Document: The Popper Newsletter (4) 1/2



The main purpose of the Annual One-Day Conference on the Philosophy of Sir Karl Popper is to stimulate fruitful debate on Popper's philosophy. Hence the challenging tone of the talks. Mere exposition is both boring and unproductive, and speakers are encouraged to be as critical as possible. Such a spirit of criticism is in line with Popper's method of conjecture and refutation: bold guess followed by severe criticism. The Conference was well attended by 150 people, some academic some from the general public.

Popper's Metaphysical Turn

Alain Boyer was concerned with Popper's changing attitude to metaphysics. Popper is probably most famous for his demarcation between science and metaphysics, which for decades has been shrouded in confusion. The logical positivists (alias the Vienna circle) were the first to bring metaphysics into disrepute, arguing that it was meaningless. Any non-verifiable or non-tautological sentence was classed as nonsense by the Vienna circle. In one stroke the whole of theology, astrology, and many long respected philosophical doctrines such as determinism, were swept away as intellectual gobbledegook. Only scientific sentences were then accepted as meaningful since the logical positivists thought they were verifiable. This is the famous verifiability criterion.

Popper also wanted to demarcate science from such things as astrology, but his approach was fundamentally different to that of the logical positivists, though Popper is even now erroneously thought to dismiss metaphysics as meaningless. On the contrary, Popper thinks that metaphysics is both meaningful and important. It is worth expanding a little on this.

In my interpretation the purpose of Popper's demarcation criterion is a solution to the problem: how do we make our knowledge grow as fast as possible without promoting error. Scientific statements for Popper are those that must be falsifiable by experiment or observation. If our aim in science is to increase knowledge, then we want to have the most general statements since they contain more information than singular statements. The most general statements are universal, applying to all space and time. At the same time, recognizing our fallibility, we want to have some control over our conjectures. There are two possibilities: confirmation or refutation. Now we cannot confirm a universal statement, since this would require an examination of every point in time and space, which is logically impossible. But we can refute a universal statement, since all we need is one negative instance. (This is where Popper differs greatly from the logical positivists, since the criterion made the most informative statements of science - universal statements - meaningless.) The positivist's criterion also ascribed scientific status to many metaphysical statements such as: "There is a Devil". Alain Boyer's talk had three parts. The first part dealt with the object and the style of Popper's The Logic of Scientific Discovery, his second great work on the philosophy of science. The second part concerned the origins of Popper's metaphysical turn, while the final section was a sketchy presentation of a Popperian philosophy of nature.

Boyer pointed to the great style of The Logic of Scientific Discovery, something which he thinks derives from the unity of the work, which in turn springs from Popper's clear view of his objectives in this work. The first target of the work is the elimination of psychologism in every problem area: sociology, logic, epistemology, and even psychology. Psychologism, the analysis of the origin of a theory, is no part of the logicof knowledge. The epistemologist should have no concern with the psychological processes that lead to the generation of an idea, since the truth of a theory or the validity of an argument can be assessed independently of its origins. Psychologism is the neglect of what Popper calls World Three: all theories and arguments, considered as objective products of the mind and having an autonomous existence.

The second target of the book was the elimination of metaphysics. Metaphysical sentences are, of course, meaningful, but in The Logic of Scientific Discovery Popper identifies the scope of rationality and scientificity with testability. Accordingly, at the stage of Popper's thought, everything which is not testable is not decidable; it is a matter of faith, an irrational decision.

The element of decision in LSD is a dominant feature, which is less conspicuous in his later work. Boyer says that Popper was never a dogmatic falsificationist, but in the thirties, popper was, one might call, a decisionist falsificationist. There is not a single reference to the concept of decision in the Post Script to LSD (subtitled: Twenty Years On).

Popper's attitude to metaphysics changed dramatically in the 1940s when he was writing The Open Society and its Enemies. In this book Popper deals with the Greek philosophers, and it is clear that in writing the book he came to realize that metaphysical ideas are arguable even if not empirically refutable. Before this metaphysical turn metaphysical assertions were made more amenable to rational assessment in the LSD by translating them into methodological rules. Thus the principle of the uniformity of nature can be rendered as the rule never to stop looking for laws.

In the article What is Dialectic (1937) Popper still held to the idea that reason alone cannot decide between theories. In the 1940s Popper came to a slightly different position: that not all metaphysical theories were as good as one another, so one could argue reasonably between various metaphysical positions. Such theories can be judged by the standards of logical coherence, compatibility with well-tested scientific theory, and the ability to solve the problem for which they were introduced.

This change of attitude brought with it a change in Popper's problem situation. Whereas in 1933 demarcation took precedence over the problem of induction, in the Postscript induction is regarded as the central problem. Boyer quotes a significant sentence from the Postscript: "The problem of demarcation is to be distinguished from the far more important problem of truth".

Alain Boyer's main conclusion was that Popper became more a speculative metaphysician and cosmologist. The transcendental logic of Kant was replaced by what Popper calls the logic of the situation, and that is why evolutionary epistemology became so important.

Freud and the Philosophy of Science: Why Popperians are in for a Shock.

Dr. Christopher Badcock's talk was excellently delivered, clear and provocative. His contribution stirred much fruitful controversy, but it lacked a substantive attack on Popper's philosophy. Most of the talk was concerned with an exposition of the marriage of Freudian theory, which Badcock regards as a loosely knit set of astute observations of behaviour, and Sociobiology, which supposedly explains the former.

Freud's theory of infantile sexuality, for instance, points to a set of behaviours which only make sense in an evolutionary context: as the infant's way of soliciting parental investment that would not otherwise be forthcoming, and therefore contributing to the survival of the infant's genetic material. For example, excessive sucking of the mother's nipples (oral stage) has a contraceptive effect, and may have evolved because any individual that practises it will postpone the birth of rival siblings and therebyincrease its own genetic reproducibility. Again, Oedipal behaviour may have evolved mainly as a way of raising parental investment.

Badcock's arguments against Popper were rather less substantive. Badcock even opened with an anecdote that was intended to belittle the philosophy of science itself. Badcock was in Italy drinking coffee in a piazza, and in the middle of the piazza there was a policeman standing on a platform holding a baton and a whistle. A chaos of traffic was circling round the policeman as he whistled and waved his baton. Badcock said to his companion: is anyone taking the slightest bit of notice of the policeman? A few moments later the policeman answered his question when he got down from the platform and went off. The traffic continued without showing any indication that he had been there at all. Badcock said that he sometimes feels that philosophers of science are just like that policeman: they wave their batons and blow their whistles, but science goes its own way nevertheless.

A strong claim, no doubt, but false. Strangely, the one example that Badcock offered of a scientist dismissing Popper's thought on method, the astro-physicist Stephen Hawking, actually enforces Popper's view. One could easily give a long list of prominent scientists who have been influenced by Popper in both their method and theory. Peter Medawar, the immunologist, has written many books on science which advocate Popper's ideas. Ilya Prigogine, the Nobel prize winning chemist, makes considerable use of Popper's ideas on constrained chaos and irreversibility in physics and chemistry. In his book, The Cosmic Blueprint, Paul Davies, Professor of Theoretical Physics at the University of Newcastle upon Tyne, draws on Popper's arguments in favour of indeterminism and the importance of World Three in evolution.

But the beneficial influence of the philosophy of science is not confined to the recruitment of Popperian knights, but also included the generation of dissent and debate.

In Badcock's view this picture of the philosopher impotently waving his baton is the most sympathetic description of the philosopher's role. At worst, says Badcock, the philosopher of science can inhibit the more radical developments within science by applying too much criticism before the new ideas have been given a chance to blossom. But Popper has been keen to encourage the defense of new theories even against what at first seems insurmountable objections. It may take some time before the real strength of a theory becomes evident. But equally, to discover the strength of a theory, one needs both bold conjecture and severe criticism. Of course, much criticism can demoralise a theorist and lead him to abandoned a possibly important breakthrough. But this is a problem of inculcating the proper attitude, and does not undermine Popper's methodology. And it is within Popper's philosophy that the answer to this problem can be found. There are three facts that a scientist can draw fortitude from.

1) There is no shame in error, for there is no systematic way of avoiding error. Newton, despite the falsity of his theory of gravitation, has lost none of his greatness. In their quest for a breakthrough geniuses often produce a great number of false ideas, which is presumably a sign of their creativity. Error is a sign of intelligence. There is shame only in perpetuating error, failing to have the courage to make mistakes and to correct them.


Theories are objective entities, and should not be seen as part of one's personality. Hence theories can be criticised and improved as one might do to a machine, without degrading the theorist. One should look on criticism of one's theories as a compliment; after all, who wants to be ignored?


Thirdly, to criticise a theory is not to imply that presenting the theory is a waste of time. On the contrary, one should look on the refutation of one's theories as a worthy discovery in itself.

Badcock argued that the philosophical "policing" of science, according to Badcock, is futile, and leads to errors of fact. For example, the "crucial" experiment of Newton's Optics - separation and recombination of colours by prisms - could not be adequately carried out in his time and the modern definition of the length of the meter means that relativity could not be falsified by any experiments using meter lengths. Nevertheless, it would have been foolish to reject these theories because they were untestable at the time. This, Badcock says, illustrates Kuhn's paradigm theory: Paradigms validate themselves to a large extent because they set research agendas and establish validation criteria.

This argument has no merit at all. The fact that a particular crucial experiment cannot be carried out does not mean that no crucial experiment can be found. More importantly, Popper's method of conjecture and refutation still applies. After all, it is only through trial and error that crucial experiments can be found and possible ways of carrying them out discovered. Badcock's Kuhnian alternative is a license for uncontrolled speculation, since the only valid control of universal statements - refutation - is forbidden.

Badcock's talk was interesting in that it showed how the Kuhnian and Lakatosian confusion between an historical account of science and a normative account of science has caught-on outside of philosophical circles. Popper was concerned with what scientists ought to do if they wanted to promote the growth of knowledge, and not with what they actually do. The fact that scientists do not always abide by Popperian rules does not invalidate them. As David Miller, principal lecturer in philosophy at Warwick University, has aptly said: the whole of science may be wrong. Not even science can act as an ultimate authority.

Popperians were not in fact very much shocked by Badcock. Most of the arguments, explicitly attributed to Kuhn, had been heard before. But Badcock did bring to our notice an important new field of problems and the first theoretical attempts to solved them. Sociobiology may well turn out to be the most exciting science to emerge in recent years, and deserves careful perusal from philosophers of science. Even if it is largely metaphysical it may be a very fruitful research programme.

Evolutionary Epistemology

Professor Michael Ruse argued that there are problems with Popper's evolutionary epistemology. Popper wished to draw a strong analogy between the growth of science and the growth or development of organisms. In particular, the growth structure of both science and biological evolution conforms to this model: Problems; Blind variation; Selection. Ruse attempted to undermine the analogy by pointing out that although science is in an important sense progressive, there is no obvious progressiveness in biological evolution. Popper, Ruse suggests, is uncomfortable about this point, and he has tried to build into evolutionary theory a quasi direction. (See Popper's Autobiography, Unended Quest. p.173-177). If he had succeeded in introducing orthogenic trends in to evolutionary theory then Popper could have upheld the analogy, but Ruse felt that Popper had failed to do this.

Ruse's argument is that Popper draws an analogy between biological evolution and scientific advance. Badcock sees that there are differences between the two and thinks therefore that the analogy fails. But analogy is not identity, and Popper did not intend to imply identity. The analogy is not intended to justify Popper's view of science, butwas chosen to aid exposition. The important similarity between evolution and science stands: neither theories nor organisms are instructed by the environment but selected by it. Ruse's reservation centres around what he takes to be the implication that scientific hypotheses are produced completely at random. He is keen to point to the systematic nature of scientific enquiry. But neither Popper nor Donald T Campbell would want to deny the systematic nature of science; indeed Campbell is at pains to distinguish his concept of blind trials from random trials. Scientific hypotheses are produced with background knowledge in mind, and this must act as a filter on the scientist's imagination. There is systematic constraint on what scientists find worth testing. But equally, we must acknowledge that while constraining our hypotheses we consider; there are still imaginative leaps into the dark, "blind variation" as Campbell likes to call it.

Debate: Popper is Substantially Wrong on Marx

The afternoon debate was between the Libertarian David McDonagh (of the Libertarian alliance) and the Marxist, Professor M. Desai. Desai expressed his astonishment as to how marxist Popper is in certain respects, for instance in his endorsement of the autonomy of sociology and his criticism of Mill's psychologism. Popper also praises Marx for his understanding of the importance of unintended consequences. Desai sees the Open Society as an attack on totalitarianism, and on that understanding Marx does not belong with Hegel and Plato who are undoubtedly totalitarian. Marx, Desai maintained, believed in real freedom.

Desai's focus of attack was on Popper's treatment of Marx's prophecies. Popper credits Marx with the discovery that unintended consequences to human action is the key to the social sciences. This, however, was not Marx's discovery but Adam Smith's. (Dr. David Miller interjected at this point to say that it was actually David Hume's discovery.) The whole Scottish Enlightenment program of explanation was based on this idea. Their program was to construct a theory of society on the basis of time series data plus variation between social circumstances. Desai emphasized that to have a stage theory of history does not tie you to a prophetic theory. Is Marx a prophet, as Popper maintains? Capital has very little prophecy in it. It is overwhelmingly concerned with the operating principles of capitalism, and not with the transition between feudalism and capitalism or that from capitalism to socialism. Desai stresses that the operation of capitalism was indeed Marx's life-long preoccupation, his prophetic period being largely confined to his early years as a writer.

Contrary to popular interpretations, the predictions that Marx made were a) conditional; b) part of a model, which has to be tested as a whole; and c) recognized as having an effect on what actually does happen.

Marx's class model is wrongly interpreted by Popper. There is, of course a two class model in the Communist Manifesto and Das Capital, and this model is used to make certain abstract explanations and predictions. But if one looks at the three pamphlets on France, with their analysis of a particular historical situation, Marx abandons the two-class model and furnishes a much more complex analysis.

David McDonach opened with an apology. Whether the motion is true or false, Popper's book The Open Society and its Enemies is one of the most stimulating books ever written, surpassing even outstanding books such as The Health Hazards of Not Going Nuclear by Petra Beckman and The Ultimate Resource, by Julian Simon. Popper himself has said that it is better to have a stimulating false theory than a dull true theory.

David did maintain that Popper is substantially right on Marx, but nevertheless was critical of certain aspects of Popper's treatment. When he first read The Open Society David was a Marxist and his adherence survived the reading, so although it is substantially right on Marx it is a very poor attack. On rereading the book he was able to see why. Popper actually eulogizes Marx to an excessive degree. And this eulogy of Marx is not in the least warranted, for the sad truth was that Marx was not only a failure but, much worse, a charlatan. By the time of the 1870s marginal revolution in economics, which Marx being an avid reader of economics, must have known about, Marx knew that the game was up. (He probably first encountered traces of it in Gossen's work of the 1850s.) In the last decade of his life Marx was looking failure in the face. (The book which prompted the insight was Marx Contra Engels: the Tragic Dilemma, by Norman Levine.) Round about 1870 Marx became demoralised, but did not admit it and did not discourage Engels. Engels had virtually to bully Marx into publishing volume one in 1867.

In his treatment of Marx Popper makes the bold claim that the labour theory of value does not matter much to Marx. a marvellously bold claim, but rather like saying that Allah does not matter to Islam. On the contrary, the labour theory of value is of central importance to Marx, and this is why Marx was such a failure. Nevertheless, Popper goes on to redeem himself, for he asserts that the labour theory of value can do no more than the theory of supply and demand. Moreover, the labour theory of value is not adequate to the task that Marx set it, and he has in the end to take on board supply and demand. Marx begins his analysis in Capital with a straightforward labour theory of value, but subsequently introduces supply and demand theory in surreptitious steps through his definition of socially necessary labour time. All this excellent argument against the labour theory of value is, unfortunately, lost in the eulogy of Marx and in Popper's strange claim that it does not matter any way.

Document: The Popper Newsletter (4) 1/2

Fri Oct 13 08:28:42 BST 1995