind, notably European mankind! One can find such claims on almost every other page of the Vienna lecture. Here are two more examples:
“The spiritual shape of Europe”—what is it? [We must] exhibit the philosophical idea which is immanent in the history of Europe (spiritual Europe) or, what is the same, the teleology which is immanent in it, which makes itself known, from the standpoint of universal mankind as such, as the breakthrough and the developmental beginning of a new human epoch—the epoch of mankind which now seeks to live, and only can live, in the free shaping of its existence, its historical life, through ideas of reason, through infinite tasks. (The Vienna Lecture, p. 274)
Universal philosophy, together with all the special sciences, makes up only a partial manifestation of European culture. Inherent in the sense of my whole presentation, however, is that this part is the functioning brain, so to speak, on whose normal function the genuine, healthy European spiritual life depends. The humanity of higher human nature or reason requires, then, a genuine philosophy. (The Vienna Lecture, pp. 290–91)
I think the last quotation makes explicit that Husserl’s intention is not to investigate history as we find it in written documents, but to model history so that it fits nicely with his idea of a new type of mankind, a mankind whose highest goal is reason, where the approach to reason is understood as an infinite task. To be aware of this circumstance is quite important for my further considerations for two practical reasons.
First, it relieves me of the difficult and boring duty of checking whether Husserl’s historical claims and suggestions are historically correct. I can simply take them as mediate expressions of his philosophical intentions and opinions dressed in historical settings; whether they are correct and concordant with the historical documents is another matter. This does not mean that it is unimportant to know where differences exist; on the contrary, such differences tell a lot about Husserl’s true philosophical intentions and opinions; this is in particular relevant with respect to the most elaborated historical parts of the Crisis, in which Husserl presents his view of the genesis of modern science as a “mathematization of nature” by Galileo. Now this view is not only a platitude, but it is also rather misleading, because the real innovation was to my mind something quite different, namely the fact that Galileo and his successors invented genuine physical experiments and made quantitative predictions and measurements. I will come back to this point.
Second, knowing that the highest goal of mankind is reason in the sense of an infinite task makes it somewhat easier to grasp what the systematic message, the philosophical point of Husserl’s excursions into the history of science and philosophy actually is. We have only to take two further steps: First, we must make clear to ourselves what the supposed “crisis of the sciences” consists in. Second, and more important, we must understand what the philosophical significance, the epistemological essence of the pretended crisis is. Once we are clear on these two points, we will see why the crisis—or at least its ghost, in the case that it does not really exist—can only be banished, according to Husserl, if we go back to the so-called Lebenswelt and make a fresh start in understanding our own existential situation in the world.
So much, for the time being, on Husserl’s Crisis. Of course, I have not yet explained what the core of the crisis is, let alone its philosophical significance. But, as I said in the beginning, I will not give an immanent interpretation but instead offer an external explication by comparing Husserl’s Crisis with similar considerations in the writings of Hilbert and Weyl. Before I start my detour, let me make two brief remarks, the first concerning a philological point, the second a conceptual one.
The expression Lebenswelt does not occur literally in the Vienna lecture; but the concept as such is already present, as the following quotation from the lecture shows. Having made a distinction between two attitudes or habits (the theoretical attitude of the Greek philosophers and the more practical attitudes in other cultures), Husserl remarks with respect to the relation of these two attitudes:
Thus the theoretical attitude, in its newness, refers back to a previous attitude, one which was earlier the norm; [with reference to this] it is characterized as a reorientation. Universally considering the historicity of human existence in all its communal forms and in its historical stages, we now see that a certain attitude is essentially and in itself the first, i.e., that a certain norm-style of human existence (speaking in formal generality) signifies a first [type of] historicity within which particular factual norm-styles of culture-creating existence remain formally the same in spite of all rising, falling, or stagnating. We speak in this connection of the natural primordial attitude, of the attitude of original natural life, of the first originally natural form of cultures, whether higher or lower, whether developing uninhibitedly or stagnating. All other attittudes are accordingly related back to this natural attitude as reorientations [of it]. (The Vienna Lecture, pp. 280–81)
One could continue this quotation at length, but the passage in question suffices to show that the term Lebenswelt roughly denotes what Husserl describes here as the original attitude or habit of the “original natural life” (des ursprünglich natürlichen Lebens). This is important for my exegesis because it makes clear that Husserl could have chosen another expression, for example Hilbert’s expression “everyday life” (tägliches Leben) instead of Lebenswelt, which indeed, I think, influenced his choice.
The second clarification relates to the notion of reason as an infinite task. What does Husserl mean by this? A relatively short answer is given when Husserl considers the first decisive Umstellung, or change of attitude, in the history of mankind, the step of the Greek philosophers from the attitude of natural life toward a theoretical habit:
The historical course of development is prefigured in a determined way by this attitude toward the surrounding world. Even the most fleeting glance at the corporeity to be found in the surrounding world shows that nature is a homogeneous, totally interrelated whole, a world by itself, so to speak, encompassed by homogeneous space-time, divided into particular things, all being alike as res extensae and determining one another causally. Quite rapidly, a first and great step of discovery is taken, namely, the overcoming of the finitude in spite of its open endlessness. Infinity is discovered, first in the form of idealized magnitudes, of measures, of numbers, figures, straight lines, poles, surfaces etc. Nature, space, time, become extendable idealiter to infinity and divisible idealiter to infinity. From the art of surveying comes geometry, from the art of numbers arithmetic, from everyday mechanics mathematical mechanics, etc. (The Vienna Lecture, p. 293)
This is a very important section, not only because in it Husserl indicates what the “infinite task of reason” is, but also because it makes clear that he distinguishes between the finiteness of nature, which is no more than an open endlessness, and the infinite (in mathematics) as an idealization of certain concepts and their underlying intuitions. We find a similar distinction in Hilbert’s writings between the finite but unlimited nature and the infinite in mathematics as ideal elements in our theoretical conception of nature. This suggests that Hilbert and other philosophically minded scientists like Weyl, Schrödinger, Bohr, and Heisenberg (to name only the best-known quantum theorists) may have encountered problems similar to those Husserl describes in the Crisis. So we should perhaps consider what they have to say about the same or at least some closely related issues. But here already I encounter a first difficulty: Which issue?
Until now I have not said very much about the proper issue of Husserl’s late work, The Crisis of European Sciences. But one thing seems quite obvious: The scientists themselves do not speak of a “crisis of the sciences”—at least not in the 1930s. So why should we assume that they treat the same or at least a similar problem as Husserl in the Crisis? There seems to be no reason that they should. But contrary to this initial impression, the scientists in question did think about the methods and limits of their own science repeatedly; and this alone seems to me reason enough to ask whether they came across problems similar to Husserl’s, even if they expressed them differently and came to quite different conclusions. A first problem, which it seems to me has a certain resemblance to Husserl’s crisis of the sciences (or at least to a certain aspect of it), is Weyl’s “ridiculous circle.”
Toward the end of his 1949 essay “Wissenschaft als symbolische Konstruktion des Menschen” (Science as Symbolic Construction of Man), Weyl touches some open questions and problems regarding the foundations of quantum mechanics. His main concern is the problem of measurement in quantum mechanics and its different treatments in Copenhagen and Zürich, namely Bohr’s philosophy of complementarity on the one hand and Schrödinger’s appeal to a kind of dialectic in the recognition of nature on the other. Dealing with the latter, its sense and justification, Weyl detects a certain resemblance between Schrödinger’s dialectic of recognition and a position that he addresses as the Existentialphilosophie. In this context Weyl develops the ridiculous circle I mentioned previously as an argument in defense of Schrödinger’s dialectic, I suppose, and hence of the so-called existential philosophy.
Before I investigate what the latter has to do with Husserl’s Crisis, let me briefly explain the ridiculous circle. As scientists, we may be tempted, says Weyl, to argue in the following way:
As we know, the chalk on the blackboard consists of molecules, and these are composed of charged and uncharged elementary particles, electrons, neutrons, etc. However, in analyzing what we mean with such words in theoretical physics, we have seen that the physical things get dissolved into a symbolism manipulated according to certain rules; the symbols themselves, however, turn out in the end to be concrete signs written with chalk on the blackboard. You recognize the ridiculous circle [den lächerlichen Zirkel]. We can escape from this circle only if we accept the manner in which we understand in daily life man and things, which we encounter, as an irreducible fundament. (Weyl, 1968, 342, my italics, my translation)
Now, I can very well imagine that most readers will agree that this circle is really ridiculous, but also that many readers will, at the same time, be very skeptical about two points: First, does anyone exist who directly and seriously affirms such a ridiculous circle or is guilty of affirming it indirectly because he labors under such a delusion? Second, what does the circle, what do Weyl’s considerations regarding the problem of measurement have to do with Husserl’s Crisis? Let me first answer the second, easier, question. Here I am on relatively safe ground, because some remarks in Husserl indicate that both authors have the same point in mind, or at least a very similar one. Considering the relation of the natural sciences to our, that is, to the human mind, Husserl remarks:
Is it not absurd and circular to want to explain the historical event “natural science” in a natural-scientific way, to explain it by bringing in natural science and its natural laws which, as spiritual accomplishment, themselves belong to the problem? (The Vienna Lecture, p. 273)
Surely, this is not exactly the same circle as Weyl’s ridiculous one, but it is closely related to the latter. This becomes obvious once we take the broader context of Weyl’s circle argument into account. I will do this in several steps. First, we must recall that the title of Weyl’s essay is “Science as Symbolic Construction of Man,” and this reveals that symbols, the symbols of science, are first and foremost mental products, products of the human mind (mind taken as a general term under which many individuals fall). So far Husserl and Weyl agree. That the symbols have to be written down on stone or paper or in semiconductors in order to store them so that we may communicate by means of them over space and time, is—seen from this perspective—only a contingent matter. This becomes clear if we consider the context in which Weyl discusses the circle argument more carefully. For this is not just the problem of measurement in quantum physics, as one might guess from what I have said so far, but also the foundations of mathematics, and in particular—and this may come as a surprise—Hilbert’s so-called formalism.
Here now I detect certain relations between quantum physics and the foundations of mathematics, and existential philosophy. When Bertrand Russell and others tried to reduce mathematics to pure logic, a residue of meaning [Bedeutung] remained in the form of the simple logical concepts. But in Hilbert’s formalism this residue disappears as well. Nonetheless we need signs, real signs written with chalk on the blackboard or with ink on paper. We have to understand what it means to place one stroke beside the other; it would be wrong to reduce this naively and roughly understood spatial order of signs to a purified spatial intuition and structure as it is expressed for example in Euclidean geometry. Instead we have to rely on the natural understanding in dealing with things in our natural world surrounding us. (Weyl, 1968, 341)
I have quoted this paragraph at full length, because it is extremely important. It contains the key to a proper understanding of Husserl’s concept of the Lebenswelt. First of all, one has to understand that Weyl accepts Hilbert’s formalism not only as tolerable but also as inevitable for a proper reflective understanding of mathematics. Because that has not always been the case, it is much more remarkable that Weyl had changed his mind in this respect already in 1926. Second, one must grasp that, although signs are necessary in order to have concrete objects of intuition, very little, indeed almost nothing, depends on their physical garb in Hilbert’s approach to mathematics. Whether you choose dots or strokes, chalk or ink (or something else) does not matter as long as one can recognize, distinguish, and order them. Third, and this is the crucial point, it would be in vain to develop a scientific theory of symbols by offering an exact geometrical, physical, or chemical analysis of signs. This would be a category mistake of the worst kind, comparable only with a confusion of body and mind, to which the confusion of sign and symbol bears a certain resemblance. For a sign to become the representative of a symbol, it suffices that the sign be a simple concrete recognizable object of our common intuition. To require a geometrical or physical analysis of a sign qua symbol is a confusion of a symbol qua an object of mind with a sign as a physical mark on paper or stone, which leads inevitably into the circle. Although both are bound closely together, symbol and sign are not identical.
What I have just pointed out with respect to the connection of sign and symbol and their different epistemological role and ontological status is, of course, not only valid in pure mathematics but also in the natural sciences, that is, in physics for the relation between the theoretical concepts (symbols) and the measurement of their values by means of real rulers and compasses (signs) in concrete experiments. The relation, as Weyl takes it, is quite analogous:
Just as we manipulate [umgehen] concrete signs in Hilbert’s formalized mathematics, so in physics, when we perform measurements and their necessary operations, we manipulate boards, wires, screws, cog-wheels, pointer and scale. We move here on the same level of understanding and action as the cabinet-maker or the mechanic in his workshop. (Weyl, 1968, 342)
I hope you see now the intimate relationship between Weyl’s ridiculous circle and Husserl’s remark regarding the absurd attempt to explain the sciences as an historically grown product of our mind by means of the sciences themselves. Furthermore, I hope you recognize why in both cases only a recursion to the so-called Lebenswelt can protect us against the danger of becoming a victim of the ridiculous circle. So far so good. But what is the so-called Lebenswelt? What does Husserl mean by this expression? How should we understand this term? A first answer, I think, can be extracted from Weyl’s last remark: “Lebenswelt” means a mode of life, a mode of human existence in which no theoretical knowledge is required, but only some practical abilities of understanding and acting are supposed, like those of the craftsman. Only in this way, only by recurring to this mode of life, can we avoid the ridiculous circle.
Now let me come back to the first question: Does there really exist somebody, maybe a scientist or a philosopher, who affirms something like Weyl’s ridiculous circle? At first glance, this seems improbable, because the circularity of the circle is so obvious (at least in Weyl’s presentation) that nobody will be guilty of it. But on second thought, doubts creep in: Is there not a tendency to explain everything naturalistically by the laws of physics and the other natural sciences, leaving nothing unexplained? Are there not scientists, such as Watson and Crick, who are proud that they have found no trace of the human mind or consciousness in their laboratories and quickly conclude that these things can only exist , if they exist at all, in the form of extremely complex physical structures (like the double helix)? From here it is only one step to philosophical positions like reductionism or strong physicalism, which look to me more like a blank check on the future than the result of serious research.
Now in spite of such doubts, the affirmation of the question of the real existence of the ridiculous circle gets further support: Couldn’t it be the case that Husserl had positions like the one just mentioned in mind, when he spoke of the “crisis of European science,” and was it not Weyl’s intention to brand certain opinions held by some scientists as absurd by his example of a ridiculous circle? The answer seems to be yes in both cases, but before I articulate this more specifically, I have to clarify two points in order not to be misunderstood.
First, I will argue that serious scientists neither assert nor fall victim to something like Weyl’s ridiculous circle; quite the contrary, they warn against such short circuits. Second, I will suggest that there is a problem in science regarding the intricate relation of body and mind (taken in the broadest sense), which is not only unsolved, but in respect to which scientists are at present relatively helpless and, consequently, postpone its solution to the future. This invites philosophers and other visionaries, who have insufficient patience, to extend the methods and results of physics beyond the limits of inanimate nature to the very different domain of living beings and their social, cultural and, last but not least, mental achievements. It seems to me, and this is my third and last point, that this is the right place for Husserl to step in with his analysis and, of course, with his critique of the crisis of European sciences. If I am not mistaken, it is the point at which he does in fact intervene.
So let’s come to the serious scientists first and inquire which stance they take with respect to the circle and the related problems of the Crisis. We know already that Weyl is sympathetic to Husserl’s rejection of scientism. But there are, of course, many more serious scientists—so many that I cannot name them all, let alone present their views in this matter. Therefore I proceed differently: I choose the champion of scientific optimism, who maintained that every problem in science that can be stated clearly can also be solved. This is, of course, no one other than Hilbert. He is most liable, because of his scientific optimism, to become a victim of the ridiculous circle. Consequently, if I can show that this is not the case, that Hilbert is quite aware of the circle, we have a good argument for supposing that the other serious scientists also resist the danger of a short-circuit.
I have to restrict my analysis of Hilbert’s scientific work to three points. First and most important: Hilbert acknowledges—as do Husserl and Weyl—the existence of something like the Lebenswelt (he refers to it as “the domain of everyday life”) as a precondition of science. Second, in two public lectures held in Copenhagen and Zürich (in 1921 and 1923, respectively),1 he makes a sharp distinction between “inanimate nature” as the proper object of his world-equations (and other physical theories) and the domain of the life sciences, to which we humans with our conscious actions and cultural institutions belong. Last but not least, Hilbert denies that it is possible to expand the range of physics in such a way that it becomes a theory of everything, including our mind and our thinking, because this leads inevitably into paradoxes, in fact a whole bundle of paradoxes.
Unfortunately, I do not have the space to go into detail on all these points. I have done this elsewhere for the first and second.2 With respect to the third point, let me briefly explain what is going on: In the lecture Natur und mathematisches Erkennen (1919) and again in the lecture Über die Einheit in der Naturerkenntnis (1924), Hilbert tackles the question of whether it is possible to complete and finish physics—vollenden and abschließen are the German words—in the sense that the resulting worldmodel encompasses literally everything. His answer to this question is a definite no, because this would lead to a number of paradoxes, of which the following is for our purposes the most interesting.
Finally, the spiritual domain as well, our thinking in particular, would have to be something merely apparent [bloß Scheinbares]—an absurd consequence for a view of nature which arises from the desire to make all content of reality accessible to our thinking.
Summarizing his reflections, Hilbert comes to the following conclusion:
Through this [and the other] paradoxes we are forced to conclude that the assumption of the perfectability [Vollendbarkeit] of physical knowledge in an all-embracing theory is not admissible, and hence, that the ideal of a perfectly completed physical knowledge remains inaccessible in principle. (Hilbert, 1924, 180, my emphasis)
Now I think this conclusion would meet with the full agreement of Husserl, because what Husserl tried to capture and to condemn by his notion of naturalism is precisely this: It is not permitted on pain of absurdity to extend the natural sciences and their “Weltbild ” (world-picture) to an all-embracing theory, capturing everything, including our own thinking and theorizing about nature. So far so good. But the interesting point in the present context is now this: If this is correct, Husserl’s own position is incoherent, to say the least, because he cannot speak of a crisis of the sciences if there are scientists like Hilbert who quite consciously warn against a “totalitarian” conception of nature, such as a complete and finished theory of the sort just mentioned, a “theory of everything” so to speak, which should, for the sake of “self-consistency,” be avoided under all circumstances.
Of course, one might think that Hilbert is only the usual exception to a general rule. Most scientists would not be so careful and reflective as Hilbert, who as a mathematician and logician of first rank has a very good nose for lurking paradoxes. This may well be, but my impression is a different one. Looking through the writings of quite a number of the great physicists, one finds in most cases similar reflections and critical remarks like Hilbert’s. I have already mentioned Weyl, but this is also true of Schrödinger, Bohr, and Born, and also of Heisenberg. If this is correct (and I see no reason why anyone should doubt this), then Husserl is at least forced to make a distinction between different types of scientists: those who reflect on their own activities as natural scientists and recognize and accept certain limits of science and those who don’t, succumbing to the temptation of an uncritical scientism, or naturalism, as Husserl calls it. But then the crisis is not a crisis of the sciences themselves but of a certain brand of uncritical scientists (who indeed should be watched suspiciously and criticized, if necessary). To this I can agree without any reservation. But I suspect Husserl’s proper message is a different one: He wants to scrutinize and criticize his own discipline, that is, philosophy, its history, and future development. But this is another topic that must be consigned to further research. Let me instead close with a remark about quantum theory and its relation to Husserl’s notion of Lebenswelt.
If there ever has been the danger that science itself would become a victim of Weyl’s ridiculous circle, then this danger existed—and still exists to a certain degree—in quantum physics. The reason is the following: Because quantum theory is one of the fundamental theories of all physics, the temptation is quite real to describe the measuring process in terms of quantum mechanics and to treat the whole system, that is, the quantum object and the measuring apparatus, as one complex interacting object of quantum theory itself. But very soon it turned out that this was not feasible, neither practically nor theoretically, and that a distinction had to be made, called cut, which divided the complex object again into a proper object of quantum theory and a measuring device. The interesting point with respect to Husserl is that the measuring apparatus had to be both treated and described as a device that does not belong to the “proper” objects of quantum mechanics—it had to be described somehow “classically.” This is Bohr’s famous principle of complementarity. It could also be called Husserl’s principle of “the indispensability of the Lebenswelt” for a proper noncircular understanding of science itself. How quantum theory and Lebenswelt are interrelated is a difficult question, which presumably will take a long time before it can be answered perspicuously without getting entangled in absurdities. I do not, however, believe, as Husserl seems to do, that a philosophical analysis of the term Lebenswelt will help very much in this respect. I presume instead that an investigation of the question “What is life?” and hence, a corresponding sedimentation of the meaning of the term Leben, will be the better approach.