This paper continues an earlier investigation into the philosophical tradition of Vienna Indeterminism until the formation of the Vienna Circle in 1929. It focuses in particular on how Philipp Frank and Richard von Mises were able to contemplate genuine indeterminism in physics before the advent of quantum mechanics. On this account, all apparently deterministic laws could well be the macroscopic limit of indeterministic basic laws valid for the single mirco-events. Philosophically Vienna Indeterminism was launched by Mach's redefinition of causality in terms of functional dependencies. This severed the rigid bond between causality and empirical realism characteristic of the Kantian conception and made possible to adjust the ontology according to the needs of a single theory. The debates between Max Planck and Franz Serafin Exner teach that the indeterminism issue was also a struggle about Boltzmann's philosophical legacy between Vienna and Berlin. Quite in line with Mach's firm empiricism, Vienna Indeterminists rejected any final decision between determinism and indeterminism on the metaphysical level. Once the frequency interpretation had won favor, the empiricist stance, moreover, permitted them to consider mass phenomena as generic observational facts coordinated to statistical collectives and to treat them on a par with moving point particles. The only condition imposed on this ontology was the uniqueness of this coordination, a condition that could be viewed as a late heir of Mach's principle of unique determination which had complemented his relational ontology.
This paper continues an earlier investigation into the philosophical tradition of Vienna Indeterminism until the formation of the Vienna Circle in 1929. It focuses in particular on how Philipp Frank and Richard von Mises were able to contemplate genuine indeterminism in physics before the advent of quantum mechanics. On this account, all apparently deterministic laws could well be the macroscopic limit of indeterministic basic laws valid for the single mirco-events. Philosophically Vienna Indeterminism was launched by Mach's redefinition of causality in terms of functional dependencies. This severed the rigid bond between causality and empirical realism characteristic of the Kantian conception and made possible to adjust the ontology according to the needs of a single theory. The debates between Max Planck and Franz Serafin Exner teach that the indeterminism issue was also a struggle about Boltzmann's philosophical legacy between Vienna and Berlin. Quite in line with Mach's firm empiricism, Vienna Indeterminists rejected any final decision between determinism and indeterminism on the metaphysical level. Once the frequency interpretation had won favor, the empiricist stance, moreover, permitted them to consider mass phenomena as generic observational facts coordinated to statistical collectives and to treat them on a par with moving point particles. The only condition imposed on this ontology was the uniqueness of this coordination, a condition that could be viewed as a late heir of Mach's principle of unique determination which had complemented his relational ontology.
My thesis investigates a debate between Vienna and Berlin about the view that the basic laws of nature are genuinely indeterministic that started long before the advent of quantum mechanics. It involved two different readings of Ludwig Boltzmann's legacy statistical mechanics and two different answers to how causality and ontology ought to be combined. Having adopted Ernst Mach's weak notion of causality, the local Viennese tradition could more easily contemplate ontologies for irreducibly statistical laws that were different from classical physics, while the Berlin tradition departed from Planck's reading of the Kantian tradition, according to which strictly deterministic laws represented an indispensable basis even for probabilistic theories.\nVienna Indeterminism, as I shall call the first reading, became characteristic for a series of physicist-philosophers connected to the Institute of Physics at the University of Vienna, among them Franz Serafin Exner, Erwin Schrödinger, Philipp Frank and Richard von Mises. It involved the acceptance of the highly improbable events admitted by the second law of thermodynamics, an assent to Mach's definition of causality in terms of functional dependencies, an empiricist shift of the burden of proof on the determinist's shoulders, and the adoption of the relative frequency interpretation of probability. Planck and his student Moritz Schlick initially rejected all of these creeds.\nWhile the Viennese reading of Boltzmann's legacy made it possible to accept probabilistic laws as genuine laws years before the advent of quantum mechanics, Schlick had to take a strictly verificationist tack to reconcile his views on probability with the failure of a Kant-inspired notion of causality enforced by the changes in physics. Until his death however, Schlick remained committed to the Spielraum interpretation of Johannes von Kries, compensating his qualified acceptance of indeterminism with an emphasis on the limits of language that were enforced by Heisenberg's uncertainty relations.\nIn view of claims that scientists' abandonment of determinism and causality was triggered, or at least enhanced, by external factors, among them the anti-scientific Weimar milieu and Bohr's power politics, the reconstruction of the philosophical debates between Vienna and Berlin requires historical contextualization. To this end, I initially recapitulate the Forman thesis and the discussions ensuing from it. Most important among them are the recent books of Cushing and Beller that, rejecting Forman's strong claims, nevertheless deny any constructive influence of the scientific aspirations of German physicists on the philosophical debates about causality and indeterminism in the 1920s.\nAgainst this picture, I argue that the philosophical aspirations of physicist-philosophers were rather genuine and followed influential role models, among them Helmholtz and Mach. They represent a characteristic trait of the German-speaking scientific world and were expressed in academic addresses and in the publication of popular writings. After 1913, this philosophical discourse was conducted, to an increasing extent, on the pages of Die Naturwissenschaften. In a separate chapter, I study the role of philosophical and cultural matters in this journal, which can hardly be separated from the personality of its founding editor Arnold Berliner. At about 1930, this discourse among physicist-philosophers partly merged into scientific philosophy, as conducted by Logical Empiricists, and the newly founded Erkenntnis.\nOne of the characteristic features of the discourse among physicist-philosophers was that they were not strictly indebted to philosophical schools but rather willing to form strategic alliances. Such alliances emphasized one philosophical aspect that was considered pivotal at the time which other features, often expressing severe disagreements of content, were played down. This process can be witnessed at the end of the discussion between the Viennese and the Berliners in the 1930s, at a time when Schlick had already become the center of the Vienna Circle. Being confronted with a plethora of "metaphysical" misinterpretations and having taken the linguistic turn, Frank and Schlick formed a strategic alliance on the 1936 Copenhagen Congress for the Unity of Science. It brought them into opposition with Schrödinger's quest for a modification of quantum mechanics, although Schrödinger continued to be a staunch advocate of indeterminism. This year thus signifies the end of the coherence of Vienna Indeterminism, a tradition that reaches back to the publication of Boltzmann's Lectures of Gas Theory.
Abstract Stöltzner coined the expression ‘Vienna indeterminism’ to describe a philosophical tradition centered on the Viennese physicist Exner, serving as the ‘historical link’ between Mach and Boltzmann, on the one hand, and von Mises and Frank, on the other. During the early 1930s debate on quantum mechanics, there was a ‘rapprochement’ between Vienna indeterminism and Schlick’s work on causality. However, it was Cassirer’s 1936 monograph Determinismus und Indeterminismus that showed a full ‘convergence’ with major tenets of Vienna indeterminism: the fundamentality of statistical laws, the frequency interpretation of probability, and the statistical interpretation of the uncertainty relations. Yet, Cassirer used these conceptual tools to pursue ‘in parallel’ different philosophical goals. While for the Viennese quantum mechanics represented a fatal blow to the already discredited notion of ‘causality,’ for Cassirer it challenged the classical notion of ‘substantiality,’ the ideas of ‘particles’ as individual substances endowed with properties. The paper concludes that this ‘parallel convergence’ is the most striking and overlooked aspect of Determinismus und Indeterminismus, serving as the keystone of its argumentative structure.
The theory of quantum mechanics has often been thought to show an affinity with logical empiricism: in both, observation plays a central role, and questions about what is unobservable are dismissed. However, there were also strong tensions between the logical empiricism of the Vienna Circle and implications drawn from quantum physics. In the 1920s and 1930s, many physicists thought that quantum mechanics revealed a limit to what could be known scientifically, and this opened the door to a wide range of speculations, in which quantum mechanics was connected with free will, organic life, psychology, and religion—speculations in which many leading quantum physicists were engaged. Members of the Vienna Circle, such as Frank and Schlick, looked at quantum mechanics for a confirmation of their empiricist views, but they were at the same time critical about these wider implications drawn from quantum mechanics, which in their eyes were connected with broader mystical and irrational trends in society. They engaged in particular with the views of Bohr and Jordan, both of whom expressed a sympathy for logical empiricism while at the same time arguing for claims that proved hard to reconcile with the scientific world conception of the Vienna Circle.
Classical physics is generally regarded as deterministic, as opposed to quantum mechanics that is considered the first theory to have introduced genuine indeterminism into physics. We challenge this view by arguing that the alleged determinism of classical physics relies on the tacit, metaphysical assumption that there exists an actual value of every physical quantity, with its infinite predetermined digits (which we name principle of infinite precision). Building on recent information-theoretic arguments showing that the principle of infinite precision (which translates into the attribution of a physical meaning to mathematical real numbers) leads to unphysical consequences, we consider possible alternative indeterministic interpretations of classical physics. We also link those to well-known interpretations of quantum mechanics. In particular, we propose a model of classical indeterminism based on finite information quantities (FIQs). Moreover, we discuss the perspectives that an indeterministic physics could open (such as strong emergence), as well as some potential problematic issues. Finally, we make evident that any indeterministic interpretation of physics would have to deal with the problem of explaining how the indeterminate values become determinate, a problem known in the context of quantum mechanics as (part of) the ``quantum measurement problem.'' We discuss some similarities between the classical and the quantum measurement problems, and propose ideas for possible solutions (e.g., ``collapse models'' and ``top-down causation'').
Quantum theory, particularly with its concepts of indeterminacy and superposition, demands of philosophers of science a profound review and a complete redefinition of the foundation of the notion of representation. This review has significant implications for assessing the Kantian heritage, especially for those among us who recognize the advances of the transcendental approach over realist and empiricist perspectives in epistemology. Kant endeavored to establish a foundation for the notion of representation consistent with the physics of his time. Today, as inheritors of Kant’s legacy in the philosophy of science, we face the challenge of establishing a new foundation for the idea of representation that aligns with the principles of contemporary science. In his Progress of Metaphysics, as well as in Religion Within the Boundaries of Mere Reason, Kant distinguishes between analogical (symbolic) schematism and real (transcendental) schematism. My aim in this work is to explore the notion of analogical schematism for evaluating the content of extra-empirical concepts in contemporary physical theories, where intuition proves to be intrinsically indeterminate.
If there's one lesson that philosophers seem to have learned from quantum mechanics it is that the quantum realm is governed by indeterministic laws. However, in 1952 David Bohm constructed a deterministic theory and proved that it is empirically equivalent to quantum mechanics. One of the three conditions that are together sufficient for the empirical adequacy of Bohm's theory is the statistical postulate. This postulate demands a very particular initial condition to hold for ensembles of quantum systems. I argue that the statistical postulate requires a justification. A justification would consist of showing how the dynamics of Bohm's theory is able to generate the initial conditions specified by the statistical postulate. I examine two deterministic justifications of the statistical postulate, one by Valentini and the other by Durr, Goldstein and Zanghi. I explain precisely the ways in which they are lacking. The basic problem is that crucial dynamical details are missing, ones needed to complete the justification. Whether these missing bits can be filled in is an open question. Until a justification is at hand, and its application to real-world ensembles is clarified, the empirical adequacy of Bohm's theory remains an open question. Bohm himself proposed a stochastic or indeterministic justification for the statistical postulate. It has been shown that the dynamics of this stochastic theory does not have the resources to justify the statistical postulate. In addition I show that the mathematical argument Bohm uses in his justification is flawed. Other stochastic theories do justify the statistical postulate but have other problems. The issue of indeterminism in the quantum realm is far from settled. Bohm's deterministic dynamics enables an investigation into the limits (if any) of a deterministic dynamics for the quantum realm. The properties of Bohm's deterministic equations of motion remain largely unknown. What we do know is that if the quantum realm is indeterministic it will not be for any of the reasons we have so far been given.