Tom Ryckman

An examination of Carnap's Aufbau in the context of Schlick's Allgemeine Erkenntnislehre of ten years earlier, suggests that Carnap's focus there on the sign-relation (Zeichenbeziehung) is an effort to retrieve a verificationist account of the meaning of individual scientific statements from the abyss of meaning-holism entailed by Schlick's proposal that scientific concepts be implicitly defined. The Aufbau's antipodal aspects, its reductive phenomenalism and quasi-Kantian concern with the constitution of objectivity, are seen as complementary moments of the marriage of empiricism and a new emphasis on scientific concepts as "free creations of the human mind".

Albert Einstein was the most influential physicist of the twentieth century. Less well-known is that fundamental philosophical problems, such as concept formation, the role of epistemology in developing and explaining the character of physical theories, and the debate between positivism and realism, played a central role in his thought as a whole. Thomas Ryckman shows that already at the beginning of his career, at a time when the twin pillars of classical physics, Newtonian mechanics and Maxwell’s electromagnetism, were known to have but limited validity, Einstein sought to advance physical theory by positing certain physical principles as secure footholds. That philosophy produced his greatest triumph, the general theory of relativity, and his greatest failure, an unwillingness to accept quantum mechanics. This book shows that Einstein’s philosophy grew from a lifelong aspiration for a unified theoretical representation encompassing all physical phenomena. It also considers how Einstein’s theories of relativity and criticisms of quantum theory have shaped the course of twentieth-century philosophy of science. Including a chronology, glossary, chapter summaries, and suggestions for further reading, _Einstein_ is an ideal introduction to this iconic figure in twentieth-century science and philosophy. It is essential reading for students of philosophy of science, and also suitable for those working in related areas such as physics, history of science, or intellectual history.

Universally recognized as bringing about a revolutionary transformation of the notions of space, time, and motion in physics, Einstein's theory of gravitation, known as "general relativity," was also a defining event for 20th century philosophy of science. During the decisive first ten years of the theory's existence, two main tendencies dominated its philosophical reception. This book is an extended argument that the path actually taken, which became logical empiricist philosophy of science, greatly contributed to the current impasse over realism, whereas new possibilities are opened in revisiting and reviving the spirit of the more sophisticated tendency, a cluster of viewpoints broadly termed transcendental idealism, and furthering its articulation. It also emerges that Einstein, while paying lip service to the emerging philosophy of logical empiricism, ended up siding de facto with the latter tendency. Ryckman's work speaks to several groups, among them philosophers of science and historians of relativity. Equations are displayed as necessary, but Ryckman gives the non-mathematical reader enough background to understand their occurrence in the context of his wider philosophical project.

Those enlightened philosophers of physics acknowledging some manner of descent from Kant’s ‘Copernican Revolution’ have long found encouragement and inspiration in the writings of Roberto Torretti. In this tribute, I focus on his “perspective on Kant’s perspective on objectivity” (2008), a short but highly stimulating attempt to extract the essential core of the Kantian doctrine that ‘objects of knowledge’ are constituted, not given, or with Roberto’s inimitable pungency, that “objectivity is an achievement, not a gift.” That essential core Roberto locates in the Kantian notion of apperception, or self-activity, manifested in cognition in the idea of combination (Verbindung) or composition, which, Kant tells us, “among all ideas … is the one that is not given through objects, but can only be performed by the subject itself, because it is an act of self-activity” (B 130). I first rehearse Roberto’s proposal for how an imaginative interplay between sensibility and understanding can be fashioned via the productive imagination or power of reflective judgment (of the third Critique). In this way, the notion of composition in general, unfettered from needless period constraints issuing in “pure forms of sensibility” and “pure concepts of the understanding”, can be seen as the intellectual motor for the “free creation” of concepts celebrated by Einstein and others, furnishing structural scaffolding required to articulate and display physical objects and processes, a conceptual panoply that “cannot be fished out of the stream of impressions”. Roberto emphasizes that historical case studies are needed to evaluate his proposal, suggesting one himself, the continuous conceptual development inaugurated by Riemann’s Habilitätionsschrift (1854) resulting, some hundred years later, in the fiber bundle formalism of modern differential geometry and topology. I sketch a related suggestion, that the gauge groups of modern particle physics are the outcome of a similar line of conceptual advance, a structural scaffolding saving the phenomena of high-energy experiment within the framework of ‘effective field theory.’

We have yet to fully understand the mariner or the measure to which logical empiricism emerged as a conventionalist response to both traditional Kantian and empiricist epistemology and to the apparent triumphs of “conventionalist stratagems” (in Popper’s aspersive locution) in the foundations of science. By “conventionalism”, however, is here understood a broader sense than customary, an extrapolation of views on the foundations of geometry and physics (associated in the first instance with Poincaré“) to an encompassing epistemological consideration of the development and validity of scientific concepts generally. In this new construal, the concepts of science are neither derivable from sense experience, nor are they transcendentally valid a priori conditions of its possibility. Rather they are “free creations of the human mind” whose provenance is “logically arbitrary”, as Poincare’ and (subsequently) Einstein put it.

Determinismus und Indeterminismus in der modernen Physik is one of Cassirer’s least known and studied works, despite his own assessment as “one of his most important achievements”. A prominent theme locates quantum mechanics as a yet further step of the tendency within physical theory towards the purely functional theory of the concept and functional characterization of objectivity. In this respect DI can be considered an “update”, like the earlier monograph Zur Einsteinschen Relativitätstheorie: Erkenntnistheoretische Betrachtungen, to Substanzbegriff und Funktionsbegriff, a seminal work considering only classical and pre-relativistic physics. But how does DI cohere with the three volumes of The Philosophy of Symbolic Forms providing a systematic survey of symbolic meanings in diverse aspects of culture, each with its own mode of “objectification” via self-created signs and images? Cassirer’s “phenomenology of cognition” via distinct types of symbolic form locates Dirac’s Principles of Quantum Mechanics as an exemplar within physical theory of purely symbolic thought, a realm of pure relations and their correlated meanings. In particular, Dirac’s characterization of the new notion of “physical state” in quantum mechanics by a “symbolic algebra of observables” severed from particular representations points to a limiting pole of the Bedeutungsfunktion, the third and highest mode of symbolic formation.

Naturalized metaphysics remains a default presupposition of much contemporary philosophy of physics. As metaphysics is supposed to be about the general structure of reality, so a naturalized metaphysics draws upon our best physical theories: Assuming the truth of such a theory, it attempts to answer the “foundational question par excellence “, “how could the world possibly be the way this theory says it is?“ It is argued that attention to historical detail in the development and formulation of physical theories serves as an ever-relevant hygienic corrective to the “sentiment of rationality“ underlying the naturalistic impulse to read ontology off of physics

Four distinguished authors have been brought together to produce this elegant study of a much-neglected figure. The book is divided into three sections: Neurath's biographical background and the economic and social context of his ideas; his theory of science; and the development of his role in debates on Marxist concepts of history and his own conception of science. Coinciding with the emerging serious interest in logical positivism, this timely publication will redress a current imbalance in the history and philosophy of science.