Logical Empiricism and the Physical Sciences

From Philosophy of Nature to Philosophy of Physics

Sebastian Lutz, Adam Tamas Tuboly, Sebastian Lutz, Adam Tamas Tuboly

• Publisher: Routledge
• Year: 2021
• Print ISBN: 9780367768218
• eBook ISBN: 9780429771156
• Edition: 1
• Topic: History
• Subtopic: Medieval & Renaissance Philosophy
• Index: History

This volume has two primary aims: to trace the traditions and changes in methods, concepts, and ideas that brought forth the logical empiricists' philosophy of physics and to present and analyze the logical empiricists' various and occasionally contrary ideas about the physical sciences and their philosophical relevance. These original chapters discuss these developments in their original contexts and social and institutional environments, thus showing the various fruitful conceptions and philosophies behind the history of 20th-century philosophy of science.

Logical Empiricism and the Natural Sciences is divided into three thematic sections. Part I surveys the influences on logical empiricism's philosophy of science and physics. It features chapters on Maxwell's role in the worldview of logical empiricism, on Reichenbach's account of objectivity, on the impact of Poincaré on Neurath's early views on scientific method, Frank's exchanges with Einstein about philosophy of physics, and on the forgotten role of Kurt Grelling. Part II focuses on specific physical theories, including Carnap's and Reichenbach's positions on Einstein's theory of general relativity, Reichenbach's critique of unified field theory, and the logical empiricists' reactions to quantum mechanics. The third and final group of chapters widens the scope to philosophy of science and physics in general. It includes contributions on von Mises' frequentism; Frank's account of concept formation and confirmation; and the interrelations between Nagel's, Feigl's, and Hempel's versions of logical empiricism.

This book offers a comprehensive account of the logical empiricists' philosophy of physics. It is a valuable resource for researchers interested in the history and philosophy of science, philosophy of physics, and the history of analytic philosophy.

1
Introduction

From Philosophy of Nature to Philosophy of Physics

Sebastian Lutz and Adam Tamas Tuboly

1.1. Introduction

Naturphilosophie, or its English counterpart, philosophy of nature, has a long and fascinating history and has undergone significant changes over time.¹ During the 19th and 20th centuries, many forms of philosophy of nature emerged, from monographs of philosophical remarks by physicists – often written as diversions and philosophically naïve – and the treatises of the German idealists – often ambiguous and scientifically naïve – to the philosophically motivated writings of revolutionary scientists.

The logical empiricists’ philosophy of nature and science, however, stands out for its ability to synthesize various forms of inquiries: while its roots reach deep into the neo-Kantian “Wissenschaftslehre” of its day, it was framed in the empiricist traditions of English philosophers and scientists of the modern era. It developed both traditions further with the help of Frege’s and Russell’s logic and amalgamated them with contemporary French thinking about the conventionalist theory and practice of science. (Katherine Dunlop discusses conventionalism in her contribution to this volume, especially with reference to Poincaré and Neurath.) As Hans Reichenbach (1931/1978, 383) claimed in his programmatic pamphlet on philosophy of nature,

philosophy of nature constitutes a great triumph of rationalism. … However, modern philosophy of nature must also be regarded as a triumph of empiricism…. Modern empiricism does not contradict rationalism because knowledge is conceived as a system constructed by reason upon which experience exerts a regulative and selective influence.

The logical empiricists’ philosophy has become a focus of research, both as a historical object of study and as a systematic philosophical position. However, there has been comparably little research on the logical empiricists’ philosophy of the natural sciences, especially that of physics. This is an unfortunate gap in the history of philosophy of science, for one because the logical empiricists’ views on physics heavily influenced their views on philosophy of science and philosophy in general. Furthermore, their analyses of scientific theories were arguably clearest when it came to physics. But the lack of research on the logical empiricists’ philosophy of physics is also unfortunate for systematic philosophy, as their views can provide new input for both the philosophy of physics and the philosophy of science and for philosophy in general.

This volume accordingly has two overarching themes: first, it traces the traditions and changes in methods, concepts, and ideas that brought forth the logical empiricists’ philosophy (or philosophies) of physics, and, second, it presents and analyzes the logical empiricists’ various and occasionally contradictory ideas about the physical sciences and their philosophical relevance. The logical empiricists’ ideas are discussed in their original contexts, including their social and institutional environments, to show the fertile ground on which the history of 20th-century philosophy of science was built. In the remainder of this chapter, we will briefly introduce the protagonists of this volume (Section 1.2) as well as some deuteragonists (Section 1.3) and circumscribe the extent of their involvement in the philosophy of nature (Section 1.4). This discussion tamely (but in keeping with the logical empiricists’ methodology) concludes with the suggestion that the extent of their involvement in the philosophy of nature depends on how “philosophy of nature” is understood.

1.2. The Protagonists

Moritz Schlick (1915/1979, 1917/1979) gave the first philosophically informed meta-scientific presentations of the special and general theories of relativity that were also accepted by Einstein. Schlick’s 1917 book on space-time (Space and Time in Contemporary Physics) was quickly translated into English, and several editions were published. After working out the epistemological consequences of relativity in his magnum opus, Allgemeine Erkenntnislehre, Schlick’s attention turned towards other issues in the philosophy of mind, language, ethics, and science in general. Nonetheless, as Herbert Feigl (1982, 61) noted, “[s]ince Wilhelm Ostwald’s rehabilitation of the concept of ‘philosophy of nature’, there can surely have been no more dedicated ‘philosopher of nature’ than Schlick”.

In 1921, Rudolf Carnap wrote his doctoral dissertation in Jena (after some back-and-forth between the physics and philosophy departments) under the supervision of Bruno Bauch, with Max Wien on the committee. It was published one year later as a separate volume of the Kant-Studien (1922/2019). The dissertation concerned the meanings of ‘space’ across the sciences (mathematics, geometry, and philosophy) and the challenge presented by the theories of relativity. Soon thereafter, he published the short monograph Physikalische Begriffsbildung (Physical Concept Formation, Carnap 1926/2019) on measurement and abstract concept formation in physics.² An investigation of the notion of entropy in statistical physics from the 1950s remained unpublished until after his death (Carnap 1977). (Carnap’s philosophy of physics and science is the subject of the chapters by Sebastian Lutz, Jordi Cat and Robert DiSalle.)

After defending his doctoral dissertation in 1906, Philipp Frank, as the successor of Einstein in Prague, published many important – though mostly forgotten – papers on the simplification of the special theory of relativity (see Frank 1932/1998, 290–296 for a list) and collaborated with the Austrian physicists and engineer Hermann Rothe: together, they derived the Lorentz transformation based on group theory, without the postulate of the constancy of the speed of light. Though their achievement was recognized now and again, Frank did not influence the mainstream of physics.³ As the director of the Physics Department at the German University of Prague for almost 25 years, before his emigration to the United States, Frank was a perfect candidate to write the Foundations of Physics monograph for Neurath’s International Encyclopedia of Unified Science.⁴ (Frank is discussed in Don Howard’s and Adam Tamas Tuboly’s chapters.)

Of all the logical empiricists, Hans Reichenbach was the most productive and well-known investigator and popularizer of the physical sciences. After a dissertation on the interpretation of probability at Erlangen (1915/2008), Reichenbach published numerous books on the philosophy (1920/1965) and axiomatization (1924/1969) of the theory of relativity. As a student in Albert Einstein’s famous seminar on relativity in Berlin during the 1918–1919 winter semester, Reichenbach had up-to-date and detailed knowledge of the debates and concerns surrounding the theory. Later, when he focused his attention on a systematic presentation of probability theory and on quantum mechanics (1944/1965), he achieved widespread recognition with his three-valued logic and scientific realist interpretations. (Reichenbach’s work is central to the chapters by Alan Richardson, Marco Giovanelli, and Flavia Padovani).

If not in physics itself, many logical empiricists had earned degrees with dissertations on the philosophy of physics or the philosophy of nature and produced new insights through their early works in this field. One of the best examples is Herbert Feigl, who defended his dissertation Zufall und Gesetz (Chance and Law) under Schlick in 1927. (The entire dissertation was later published in Haller and Binder 1999, 1–191.) Feigl had studied physics in Vienna with Schlick and Hans Thirring until Edgar Zilsel’s first monograph, on the problem of applying mathematical-numerical descriptions to the natural world, had convinced him to pursue philosophy instead. His dissertation focused on probability and induction – an interest that Feigl never abandoned throughout his career. This work also enabled him to write a short monograph about theory and experience in physics (Feigl 1929).⁵ Though Feigl later became known mainly for his writings on the philosophy of mind and as the leader of the Minnesota Center for the Philosophy of Science, he kept publishing papers on induction and probability for years.⁶ (Matthias Neuber’s chapter examines Feigl’s mature views.)

1.3. Some Deuteragonists

There were at least two other students of Schlick’s whose dissertations concerned issues in physics. The first was Marcel Natkin, who wrote a dissertation on simplicity, causality, and induction (see Haller and Binder 1999, 193–301). After leaving academia, Natkin worked as a photographer and never returned to the philosophy of nature (although he occasionally wrote about photography). His dissertation is an interesting document of the inner tensions within the Circle: while Feigl (1929) reserved some role for explanation, in contrast to the tradition of Mach, Kirchhoff, and Duhem (though, according to Feigl, this was mainly just a terminological issue in the face of the new philosophy), Natkin followed Mach and Duhem, stating that science shall aspire to the production of the most economical descriptions of the natural world.

The third student of Schlick’s who wrote a dissertation on the physical sciences was Tscha Hung, who discussed causality in the new physics (see Haller and Binder 1999, 303–353). He studied physics, mathematics, and philosophy, first with Reichenbach in Berlin and from 1928 on with Schlick and others in Vienna. He was a regular member of the Circle meetings but left for China after Schlick’s death. Although he published many papers in German and English about the Vienna Circle in the 1980s (when he held visiting fellowships at Oxford and Cambridge), they were mainly concerned with the protocol-sentence debate. Nonetheless, his dissertation under Schlick again testifies to the breadth and direction of the latter’s interests in physical theories during the early 1930s.

Though his dissertation was on moral philosophy, Béla Juhos published several articles and books about the epistemological dimension of physical theories and on general philosophy of science. Juhos had always worked on the periphery of the Circle, but as one of the few original members who stayed in Vienna during and after the Second World War, he tried to preserve the spirit of logical empiricism in Austria (with limited success). Those works of his that were published in English under the title Selected Papers on Epistemology and Physics (Juhos 1976) mainly concern questions of causality, but in the 1960s, Juhos also published two books on the epistemic-logical foundations of classical and modern physics (Juhos and Schleichert 1963; Juhos 1967).

1.4. Doubts

As even this rather short and cursory overview shows, the logical empiricists (those in the center as well as those working on the periphery) were occupied with questions of physics, natural sciences, and the philosophy of nature,⁷ perhaps more so than with any other topic. Nevertheless, there are doubts about this positive conclusion. (These are also discussed in Clark Glymour’s chapter.) Thomas Ryckman (2007, 193) notes that the term “‘philosophy of physics’ was little used by the logical empiricists themselves, and that, with notable exceptions, they produced little of what is currently understood by that name, viz., detailed investigations into particular aspects or interpretations of physical theories”. While many scholars agree that logical empiricism played a major (if not the most important) role in institutionalizing philosophy of physics and bringing it into the mainstream in the second half of the 20th century, “it is something of an anachronism”, concludes Ryckman (ibid.), “to speak of logical empiricism’s ‘philosophy of physics’”.

For instance, none of the members of the Vienna Circle published any detailed work on the theories of relativity during what Friedrich Stadler (2001/2015) calls the constitutive non-public (1924–1929) and the public (1929–1936) phases of the Circle. From the mid-1920s on (following his textbook article on Naturphilosophie, which was presumably commissioned years before), when Schlick started to organize the informal Thursday discussions in the Mathematical Institute’s library, he did not publish anything on the nature and analysis of physical theories.

Although Carnap’s papers in the early 1920s on space-time and physics (now published in Carnap 2019) related, in varying degrees, to the logico-mathematical questions of the physical sciences, they were mainly produced before his permanent move to Vienna and thus still during his neo-Kantian period.⁸ (Interestingly, Carnap’s dissertation on space was intended to be “a contribution to the theory of science”, i.e. “Wissenschaftslehre”, as its subtitle says, and not to philosophy of nature.) And in contrast to Reichenbach, Schlick, and Frank, Carnap did not keep up with the latest developments in physics by himself. Having devoted most of his time during his student and doctoral years to relativity, he needed help following the latest debates and results in quantum mechanics. In Prague, Frank presumably provided this assistance, and otherwise, as Carnap (1963, 14–15) mentions in his autobiography, Reichenbach was always at hand in correspondence.⁹ Especially during its American ...

Table of contents

• Cover
• Half Title
• Series Page
• Title Page
• Copyright Page
• Dedication Page
• Contents
• 1 Introduction: From Philosophy of Nature to Philosophy of Physics
• Part 1 The Rise of Philosophy of Physics
• Part 2 The Philosophy of Physical Theories
• Part 3 General Philosophy of Physics
• About the Editors and Authors
• Index