The Vienna Circle on interdisciplinary science

Image: in place of a network map of the contributors to the Vienna Circle

One of the central projects of the Vienna Circle in the 1920s and 1930s was an ambitious one: to create an International Encyclopedia of Unified Science that would demonstrate the crucial unity of all the empirical sciences -- including sociology and psychology (INTERNATIONAL ENCYCLOPEDIA OF UNIFIED SCIENCE. VOLUME I; 1938). The Vienna Circle group included a distinguished number of philosophers and scientists, including Moritz Schlick, Otto Neurath, Rudolph Carnap, and Charles W. Morris; and non-Circle members Niels Bohr, John Dewey, and Bertrand Russell lent their names to the project as well. Their central intellectual commitments constituted the cutting edge of positivist empiricism in the early part of the twentieth century; they advocated for the unity of science, inter-theoretic coherence, and the aspiration to a comprehensive empirical-logical method of scientific knowledge validation. This group was highly influential in the development of subsequent analytic philosophy of science (e.g., Herbert Feigl, Ernest Nagel, and Carl Hempel); in fact, Neurath's description of "logical empiricism" is one that pretty well describes the philosophy of science of the 1940s through the early 1960s. This was a very important stage in the development of twentieth-century thinking about the sciences, and some of the most incisive thinkers in the world were involved in the project. (See Thomas Uebel's article on the Vienna Circle in the Stanford Encyclopedia of Philosophy.)

The positions and interpretations of Vienna Circle thinkers are particularly important here because these philosophers and scientists concentrated their thoughts on the question, what is science? And how do the various areas of scientific research relate to each other? And their writings have the advantage of a close acquaintance with some of the most important advances in a wide range of the sciences in the first several decades in the twentieth century, including physics, biology, psychology, and economics. So their writings have one of the characteristics that I think is most important in doing the philosophy of science: they formed their views in close engagement with particular areas of scientific research. These were brilliant thinkers; they were, on the whole, not dogmatic in their assumptions and judgments; they were sensitive to nuance in the doing of science; and they were deeply respectful of scientific work across a range of areas.

The first part of the Encyclopedia appeared in 1938, and it set the stage for the work that this international group of scientists and philosophers proposed to do (International Encyclopedia of Unified Science ; Volume 1 Part 2). Otto Neurath edited this volume, and his opening sentences in the initial essay set the stage:

Unified science became historically the subject of this Encyclopedia as a result of the efforts of the unity of science movement, which includes scientists and persons interested in science who are conscious of the importance of a universal scientific attitude. (1)

A bit later he links the work of the "unity of science" movement of his time to the writings of John Stuart Mill (discussed in an earlier post):

Modern scientific empiricism attained very late in its development a comprehensive work which analyzes empirical procedure in all scientific fields: John Stuart Mill's A System of Logic, Ratiocinative and Inductive, Being a Connected View of the Principles of Evidence and the Methods of Scientific Investigation. Mill does not question the fact that astronomy and social science, physics and biology, are sciences of the same type. ... Mill's work influenced modern empiricism despite the fact that many of his particularly statements were criticized. (9)

The central thrust of the Vienna Circle position on scientific knowledge is a joining of "empiricism" -- the view that all knowledge depends on empirical observations -- with "logicism" -- the idea that it is possible to give exact and rigorous interpretation of the idea of a valid inference. So the sciences are the ways in which we attempt to logically organize and express the facts of observations and the inferences we draw from these observations. And the work of the great logicians around the turn of the 20th century on the foundations of arithmetic -- Piano, Frege, Tarski, Russell -- gave the Vienna Circle thinkers a great deal of confidence in the power that is brought to scientific knowledge by formal systems of deductive logic.

The most extreme version of empiricism -- "knowledge consists of statements based on observations and deductively valid inferences from those statements" -- doesn't quite do the job, because it was quickly recognized that hypotheses and theories are not deductively entailed by a set of facts of observation. Consequently it is necessary to formulate a formal logic of confirmation (the task that Carl Hempel picked up with his hypothetico-deductive model of confirmation). In other words, empiricism needs something like an inductive logic in order to get the enterprise of science going. But the main elements of scientific knowledge are here: observation and inference.

The project of the Encyclopedia is to investigate how the various areas of existing science fit into this conception of scientific knowledge, and how they relate to each other. And the collaborators in the project think that there is a common scientific attitude -- respect for the empirical facts and logical deductions -- that extends across all the sciences.

It is interesting to notice the fact that Neurath's version of the unity of science does not imply reduction of all science to one super-theory:

Science itself is supplying its own integrating glue instead of aiming at a synthesis on the basis of a "super science" which is to legislate for the special scientific activities. The historical tendency of the unity of science movement is toward a unified science departmentalized into special sciences, and not toward a speculative juxtaposition of an autonomous philosophy and a group of scientific disciplines. (20)

Some of these observations make me think that it might be worth rethinking the import of the Vienna Circle. We're inclined to caricature the Vienna Circle as reductionist, positivist, and hyper-empiricist; and we tend to think of the movement as eliding the important differences across scientific disciplines. But there is a strong strand of scientific pluralism that flows through the project that is at odds with the reductionist reputation the movement has.

One might almost be inclined to call the Encyclopedia project one that emphasizes the value of inter-disciplinary collaboration, rather than a reductionist programme that seeks to impose a single set of principles and methods on all sciences. And in fact, Neurath seems to go out of his way to disavow the hope of reducing the special sciences to some single core science. Here is how Charles H. Morris ends his contribution in this opening volume with the title, "Scientific Empiricism":

This Encyclopedia, reflecting this inclusive standpoint, rightfully sounds the roll call of those distinguished logicians, scientists, and empiricists whom the traditional history of ideas has so shamefully neglected. But basically it aims to present through extensive co-operation the existing status and the unrealized possibilities for the integration of science. Its existence signalizes the union of scientific and philosophic traditions in a common task. (74-75)

And the scientific value of cross-disciplinary collaboration that the Vienna Circle members shared is reflected in the international group of scholars they gathered together in the 1930s. Here is the International Committee of the International Congresses for the Unity of Science (International Encyclopedia of Unified Science ; Volume 1 Part 2, p. 26):

N. Bohr, M. Boll, H. Bonnet, P. W. Bridgman, E. Brunswik, R. Carnap, E. Cartan, J. Clay, M. R. Cohen, J. Dewey, F. Enriques, P. Frank, M. Frechet, F. Gonseth, J. Hadamard, P. Janet, H. S. Jennings, J. Joergensen, E. Kaila, T. Kotarbinski, A. Lalande, P. Langevin, K. S. Lashley, C. I. Lewis, J. Lukasiewicz, G. Mannoury, R. von Mises, C. W. Morris, O. Neurath, C. K. Ogden, J. Perrin, H. Reichenbach, A. Rey, C. Rist, L. Rougier, B. Russell, L. S. Stebbing, J. H. Woodger

Later volumes add several additional names to the list of the membership of the Advisory Committee:

Herbert Feigl, Clark Hull, Waldemar Kaempffert, Victor Lenzen, William M. Malissoff, Ernest Nagel, Arne Naess, Alfred Tarski, Edward C. Tolman (1944)

Out of the 46 individuals listed, 11 are from France; 15 are located in the United States; and only one is located in Austria. The disciplines of philosophy, psychology, physics and logic are the largest groups, and there are a few economists included as well. It would be very interesting to extend this into a map of networks of influence in the next generation.

Here are the tables of contents for Volumes I and II. There are a few surprises on the contents for the second volume.

Volume 1

• Encyclopedia and Unified Science / Otto Neurath et al
• Foundations of the Theory of Signs / Charles Morris
• Foundations of Logic and Mathematics / Rudolph Carnap
• Linguistic Aspects of Science / Leonard Bloomfield
• Procedures of Empirical Science / Victor Lenzen
• Principles of the Theory of Probability / Ernest Nagel
• Foundations of Physics / Phillipp Frank
• Cosmology / E. Finlay-Freundlich
• Foundations of Biology / Felix Mainx
• The Conceptual Framework of Psychology / Egon Brunswik

Volume 2

• Foundations of the social sciences / Otto Neurath
• Structure of scientific revolutions / Thomas Kuhn
• Science and the structure of ethics / Abraham Edel
• Theory of valuation / John Dewey
• Technique of theory construction / J. H. Woodger
• Methodology of mathematical economics / Gerhard Tintner
• Fundamentals of concept formation in empirical science / Carl Hempel
• Development of rationalism and empiricism / Giorgio De Santillana and Edgar Zilsel
• Development of logical empiricism / Jorgen Jorgensen
• Bibliography and index / Herbert Feigl and Charles Morris