_Popper’s Critical Rationalism_ presents Popper’s views on science, knowledge, and inquiry, and examines the significance and tenability of these in light of recent developments in philosophy of science, philosophy of probability, and epistemology. It develops a fresh and novel philosophical position on science, which employs key insights from Popper while rejecting other elements of his philosophy. Central theses include: Crucial questions about scientific method arise at the level of the group, rather than that of the individual. Although criticism (...) is vital for science, dogmatism is important too. Belief in scientific theories is permissible even in the absence of evidence in their favour. The aim of science is to eliminate false theories. Critical rationalism can be understood as a form of virtue epistemology. (shrink)

Kaum einer hat die offene Gesellschaft in der politischen Philosophie des 20. Jahrhunderts so leidenschaftlich verteidigt wie Karl Popper. Sein Demokratieverstandnis ist eng gekoppelt an seine Wissenschaftstheorie und die Kritik an Platon, Hegel, Marx. Als Liberaler und sozialer Reformist wird er parteiubergreifend zum Stichwortgeber bundesdeutscher Politik seit den 70er Jahren. Popper-Rezeptionen finden sich bis in die Staatsrechtslehre (namentlich Peter Haberle) und das Bundesverfassungsgericht hinein. Noch heute lasst sich mit Popper gegen Diktaturen wie uberhaupt gegen Konzepte von "Gemeinschaft" (...) Position beziehen - aber auch gegen einen pseudo-liberalen, gnadenlosen Kapitalismus der "Ich-AGs". Mit Beitragen von Dorothea Frede, Peter Haberle, Herbert Keuth, Hubert Kiesewetter, Martin H. W. Mollers, Jurgen Nordmann, Harald Stelzer, Robert Chr. van Ooyen, Robert Zimmer. (shrink)

Popper functions allow one to take conditional probabilities as primitive instead of deriving them from unconditional probabilities via the ratio formula P=P/P. A major advantage of this approach is it allows one to condition on events of zero probability. I will show that under plausible symmetry conditions, Popper functions often fail to do what they were supposed to do. For instance, suppose we want to define the Popper function for an isometrically invariant case in two dimensions and (...) hence require the Popper function to be rotationally invariant and defined on pairs of sets from some algebra that contains at least all countable subsets. Then it turns out that the Popper function trivializes for all finite sets: P=1 for all A ) if B is finite. Likewise, Popper functions invariant under all sequence reflections can’t be defined in a way that models a bidirectionally infinite sequence of independent coin tosses. (shrink)

2 Popper's Logical Definition of Verisimilitude. 3 Popper's Probabilistic Definition of Verisimilitude. 4 Conclusion.

Karl Popper is famous for having proposed that science advances by a process of conjecture and refutation. He is also famous for defending the open society against what he saw as its arch enemies – Plato and Marx. Popper’s contributions to thought are of profound importance, but they are not the last word on the subject. They need to be improved. My concern in this book is to spell out what is of greatest importance in Popper’s work, (...) what its failings are, how it needs to be improved to overcome these failings, and what implications emerge as a result. The book consists of a collection of essays which dramatically develop Karl Popper’s views about natural and social science, and how we should go about trying to solve social problems. Criticism of Popper’s falsificationist philosophy of natural science leads to a conception of science that I call aim-oriented empiricism. This makes explicit metaphysical theses concerning the comprehensibility and knowability of the universe that are an implicit part of scientific knowledge – implicit in the way science excludes all theories that are not explanatory, even those that are more successful empirically than accepted theories. Aim-oriented empiricism has major implications, not just for the academic discipline of philosophy of science, but for science itself. Popper generalized his philosophy of science of falsificationism to arrive at a new conception of rationality – critical rationalism – the key methodological idea of Popper’s profound critical exploration of political and social issues in his The Open Society and Its Enemies, and The Poverty of Historicism. This path of Popper, from scientific method to rationality and social and political issues is followed here, but the starting point is aim-oriented empiricism rather than falsificationism. Aim-oriented empiricism is generalized to form a conception of rationality I call aim-oriented rationalism. This has far-reaching implications for political and social issues, for the nature of social inquiry and the humanities, and indeed for academic inquiry as a whole. The strategies for tackling social problems that arise from aim-oriented rationalism improve on Popper’s recommended strategies of piecemeal social engineering and critical rationalism, associated with Popper’s conception of the open society. This book thus sets out to develop Popper’s philosophy in new and fruitful directions. The theme of the book, in short, is to discover what can be learned from scientific progress about how to achieve social progress towards a better world. (shrink)

Popper’s Critical Rationalism presents Popper’s views on science, knowledge, and inquiry, and examines the significance and tenability of these in light of recent developments in philosophy of science, philosophy of probability, and epistemology. It develops a fresh and novel philosophical position on science, which employs key insights from Popper while rejecting other elements of his philosophy.

In this paper I argue that aim-oriented empiricism (AOE), a conception of natural science that I have defended at some length elsewhere[1], is a kind of synthesis of the views of Popper, Kuhn and Lakatos, but is also an improvement over the views of all three. Whereas Popper's falsificationism protects metaphysical assumptions implicitly made by science from criticism, AOE exposes all such assumptions to sustained criticism, and furthermore focuses criticism on those assumptions most likely to need revision if (...) science is to make progress. Even though AOE is, in this way, more Popperian than Popper, it is also, in some respects, more like the views of Kuhn and Lakatos than falsificationism is. AOE is able, however, to solve problems which Kuhn's and Lakatos's views cannot solve. [Back to Top]. (shrink)

Karl Popper argued in 1974 that evolutionary theory contains no testable laws and is therefore a metaphysical research program. Four years later, he said that he had changed his mind. Here we seek to understand Popper’s initial position and his subsequent retraction. We argue, contrary to Popper’s own assessment, that he did not change his mind at all about the substance of his original claim. We also explore how Popper’s views have ramifications for contemporary discussion of (...) the nature of laws and the structure of evolutionary theory. (shrink)

Philosophy of science is seen by most as a meta-discipline – one that takes science as its subject matter, and seeks to acquire knowledge and understanding about science without in any way affecting, or contributing to, science itself. Karl Popper’s approach is very different. His first love is natural philosophy or, as he would put it, cosmology. This intermingles cosmology and the rest of natural science with epistemology, methodology and metaphysics. Paradoxically, however, one of his best known contributions, his (...) proposed solution to the problem of demarcation, helps to maintain the gulf that separates science from metaphysics, thus fragmenting cosmology into falsifiable science on the one hand, untestable philosophy on the other. This has damaging repercussions for a number of issues Popper tackles, from the problem of induction to simplicity of theory and quantum theory. But his proposed solution to the demarcation problem is untenable. Metaphysical assumptions are an integral part of scientific knowledge, inherent in the persistent acceptance of unified theories against the evidence. Once this is appreciated, it becomes obvious that natural philosophy, a synthesis of science and philosophy, is both more rigorous and of greater intellectual value than the two dissociated components we have today. What Popper sought for could come to full fruition. Problems that Popper tackled, from the problem of induction, to the problem of unity of theory, problems of quantum theory, and problems concerning the scope and limits of physics, all receive more adequate resolution within the new, fully-fledged natural philosophy. (shrink)

According to Karl Popper, science cannot verify its theories empirically, but it can falsify them, and that suffices to account for scientific progress. For Popper, a law or theory remains a pure conjecture, probability equal to zero, however massively corroborated empirically it may be. But it does just seem to be the case that science does verify empirically laws and theories. We trust our lives to such verifications when we fly in aeroplanes, cross bridges and take modern medicines. (...) We can do some justice to this apparent capacity of science to verify if we make a number of improvements to Popper’s philosophy of science. The key step is to recognize that physics, in accepting unified theories only, thereby makes a big metaphysical assumption about the nature of the universe. The outcome is a conception of scientific method which facilitates the criticism and improvement of metaphysical assumptions of physics. This view provides, not verification, but a perfect simulacrum of verification indistinguishable from the real thing. (shrink)

Stove argues that Popper and his successors in the philosophy of science, Kuhn, Lakatos and Feyerabend, were irrationalists because they were deductivists. That is, they believed all logic is deductive, and thus denied that experimental evidence could make scientific theories logically more probable. The book was reprinted as Anything Goes (1998) and Scientific Irrationalism: Origins of a Postmodern Cult (1998).

This book is about Karl Popper's early writings before he began his career as a philosopher. The purpose of the book is to demonstrate that Popper's philosophy of science, with its emphasis on the method of trial and error, is largely based on the psychology of Otto Selz, whose theory of problem solving and scientific discovery laid the foundation for much of contemporary cognitive psychology. By arguing that Popper's famous defence of the method of falsification as well (...) as his elaboration of an evolutionary theory of knowledge are equally indebted to German psychology, Michel ter Hark challenges the received view of the development of Popper's philosophy. The book concludes with a reinterpretation of Popper's theory of the mind-body problem, emphasizing its contemporary relevance. (shrink)

Overzicht van de ideeën van de Oostenrijks-Engelse wijsgeer (geb. 1902) over de wetenschap en de maatschappij.

One of the most original thinkers of the century, Karl Popper has inspired generations of philosophers, historians, and politicians. This collection of papers, specially written for this volume, offers fresh philosophical examination of key themes in Popper's philosophy, including philosophy of knowledge, science and political philosophy. Drawing from some of Popper's most important works, contributors address his solution to the problem of induction, his views on conventionalism and criticism in an open society, and his unique position in (...) 20th century philosophy. They also examine the current relevance of Popper to understanding liberal democracy, his critique of tribalism and his relationship with analytic philosophy in general - and with Wittgenstein in particular - as well as drawing on the studies of Isaac Newton and Albert Einstein to assess Popper's conception of science. (shrink)

First, a brief history is provided of Popper's views on the status of evolutionary biology as a science. The views of some prominent biologists are then canvassed on the matter of falsifiability and its relation to evolutionary biology. Following that, I argue that Popper's programme of falsifiability does indeed exclude evolutionary biology from within the circumference of genuine science, that Popper's programme is fundamentally incoherent, and that the correction of this incoherence results in a greatly expanded and (...) much more realistic concept of what is empirical, resulting in the inclusion of evolutionary biology. Finally, this expanded concept of empirical is applied to two particular problems in evolutionary biology — viz., the species problem and the debate over the theory of punctuated equilibria — and it is argued that both of them are still mainly metaphysical. (shrink)

Popper restricted his definition of falsifiability to consistent theories through what we may call his requirement of consistency. His main argument was that an inconsistent theory does not distinguish the sentences that corroborate it from those that contradict it, for all sentences follow from it. I propose to replace this requirement by the more basic requirement that the classes of potential corroborators and falsifiers of a theory do not overlap. This results not only in an unrestricted definition of falsifiability (...) but also in some inconsistent theories being falsifiable whenever that inconsistency is not located among its observational statements. Although this assumes a restriction of the principle of explosion or ex contradictione sequitur quodlibet (ECQ), it does not depend on any particular system or approach of paraconsistent logic. Finally, I propose to define the class of potential refuters of a theory, which is obtained by subtracting the class of potential corroborators from the class of potential falsifiers. Given that, by definition, the classes of potential refuters and corroborators of a theory do not overlap, it immediately follows that some observationally inconsistent theories are refutable in this sense. This establishes the bases for a new and more general formal theory of falsifiability of scientific factual/empirical theories. (shrink)

Popper’s theory of learning is sometimes met with incredulity because Popper claims that there is no transference of knowledge or knowledge elements from outside the individual, neither from the physical environment nor from others. Instead, he claims that we can improve our present theories by discovering their inadequacies.The intent of this article is not to persuade educators to adopt Popper’s approach uncritically to build their professional knowledge. Rather, it presents a discussion on the need for teachers to (...) adopt a critical approach in eliminating what is inadequate and preserve what is adequate by modifying or abandoning whatever traditions or practices that are inadequate to improve their teaching practice. Popper claims that knowledge advances by searching for and eliminating error contained in our theory. In other words, we can improve our present theories by finding out their inadequacies. (shrink)

Karl Popper is one of this century's most influential philosophers, but his life in fin-de siècle and interwar Vienna, and his exile in New Zealand during World War II, have so far remained shrouded in mystery. This intellectual 2001 biography recovers the legacy of the young Popper; the progressive, cosmopolitan, Viennese socialist who combated fascism, revolutionized the philosophy of science, and envisioned the Open Society. Malachi Hacohen delves into his archives and draws a compelling portrait of the philosopher, (...) the assimilated Jewish intelligentsia, and the vanished culture of Red Vienna, which was decimated by Nazism. Hacohen's adventurous biography restores Popper's works to their original Central European contexts and, at the same time, shows that they have urgent messages for contemporary politics and philosophy. (shrink)

Karl Popper hat eine Erkenntnis- und Wissenschaftstheorie, eine Philosophie der Naturwissenschaften, eine Sozialphilosophie, eine Philosophie des Geistes und sogar Beiträge zur Ästhetik geliefert. Lediglich eine Ethik fehlt, was bei Popper, der sich immer als Philosoph der Aufklärung bezeichnete, doch etwas erstaunt. Ich werde versuchen, Elemente einer solchen Ethik zu rekonstruieren. Karl Poppers Beiträge zur Ethik sind relativ wenig bekannt. Dies dürfte vor allem daran liegen, dass sich keine seiner Arbeiten ausschließlich mit Ethik beschäftigt. Stattdessen findet man Bemerkungen zu (...) diesem Thema verstreut in ganz verschiedenen Werken, vor allem in der Offenen Gesellschaft. Da Popper keine systematische Darstellung seiner Ansichten zur Ethik geliefert hat, soll dieser Artikel dazu beitragen, diese Lücke zu schließen. (shrink)

Karl Popper defines an ad hoc hypothesis as one that is introduced to immunize a theory from some (or all) refutation but which cannot be tested independently. He has also attempted to explicate ad hocness in terms of certain other allegedly undesirable properties of hypotheses or of the explanations they would provide, but his account is confused and mistaken. The first such property is circularity, which is undesirable; the second such property is reduction in empirical content, which need not (...) be. In the former case, I argue that non-circularity is in any event preferable to non-ad hocness as a necessary condition for a satisfactory explanation or an explanans, as the case may be, and I try to sort out various persistent errors surrounding this comparison. In the latter case, I suggest that Popper is barking up the wrong tree, that important scientific progress sometimes does consist in just such reductions in empirical content as he proscribes. This provides a further reason for not taking ad hoc hypotheses as Popper conceives them to pose the danger for science he believes they do. (shrink)

Karl Popper’s critique of idealism manifests itself with the application of his method, falsificationism, to metaphysics, epistemology, and social and political philosophy. According to Popper, who identifies himself as a philosophical realist, idealism has emerged as a result of the idea that reality cannot be known by reason and of the search for certainty which is erroneous, and it has begotten two mistaken and detrimental views. These views are historicism, the notion that history has an irresistible course, and (...) holism, the notion that social wholes are organic structures that amount to more than the individuals constituting them. Historicism and holism have become the philosophical underpinnings of closed societies throughout history, such as the totalitarian regimes of the 20th century. Therefore, with a practical leaning, Popper actually takes aim at these pernicious consequences of idealism while criticizing it. In this study, idealism and the contours of Popper’s philosophy are examined, and then Popper’s metaphysical, epistemological, social, and political critiques against idealism are investigated. Keywords: Karl Popper, idealism, historicism, holism, falsificationism. (shrink)

This article revisits Karl Popper’s falsificationist methodology with respect to three tasks. The first is to illuminate and systematize Popper’s methodological views in light of his core epistemological commitments. A second and related objective is to gauge which aspects of falsificationism should be identified as “conventionalist”—a label that Popper himself uses (albeit with qualifications) but that is compromised by and, thus, stands in need of elucidation because of Popper’s idiosyncratic understanding of conventionalism. Third, by elaborating (...) class='Hi'>Popper’s virtue-epistemological, dialogical model of rationality, I show how Popper’s conventionalism, fallibilism, and critical rationalism form a coherent system. This system allows Popper to accord science the status of a privileged source of knowledge—without naïve appeal to authority. My systematization of Popper’s views yields an intrinsically and exegetically more satisfactory reading of Popper’s falsificationism than usual presentations. Thanks to its marked flexibility and methodological liberalism, it bypasses many standard objections but still offers sound and relevant methodological advice. With its “virtue-methodological” thrust, Popper sketches an original and promising approach to methodology, the fertility of which deserves further exploration for contemporary debates. (shrink)

Three main conflicts between Popper and Agassi are discussed. Over the ethics of hard work which in reality turns out to be over perfectionism and optimism. Over the role of metaphysics in science. Over methodological individualism where is it argued that Popper's views are contradictory and that Agassi' Institutionalism prevails.

Popper wrote extensively on the quantum theory. In Logic der Forschung he devoted a whole chapter to the topic, while the whole of Volume 3 of the Postscript to the Logic of Scientific Discovery is devoted to the quantum theory. This volume entitled Quantum Theory and the Schism in Physics incorporated a famous earlier essay, ‘Quantum Mechanics without “the Observer”’ . In addition Popper's development of the propensity interpretation of probability was much influenced by his views on the (...) role of probability in quantum theory, and he also wrote an insightful critique of the 1936 paper of Birkhoff and von Neumann on nondistributive quantum logic. (shrink)

This paper aims to critically discuss the versatility of Popper’s theory of three worlds in the analysis of issues related to the ontological status and character of technical artifacts. Despite being discussed over years and hit with numerous criticisms it is still little known that Popper’s thesis has an important bearing on the philosophical characterization of technical artifacts. His key perspectives on the reality, autonomy, and ontological status of artifacts are rarely taken into consideration by scholars known to (...) be engaged in the study of artifacts. This paper consists of two main sections. The first section attempts to present a critical exposition of Popper’s account of reality and autonomy of artifacts. Recent discussions about the longstanding distinction between natural objects and artifacts are brought up and the relevance of Popper’s pluralistic thesis to this debate is pointed out. In addition, attention is drawn towards how to read his notion of the autonomy of artifacts. The primary emphasis of the second section is the ontological position of artifacts. Two separate arguments are posed to challenge the dual ontological status of what Popper called ‘embodied’ World 3 objects or artifacts. The first argument is concerned with the material composition and characteristic features of artifacts. The second one addresses the creative and epistemic value of these artificial products. (shrink)

Karl Popper (1902-1994) was one of the most influential philosophers of science of the 20th century. He made significant contributions to debates concerning general scientific methodology and theory choice, the demarcation of science from non-science, the nature of probability and quantum mechanics, and the methodology of the social sciences. His work is notable for its wide influence both within the philosophy of science, within science itself, and within a broader social context. Popper’s early work attempts to solve the (...) problem of demarcation and offer a clear criterion that distinguishes scientific theories from metaphysical or mythological claims. Popper’s falsificationist methodology holds that scientific theories are characterized by entailing predictions that future observations might reveal to be false. When theories are falsified by such observations, scientists can respond by revising the theory, or by rejecting the theory in favor of a rival or by maintaining the theory as is and changing an auxiliary hypothesis. In either case, however, this process must aim at the production of new, falsifiable predictions. While Popper recognizes that scientists can and do hold onto theories in the face of failed predictions when there are no predictively superior rivals to turn to. He holds that scientific practice is characterized by its continual effort to test theories against experience and make revisions based on the outcomes of these tests. By contrast, theories that are permanently immunized from falsification by the introduction of untestable ad hoc hypotheses can no longer be classified as scientific. Among other things, Popper argues that his falsificationist proposal allows for a solution of the problem of induction, since inductive reasoning plays no role in his account of theory choice. Along with his general proposals regarding falsification and scientific methodology, Popper is notable for his work on probability and quantum mechanics and on the methodology of the social sciences. Popper defends a propensity theory of probability, according to which probabilities are interpreted as objective, mind-independent properties of experimental setups. Popper then uses this theory to provide a realist interpretation of quantum mechanics, though its applicability goes beyond this specific case. With respect to the social sciences, Popper argued against the historicist attempt to formulate universal laws covering the whole of human history and instead argued in favor of methodological individualism and situational logic. Table of Contents 1. Background 2. Falsification and the Criterion of Demarcation a. Popper on Physics and Psychoanalysis b. Auxiliary and Ad Hoc Hypotheses c. Basic Sentences and the Role of Convention d. Induction, Corroboration, and Verisimilitude 3. Criticisms of Falsificationism 4. Realism, Quantum Mechanics, and Probability 5. Methodology in the Social Sciences 6. Popper’s Legacy 7. References and Further Reading a. Primary Sources b. Secondary Sources -/- . (shrink)

Karl Popper has often been cast as one of the most solitary figures of twentieth-century philosophy. The received image is of a thinker who developed his scientific philosophy virtually alone and in opposition to a crowd of brilliant members of the Vienna Circle. This paper challenges the received view and undertakes to correctly situate on the map of the history of philosophy Popper’s contribution, in particular, his renowned fallibilist theory of knowledge. The motive for doing so is the (...) conviction that the mainstream perspective on Popper’s philosophy makes him more difficult to understand than might otherwise be the case. The thinker who figures most significantly in the account of Popper developed in these pages is Leonard Nelson. Both a neo-Friesian and neo-Kantian, this philosopher deeply influenced Popper through his student Julius Kraft, who met with Popper on numerous occasions in the mid 1920s. It is in the light of this influence that we understand Popper’s recollection that when he criticized the Vienna Circle in the early 1930s, he looked upon himself “as an unorthodox Kantian”. (shrink)

Popper uses the "Humean challenge" as a justification for his falsificationism. It is claimed that in his basic argument he confuses two different doubts: (a) the Humean doubt (Popper's problem of induction), and (b) the "Popperean" doubt whether - presupposing that there are laws of nature - the laws we accept are in fact valid. Popper's alleged solution of the problem of induction does not solve the problem in a straightforward way (as Levison and Salmon have remarked (...) before). But if Popper's solution of the Humean challenge is re-interpreted as being close to Kant's it makes sense. Even though Popper explicitly rejects Kant's synthetic judgements a priori, it is claimed here that this is so because he misinterprets Kant's argument. If he had understood Kant correctly he should have been a modern "Kantianer"! (shrink)

Discussions of Karl Popper's falsificationist philosophy of science appear regularly in the recent literature on economic methodology. In this literature, there seem to be two fundamental points of agreement about Popper. First, most economists take Popper's falsificationist method of bold conjecture and severe test to be the correct characterization of scientific conduct in the physical sciences. Second, most economists admit that economic theory fails miserably when judged by these same falsificationist standards. As Latsis states, “the development of (...) economic analysis would look a dismal affair through falsificationist spectacles.”. (shrink)

In this chapter, I argue that Karl Popper was a communitarian philosopher. This will surprise some readers. Liberals often tout Popper as one of their champions. Indeed, there is no doubt that Popper shared much in common with liberals. However, I will argue that Popper rejected a central, though perhaps not essential, pillar of liberal theory, namely, individualism. This claim may seem to contradict Popper's professed methodological individualism. Yet I argue that Popper was a (...) methodological individualist in name only. In fact, methodological individualism faded from Popper's vocabulary as he moved institutions and situational analysis more firmly to centre-stage. Popper's focus on institutions and situations constitutes what I call his communitarianism. If my interpretation is correct, then theorists in the socio logy of scientific knowledge and communitarian epistemology should reconsider their long-standing distrust of Popper's philosophy. Indeed, they may have much to gain by treating Popper as a friend rather than a foe. (shrink)

Popper has provided a model for the scientific explanation of human actions and a metaphysical theory of man which can guide scientific research. In this paper I discuss the problems of the empirical content and nomicity of the Rationality Principle and extend the method of situational analysis to the problem of explaining beliefs. The domain of applicability of the Rationality Principle is bounded on one side by cases in which behavior is determined by processes which can not be influenced (...) by criticism and on the other side by the phenomenon of substantive creativity. However, a large part of human activity lies within its scope. (shrink)

‘Situational Analysis’ constitutes Popper's methodological proposal for the social sciences. There is an apparent inconsistency in the fact that, on the one hand, Popper maintains that we lear...

Popper's theory of the attraction of closed societies conflicts with his theory of research: the former sees rational thought as contrary to man's nature, whereas the latter sees it as an innate psychological process. This conflict arose because Popper developed a theory of the movement from the closed society—Heimat—to civilized society, which sees civilized society as a burden, before he adapted Selz's view of directed thought processes as problem solving, which sees rationality as natural. Rejecting the earlier view (...) and retaining the latter one opens up possibilities for better explanations of closed societies and better means of combating them. Key Words: closed society • Popper • Selz • problems • institutions. (shrink)