The way in which knowledge progresses, and especially our scientific knowledge, is by unjustified anticipations, by guesses, by tentative solutions to our problems, by conjectures. These conjectures are controlled by criticism: that is, by attempted refutations, which include severely critical tests. They may survive these tests; but they can never be positively justified: they can neither be established as certainly true nor even as 'probable'. Criticism of our conjectures is of decisive importance: by bringing out our mistakes it makes us (...) understand the difficulties of the problems which we try to solve. This is how we become better acquainted with our problem, and able to propose more mature solutions: the very refutation of a theory - that is, of a tentative solution to our problem - is always a step forward that takes us nearer the truth. And this is how we can learn from our mistakes. As we learn from our mistakes our knowledge grows, even though we may never know - that is, know for certain. Since our knowledge can grow, there can be no reason here for despair of reason. And since we can never know for certain, the can be no authority here for any claim to authority, for conceit over our knowledge, or for smugness. The essays and lectures of which this book is composed apply this thesis to many topics, ranging from problems of the philosophy and history of the physical and social sciences to historical and political problems. (shrink)

This 1983 book is a lively and clearly written introduction to the philosophy of natural science, organized around the central theme of scientific realism. It has two parts. 'Representing' deals with the different philosophical accounts of scientific objectivity and the reality of scientific entities. The views of Kuhn, Feyerabend, Lakatos, Putnam, van Fraassen, and others, are all considered. 'Intervening' presents the first sustained treatment of experimental science for many years and uses it to give a new direction to debates about (...) realism. Hacking illustrates how experimentation often has a life independent of theory. He argues that although the philosophical problems of scientific realism can not be resolved when put in terms of theory alone, a sound philosophy of experiment provides compelling grounds for a realistic attitude. A great many scientific examples are described in both parts of the book, which also includes lucid expositions of recent high energy physics and a remarkable chapter on the microscope in cell biology. (shrink)

_Conjectures and Refutations_ is one of Karl Popper's most wide-ranging and popular works, notable not only for its acute insight into the way scientific knowledge grows, but also for applying those insights to politics and to history. It provides one of the clearest and most accessible statements of the fundamental idea that guided his work: not only our knowledge, but our aims and our standards, grow through an unending process of trial and error.

Using astrology as a case study, this paper attempts to establish a criterion for demarcating science from pseudoscience. Numerous reasons for considering astrology to be a pseudoscience are evaluated and rejected; verifiability and falsifiability are briefly discussed. A theory is said to be pseudoscientific if and only if (1) it has been less progressive than alternative theories over a long period of time, and faces many unsolved problems, but (2) the community of practitioners makes little attempt to develop the theory (...) towards solutions of the problems, shows no concern for attempts to evaluate the theory in relation to others, and is selective in considering confirmations and disconfirmations. This criterion has the interesting consequence that a theory can be scientific at one time but pseudoscientific at another. (shrink)

Modern empiricism has been conditioned in large part by two dogmas. One is a belief in some fundamental cleavage between truths which are analytic, or grounded in meanings independently of matters of fact, and truth which are synthetic, or grounded in fact. The other dogma is reductionism: the belief that each meaningful statement is equivalent to some logical construct upon terms which refer to immediate experience. Both dogmas, I shall argue, are ill founded. One effect of abandoning them is, as (...) we shall see, a blurring of the supposed boundary between speculative metaphysics and natural science. Another effect is a shift toward pragmatism. (shrink)

The essays in this volume represent an approach to human knowledge that has had a profound influence on many recent thinkers. Popper breaks with a traditional commonsense theory of knowledge that can be traced back to Aristotle. A realist and fallibilist, he argues closely and in simple language that scientific knowledge, once stated in human language, is no longer part of ourselves but a separate entity that grows through critical selection.

This book is available either individually, or as part of the specially-priced Arguments of the Philosphers Collection.

Feyerabrend argues that intellectual progress relies on the creativity of the scientist, against the authority of science.

A conceptual analysis of falsificationism is performed, in which the central falsificationist thesis is divided into several components. Furthermore, an empirical study of falsification in science is reported, based on the 70 scientific contributions that were published as articles in Nature in 2000. Only one of these articles conformed to the falsificationist recipe for successful science, namely the falsification of a hypothesis that is more accessible to falsification than to verification. It is argued that falsificationism relies on an incorrect view (...) of the nature of scientific inquiry and that it is, therefore, not a tenable research methodology. (shrink)

In 1996 physicist Alan Sokal published an essay in Social Text--an influential academic journal of cultural studies--touting the deep similarities between quantum gravitational theory and postmodern philosophy. Soon thereafter, the essay was revealed as a brilliant parody, a catalog of nonsense written in the cutting-edge but impenetrable lingo of postmodern theorists. The event sparked a furious debate in academic circles and made the headlines of newspapers in the U.S. and abroad. In Fashionable Nonsense: Postmodern Intellectuals' Abuse of Science, Sokal and (...) his fellow physicist Jean Bricmont expand from where the hoax left off. In a delightfully witty and clear voice, the two thoughtfully and thoroughly dismantle the pseudo-scientific writings of some of the most fashionable French and American intellectuals. More generally, they challenge the widespread notion that scientific theories are mere "narrations" or social constructions. (shrink)

Coming from a mathematical background, I was always puzzled by Popper’s view, according to which, after the falsification of a scientific theory its degree of corroboration becomes zero. Most of the scientific theories taught in the physics departments have already been falsified, and what is the point of teaching theories, whose degree of corroboration is zero? The first important observation to make is that not all cases of falsification are the same. In some cases, as for instance in the case (...) of the theory of phlogiston, the falsification happened in agreement with the Popperian picture. Scientists discarded the falsified theory and opted for its alternative. Therefore, nowadays nobody tries to make a scientific contribution to the theory of phlogiston. Nevertheless, there are cases, and Newtonian mechanics is surely the most important among them, when the behaviour of the scientists after the falsification of the theory is from the Popperian point of view incomprehensible. Many scientists were not ready to discard the falsified theory, and not for irrational reasons. Some of the deepest discoveries in Newtonian mechanics as for instance the famous Kolmogorov, Arnold, Moser theorem were made many years after this theory was falsified. I think that Andrej Kolmogorov, Vladimir Arnold or Jürgen Moser cannot be compared to an Aristotelian philosopher, who adheres to his pet theory after its falsification. What these three mathematicians did was a fundamental contribution to modern science. (shrink)

It is obvious that two contingent statements, each of which denies the existence of something, can be inconsistent with one another: for example, ‘There are no non-black ravens, and there is at least one raven’, and ‘There are no black ravens’. But it is also obvious that these two statements are inconsistent only because one of them, as well as denying the existence of something, asserts the existence of something. The mere denials of existence, ‘There are no non-black ravens’ and (...) ‘There are no black ravens’, are consistent with one another. Indeed, it must hold quite generally that two contingent statements cannot be inconsistent, where each is a mere denial of existence in the sense that it denies existence and does not also assert existence. For in order to be inconsistent with a mere denial of existence, a second statement must assert existence, whatever else it may do; and if it asserts existence, it is not itself a mere denial of existence. (shrink)

I criticize conceptual pluralism, as endorsed recently by John Dupre and Philip Kitcher, for failing to supply strategies for demarcating science from non-science. Using creation-science as a test case, I argue that pluralism blocks arguments that keep creation-science in check and that metaphysical pluralism offers it positive, metaphysical support. Logical empiricism, however, still provides useful resources to reconfigure and manage the problem of creation-science in those practical and political contexts where pluralism will fail.

Coming from a mathematical background, I was always puzzled by Popper’s view, according to which, after the falsification of a scientific theory its degree of corroboration becomes zero. Most of the scientific theories taught in the physics departments have already been falsified, and what is the point of teaching theories, whose degree of corroboration is zero? The first important observation to make is that not all cases of falsification are the same. In some cases, as for instance in the case (...) of the theory of phlogiston, the falsification happened in agreement with the Popperian picture. Scientists discarded the falsified theory and opted for its alternative. Therefore, nowadays nobody tries to make a scientific contribution to the theory of phlogiston. Nevertheless, there are cases, and Newtonian mechanics is surely the most important among them, when the behaviour of the scientists after the falsification of the theory is from the Popperian point of view incomprehensible. Many scientists were not ready to discard the falsified theory, and not for irrational reasons. Some of the deepest discoveries in Newtonian mechanics as for instance the famous Kolmogorov, Arnold, Moser theorem were made many years after this theory was falsified. I think that Andrej Kolmogorov, Vladimir Arnold or Jürgen Moser cannot be compared to an Aristotelian philosopher, who adheres to his pet theory after its falsification. What these three mathematicians did was a fundamental contribution to modern science. (shrink)

‘What distinguishes science from all other human endeavours is that the accounts of the world that our best, mature sciences deliver are strongly supported by evidence and this evidence gives us the strongest reason to believe them.’ That anyway is what is said at the beginning of the advertisement for a conference on induction at a celebrated British seat of learning in 2007. It shows how much critical rationalists still have to do to make known the message of Logik der (...) Forschung concerning what empirical evidence is able to do and what it does. (shrink)

(1968 [1922]). It amounts to the claim that social phenomena must be explained by showing how they result from individual actions, which in turn must be explained through reference to the intentional states that motivate the individual actors. It involves, in other words, a commitment to the primacy of what Talcott Parsons would later call “the action frame of reference” (Parsons 1937: 43-51) in social-scientific explanation. It is also sometimes described as the claim that explanations of “macro” social phenomena must (...) be supplied with “micro” foundations, ones that specify an action-theoretic mechanism (Alexander, 1987). (shrink)