Başak Aray (Boğaziçi Üniversitesi)

Vienna Circle in the international auxiliary language movement

The rediscovery of the Vienna Circle in the last few decades visibilised some of the previously neglected socio-political contributions of its members, especially from its left wing. Neurath is possibly the most prolific and significant figure of the Circle in this respect, his activities ranging from the defence of a socialist planned economy to mass education, for which he was instrumental in the development of a visual communication method accessible to people from all nations and all backgrounds (Isotype). Yet, alongside Neurath, Carnap actively advocated for another major way of universal communication: international auxiliary language. The literature detailing their involvement in this movement is relatively recent and includes works such as McElvenny 2018, Aray 2019 and 2024, Lins 2022 and Matsui 2024. Based on these updates, I make a logical empiricist case for the benefits of a constructed international language.

Başak Aray is an assistant professor of philosophy at Boğaziçi University. She received her PhD at the Paris 1 Panthéon-Sorbonne University with a dissertation on Otto Neurath and the Left Vienna Circle. Her later publications deal with connections between early analytic philosophy and international auxiliary languages.

References:

Aray, B. (2019). Louis Couturat, modern logic, and the international auxiliary language. British Journal for the History of Philosophy, 27(5), 979–1001.

Aray, B. (2024). Metaphysics, tolerance, and language planning: Carnap on international auxiliary languages. In A. Richardson & A. Tuboly (Eds.), Interpreting Carnap (pp. 214–233). Cambridge University Press.

Aray, B. (forthcoming). Planned languages: Esperanto and Basic English. In Ch. Damböck & G. Schiemer (Eds.), Carnap Handbuch, Metzler Verlag.

Lins, U. (2022). Sprache transnational: Rudolf Carnap und die Esperantobewegung. In Ch. Damböck, G. Sandner, & M. G. Werner (Eds.), Logical empiricism, life reform, and the German youth movement (pp. 55–77). NY: Springer.

Matsui, T. (2024) Carnap, Esperanto, and Language Engineering. Erkenntnis: 10.1007/s10670-024-00885-6

McElvenny, J. (2013). International language and the everyday: Contact and collaboration between C.K. Ogden, Rudolf Carnap and Otto Neurath. British Journal for the History of Philosophy, 21(6), 1194–1218.

McElvenny, James. (2018). Language and meaning in the age of modernism: C.K. Ogden and his contemporaries. Edinburgh University Press.

 

Ulrich Arnswald (University of Innsbruck / University of Kaiserslautern-Landau, Oles Honchar Dnipro National University)

»The Whole Modern Conception of the World is Founded on the Illusion That the So-called Laws of Nature are the Explanations of Natural Phenomena.« (TLP 6.371) – The Core of the Debate Between Ludwig Wittgenstein and the Vienna Circle

Although there are now many publications on both Ludwig Wittgenstein and the Vienna Circle, Friedrich Stadler notes as recently as 2023 that “all is not as well as it could be regarding the scholarship on the relationship between Wittgenstein and the Vienna Circle.” At first glance, this may suggest that there is a lack of academic research on the specific aspect of “Wittgenstein and the Vienna Circle,” but there are more than sufficient publications on this subject. Rather, Stadler complains on the fact that the core of the conflict between Ludwig Wittgenstein and the Vienna Circle has still not been adequately identified and elaborated upon today: „It is surprising then that despite these flourishing scholarly activities the crucial interaction of Wittgenstein with members of the Vienna Circle (mainly with the Schlick and Waismann) in the decade between the two World Wars has still not been investigated in sufficient depth.”

Basically, the misunderstanding between Wittgenstein and the Vienna Circle began right from the start: The manifesto “Scientific Worldview. The Vienna Circle [1929]” was printed with Wittgenstein's agreement, only to be criticized by him and Schlick for its programmatic style. At the same time, it must be assumed that the signatories of the manifesto, Hans Hahn, Otto Neurath, and Rudolf Carnap, understood Wittgenstein's Tractatus Logico-Philosophicus primarily as what is now referred to as Wittgenstein's “picture theory of language.” The inclusion of ethics, religion, mysticism and aesthetics in the Tractatus certainly did not escape the attention of the Vienna Circle members, but whether they understood the consequences that Wittgenstein meant for the program of the Vienna Circle is rather unlikely, as Waismann's volume Wittgenstein and the Vienna Circle shows.

According to this volume published after Wittgenstein's death, the core of the conflict must already be laid out in the Tractatus. While most studies focus on the influence of Wittgenstein's Tractatus on the Vienna Circle and only a few on the views of the members of the Vienna Circle on Wittgenstein's significance, to date no one has consulted the Tractatus itself, although this would seem to be the obvious thing to do. The lecture argues that the thesis of Wittgenstein's gradual distancing from his Tractatus philosophy is false and that the points raised by Wittgenstein in his discussions with the Vienna Circle can already be found in his groundbreaking Tractatus.

Ulrich Arnswald received his doctorate in philosophy from the Karlsruhe Institute of Technology in Germany and habilitated at the University of Innsbruck in Austria. Arnswald has written more than 170 articles. He is the author of fourteen books, including, in English: In Search of Meaning: Ludwig Wittgenstein on Ethics, Mysticism and Religion (2009) and Gadamer's Century: Essays in Honor of Hans-Georg Gadamer (2000). A further book is forthcoming in English, co-edited with Joaquín Jareño-Alarcon, titled The Nature of Religious Belief in Wittgenstein's Philosophy (2026). He has been teaching at the University of Kaiserslautern-Landau since 2023. Since 2024, he has also been teaching at the Oles Honchar Dnipro National University, Dnipro, Ukraine.

 

Anna Brożek (University of Warsaw)

 Interpersonal and intertextual connections between the Vienna Circle and the Lvov‑Warsaw School: The current stage of research

Between 1929 and 1937, there were intense contacts between representatives of the Lvov-Warsaw School and members of the Vienna Circle, which came to an end due to political turbulence. The investigation into the connections between these two centers of scientific philosophy began several decades ago, with the first monograph—edited by Klemens Szaniawski—being published in 1989. Thanks to intensive research conducted in recent years on the history of logical empiricism and the tradition of the Lvov-Warsaw School, we now know significantly more about these relations.

This lecture aims to summarize research on both the interpersonal contacts and the substantive philosophical influences between the two groups. On the interpersonal level, I will present recent findings that shed new light on the early history of analytic philosophy. On the intertextual level, I will propose an interpretation of the similarities and differences between the metaphilosophical programs developed in Lvov, Warsaw, and Vienna.

Anna Brożek is a philosopher, pianist, and theorist of music; titular professor at the Institute of Philosophy, University of Warsaw. She is the author or coauthor of 13 books (e.g., Theory of Questions: Erotetics Through the Prism of Its Philosophical Background and Practical Applications, Rodopi 2010; Kazimierz Twardowski: Die Wiener Jahre, Springer 2011) and several dozens of articles concerning various domains of philosophy.

 

Matteo Collodel (Università Ca’ Foscari Venezia)

Feyerabend and the Alleged Conservatism of Logical Empiricism

Feyerabend became familiar with the Vienna Circle tradition and Logical Empiricism in his formative years in post-war Vienna. However, since the mid-1950s, he made LE one of his favourite critical targets, articulating his criticism in personal dialogue with some of its most distinguished representatives, in an attempt to expose some conservative and even authoritarian tendencies of contemporary empiricism. This paper accounts for the different stages of Feyerabend’s sustained assault against LE, examining both Feyerabend’s reception of LE and the logical empiricists' responses to Feyerabend’s challenge.

In the second half of the 1950s, Feyerabend found fault with Carnap's two-language model for rationally reconstructing the structure of scientific theories and its assumption of an autonomous and theory-neutral thing-language, while in a series of papers published in the first half of the 1960s, he relentlessly questioned the descriptive adequacy and the normative desirability of the ‘orthodox’, logical empiricist, accounts of reduction and explanation advanced by Hempel and Nagel. Feyerabend’s persistent criticism shook North American philosophy of science and prompted Hempel’s reaction: first in their correspondence and later in print. 

Initially, Hempel retorted that Feyerabend’s methodological analysis was ‘completely mistaken’ and Feyerabend could offer ‘no support’ for his allegations. This raises interesting historiographical questions about the later reception of LE, as it seems that Feyerabend, driven by his anti-authoritarian stance and his vantage point notwithstanding, substantially misinterpreted the logical empiricist research programme. On the other hand, Hempel also recognised that the descriptive issues on which Feyerabend insisted, despite having been long acknowledged by LE, could have farther-reaching consequences than previously envisaged. In fact, by the end of the 1960s, Hempel came to make quite radical concessions, admitting that the standard logical empiricist model for rationally reconstructing scientific theories was essentially ‘misleading’, that the logical empiricist account of reduction was ‘an untenable oversimplification’, and that the logical empiricist approach as to the meaning of scientific terms was actually ‘misconceived’. In this respect, there are good reasons to consider the decline of the logical empiricist research programme in the 1970s at least partly as the result of Feyerabend’s stimulating, however misrepresenting, insights.

Matteo Collodel earned his Ph.D. in Philosophy from the Ca’ Foscari University of Venice, and pursued his research at the Humboldt University of Berlin and at the Institute Vienna Circle, University of Vienna. His work focuses on the historical and psycho-sociological dimensions of philosophical research with a special attention to the development of the philosophical movements of logical empiricism and critical rationalism and to the life and work of Paul K. Feyerabend. His most significant publications include “Was Feyerabend a Popperian? Methodological Issues in the Historiography of the Philosophy of Science,” Studies in History and Philosophy of Science (2016) and “Ehrenhaft’s Experiments on Magnetic Monopoles: Reconsidering the Feyerabend-Ehrenhaft Connection,” International Studies in the Philosophy of Science (2022); he recently co-edited the collections of correspondence and unpublished papers Feyerabend’s Formative Years. Volume 1. Feyerabend and Popper (2020) and Volume 2. Feyrabend on Logical Empiricism, Bohm & Kuhn (2024).

 

Christian Damböck (University of Vienna)

The Development of Otto Neurath's Views on Democracy

Otto Neurath's views on democracy, part of the largely forgotten political legacy of logical empiricism, grew out of his theoretical views on human decision making by means of “auxiliary motives” that he developed early in his career. After refinements during his time in the Vienna Circle, where, together with Rudolf Carnap, he developed a view of rationality based on science and instrumental rationality, it was not until his last years that Neurath developed an explicitly democratic view that combined auxiliary motives with the concept of “orchestrating” politics in a setting of “scientific humanism.” This view is strikingly relevant today, because it allows us to understand politics as both grounded in science and expert knowledge, and attentive to the individual attitudes and desires of ordinary citizens.

Christian Damböck is a privatdozent at the Philosophy Department (University of Vienna) and director of the research project "Carnap in Context III: 'practical' philosophy in the US" (FWF proposal P 34887, 2021-2025). The project is located at the Institute Vienna Circle.

 

Paweł Kawalec (KUL)

Carnap and Conceptual Re-Engineering

The recent revival of conceptual engineering in experimental philosophy is often linked to Rudolf Carnap. To highlight some key discrepancies between this contemporary approach and Carnap’s original vision, I focus on the case of reflective equilibrium, as discussed by Brun (2017). From Carnap’s perspective, the integration of explication with reflective equilibrium, as proposed in that paper, may appear to be a promising and theoretically fruitful step toward a more comprehensive method of conceptual re-engineering. The emphasis on theoretical virtues and the recognition of historical and systematic links between the two approaches would likely be welcomed, as would the acknowledgment of concept systems and the move beyond linear processes, which better reflect actual theory development. Nevertheless, several critical concerns would arise. Chief among them is the lack of formal precision in the iterative adjustments of reflective equilibrium. The process of ‘mutual adjustment’ remains too vague and intuitive; clearer rules would be needed to guide and evaluate the process systematically. The method also underplays the transformative power of explication, favoring continuity and similarity over radical conceptual innovation, which could limit progress in theoretical frameworks. The treatment of conceptual systems presents another issue. The combined approach lacks a clear methodology for managing interdependent concepts or coordinating multiple explications. Its non-linear structure, though flexible, introduces uncertainty about the direction and endpoint of the adjustment process. Criteria for achieving equilibrium and resolving competing outcomes remain underdeveloped. Another shortcoming lies in the insufficient attention to background theories. Any method of conceptual revision, from this perspective, must be grounded in an explicit and coherent theoretical framework. Finally, the response to the subject-change challenge appears too cautious, leaning toward preservation rather than embracing explication as a tool for systematic replacement and theoretical advancement. In sum, while the combined method is a valuable contribution, it remains incomplete. Further refinement is needed to enhance formal rigor, emphasize conceptual transformation, and provide clearer strategies for handling complex systems and background commitments – essential steps for a scientifically oriented philosophy. I conclude by examining the extent to which Carnap’s likely objections – viewing the method as incomplete and in need of greater formal rigor, a stronger emphasis on theoretical transformation, and clearer strategies for handling systems of concepts and background theories – might apply more broadly to conceptual re-engineering.

Kawalec Paweł: Full Professor, Department of Epistemology, Faculty of Philosophy, John Paul II Catholic University of Lublin (KUL). Member of the Science of Science Committee of the Polish Academy of Sciences. Publishes on the theory and methodology of science, Bayesian epistemology, argumentation theory and early analytic philosophy.

Monographs: Pluralistic Progress in Economics (Routledge 2026, forthcoming), Integral Methodology (2018, in Polish); Causality and Explanation (2006, in Polish) and Structural Reliabilism (2003, Kluwer). Editor and translator of the Polish editions of Carnap’s Der logische Aufbau der Welt (2011) and Logical foundations of probability (2024). Editor of over 15 collective volumes in the field of science studies.

 

Thomas Uebel (University of Manchester)

Pragmatism and the Vienna Circle, 1928-1932: A Cautionary Tale

This paper considers the contention that pragmatist thought entered the Vienna Circle via Wittgenstein’s dissemination of Ramsey’s conception of variable hypotheticals in the guise of his view of “hypotheses” as linguistic rules. It is argued that support for this view on the Circle’s left wing was spotty and lasted at best until 1931 and that, given it was accompanied by the demand for strict verificationism, it was not understood by them in a pragmatist spirit at all but as deeply foundationalist and therefore rejected. The sources of the left wing’s pragmatism lie elsewhere.

Thomas Uebel is Professor Emeritus of Philosophy at the University of Manchester, UK. His books include Empiricism at the Crossroads: The Vienna Circle’s Protocol-Sentence Debate (2007) and an edition of Neurath’s Economic Writings (2004).

 

Georg Schiemer (University of Vienna)

From Hilbert’s program to Carnap’s Wissenschaftslogik

The talk will focus on several points of contact between David Hilbert's logical work and Rudolf Carnap’s early contributions to the logical reconstruction of mathematical and scientific theories until the publication of Carnap’s monograph Foundations of Logic and Mathematics in 1939. The comparison between Hilbert and Carnap will focus on two interpretative points: first, the extent to which Carnap’s own project on "general axiomatics" from the 1920s with its focus on metatheoretical properties of axiomatic theories was motivated by Hilbert’s foundational work. Second, the talk will analyze to what extent Carnap’s later views on theoretical languages, in particular, on the status of theoretical terms in science, were directly influenced by Hilbert’s instrumental formalism about logic and mathematics.

Georg Schiemer is professor at the Department of Philosophy and head of department of the Institute Vienna Circle at the University of Vienna. I am also an external fellow at the Munich Center for Mathematical Philosophy at LMU Munich. His research focuses on the history and philosophy of mathematics and early analytic philosophy. He is also interested in logic, the history and philosophy of logic and formal philosophy of science.