This paper investigates the historical origins of the notion of incommensurability in contemporary philosophy of science. The aim is not to establish claims of priority, but to enhance our understanding of the notion by illuminating the various issues that contributed to its development. Kuhn developed his notion of incommensurability primarily under the influence of Fleck, Polanyi, and Köhler. Feyerabend, who had developed his notion more than a decade earlier, drew directly from Duhem, who had developed a notion of incommensurability in (...) 1906. The idea is that in the course of scientific advance, when fundamental theories change, meanings change, which can result in a new conception of the nature of reality. Feyerabend repeatedly used this notion of incommensurability to attack various forms of conceptual conservativism. These include the logical positivists’ foundational use of protocol statements, Heisenberg’s methodological principle that established results must be presupposed by all further research, attempts to separate philosophical accounts of ontology from physics, Bohr’s principle of complementarity, and logical empiricist accounts of reduction and explanation. Focusing on the function of the notion of incommensurability common to Feyerabend’s various critiques explicates Feyerabend’s early philosophy as a series of challenges to forms of conceptual conservativism.Keywords: Incommensurability; Paul Feyerabend; Thomas Kuhn; Pierre Duhem; Wolfgang Köhler; Ludwik Fleck. (shrink)

This essay offers a discussion and contextualisation of a series of letters exchanged between Jordi Cat and Paul Feyerabend from 1989 to 1994. These letters provide insights into Feyerabend’s later thought on a variety of themes including quantum holism, the disunity of science, the development of logical empiricism, and science activism. In doing so, we provide some original analysis and exegesis of Feyerabend’s evolving views on scientific methodology and quantum mechanics by focusing on Feyerabend’s changing attitudes towards Bohm, Bohr, and (...) his eventual colleague Hans Primas and his later sympathies with the algebraic approach. We also highlight Feyerabend’s role in the growth of the Disunity of Science movement and how he connected disunity to practical considerations in the philosophy of action. (shrink)

Although quantum theory is applicable, in principle, to both the microscopic and macroscopic realms, the strategy of practically applying quantum theory by retaining a classical conception of the macroscopic world has had tremendous success. This has nevertheless rendered the task of interpretation daunting. We argue the need for recognizing and solving the ‘observation problem', namely constructing a ‘quantum-compatible’ view of the properties and states of macroscopic objects in everyday thinking to realistically interpret quantum theory consistently at both the microscopic and (...) macroscopic levels. Toward a solution to this problem, we point out a category of properties called ‘relational properties’ that we regularly associate with everyday objects. We see them as being potentially quantum-compatible. Some possible physical implications are discussed. We conclude by touching upon the nexus between the relational property view within quantum physics and some neurobiological issues underlying cognition. (shrink)