by Gereon Wolters,
Dedication: I would like to dedicate this lecture to the memory of Wesley C. Salmon - model and friend
0. Before Day One: Nothing But Preliminaries
James Ussher (1581-1656)
From James Ussher (1581-1656), Archbishop of
Here I will risk political correctness, a
sensitive issue in this country. Different from most American creationists I
understand the six-day-work of creating modern German philosophy of science in
an allegorical way. However, because no lesser person than
The second instance of my political incorrectness concerns gender. There are no women in my story, at least no until Prof. Merrilee Salmon joined, to their great advantage, the Pittsburgh HPS Department as well as the Center for Philosophy of Science in 1981 - which is part of Day Four of my story. To the best of my knowledge there were no women around in the time and places of my story, not even those whose careers could have been stymied by male competitors.
While the gender situation certainly has
improved a bit during recent years, the third political correctness issue, I
would like to touch upon, i.e. concerning ethnic minorities, leaves almost
everything still to be desired. A quick glance over the list of visiting
scholars reveals something that gives cause for concern: So far no fellow at
the Center has come from the African
continent, and from countries with predominantly Muslim population, the Center
has had only three Turkish colleagues. That is fine. But one has to remember
that our three Turkish friends all come from
So much for political correctness. Because I
have already put my foot into my mouth, I will touch on another sensitive issue
right at the outset, i.e. the meaning of „German“. It is almost as tricky as
the meaning of „Jewish“. This has to do with the fact that „German“, on the one
hand, denotes the language which happens to be my mother tongue, and, on the
other, „Germany“ is a country. Now language is the heart of culture. And there
is something like German culture that transcends the boundaries of Germany and
includes those countries in which German or some sort of it is spoken by the
whole population, as is the case in Austria, or in parts, as, for example, in
Switzerland. I can simplify my task for pragmatic reasons by excluding
So, the story that I am going to tell about „German“ philosophy of science will prominently include Austria as being „German“ - until the end of Day Two. In recent decades it has been claimed that there exists something like „Austrian philosophy“. I do not agree, at least as long as „Austrian“ is to mean more than a geographical category. But I admire the shrewdness of the inventor of „Austrian philosophy“. This expression has become an unstoppable wellspring of state financial support.
Unfortunately, we are not yet at the end of my
list of German complexities. I have told you how I am to understand the
adjective „German“. But how about the noun „
Now we are almost at the end of the
preliminaries. I have only to give you a quick overview of the main features of
the six days of the creation of modern German philosophy of science. Day One
gets us from the last third of the 19th century until the end of
World War One. Day Two extends from the early twenties of the 20th
century until the mid-thirties. Day Three takes us from
I. Day One: Philosopher-Scientists
Hermann von Helmholtz (1821-1894)
Ernst Haeckel (1834-1919)
Ludwig Boltzmann (1844-1909)
As I said in the beginning, the creation of modern German philosophy of science is a concept with fuzzy extension. But there are names that certainly belong here. They are not names, however, of philosophers but rather of scientists. Several are prominent: Hermann von Helmholtz (1821-1894), Ernst Haeckel (1834-1919), Ernst Mach (1838-1916) , Ludwig Boltzmann (1844-1909), Gottlob Frege (1848-1925), Wilhelm von Ostwald (1853-1932), and Heinrich Hertz (1857-1894). The time frame is the last third of the 19th century. I am not sure whether I am completely biased when I even dare to give a sort of date: It is Ernst Mach’s short article „Über den Begriff der Masse“ (On the concept of mass), which was published in 1868 in Carl’s Repertorium der Physik. I would like to regard this short essay as the beginning of modern German philosophy of science.
Wilhelm von Ostwald (1853-1932)
Heinrich Hertz (1857-1894)
But first I would like to briefly deal with the question what „philosophy of science“ means in the modern, i.e. contemporary, sense. I am not going to give a definition here but prefer to just list a few characteristics. Modern philosophy of science deals with the language of science, or of the sciences in general, and the meaning of scientific concepts, hypotheses, laws and theories in particular. It also deals with the meaning of fundamental concepts of the sciences, like space, time and mass in physics or gene, species, adaptation and selection in biology. Philosophy of science also attempts to clarify central methodological concepts like explanation, confirmation, and probability, and investigates their use in the sciences. And, finally, philosophy of science wants to explain the dynamics of science, i.e., it wants to understand scientific progress and at the same time the limits of science.
Each of the 19th century scientists just mentioned contributed more or less to one or more of these areas. But two of them clearly stand out with respect to their achievements and their influence on subsequent developments: Ernst Mach and Gottlob Frege. In a sense these two men represent the two components of the later logical empiricism: Mach for „empiricism“ itself, and Frege (besides the British philosopher Bertrand Russell) for its „logical“ aspect.
Ernst Mach (1838-1916)
Let me first turn to Mach. Mach started out as a physiologist, and turned afterwards to experimental physics. Among his achievements in the latter field is the first comprehensive study of the velocity of sound, subsequently named in Mach’s honor. From the beginning of his career Mach had taken great interest in philosophical questions. He did this in two directions. First, he developed a phenomenalist epistemology, i.e., an epistemology which takes data of sense as the ultimate elements of all our knowledge; and second, in his so called „historico-critical“ works, he provided the outline of the first comprehensive modern German empiricist philosophy of science. The impact of his work can hardly be underestimated - in physics as well as in philosophy. Mach’s historico-critical account of mechanics influenced greatly, for example, the development of special and general relativity, an influence that Einstein gratefully acknowledged throughout his life.
The impression that Mach had created something really new reached even the Austrian Royal Imperial („k.k.“) administration: in 1895 Mach was given a newly created chair at the University of Vienna for „Philosophy, especially theory and history of the inductive sciences“. This was the first chair for philosophy of science in the German-speaking world.
Gottlob Frege (1848-1925)
I now would like to address the originator of the other, the „logical“ component of „logical empiricism“, i.e., Gottlob Frege. Frege - who did not advance beyond the rank of unsalaried professor at the University of Jena - but invented, among other things, predicate logic. Predicate logic is the sort of logic that deals with the validity of arguments that consist of sentences that contain so called existential and universal quantifiers. This basically means sentences that have the structure of „there is such and such“, or „for all x such and such holds of x or is the case“. Although this does not sound very exciting, the invention of predicate logic meant a secular achievement, because predicate logic replaced Aristotelian syllogistics which up to that point had represented the only form of logical reasoning, if one for the moment does not take into account (1) algebraic versions of logical inference that had been established earlier in the 19th century by George Boole and others, and (2) the propositional logic that had flourished in the Middle Ages, but had been completely forgotten in the meantime. On the basis of predicate logic Frege undertook penetrating analyses of mathematical and logical systems and concepts like „function“, „concept“, „object“, „meaning“ and so on.
You might find it strange that I have claimed that modern German philosophy of science originated with scientists, and might ask: weren’t there philosophers around in the German speaking world in those days? Didn’t they care about science? The answer is a firm „yes and no“. Yes, there were quite a few philosophers, and some of them even cared about philosophical issues in science. But it seems to me that they did not really aim at understanding science as an enterprise in its own right, but rather worked at incorporating what they took to be science into their general philosophical systems. This holds also for Neo-Kantianism, particularly in the science-oriented so-called Marburg School . Here philosophy of science was not dealt with for science’s sake, but science was rather used for philosophy’s sake.
The fine beginnings of German philosophy of science came to an abrupt end, when in 1914 the Great War began, the first major disaster of the 20th century.
II. Day Two: Vienna and Berlin - The Rise of Logical Empiricism
For German philosophy of science Day Two brought the most radiant sunrise of its history, and issued at that time in a day of unparalleled intellectual brilliance. It brought the rise of logical empiricism.
Moritz Schlick (1882-1936)
Otto Neurath (1882-1945)
Rudolf Carnap (1891-1970)
A few words seem to be in place to briefly characterize the logico-empiricist conception of philosophy of science. As its very name suggests, and as I said a minute ago, logical empiricism has two main roots, the first is Mach’s empiricism, the second Frege’s logical calculus as well as his model of analysis of methodological concepts. Two groups of men became the leaders of logical empiricism in the Germanic lands: one, the „Vienna Circle“, which began in the winter semester 1923/24, had as its core a trinity of scholars who first consisted of Moritz Schlick (1882-1936), who in 1922, coming from Germany, had taken over Mach’s chair in Vienna; second, the Viennese Otto Neurath (1882-1945), the indefatigable organizational motor of logical empiricism, and, perhaps therefore, often badly underrated in his philosophical achievements. The third intellectual heavyweight was Rudolf Carnap (1891-1970) who, coming from Germany, had joined the Circle first in 1925, and then permanently in 1926.
Hans Reichenbach (1891-1953)
There was close cooperation between Vienna and Berlin, that culminated in 1930 with Carnap and Reichenbach taking over an existing philosophical journal, renaming it Erkenntnis, and making it to a sort of central organ of logical empiricism. In 1937 Erkenntnis had to cease publication by order of the Nazis.
What were the teachings of logical empiricism? I restrict myself to only two points of which only the first is a doctrine in the strict sense of the word. The second relates to the philosophical attitude or to the style of philosophy.
Logical empiricism first introduced a revolutionary and secular change in the concept of philosophy. Despite warnings, which Immanuel Kant had already issued 150 years earlier, philosophy by and large still claimed to be able to produce factual knowledge about a variety of things. If one now has to give up that claim, as logical empiricists believed, what, if anything, remains for philosophy? Carnap’s programmatic answer in the first volume of Erkenntnis is:
„There is no such thing as speculative philosophy, a system of sentences with a special subject matter on a par with those of the sciences. To pursue philosophy can be only to clarify the concepts and sentences of science by logical analysis.“
These are strong words. They mean no less than the end of philosophy as the Western world had known it for two and a half millennia. Philosophy, in the logico-empiricist perspective, is basically reduced to philosophy of science. In ethics logical empiricists took a non-cognitivist position, which basically meant that philosophical ethics had also to restrict itself to the analysis of moral sentences that, in any case, were not propositions that could be either true or false. Consequently there could not be moral knowledge in the strict sense of the word „knowledge“. - Quite understandably from a psychological point of view, this and many similar messages were not taken with exuberant enthusiasm by the German philosophical community. I can also hardly imagine that it appreciated Schlick’s irony at the end of his programmatic article, which opened the first volume of Erkenntnis:
„Certainly many will for centuries continue to wander further along the traditional paths. Philosophical writers will long continue to discuss the old pseudo-questions. But in the end they will no longer be listened to; they will come to resemble actors who continue to play for some time before noticing that the audience has stolen away. Then it will no longer be necessary to speak about „philosophical problems“, because one speaks philosophically concerning all problems, that is: clearly and meaningfully.“
This brings me to my second point. According to logical empiricism, the philosophical attitude or philosophical style is characterized by two essential ingredients: (1) philosophical work is, much like work in the sciences, a communal enterprise, thus securing critical control of ideas and thereby scientific progress ; and (2) as a necessary condition for the first, philosophy must be presented in a clear, precise language.
This sounds rather natural these days, but it was, and - alas! - in part still is, far from being so in German philosophy. For, being a German philosopher, had mostly been a one-man business: There had been and still are - I am only slightly exaggerating - in a sense no colleagues but only disciples; philosophy had only rested on quasi-revelational insights and not on thoughts accessible to everybody. One did not acquire the teachings of a philosopher like those of a scientist, one was rather élite. Consequently philosophical language need not necessarily have been accessible to everybody but only to the elected. Hegel and Heidegger, in large parts of their work, are only the most notorious, though not the only, examples of this tradition in German philosophy
There is no evidence more illuminating on this point than when Carnap in his autobiography writes about the difficulties of getting Wittgenstein into the Circle. Although Wittgenstein lived in Vienna, in 1926 he bluntly refused to come to the Circle in order to discuss his Tractatus, in which the Circle was enormously interested. Schlick, after several talks with Wittgenstein, finally succeeded in getting him to accept Waismann and Carnap as mediators with the Circle. Being a go-between for Wittgenstein was not an easy task. Here is what Carnap tells us:
„Before the first meeting [with Wittgenstein], Schlick admonished us urgently not to start a discussion of the kind to which we were accustomed in the Circle, because Wittgenstein did not want such a thing under any circumstances. We should even be cautious in asking questions, because Wittgenstein was very sensitive and easily disturbed by a direct question. The best approach, Schlick said, would be to let Wittgenstein talk and then ask only very cautiously for the necessary elucidations.“
Carnap correctly identified this as a totally different style of conducting philosophy:
„Our [i.e. the Vienna Circle’s] attitude toward philosophical problems was not very different from that which scientists have toward their problems. For us the discussion of doubts and objections of others seems the best way of testing a new idea in the field of philosophy just as much as in the fields of science; Wittgenstein, on the other hand, tolerated no critical examination by others, once the insight had been gained by an act of inspiration. I sometimes had the impression that the deliberately rational and unemotional attitude of the scientist and likewise any ideas which had the flavor of „enlightenment“ were repugnant to Wittgenstein.“
I am not quoting this to ridicule Wittgenstein. Rather I would like to point to the strong contrast in philosophical attitude or style that is on display here.
The second day of the creation of modern German philosophy of science that had been illuminated so brilliantly by the sun of reason ended in a total eclipse, i.e., in the intellectual and moral darkness of Nazism. The eclipse began in Germany in 1933 with Hitler’s rise to power and Reichenbach’s almost immediate emigration to Turkey. In Austria it started a year later, in 1934, when a clerico-authoritarian regime took over and soon banned the Verein Ernst Mach. Schlick was shot dead in 1936 by a mentally sick former student - much to the praise of Catholic reactionaries who were of the opinion that he deserved it. After the 1934 putsch, Otto Neurath preferred not to return to Austria from a trip to the Soviet Union, and instead emigrated to Holland. Carnap was happy enough to emigrate from Prague to the U.S. in 1936. Finally, in March 1938, German troops marched into Austria, and before hundreds of thousands of shouting and cheering fellow Austrians, Hitler could solemnly report, as he claimed before history, „the homecoming of his native land to the German Reich“. At that point there wasn’t much left any more of logical empiricism and its allies in science, neither in Vienna nor in Berlin. Here is a list of logico-empiricist emigrants to the U.S.
Carl Gustav („Peter“) Hempel
Richard von Mises
Let me end this short account of the eclipse of reason with something I personally cherish enormously and which shows the great orientational value of logical empiricism, despite its non-cognitivism in ethics: Not a single logical empiricist ever compromised, let alone cooperated, with the Nazis. This holds also for those who stayed or had to stay, as, for example, Bela Juhos or Viktor Kraft in Vienna.
III. Day Three: Transatlantic Transplantations
Carl Gustav Hempel (1905-1997)
It was American philosophy of science that took the greatest advantage of the brain drain caused by Nazism. I mention only three people: as I said already, Reichenbach first emigrated to Istanbul in 1933, where the newly founded University offered generous refuge to dozens of German professors sacked for political or so called „racial“ reasons. Then, in 1938 he emigrated to Los Angeles. Carnap in 1936 first went to Chicago and then in 1954 to Los Angeles as successor to Reichenbach who had died in 1953 at the age 61. Carl Gustav Hempel, or, as his friends used to call him „Peter“, had received his doctorate in philosophy in 1934 in Berlin with Reichenbach as his adviser. He did not yet have a university position in Germany, when he, finally, came to the States in 1939. Here he served first as an instructor in philosophy for summer courses and for courses in the evening school at New York City College before he went to Queens College in 1940. In 1948 he became an associate professor at Yale and went to Princeton in 1955, receiving the chair of Stuart Professor of Philosophy. After he had to retire at Princeton (1973) he came to Pittsburgh in 1977. Here he taught for eight years as university professor until he retired in 1985 at the age of eighty.
These logico-empiricist German emigrants to the U.S. were received on the whole by a friendly philosophical environment, especially in comparison to their reception in Germany and Austria. They soon became catalysts for an enormous proliferation of thought in the philosophy of science in this country. It was not they alone, of course, who achieved this. There were in the U.S. people like Van Quine and Charles Morris, who had already had for several years close contacts to the European logical empiricists and who had visited Vienna or attended conferences in Europe. There were also a number of excellent logicians and, finally, there had long existed a strong pragmatist orientation in American philosophy that offered interesting points of contact and common interests with logical empiricism. One can say that logical empiricism seized the opportunity. For around a quarter of a century, it itself and kindred analytical groups dominated the philosophical scene in America.
My personal view is that contemporary philosophy of science not only stands on the shoulders of those logical empiricists I have talked about, but rather that - to a certain degree - it still is logical empiricism. The founders of logical empiricism have always emphasized the analogy of science and philosophy, they have emphasized that it is the methods or style of conducting philosophy that defines it, not its results. Correspondingly, the specific teachings of the logical empiricists have been in continuous flux, usually they themselves being their most incisive and persistent critics. Just as we call 18th century physics „physics“, although scholarship in physics has left behind most of it, we are entitled to regard contemporary philosophy of science in a sense as still logical empiricism.
IV. Day Four: Germanic Heritage at the Center
The Pittsburgh Center for Philosophy of Science is the legitimate heir of logical empiricism. This is true both for institutional reasons as well as in a more genealogical sense.
To the first: as an institution of professional cooperation and mutual critical control, the Center, to some extent, even outdoes the Vienna Circle, which was restricted to Vienna and its surroundings only, as far as Prague. The geographical area of the Center is neither only Pittsburgh, nor only the U.S., but - as a quick look at the list of fellows shows - indeed the world, with the conspicuous restrictions I mentioned at the beginning. The Center thus has become the institutional mediator of a worldwide dialogue and a worldwide communication network of philosophers of science. Prof. Machamer has rightly remarked in private conversation that when he looked at the list of participants in a recent philosophy of science conference sponsored by the European Community he realized that most of the participants had gotten to know each other before through the Center and its various activities.
In this sense I personally regard the Center as one of the rare examples of globalization that I find acceptable, and not only acceptable, but rather desirable and even necessary. As the stronger part, the Center is generously sharing its resources and means with the less strong and less sophisticated, helping them to mobilize and develop philosophy of science in their own countries. But the Center is not just an institution, it is the people who matter. Although one finds here in Pittsburgh possibly more philosophical celebrities in one spot than elsewhere in the world, nothing has been more alien to any of them than arrogance, pomposity, or unapproachableness. Discussions at the Center proceed pretty much in the problem-oriented way that Carnap was warned not to use when talking to Wittgenstein. One cannot possibly imagine happening in Pittsburgh what happened to poor Peter Hempel, when as a student of physics in Berlin, he dared to address Max Planck after a lecture. Planck snubbed him, without looking into his face and said: „Go to my assistant!“.
Second, genealogy: the Center has deep German roots. In German, one calls the Ph.D. thesis adviser „Doktorvater“, nowadays there are also „Doktormütter“. This genealogical metaphor points to institutional cross generational scholarly influence.
Kluger Hans / Clever Hans (* ca. 1895)
When we now look at some of the most distinguished members of the Center then we clearly see a German connection of this sort. Adolf Grünbaum, its most meritorious founder (a true creatio ex nihilo), first director (1960-1978), chairman since then, and spiritus rector up to the present day, is not only a refugee from Nazi Germany. Peter Hempel was also his Doktorvater at Yale. The same is true for Larry Laudan, the second director (1978-1981), who got his Ph.D. with Hempel at Princeton. And Nicholas Rescher, the third director (1981-1988) and current vice chairman. The only difference is that Rescher did his undergraduate work with Hempel at Queens College. Also the fourth director (1988-1997), Jerry Massey, had Hempel as thesis adviser. Prof. Massey likes to trace his academic pedigree even further back to Hempel’s examiner, the psychologist Wolfgang Köhler, who in turn was a disciple of the philosopher-psychologist Carl Stumpf. And Stumpf was, among other things, famous for having chaired a committee which found out that Clever Hans, the fabulous calculating horse, was, indeed, clever but not in arithmetic as his master, a Herr von Osten, had thought. Hans’s was more of what we call „emotional intelligence“ these days.
Finally, Wesley Salmon, whose untimely, terrible death we mourn so much, had Reichenbach as his thesis adviser.
V. Day Five: Abject Recommencement and First Steps to Resurrection
Day Five of our story brings us back to Germany after the eclipse of reason there. In 1945, many German cities looked like Kabul and Kandahar these days. Physical destruction corresponded to moral disaster. There was the widespread conviction that something had gone terribly wrong and that the Germans were responsible for this. But one cannot say that there was an open and explicit nationwide examination of conscience. That started only some twenty years later, in the sixties. In 1945 and in subsequent years, the general mood was something like the following: „Well, we were wrong, but we were punished for that by the destruction of our cities and villages, by the death of millions of soldiers, civilians and refugees, and by the division and the occupation of the country. Now, so goes my reconstruction of the then prevailing spirit, we have to care for our physical survival and for rebuilding the country.“ And that is what people did, and they did it with great success, not least thanks to Marshall Plan dollars.
Also in the winter semester of 1945 the universities started again. They had lost only the second part of the summer semester. And they restarted in the same spirit as did the country at large: one should just go on as best one could, not dig into the past, and simply look forward. But what an abject institution the German university had become during the twelve years of Nazi rule! It had lost perhaps the majority of its best scholars, either because they were Jewish, or because they left the country for political reasons. In philosophy, as in other fields, the majority of those who had stayed were either outright Nazis like Martin Heidegger, or were opportunistic compromisers like Hans-Georg Gadamer. Only few had remained upright.
In this situation nobody thought of re-establishing logical empiricism in Germany. I even have the impression that the philosophical community was actually very relieved that logical empiricism had left the country.
Wolfgang Stegmüller (1923-1991)
It is also fair to say that after 1945 for a while there also wasn’t
much of philosophy of science in
The other development of German philosophy of science that started in the 1960s consists in the long overdue attempt of a revival of logical empiricism that was brought about by the Austrian Wolfgang Stegmüller (1923-1991), who became a professor at the University of Munich in 1958. Among other things, he undertook the enormous task of giving a detailed overview of philosophy of science and science- related analytical philosophy in four volumes of some 3.000 pages. When I myself studied philosophy in Tübingen in the late sixties and early seventies no philosophy of science was taught there. And I worked my way through the two Stegmüller volumes that had been published up to that time. So, in a sense, I am also student of Stegmüller, although we never met in person.
To me it comes as a great surprise and puzzle that the contacts between the Center and German philosophy of science have predominantly gone along the Erlangen-Konstanz connection. Out of the 26 German fellows at the Center 13 have come directly or indirectly on the Konstanz ticket, and only three on the Stegmüller-Munich ticket. But this is already part of what happened during
VI. Day Six:
The first contacts between
An important step in the development of the Konstanz-Pittsburgh connection was reached in 1983 when Adolf Grünbaum inaugurated the Konstanzer Dialoge, a lecture series given by distinguished foreign scholars.
The Konstanz-Pittsburgh relationship saw a
quantum leap when Gerald Massey became director of the Center in 1988. He soon
established a unique cooperative program between the two universities. The
Massey-Plan comprised (1) archival cooperation between the Pittsburgh Archives
of Scientific Philosophy and the Konstanz Philosophical Archive. This included
the generous offer to reproduce and collect the entire contents of the
Pittsburgh Archives in microfilmed form for placement in
My gratitude includes, of course, all directors of the Center, from the first, Adolf Grünbaum, to the current person, Jim Lennox, who assumed the directorship in 1997. For me it has been an honor and a pleasure to work with each of them. My gratitude also extends to the staff - past and present - I very much enjoyed working with the following people: Jerry Heverly of the Special Collections Department of Hillman Library; Linda Butera, Karen Kovalchik, and Joyce McDonald at the Center – and last but not least, Elizabeth McMunn, Adolf Grünbaum’s long-time secretary, who on my first visit reluctantly agreed to my request for a bicycle, continuously worrying that Pittsburgh car drivers would run over and probably kill me.
To sum up this sixth day, the
This brings me to Day Seven. On several evenings during his six-day work of creation, God looked at what he had done so far, and said to himself that it was done well. One cannot say the same with respect to each of the six days of the story of German philosophy of science. But certainly Day Six, its „Pittsburgh Day“, deserves not only a „well done“, but rather an unequivocal „very well done“. This does not seem to be an accident, since also in the book of Genesis, only the sixth day gets the mark „very well“.
As we know, on the seventh day God „took a rest from all the labor he had performed“. You, too, might feel like resting after this long lecture, but let us do something better: let us celebrate the historical merits of the Pittsburgh Center for Philosophy of Science in its own right and the uneasy homecoming of philosophy of science to Germany.
 I would like to thank Alan Paskow (St. Mary’s