Thomas Kuhn's 'Linguistic Turn' and the Legacy of Logical Empiricism

Incommensurability, Rationality and the Search for Truth

Stefano Gattei

• Publisher: Routledge
• Year: 2016
• Print ISBN: 9780754661603
• eBook ISBN: 9781351879101
• Edition: 1
• Topic: Philosophy
• Subtopic: Philosophy History & Theory

Presenting a critical history of the philosophy of science in the twentieth century, focusing on the transition from logical positivism in its first half to the "new philosophy of science" in its second, Stefano Gattei examines the influence of several key figures, but the main focus of the book are Thomas Kuhn and Karl Popper. Kuhn as the central figure of the new philosophy of science, and Popper as a key philosopher of the time who stands outside both traditions. Gattei makes two important claims about the development of the philosophy of science in the twentieth century; that Kuhn is much closer to positivism than many have supposed, failing to solve the crisis of neopostivism, and that Popper, in responding to the deeper crisis of foundationalism that spans the whole of the Western philosophical tradition, ultimately shows what is untenable in Kuhn's view. Gattei has written a very detailed and fine grained, yet accessible discussion making exceptionally interesting use of archive materials.

Chapter 1
Two Revolutions in Twentieth-Century Philosophy of science

Her government, under the administration of the dogmatists, was at first despotic. But inasmuch as the legislation still bore traces of the ancient barbarism, her empire gradually through intestine wars gave way to complete anarchy; and the sceptics, a species of nomads, despising all settled modes of life, broke up from time to time all civil society.

Immanuel Kant

The notion of incommensurability between scientific theories is one of the most controversial theses to have emerged during the epistemological debate in the twentieth century. The controversy dates back to 1962, when the incommensurability thesis was first advanced by its major advocates, Thomas S. Kuhn and Paul K. Feyerabend. However, despite usual references to this year, the transforming process within the philosophy of science had been under way for a long period.

Indeed, from the epistemological point of view, the past century witnessed two major revolutions, one in the 1920s and one in the early 1960s. In between them, the counter-revolution of critical rationalism. However, while the first revolution – that of Logical Positivism – aimed at re-establishing science in its role as reliable knowledge, after the progress made in mathematics and physics during the early decades of the twentieth century shook its foundations,¹ the second – that of the so-called “new philosophy of science” – had the effect of undermining the privileged position science had been occupying since Francis Bacon’s time.

The Idol of Certainty

From the seventeenth century onwards, until a few decades ago, science enjoyed the greatest intellectual authority as the best form of knowledge, and the highest social consideration as the most appropriate and reliable instrument for the solution of our problems and the cure of our diseases. As a consequence, philosophers had been engaged in inquiring into “the reason why science has to be regarded as the supreme and most reliable form of knowledge. That it was, it was never actually called into question.”² In the 1960s, however, philosophers of science raised the problem in these very terms, “causing an unprecedented storm in a relatively well-sheltered region of philosophical reflection”.³

Modern philosophy, following Bacon and Descartes, equated science and rationality. In the nineteenth century, such a view was reinforced by Positivism which, by acknowledging its certitude and incontrovertibility, granted science the hallmark of episteme. This view of solidity and linear progress was undermined by the discovery of non-Euclidean geometries and, later on, by the use Albert Einstein made of them in constructing his general theory of relativity. The turn thus imprinted in physics was tantamount to admitting that science is revisable – even if, as Joseph Agassi has noted, “it is not so much the occurrence of revolutions in science, the fact that science is in flux, that created the major change in the philosophical scene; rather, what has happened is that suddenly the fact that science is in flux ceased to be a secret”.⁴

The early version of positivism was proven wrong and the foundations of classical physics were shaken. In the early 1920s a group of philosophers and scientists undertook the task of winning back science’s status, regaining its character of episteme. At the roots of their reflections on science they assumed classical empiricism and the tools provided by symbolic logic. The origins of this school as an organized philosophical movement can be traced to the roughly concurrent constitution, in Vienna, of the Wiener Kreis (Vienna circle),⁵ which grouped around Moritz schlick,⁶ and, in Berlin, of the Gesellschaft für empirische Philosophie (Society for Empirical Philosophy), fostered by the physicist and philosopher Hans Reichenbach.⁷ Another fruitful connection was established with the Polish school of logic (Jan Łukasiewicz, Tadeusz Kotarbińsky, Kazimierz Ajdukiewicz, Alfred Tarski, Stanisław Leśniewski).⁸

The circle aimed at forming an Einheitwissenschaft, that is, a “unified science”, empirically connoted and comprising all the knowledge deriving from single scientific specialties.⁹ Unification was to be gained by adopting a precise method, that of the logical analysis of the assertions of the sciences (developed by Giuseppe Peano, Gottlob Frege, Alfred N. Whitehead and Bertrand Russell): such a logical analysis was the only one which was allegedly able to provide a real unification of the various sciences by showing their common logical-linguistic foundation. The outcome of the application of this method should have been twofold: on the one hand, it should have taken to the clarification and precise determination of concepts and theories of empirical sciences, besides the ultimate definition of the logical foundations of mathematics and logic;¹⁰ on the other, to the elimination of metaphysics through the proof of the meaninglessness of its propositions and (alleged) problems.¹¹ It aimed not only at producing an autonomous philosophy of science, but an overall scientifically-based worldview,¹² in sharp contrast with the previous ones, which were theologically or metaphysically-based.¹³

As Peter Achinstein and Stephen Barker remarked in a volume devoted to its legacy, Logical Positivism “was a revolutionary force in philosophy, for it stigmatized metaphysical, theological and ethical pronouncements as devoid of cognitive meaning and advocated a radical reconstruction of philosophical thinking which should give pride of place to the methods of physical science and mathematical logic”.¹⁴ By combining the results of different traditions such as empiricism and formal logic, the neopositivists transformed philosophy of science into logic of science – that, not dealing any more with particular scientific theories or with their contents, is immune from the vicissitudes which trouble the scientific enterprise, and devotes itself only to defining the requirements which any scientific theory must meet. In so doing, the knowledge that looked shaky and wavering from the point of view of nineteenth-century positivistic canons, was secured to the twofold warrant of empirical verification and formal logic.¹⁵

Karl Popper, "Boundary" Philosopher Between Neopositivists and New Philosophers of Science

Having never been invited by Schlick to take part in their meetings, Karl R. Popper never became a member of the Vienna Circle. Nevertheless, he was a pupil of, got to know and had long exchanges with a number of its members.¹⁶ Critical dialogue with Logical Positivism propelled Popper’s revolution from the beginning: he used to work in virtual isolation, withdrawing into seclusion for lengthy periods, then reappeared to confront the Circle with new ideas. Circle members were, at intervals, a source of critical feedback that led him to crucial developments.¹⁷ However, although they were a crucial context for his philosophy, Popper’s differences with the Circle were significant: for not only did Popper work out innovative solutions to the problems dealt with by the Circle members, but his critique sprang from a marginal Kantian perspective foreign to Logical Positivism.¹⁸

As Malachi Hacohen has shown, it was Julius Kraft who introduced Popper to the unorthodox Kantian philosophy of Jacob F. Fries and Leonard Nelson:¹⁹ their philosophies provided the background for Popper’s solution of the foundation problem. But while Kraft accepted Fries’ psychological critique of Kant and his alternative foundation for knowledge, Popper dismissed Fries’ proposal as psychologistic and, by the early 1930s, disposed of foundationalism altogether.²⁰

Fries, said Popper, was the first to notice the confusion of psychology and epistemology in Kant. Kant’s transcendental proof showed synthetic propositions to be necessary a priori, but did not prove them valid: “He demonstrates the basic metaphysical statements of natural science through the possibility of experience. But this does not constitute ontological justification of a natural law. Rather, [it is] psychological justification of […] human reason’s need to presuppose laws’ truth in order to regard appearances as unified in experience. The entire observation is correctly understood as psychic-anthropological”.²¹ The transcendental proof, Fries argued, had to be psychologically grounded, or it would be caught in a circular argument. Epistemology independent of psychology, he concluded, was impossible.²² Fries’ proposal grounded epistemology in psychology. In so doing, Nelson argued, he dispelled Kant’s agnosticism concerning the “thing in itself” (Ding-an-sich), renewing the self-confidence of reason: immediate knowledge provided epistemology’s foundation.

Popper regarded Fries’ and Nelson’s demonstration of endless regress in epistemology as impeccable and took it as the point of departure for epistemology. However, he thought that Fries and Nelson were wrong to assume that the task of epistemology was grounding knowledge: it was foundationalism, rather than endless regress, that made epistemology impossible. Epistemology, for Popper, was nothing but general scientific methodology: it did not justify statements, but offered rules, investigated methods and criticized procedures, pointing out contradictions and misapplications. As its subject matter was scientific practice, it required no foundation: it sought to clarify, criticize and improve practice. In Popper’s eyes, Carnap and Neurath committed Fries’ very same mistake: their protocols were psychological reports in physicalist disguise.²³ Experience, or experiential language, can not directly exercise empirical control over science: science has no absolute empirical basis.

Therefore, Popper recast the basic problem of epistemology. All epistemologists, he said, confronted “Fries’ trilemma”. They could reconcile themselves to dogmatism, i.e. accept basic propositions without justification. Or they could admit infinite regress, whereby no statement would ever reach conclusive validation. Or else, they could opt for psychologism, justifying statements by appealing to “experience”. With the exception of conventionalists, epistemologists had historically chosen, like fries, psychologism: in order to avoid dogmatism, they called on experience, perceptions or immediate knowledge to justify statements. Popper dissented: observation and experiential reports are scientifically admissible only if they can be intersubjectively checked. Scientists’ personal convictions have no epistemological significance: they could contribute to the discovery of a theory or explain subjective preference for it – but they cannot justify it. To retain objectivity, epistemology has to exclude psychologism.

Earlier, Popper had believed that infinite regress ended with verification or falsification of specific prognoses. In Logik der Forschung he recognized that even these prognoses – or, as he began calling them, singular (or basic) statements²⁴ – were theories of a lower degree of universality, testable hypotheses of their own. No foundation is required: dogmatism (i.e. the tentative and temporary acceptance of scientific statements), psychologism (i.e. scientists’ subjective convictions, contributing to the consensus that ends the testing process) and endless regress all play a role in scientific work – but none constitutes a real threat to epistemology given science’s hypothetical, falsifiable character.²⁵

The Kant–Fries critique reshaped Popper’s epistemology, introducing issues and concepts that gained permanent hold on his philosophy: fries’ trilemma; exclusion of psychologism; theory as a system of statements; basic (singular) statement; empirical basis; methodological decision. He negotiated convention, experience, and logic, forming a unique synthesis of conventionalism and empiricism. He showed that convention and experience modified, rather than determined each other. Experience always remained problematic, but one could learn...

Table of contents

• Cover
• Title
• Copyright
• Dedication
• Contents
• Preface
• Acknowledgments
• List of Abbreviations
• 1 Two Revolutions in Twentieth-Century Philosophy of Science
• 2 Kuhn and the "New Philosophy of Science"
• 3 Incommensurability
• 4 Kuhn's "Linguistic Turn"
• 5 The Shadow of Positivism
• Bibliography
• Index