Karl Popper, Science and Enlightenment

Karl Popper, Science and Enlightenment

Karl Popper, Science and Enlightenment

Nicholas Maxwell

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To my good friend Leemon McHenry

Acknowledgements

The Prologue, ‘An Idea to Help Save the World’, adapted from the Preface to the 2nd edition of What’s Wrong With Science? (Pentire Press, 2009), was first published in Sublime, Issue 17, 2009, pp. 90-93. An earlier version of Chapter 1, ‘Karl Raimund Popper’, was first published in British Philosophers, 1800-2000, ed., P. Dematteis, P. Fosl and L. McHenry, Bruccoli Clark Layman, Columbia, 2002, pp. 176-194. Chapter 2, ‘Popper, Kuhn, Lakatos and aim-oriented empiricism’ is an updated version of an article first published in Philosophia 32, nos. 1–4, 2005, pp. 181-239 (Springer). An earlier version of Chapter 3, ‘Einstein’s Rational Discovery of Special and General Relativity’ was first published in The British Journal for the Philosophy of Science 44, 1993, pp. 275-305 (Oxford University Press). Chapter 8, ‘Does probabilism solve the great quantum mystery?’, is an updated version of an article first published in Theoria, vol. 19/3, no. 51, 2004, pp. 321-336. Chapter 9, ‘Science, reason, knowledge and wisdom: a critique of specialism’, is a modified version of an article first published in Inquiry 23, 1980, pp. 19-81 (Taylor and Francis). Chapter 10, ‘Karl Popper and the Enlightenment Programme’ is an updated version of chapter 11 of Karl Popper: A Centenary Assessment. Vol. 1: Life and Times, Values in a World of Facts, ed. I. Jarview, K. Milford and D. Miller, Ashgate, London, pp. 177-190. The author is grateful to the editors and publishers of the above journals and books for permission to publish these updated essays. The Introduction and Chapters 4–7 have not been published before.

Contents

List of figures

Prologue: An idea to help save the world

Introduction

1.Karl Raimund Popper

2.Popper, Kuhn, Lakatos and aim-oriented empiricism

3.Einstein, aim-oriented empiricism, and the discovery of special and general relativity

4.Non-empirical requirements scientific theories must satisfy: simplicity, unity, explanation, beauty

5.Scientific metaphysics

6.Comprehensibility rather than beauty

7.A mug’s game? Solving the problem of induction with metaphysical presuppositions

8.Does probabilism solve the great quantum mystery?

9.Science, reason, knowledge and wisdom: a critique of specialism

10.Karl Popper and the Enlightenment Programme

Notes

References

Index

List of figures

2.1Aim-oriented empiricism

5.1Another version of aim-oriented empiricism

9.1Specio-universalism, integrating specialized and fundamental problem solving

9.2Specio-universalist academic inquiry devoted to helping people realize what is of value in life

10.1Aim-oriented rationality applied to the task of making progress towards a civilized world

Prologue: An idea to help save the world

Here is an idea that just might save the world. It is that science, properly understood, provides us with the methodological key to the salvation of humanity.

A version of this idea can be found buried in the works of Karl Popper. Famously, Popper argued that science cannot verify theories, but can only refute them. This sounds very negative, but actually it is not, for science succeeds in making such astonishing progress by subjecting its theories to sustained, ferocious attempted falsification. Every time a scientific theory is refuted by experiment or observation, scientists are forced to try to think up something better, and it is this, according to Popper, which drives science forward.

Popper went on to generalize this falsificationist conception of scientific method to form a notion of rationality, critical rationalism, applicable to all aspects of human life. Falsification becomes the more general idea of criticism. Just as scientists make progress by subjecting their theories to sustained attempted empirical falsification, so too all of us, whatever we may be doing, can best hope to achieve progress by subjecting relevant ideas to sustained, severe criticism. By subjecting our attempts at solving our problems to criticism, we give ourselves the best hope of discovering (when relevant) that our attempted solutions are inadequate or fail, and we are thus compelled to try to think up something better. By means of judicious use of criticism, in personal, social and political life, we may be able to achieve, in life, progressive success somewhat like the progressive success achieved by science. We can, in this way, in short, learn from scientific progress how to make personal and social progress in life. Science, as I have said, provides the methodological key to our salvation.

I discovered Karl Popper’s work when I was a graduate student doing philosophy at the University of Manchester, in the early 1960s. As an undergraduate, I was appalled at the triviality, the sterility, of so-called Oxford philosophy. This turned its back on all the immense and agonizing problems of the real world – the mysteries and grandeur of the universe, the wonder of our life on earth, the dreadful toll of human suffering – and instead busied itself with the trite activity of analysing the meaning of words. Then I discovered Popper, and breathed a sigh of relief. Here was a philosopher who, with exemplary intellectual integrity and passion, concerned himself with the profound problems of human existence, and had extraordinarily original and fruitful things to say about them. The problems that had tormented me had in essence, I felt, already been solved.

But then it dawned on me that Popper had failed to solve his fundamental problem: the problem of understanding how science makes progress. In one respect, Popper’s conception of science is highly unorthodox: all scientific knowledge is conjectural; theories are falsified but cannot be verified. But in other respects, Popper’s conception of science is highly orthodox. For Popper, as for most scientists and philosophers, the basic aim of science is knowledge of truth, the basic method being to assess theories with respect to evidence, nothing being accepted as a part of scientific knowledge independently of evidence. This orthodox view – which I came to call standard empiricism – is, I realized, false. Physicists only ever accept theories that are unified – theories that depict the same laws applying to the range of phenomena to which the theory applies. Endlessly many empirically more successful disunified rivals can always be concocted, but these are always ignored. This means, I realized, that science does make a big, permanent and highly problematic assumption about the nature of the universe independently of empirical considerations and even, in a sense, in violation of empirical considerations: namely, that the universe is such that all grossly disunified theories are false. Without some such presupposition as this, the whole empirical method of science breaks down.

It occurred to me that Popper, along with most scientists and philosophers, had misidentified the basic aim of science. This is not truth per se. It is rather truth presupposed to be unified, presupposed to be explanatory or comprehensible (unified theories being explanatory). Inherent in the aim of science there is the metaphysical – that is, untestable – assumption that there is some kind of underlying unity in nature, that the universe is, in some way, physically comprehensible.

But this assumption is profoundly problematic. We do not know that the universe is comprehensible. This is a conjecture. Even if it is comprehensible, almost certainly it is not comprehensible in the way science presupposes it is today. For good Popperian reasons, this metaphysical assumption must be made explicit within science and subjected to sustained criticism, as an integral part of science, in an attempt to improve it.

The outcome is a new conception of science, and a new kind of science, which I call aim-oriented empiricism. This subjects the aims, and associated methods, of science to sustained critical scrutiny, the aims and methods of science evolving with evolving knowledge. Philosophy of science (the study of the aims and methods of science) becomes an integral, vital part of science itself. And science becomes much more like natural philosophy in the time of Newton, a synthesis of science, methodology, epistemology, metaphysics and philosophy.

The aim of seeking explanatory truth is, however, a special case of a more general aim, that of seeking valuable truth. And this is sought in order that it be used by people to enrich their lives. In other words, in addition to metaphysical assumptions, inherent in the aims of science there are value assumptions, and political assumptions, assumptions about how science should be used in life. These are, if anything, even more problematic than metaphysical assumptions. Here, too, assumptions need to be made explicit and critically assessed, as an integral part of science, in an attempt to improve them.

Released from the crippling constraints of standard empiricism, science would burst out into a wonderful new life, realizing its full potential, responding fully both to our sense of wonder and to human suffering, becoming both more rigorous and of greater human value.

And then, in a flash of inspiration, I had my great idea. I could tread a path parallel to Popper’s. Just as Popper had generalized falsificationism to form critical rationalism, so I could generalize my aim-oriented empiricist conception of scientific method to form an aim-oriented conception of rationality, potentially fruitfully applicable to all that we do, to all spheres of human life. But the great difference would be this. I would be starting out from a conception of science – of scientific method – that enormously improves on Popper’s notion. In generalizing this, to form a general idea of progress-achieving rationality, I would be creating an idea of immense power and fruitfulness.

I knew already that the line of argument developed by Popper, from falsificationism to critical rationalism, was of profound importance for our whole culture and social order, and had far-reaching implications and application for science, art and art criticism, literature, music, academic inquiry quite generally, politics, law, morality, economics, psychoanalytic theory, evolution, education, history – for almost all aspects of human life and culture. The analogous line of argument I was developing, from aim-oriented empiricism to aim-oriented rationalism, would have even more fruitful implications and applications for all these fields, starting as it did from a much improved initial conception of the progress-achieving methods of science.

The key point is extremely simple. It is not just in science that aims are profoundly problematic; this is true in life as well. Above all, it is true of the aim of creating a good world – an aim inherently problematic for all sorts of more or less obvious reasons. It is not just in science that problematic aims are misconstrued or repressed; this happens all too often in life, too, both at the level of individuals, and at the institutional or social level. We urgently need to build into our scientific institutions and activities the aims-and-methods-improving methods of aim-oriented empiricism, so that scientific aims and methods improve as our scientific knowledge and understanding improve. Likewise, and even more urgently, we need to build into all our other institutions, into the fabric of our personal and social lives, the aims-and-methods-improving methods of aim-oriented rationality, so that we may improve our personal, social and global aims and methods as we live.

One outcome of the twentieth century is a widespread and deep-seated cynicism concerning the capacity of humanity to make real progress towards a genuinely civilized, good world. Utopian ideals and programmes, whether of the far left or right, that have promised heaven on earth, have led to horrors. Stalin’s and Hitler’s grandiose plans led to the murder of millions. Even saner, more modest, more humane and rational political programmes, based on democratic socialism, liberalism or free markets and capitalism, seem to have failed us. Thanks largely to modern science and technology, many of us today enjoy far richer, healthier and longer lives than our grandparents or great grandparents, or those who came before. Nevertheless, the modern world is confronted by grave global problems: the lethal character of modern war; the spread and threat of armaments, conventional, chemical, biological and nuclear; rapid population growth; severe poverty of millions in Africa, Asia and elsewhere; destruction of tropical rainforests and other natural habitats; rapid extinction of species; annihilation of languages and cultures. And over everything hangs the menace of climate change, threatening to intensify all the other problems (apart, perhaps, from population growth).

All these grave global problems are the almost inevitable outcome of the successful exploitation of science and technology plus the failure to build aim-oriented rationality into the fabric of our personal, social and institutional lives. Modern science and technology make modern industry and agriculture possible, which in turn make possible population growth, modern armaments and war, destruction of natural habitats and extinction of species, and global warming. Modern science and technology, in other words, make it possible for us to achieve the goals of more people, more industry and agriculture, more wealth, longer lives, more development, housing and roads, more travel, more cars and aeroplanes, more energy production and use, more and more lethal armaments (for defence only, of course!). These things seem inherently desirable and, in many ways, are highly desirable. But our successes in achieving these ends also bring about global warming, war, vast inequalities across the globe, destruction of habitats and extinction of species.

All our current global problems are the almost inevitable outcome of our long-term failure to put aim-oriented rationality into practice in life. Were we to do so, we would actively seek to discover problems associated with our long-term aims, actively explore ways in which problematic aims can be modified in less problematic directions, and at the same time develop the social, political, economic and industrial muscle able to change what we do, how we live, so that our aims become less problematic, less destructive in both the short and long term. Were we to do all this, we would at least be taking active steps to anticipate, and to avert the development of, grave global problems of the kind we face today. As it is, we have failed even to appreciate the fundamental need to improve aims and methods as the decades go by. Conventional ideas about rationality are all about means, not about ends, and are not designed to help us improve our ends as we proceed. Our current global problems are the outcome. Implementing aim-oriented rationality is essential if we are merely to survive in the long term. To repeat, the idea spelled out in this book, if taken seriously, just might save the world.

Einstein put his finger on what is wrong when he said, Perfection of means and confusion of goals seems, to my opinion, to characterize our age. This outcome is inevitable if we restrict rationality to means, and fail to demand that rationality – the authentic article – must quite essentially include the sustained critical scrutiny of ends.

Scientists, and academics more generally, bear a heavy burden of responsibility for allowing our present impending state of crisis to develop. Putting aim-oriented rationality into practice in life can be painful, difficult and counterintuitive. It involves calling into question some of our most cherished aspirations and ideals. We have to learn how to live in aim-oriented rationalistic ways. And here, academic inquiry ought to have taken a lead. The primary task of our schools and universities, indeed, ought to have been, over the decades, to help us learn how to improve aims and methods as we live. Not only has academia failed miserably to take up this task, or even see it as necessary or desirable, even worse, perhaps, academia has failed itself to put aim-oriented rationality into practice. Science has met with such astonishing success because it has put something like aim-oriented empiricism into scientific practice, but this has been obscured and obstructed by the conviction of scientists that science ought to proceed in accordance with standard empiricism – with its fixed aim and fixed methods. Science has achieved success despite, and not because of, general allegiance of scientists to standard empiricism.

The pursuit of scientific knowledge dissociated from a more fundamental concern to help humanity improve aims and methods in life is, as we have seen, a recipe for disaster. This is the crisis behind all the others. We are in deep trouble. We can no longer afford to blunder blindly on our way. We must strive to peer into the future and steer a course less doomed to disaster. Humanity must learn to take intelligent and humane responsibility for the unfolding of history.

Introduction

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 those 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 basic theme of the book has already been summarized in the Prologue. In what follows I spell out this theme in greater detail. The book consists of a collection of essays that 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 new philosophy of science, which I call aim-oriented empiricism.¹ 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 (1966a) and The Poverty of Historicism (1961). 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 new conception of rationality – aim-oriented rationalism – which 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 his 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. That there is indeed much to be learned from scientific progress about how to achieve social progress was the big idea of the eighteenth-century Enlightenment. This was immensely influential. But the philosophes of the Enlightenment made mistakes, and these mistakes, inherited from the Enlightenment, are built into the institutional and intellectual structure of academic inquiry today. In his two great works, The Logic of Scientific Discovery (1959) and The Open Society and Its Enemies (1966a), Popper corrected some of the mistakes of the Enlightenment – mistakes about the nature of scientific method and rationality. But Popper left other mistakes undetected and uncorrected. The present book seeks to push the Popperian research programme further, and correct what Popper left uncorrected.

The fundamental idea that emerges is that there is an urgent need to bring about a revolution in academic inquiry so that it takes up its proper task of promoting wisdom and not just acquiring knowledge – wisdom being the capacity to realize what is of value in life for oneself and others, thus including knowledge and technological know-how, but much else besides. I have devoted much of my working life to trying to get this idea across. The essays that follow provide a record of this life work.

Most philosophers of science see their work as contributing to a meta-discipline. The object of study is science, and the task is to describe, explain and understand this object. It is no more the proper task of the philosopher of science to criticize science, or to make suggestion as to how science can be improved, than it is the task of the astronomer to criticize the moon. But this standard meta-discipline way of conceiving the subject entirely misconstrues what ought to be the proper relationship between science and the philosophy of science. A major implication of the view to be expounded and defended here, aim-oriented empiricism, is that the rationality of science requires that the philosophy of science – critical exploration of views concerning the aims and methods of science – is an integral, influential part of science itself, both being influenced by, and influencing, science. In other words, in order to be rigorous, science must include some imaginative and critical exploration of problematic aims and methods. The very act of setting up the philosophy of science as a meta-discipline, distinct from science itself, looking down on science from above, as it were, describing and seeking to explain and understand what goes on, but in no way interfering with, contributing to or criticizing science, serves to undermine the very thing the discipline seeks to understand, namely the rationality of science. The orthodox meta-discipline approach not only makes the subject sterile (in that it can have nothing to contribute to science itself), it makes it quite impossible to solve the fundamental problem of the discipline – the rationality of science. Indeed, the discipline, so conceived, actually becomes the source of a pervasive and damaging irrationality in science.²

I make no apology, therefore, for criticizing science, for attempting to contribute to and improve science, in what follows. Philosophy of science pursued within the framework of aim-oriented empiricism might be compared to the work Weierstrass, Dedekind and others did in the late nineteenth and early twentieth century in bringing greater rigour to mathematics: they made mathematics more rigorous, and contributed to mathematics itself, at one and the same time. Somewhat analogously, I seek to increase the rigour of science, and make a contribution to science at the same time. I might add that in criticizing science and suggesting how it might be improved (made more rigorous and of greater human value) I am again developing a tendency to be found scattered among Popper’s works. Despite – or perhaps because of – his great admiration for science at its best, Popper does not shrink from criticizing what he sees as deplorable aspects of science: specialization, authoritarianism, submission to mere intellectual fashion, failure to grapple with the fundamental problems of cosmology. Again, Popper depicts graphically some of the bad consequences, for science itself, of attempting to put bad inductivist methods into scientific practice. But all this is paradoxically at odds with a major tenet of Popper’s philosophy of science, namely his proposed solution to the problem of demarcation. Popper holds that an idea, in order to be scientific, must be empirically falsifiable. Philosophies of science, because they are not empirically falsifiable, are not a part of science. They are to be severely demarcated from science. Thus Popper, in actively criticizing aspects of science, violates the precepts of his own philosophy of science. All this changes dramatically once Popper’s philosophy of science has been amended to become the doctrine espoused here, aim-oriented empiricism.³

The points just made concerning the proper relationship between science on the one hand and the philosophy of science on the other, will turn out to have a major bearing on further developments of the argument concerning social inquiry. I argue that social inquiry needs to be construed, not primarily as social science, but rather as social philosophy or social methodology. Social inquiry is not to be related to the social world as astronomy is to the moon, or geology is to the earth. Social inquiry is not, fundamentally, engaged in seeking to acquire knowledge about social phenomena. Rather, social inquiry needs to take the relationship between science and the philosophy of science (as specified by aim-oriented empiricism) to be the model, the ideal, of how social inquiry ought to be related to society. What the philosophy of science is to science, so social inquiry is to society. The proper task of social inquiry is to help worthwhile social endeavours improve their problematic aims and methods as they proceed, just as the proper task of the philosophy of science is to help science improve its problematic aims and methods as it proceeds. On this view, indeed, the philosophy of natural science is just that small, but crucial, bit of social inquiry that deals with the worthwhile social endeavour of natural science.

Let me now indicate, in a little more detail, the contents of the chapters of this book.

Chapter 1 gives an account of Karl Popper’s life and work. I make it quite clear that, in my view, Popper is the greatest philosopher of the twentieth century. I am nevertheless critical of aspects of his work – it would be a betrayal of his critical philosophy not to be. In a preliminary way, I indicate what are, in my view, unsolved problems inherent in his views, and outline what needs to be done to overcome these difficulties. Subsequent chapters seek to improve Popper’s philosophy in some key respects in order to overcome these defects.

In Chapter 2 I argue that aim-oriented empiricism is a kind of synthesis of the views of Popper, Thomas Kuhn and Imre Lakatos, but also a dramatic improvement over all three views. Aim-oriented empiricism stands in sharp contrast to standard empiricism, versions of which are defended by Popper, Kuhn and Lakatos, and are taken for granted by most scientists and philosophers of science. According to standard empiricism, the basic intellectual aim of science is truth,⁴ and the basic method is to assess claims to knowledge of truth impartially with respect to evidence. Considerations of simplicity, unity or explanatory character may legitimately influence preference for a theory for a time, but not in such a way that the universe itself is permanently presumed to be simple, unified or comprehensible. Choice of theory may be biased in the direction of a paradigm or metaphysical view for a time, but in the end empirical considerations must decide what theories are accepted and rejected. The key tenet of all versions of standard empiricism is that no assumption about the universe can be accepted permanently as a part of scientific knowledge independent of evidence, let alone in conflict with evidence. But physics, in accepting unified fundamental physical theories only, and persistently rejecting empirically more successful disunified rivals, does thereby make a persistent metaphysical assumption about the world: some kind of unified pattern of physical law runs through all phenomena. Standard empiricism is thus untenable. Aim-oriented empiricism, by contrast, acknowledges that persistent scientific acceptance of unified theories means that science implicitly accepts that the universe itself possesses some kind of underlying unity. Rigour demands that this highly problematic, implicit metaphysical conjecture be made explicit, so that it can be critically assessed, and so that alternatives can be developed and assessed, in the hope of improving the specific assumption that physics makes at any time. Aim-oriented empiricism holds that we need to represent this highly problematic assumption in the form of a hierarchy of assumptions, these becoming less and less substantial, and so less and less problematic, and more nearly such that their truth is required for science to be possible at all, as one goes up the hierarchy. In this way, we form a framework of relatively stable and unproblematic assumptions, high up in the hierarchy, within which much more substantial and problematic assumptions, low down in the hierarchy, may be critically assessed, and improved, in the light of which best help promote empirical knowledge, and comply with assumptions higher up in the hierarchy. This is the view that provides a triumphant synthesis of, and improvement over, the views of Popper, Kuhn and Lakatos – more Popperian than Popper, more Kuhnian than Kuhn and more Lakatosian than Lakatos.

Chapter 3 argues that Einstein was the first scientist to put something like aim-oriented empiricism explicitly into scientific practice in discovering special and general relativity. The method of discovery of aim-oriented empiricism played a crucial role in Einstein’s discovery of these theories. And not only did Einstein implement aim-oriented empiricism in scientific practice: after his discovery of general relativity, Einstein came to advocate a view that came closer and closer to aim-oriented empiricism as the years passed.

Chapter 4 solves the problem of what it means to say of a scientific theory that it is simple, unified or explanatory. This problem was recognized by Popper (1963, p. 241), but Popper did not know how to solve it. Einstein recognized the problem too, but did not know how to solve it, either. It is one of the great successes of aim-oriented empiricism that it provides the means for the problem to be solved.

Chapter 5 gives a careful and more detailed argument in support of aim-oriented empiricism, attention being given to some of the difficulties that arise in connection with the view, and the argument in support of the view.

Chapter 6 compares and contrasts views about simplicity, unity, explanatory power or beauty associated with aim-oriented empiricism on the one hand, and a view put forward by James McAllister on the other hand (see his influential Beauty and Revolution in Science [McAllister, 1996]).

Chapter 7 argues that aim-oriented empiricism succeeds in doing what Popper’s falsificationism fails to do, namely solve the problem of induction.

Chapter 8 takes up a theme close to Popper’s heart: the problems of interpreting quantum theory in a realist way – so that the theory can be understood to be about electrons, nuclei, atoms and other denizens of the quantum world, and is not doomed to be a mere instrument for the prediction of experimental results. I argue that probabilism is the key to solving the fundamental quantum mystery – the apparent capacity of quantum entities (electrons, atoms and so on) to behave both as particles and waves. Probabilism, here, is the doctrine that nature herself is probabilistic. What exists at one moment may only determine what exists next probabilistically, and not deterministically. This develops basic ideas of Popper about quantum theory, but in ways of which he strongly disapproved.

Chapter 9 criticizes specialism, the doctrine that academic inquiry quite properly consists of a great number of specialized disciplines, only specialized intellectual standards being worthwhile. This is opposed by the view that academic inquiry must engage in sustained exploration of fundamental problems that cut across disciplinary boundaries, this exploration being undertaken in a way that influences, and is influenced by, specialized research. This is an improvement of anti-specialist remarks scattered throughout Popper’s works.

Chapter 10 argues that Popper’s The Logic of Scientific Discovery and The Open Society and Its Enemies, taken together, constitute a major development of the Enlightenment programme of learning from scientific progress how to achieve social progress towards a more enlightened world. But what Popper has to say is not the last word on the subject. Popper’s version of the Enlightenment programme needs further improvement, partly because Popper’s conception of scientific method needs to be improved, but mainly because, in order to implement the programme, we need to apply scientific method, not to social science, but to the social world itself. How and why Popper’s version of the Enlightenment programme needs to be improved is outlined in this chapter.

1

Karl Raimund Popper

Karl Popper is the greatest philosopher of the twentieth century. No other philosopher of the period has produced a body of work that is as significant. What is best in Popper’s output is contained in his first four published books. These tackle fundamental problems with ferocious, exemplary integrity, clarity, simplicity and originality. They have widespread, fruitful implications, for science, for philosophy, for the social sciences, for education, for art, for politics and political philosophy.

In his first published book The Logic of Scientific Discovery (1959, first published in German in 1934), Popper argues that, although scientific theories cannot be verified, or even rendered probable, by evidence, they can be falsified. Science makes progress by putting forward falsifiable conjectures – theories which say as much as possible about the world, and which thus expose themselves as much as possible to the risk of empirical refutation; they are then subjected to a ruthless onslaught of attempted observational and experimental refutation. When finally a scientific theory is falsified empirically, the task then becomes to think up an even better theory, which says even more about the world. The new theory must predict all the success of the old theory, predict successfully the phenomena that falsified the old theory, and predict new phenomena as well. In his next book, The Open Society and Its Enemies (1966), written during the Second World War and first published in 1945, Popper tackles problems that arise in connection with creating an open society, one which tolerates diversity of views and ways of life. Popper argues that some of the greatest thinkers have been opposed to the open society, most notably Plato and Marx. In The Poverty of Historicism (1961), first published in 1957, Popper is concerned to demolish the view that social science should, or can, predict the way societies evolve. Popper spells out his view of how social science should be developed, closely modelled on the account of natural science given in The Logic of Scientific Discovery. The next book, Conjectures and Refutations (1963), is a collection of essays which restate in a more accessible way Popper’s falsificationist view of science, and draw out implications for a range of philosophical problems. Further books include Objective Knowledge (1972), a collection of essays which draw on the analogy between Darwinian evolution and scientific progress, and which expound Popper’s view that there exists, in addition to the material world and the psychological world, a third world of theories, problems and arguments; The Self and Its Brain (1977), written with the neurologist John Eccles, which applies Popper’s third world view to the mind-body problem; and the three-volume The Postscript (1982a, 1982b, 1983), which amounts to a massive restatement and development of Popper’s falsificationist conception of science. A volume of The Library of Living Philosophers (Schilpp, 1974) is devoted to Popper’s work; this includes Popper’s intellectual autobiography, published subsequently as a separate book with the title Unended Quest (1976a). This gives a fascinating and gripping account of the development of Popper’s thought. The Two Fundamental Problems of the Theory of Knowledge was a precursor to The Logic of Scientific Discovery. Its two problems are the problem of induction (the problem of how theories can be verified by evidence), and the problem of demarcation (the problem of how science is to be demarcated from non-science). The book was not published until 1979 in German, and in 2009 in English.

Fundamental to Popper’s philosophy is the idea that criticism lies at the heart of rationality. It would be a betrayal of Popper’s philosophy to give an entirely uncritical exposition of his work; some criticism of key tenets of his philosophy will therefore be included in what follows.

1.1 Life

Karl Raimund Popper was born in Vienna on 28 July 1902. His parents were Jewish but converted to Protestantism before their children were born. Popper’s father, Simon Carl Siegmund (1856–1932), was a doctor of law of the University of Vienna. He had a successful legal practice in Vienna, at which he apparently worked hard, but his real interests lay in the direction of scholarship and literature. Popper’s mother, Jenny Schiff (1864–1938), came from a musical family, and was herself musical. Popper tells us that she played the piano beautifully; music had an important place in Popper’s life.

During Popper’s early childhood, his parents were prosperous. They lived in a large apartment in an eighteenth-century house in the centre of Vienna, where Popper’s father conducted his legal practice. Popper’s father had an enormous library, which included many works of philosophy; books were everywhere, Popper tells us, except in the dining room, where stood a concert grand piano.

As a young boy, Popper was much concerned with the poverty he saw all around him in Vienna. In his autobiography, Popper recounts an early brush with philosophy. His father had suggested he read some volumes of August Strindberg’s autobiography. Finding that Strindberg gave much too much importance to words and their meanings, Popper tried to point this out to his father, and was surprised to discover that he did not agree. Popper later saw this as his first brush with a lifelong battle to combat the influential view that philosophy must concern itself with analysis of meaning.

Popper left school at 16 because of the tedium of the classes, and enrolled at the University of Vienna, initially as a non-matriculated student. Four years later, at the second attempt, he passed the exam to become a matriculated student. Any student could take any lecture course, and, initially, Popper sampled lectures in a wide range of subjects – history, literature, psychology, philosophy – before concentrating on physics and mathematics. In these fields Popper had excellent, if remote and autocratic, teachers: Hans Thirring, Wilhelm Wirtinger, Philipp Furtwängler and Hans Hahn. Later, Popper devoted himself to the study of the psychology of thinking, influenced by Karl Bühler and the writings of Otto Selz.

The First World War and its aftermath brought dramatic changes to conditions of life in Vienna. Popper’s father lost much of his savings. Popper left home and moved into part of a disused military hospital converted by students into a primitive students’ home, and joined socialist groups seeking political change. For a time, Popper thought of himself as a communist. But then, on 15 June 1919, an event occurred which Popper was later to describe as one of the most important in his life; it caused him to become critical of communism and Marxism, and, years later, led to the writing of his The Open Society and Its Enemies. The communists organized a demonstration with the intention of freeing communists held in a police station in Vienna. The police opened fire, and some of the demonstrators were killed. Popper was deeply shocked, and even felt some personal responsibility for the tragedy, in that he had endorsed a doctrine, Marxism, which required that there should be just such incidents, so that the struggle to overcome capitalism might be intensified.

Popper nevertheless continued to think of himself as a socialist, and to associate with socialist groups. In his autobiography, Popper celebrates these groups of working people for their dedication, their eagerness to become educated. Even though the times were troubled, the economic and political outlook bleak, Popper says that he and his friends were often exhilarated at the intellectual and political challenges that lay before them. For a time Popper worked as a labourer, but found the work too hard; he then tried his hand at cabinet making, but was distracted by the intellectual problems that he was working on. Popper also worked for the psychologist Adler, and as a social worker concerned with neglected children.

Shortly before submitting his dissertation for his PhD, the focus of Popper’s interest switched from the psychology, to the methodology, of thought and problem solving, and in particular to the methodology of science. This came about partly as a result of long discussions with two friends, the philosophers Julius Kraft and Heinrich Gomperz. The dissertation was hastily written. Popper’s examiners were Bühler and Schlick; Popper thought he had failed, but in fact he passed with distinction.

At this time a Pedagogic Institute was created in Vienna to train teachers in new methods of education. Popper decided to become a teacher, joined the course, held informal seminars for fellow students, and duly became qualified to teach physics and mathematics in secondary schools. He met, and later married, a fellow student, Josephine Henninger (Hennie), who also became a teacher.

While employed full-time as a teacher, Popper continued to work hard at epistemological and methodological problems of science, writing down his thoughts as an aid to research, rather than with the idea that the work might eventually be published. During this time, Popper got to know a number of people associated with the Vienna Circle, famous for promoting logical positivism. The Vienna Circle was essentially a seminar which one attended when invited by its convenor, Moritz Schlick. Rudolf Carnap, Otto Neurath, Herbert Feigl, Kurt Gödel, Friedrich Waismann, Victor Kraft, Karl Menger, Hans Hahn, Philipp Frank, Richard von Mises, Hans Reichenbach and Carl Hempel were among the members; Ludwig Wittgenstein, much admired by Schlick, was the intellectual godfather (together, perhaps, with Ernst Mach and Bertrand Russell). Visitors from abroad included A. J. Ayer and Frank Ramsey from England, Ernest Nagel and W. V. Quine from the USA, Arne Næss from Norway, and Alfred Tarski from Poland. But Popper was never invited to join the Circle (possibly because Schlick was aware of Popper’s low opinion of Wittgenstein).¹ Nevertheless, Popper did attend, and give papers at, a number of fringe seminars, and his work was strongly influenced by, but also critical of, the doctrines of the Circle.

1.2 Early work

Two issues were of central concern to Popper. The first was the problem of how to distinguish science from pseudoscience. Popper was impressed by the difference between the theories of Marx, Freud and Adler on the one hand, and Einstein’s general theory of relativity, on the other. The former theories seemed able to explain phenomena whatever happened; nothing, it seemed, could tell against these theories. Einstein’s theory, by contrast, issued in a definite prediction: light travelling near the sun would pursue a curved path due to the gravitational field of the sun. If this did not happen, Einstein’s theory would be refuted. Popper decided, around 1921 (he tells us) that this constituted the key difference between pseudo and genuine scientific theories: whereas the former were unrefutable, the latter were open to empirical refutation (see Popper, 1963, pp. 34–9; 1976a, p. 38; see also Hacohen, 2000, pp. 91–6).

The other problem that preoccupied Popper was that of the logic, or methodology, of scientific discovery: How does science acquire new knowledge? This was the problem that confronted Popper when his earlier interest in the psychology of thinking transmuted into interest in the logic of thinking, the logic of discovery.

Suddenly, Popper tells us, he put two and two together (Popper, 1976a, p. 79). His earlier solution to the first problem also solves the second problem. There is no such thing as the verification of theories in science; there is only refutation. Scientists put forward theories as empirically falsifiable conjectures or guesses, and these are then subjected to sustained attempted empirical refutation. Science advances through a process of trial and error, of conjecture and refutation.

Encouraged by Feigl, Popper wrote the first volume of what was intended to be a two-volume work, entitled Die beiden Grundprobleme der Erkenntnistheorie (The Two Fundamental Problems of the Theory of Knowledge). The first volume was accepted for publication by Schlick and Frank, the editors of a series of publications written mostly by members of the Vienna Circle. The publisher, Springer, insisted the book must be shortened. But in the meantime Popper had finished the second volume. He offered a new work consisting of extracts from both volumes, but this was still judged by Springer to be too long. Popper’s uncle, Walter Schiff, cut the manuscript by about a half, and this was finally published late in 1934 as Logik der Forschung. Thus emerged into the public domain, in the shadow of Hitler and impending war, what is, perhaps, the most important book on scientific method to be published in the last century. The book was only published in English translation, as The Logic of Scientific Discovery (with many additional appendices and footnotes), in 1959. (Die beiden Grundprobleme der Erkenntnistheorie was not published until much later, in 1979.)

1.3 The Logic of Scientific Discovery

The Logic of Scientific Discovery (L.Sc.D.) begins by spelling out what are, for Popper, the two fundamental problems concerning the nature of scientific inquiry. (1) The problem of induction: how can scientific theories be verified by evidence, in view of Hume’s arguments which seem to show that this is impossible? (2) The problem of demarcation: How is science to be demarcated from non-science (pseudoscience and metaphysics)? As we saw above, Popper’s solution to the second problem is that, in order to be scientific, a theory must be empirically falsifiable. This, for Popper, solves the first problem as well. Scientific laws and theories cannot be verified by evidence at all; they can only be falsified. However much evidence may be amassed in support of a theory, its probability remains zero. But despite this negative conclusion, science can still make progress. This comes about as a result of theories being proposed as conjectures, in response to problems; these conjectures are then subjected to a ruthless barrage of attempted empirical refutation. The purpose of observation and experimentation is not to verify, but to refute. When a theory is refuted empirically, this creates the problem of discovering a new conjecture, a new theory, which is even more successful than its predecessor in that it meets with all the success of its predecessor, successfully predicts the phenomena that refuted its predecessor, and predicts new phenomena as well. When such a theory is formulated, the task then becomes to try to refute this new theory in turn. Thus science advances, from one falsifiable conjecture to another, each successfully predicting more than its predecessor, but none ever having probability greater than zero. All theoretical knowledge in science is irredeemably conjectural in character. But science makes progress precisely because, in science, it is possible to discover that theories are false, and thus need to be replaced by something better.

Popper has been much criticized for not appreciating that even empirical refutations are not decisive: it is always a conjecture that a theory has been falsified, since it is always a conjecture that a given observation or experiment has yielded a falsifying result. But Popper has at least two replies to such criticisms.

First, there is a decisive logical asymmetry between verification and falsification. Any theory has infinitely many empirical consequences, for infinitely many times and places. We, however, can only ever verify finitely many of these consequences, and thus must forever be infinitely far away from verifying the theory. But we only need to discover one false empirical consequence of a theory in order to show decisively that the theory is false.

Second, Popper emphasizes that a theory is only falsifiable with respect to the adoption of a methodology. Given that a theory is empirically falsified, it is always possible to rescue the theory from falsification by adopting what Popper calls conventionalist stratagems. These include explaining the experimental result away in some way, or modifying the theory, in an ad hoc way, so that it no longer clashes with the empirical result. Popper proposes that science should adopt methodological rules governing the way theories are to be accepted and rejected in science in the light of evidence: these rules need to be designed to expose theories to the maximum risk of empirical refutation. Conventionalist stratagems, in particular, are to be banned. Faced by a refutation, a theory may be modified so as to overcome the refutation, but only if the modification increases the empirical content, the degree of falsifiability, of the theory – the modified theory predicting more, excluding more potentially falsifying observational statements, than before. Scientists should always strive to put forward theories that say as much as possible about the empirical world, that expose themselves to the greatest risk of refutation, that have the highest possible degree of falsifiability. The supreme methodological principle of science, for Popper, says that the other rules of scientific procedure must be designed in such a way that they do not protect any statement in science against falsification (1959, p. 54).

Even though theories cannot be verified, they can be corroborated. For Popper, corroboration is a measure of how well a theory has stood up to attempts to refute it. If a highly falsifiable theory has survived an onslaught of severe testing, then it has proved its worth. It deserves to be taken more seriously than an untested theory, or an unfalsifiable speculation.

According to Popper, then, science makes progress by means of wild imagining, bold guesswork, on the one hand, controlled by ferocious attempted empirical refutation on the other hand.

L.Sc.D. was influenced by the thought of the Vienna Circle, but also differs from, and is highly critical of, some of the main tenets of the Circle. Logical positivism sought to demarcate the meaningful from the meaningless, with only those propositions capable of being verified being meaningful, the hope being that all meaningful factual propositions would be scientific. Popper stressed that any such criterion would condemn scientific theories to being meaningless, since they could not be verified. Popper’s demarcation problem differed from that of the positivists. For Popper, as we have seen, the problem was to demarcate science from non-science (pseudoscience and metaphysics); falsifiability, not verifiability, is the key requirement; but non-scientific, metaphysical theories, though neither verifiable nor falsifiable, may nevertheless be entirely meaningful, and may even have a fruitful role to play in the development of science. Metaphysical theses, such as atomism, may suggest, and may (as a result of acquiring precision) be transformed into, falsifiable scientific theories.

1.4 Criticism

Does L.Sc.D. succeed in solving its two basic problems? Three great merits