Popper, K. (1979). Two faces of common sense: An argument for commonsense realism and against the commonsense theory of knowledge. In Objective Knowledge Oxford: Clarendon Press.
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|p.32 This long essay, so far unpublished, is a revised and expanded version of a talk I gave to my former Seminar early in 1970. It is intended as a fairly full answer to the critics of my views on science. Added by: admin|
1. An Apology for Philosophy
It is very necessary these days to apologize for being concerned with philosophy in any form whatever. Apart perhaps from some Marxists, most professional philosophers seem to have lost touch with reality. And as for the Marxists — « The Marxists have merely interpreted Marxism in various ways ; the point, however, is to change it (*). »
In my opinion, the greatest scandal of philosophy is that, while all around us the world of nature perishes — and not the world of nature alone — philosophers continue to talk, sometimes cleverly and sometimes not, about the question of whether this world exists. They get involved in scholasticism (°) in linguistic puzzles such as, for example, whether or not there are differences between « being » and « existing ». (As in contemporary art, there are no standards in these worlds of philosophy.)
It goes without saying that the widespread anti-intellectual attitude which was so strong among the National Socialists, and which is again becoming strong among disappointed young people, especially students, is just as bad as this kind of scholasticism, and if possible a little worse even than the pretentious and spurious, though sometimes quite brilliant, verbiage of philosophers and other intellectuals. […]
Under these circumstances there is a need to apologize for being a philosopher, and more particularly for restating (as I intend to do, if only in passing) what should be a triviality, such as realism, the thesis of the reality of the world. What is my excuse ?
My excuse is this. We all have our philosophies, whether or not we are aware of this fact, and our philosophies are not worth very much. But the impact of our philosophies upon our actions and our lives is often devastating. This makes it necessary to try to improve our philosophies by criticism. This is the only apology for the continued existence of philosophy which I am able to offer.
(*) Marx, of course, said (in the eleventh of his Theses on Feuerbach) : « The philosophers have merely interpreted the world in various ways ; the point, however, is to change it. » The brilliant and timely variation quoted in the text seems to be due to R. Hochhuth.
(°) I am using the term « scholasticism » to indicate an attitude of arguing without a serious problem — an attitude that was by no means universal among the schoolmen of the Middle Ages. Added by: admin
Il est amusant de voir que pour l’anticommuniste Popper, seuls certains philosophes marxistes font encore sérieusement de la philosophie. Il entend sans doute l’amusante paraphrase de la onzième thèse sur Feuerbach de manière totalement négative, mais on pourrait la récupérer pour en faire une critique d’un certain dogmatisme. Added by: admin (2008-12-01 16:22:23)
2. The Insecure Starting-Point : Common Sense and Criticism
Science, philosophy, rational thought, must all start from common sense.
Not, perhaps, because common sense is a secure starting point : the term » common sense » which I am using here is a very vague term, simply because it denotes a vague and changing thing — the often adequate or true and often inadequate or false instincts or opinions of many men.
How can such a vague and insecure thing as common sense provide us with a starting-point ? My answer is : because we do not aim or try to build (as did, say, Descartes or Spinoza or Locke or Berkeley or Kant) a secure system on these « foundations ». Any of our many commonsense assumptions — our commonsense background knowledge, as it may be called — from which we start can be challenged and criticized at any time ; often such an assumption is successfully criticized and rejected (for example, the theory that the earth is flat). In such a case, common sense is either modified by the correction, or it is transcended and replaced by a theory which may appear to some people for a shorter or longer period of time as being more or less « crazy ». If such a theory needs much training to be understood, it may even fail for ever to be absorbed by common sense. Yet even then we can demand that we try to get as close as possible to the ideal : all science, and all philosophy, are enlightened common sense.
Thus we begin with a vague starting-point, and we build on insecure foundations. But we can make progress : we sometimes can, after some criticism, see that we have been wrong : we can learn from our mistakes, from realizing that we have made a mistake.
(Incidentally, I shall try to show later that common sense has been particularly misleading in the theory of knowledge. For there seems to be a commonsense theory of knowledge : it is the mistaken theory that we acquire knowledge about the world by opening our eyes and looking at it, or, more generally, by observation.)
My first thesis is thus that our starting-point is common sense, and that our great instrument for progress is criticism. Added by: admin
Il se méfie de l’empirisme et de l’induction (Bacon) et il fera plus loin une sévère critique d’une conception naïve de la connaissance. Chez lui, les idées du sens commun semblent venir de nulle part et seulement être exposées à une critique a posteriori. Il ne peut admettre que la pratique peut donner et confirmer une idée, pas seulement apporter le contrexemple qui la réfuterait. Added by: admin (2008-12-01 11:07:02)
3. Contrast with Other Approaches
What I have said so far may appear quite trivial. To give it a point, I shall very briefly contrast it with other approaches.
Descartes was perhaps the first to say that everything depends upon the security of our starting-point. In order to render this starting-point really secure, he suggested the method of doubt : accept only what is absolutely indubitable.
He then started from his own existence, which seemed to him indubitable, since even doubting our own existence seems to presuppose the existence of a doubter (a doubting subject).
Now I am no more sceptical about the existence of my own self than Descartes was of his. But I also think (as did Descartes) that I shall die soon and that this will make little difference to the world, except to myself and two or three friends. Obviously the issues of one’s own life and death are of some significance, but I conjecture (and I think Descartes would agree) that my own existence will come to an end without the world’s coming to an end too. This is a commonsense view, and it is the central tenet of what may be termed « realism ». (Realism will soon be discussed more fully.)
Locke, Berkeley, and even the « sceptic » Hume, and their many successors, especially Russell and Moore (*), shared with Descartes the view that subjective experiences were particularly secure and therefore suitable as a stable starting-point or foundation ; but they relied mainly on experiences of an observational character.
(*) G. E. Moore was a great realist because he had a strong love for truth and felt clearly that idealism was false. Unfortunately, he believed in the commonsense subjectivist theory of knowledge, and thus throughout his whole life he hoped, in vain, that a proof of realism based on perception could be found — a thing that cannot exist. Russell relapsed from realism into positivism for the same reason. Added by: admin
Je trouve très intéressante la remarque que tous ces philosophes « réalistes » à divers degrés centrent leur philosophie sur le sujet (individuel) (et sur ses perceptions) plutôt que sur le monde. Ils sont en cela plus proches de Berkeley qu’il n’y paraît. Added by: admin (2008-12-01 16:22:57)
Realism is essential to common sense. Common sense, or enlightened common sense, distinguishes between appearance and reality. (This may be illustrated by examples such as « Today the air is so clear that the mountains appear much nearer than they really are ». Or perhaps, « He appears to do it without effort, but he has confessed to me that the tension is almost unbearable ».) But common sense also realizes that appearances (say, a reflection in a looking-glass) have a sort of reality ; in other words, that there can be a surface reality — that is, an appearance — and a depth reality. Moreover, there are many sorts of real things. The most obvious sort is that of foodstuffs (I conjecture that they produce the basis of the feeling of reality), or more resistant objects (objectum = what lies in the way of our action) like stones, and trees, and humans. But there are many sorts of reality which are quite different, such as our subjective decoding of our experiences of foodstuffs, stones, and trees, and human bodies. The taste and weight of foodstuffs and of stones involve another sort of reality, and so do the properties of trees and human bodies. Examples of other sorts in this many-sorted universe are : a toothache, a word, a language, a highway code, a novel, a governmental decision ; a valid or invalid proof ; perhaps forces, fields of forces, propensities, structures ; and regularities. (My remarks here leave it entirely open whether, and how, these many sorts of objects can be related to each other.) Added by: admin
Tous les philosophes, sauf Bunge et les marxistes, et tous les scientifiques, même Weinberg, parlent de réalisme. Ils croiraient déchoir et parlant de matérialisme. Ce n’est pas innocent. Sans matérialisme, le réalisme peut être idéaliste (Platon) ou y glisser facilement. On voit bien ailleurs que Popper n’échappe pas toujours à ce piège. Added by: admin (2008-12-01 19:03:16)
5. Arguments for Realism
My thesis is that realism is neither demonstrable nor refutable. Realism like anything else outside logic and finite arithmetic is not demonstrable ; but while empirical scientific theories are refutable (*), realism is not even refutable. (It shares this irrefutability with many philosophical or « metaphysical » theories, in particular also with idealism.) But it is arguable, and the weight of the arguments is overwhelmingly in its favour. Common sense is unquestioningly on the side of realism ; there are, of course, even before Descartes — in fact ever since Heraclitus — a few hints of doubt whether or not our ordinary world is perhaps just our dream. But even Descartes and Locke were realists. A philosophical theory competing with realism did not seriously start before Berkeley, Hume, and Kant (°). Kant, incidentally, even provided a proof for realism. But it was not a valid proof ; and I think it important that we should be clear why no valid proof of realism can exist.
In its simplest form, idealism says : the world (which includes my present audience) is just my dream. Now it is clear that this theory (though you will know that it is false) is not refutable : whatever you, my audience, may do to convince me of your reality — talking to me, or writing a letter, or perhaps kicking me — it cannot possibly assume the force of a refutation ; for I would continue to say that I am dreaming that you are talking to I me, or that I received a letter, or felt a kick. (One might say that these answers are all, in various ways, immunizing stratagems. This is so, and it is a strong argument against idealism. But again, that it is a self-immunizing theory does not refute it.)
Thus idealism is irrefutable ; and this means, of course, that realism is indemonstrable. But I am prepared to concede that realism is not only indemonstrable but, like idealism, irrefutable also ; that no describable event, and no conceivable experience, can be taken as an effective refutation of realism. Thus there will be in this issue, as in so many, no conclusive argument. But there are arguments in favour of realism ; or, rather, against idealism.
(*) This, of course, is one of my oldest theories. See, for example, chapter 1 of my Conjectures and Refutations (Popper, 1976, pp.37–ff.) […]
(°) Positivism, phenomenalism, and also phenomenology are all of course infected by the subjectivism of the Cartesian starting-point.
Popper, K. (1976). Conjectures and refutations: The growth of scientific knowledge. Londres: Routledge et Kegan Paul. Added by: admin
Pour que le fait que l’idéalisme n’est pas réfutable entraîne le fait que le réalisme n’est pas démontrable suppose que l’idéalisme soit la négation du réalisme. Cela demanderait du réalisme et de l’idéalisme des définitions relativement formelles et je ne les ai pas trouvées dans ce texte. Mais, bon, on se comprend. Added by: admin (2008-12-01 19:02:15)
|p.39 (1) Perhaps the strongest argument consists of a combination of two : (a) that realism is part of common sense, and (b) that all the alleged arguments against it are not only philosophical in the most derogatory sense of this term, but are at the same time based upon an uncritically accepted part of common sense ; that is to say, upon that mistaken part of the commonsense theory of knowledge which I have called the « bucket theory of the mind » ; see below, sections I2 and 13. Added by: admin|
(2) Although science is a bit out of fashion today with some people, for reasons which are, regrettably, far from negligible, we should not ignore its relevance to realism, despite the fact that there are scientists who are not realists, such as Ernst Mach […]. We can then assert that almost all, if not all, physical, chemical, or biological theories imply realism, in the sense that if they are true, realism must also be true. This is one of the reasons why some people speak of « scientific realism ». It is quite a good reason. Because of its (apparent) lack of testability, I myself happen to prefer to call realism « metaphysical » rather than « scientific » (*).
However one may look at this, there are excellent reasons for saying that what we attempt in science is to describe and (so far as possible) explain reality. We do so with the help of conjectural theories ; that is, theories which we hope are true (or near the truth), but which we cannot establish as certain or even as probable in the sense of the probability calculus), even though they are the best theories which we are able to produce, and may therefore be called « probable » as long as this term is kept free from any association with the calculus of probability.
There is a closely related and excellent sense in which we can speak of « scientific realism » : the procedure we adopt may lead (as long as it does not break down, for example because of anti-rational attitudes) to success, in the sense that our conjectural theories tend progressively to come nearer to the truth ; that is, to true descriptions of certain facts, or aspects of reality.
(*) See my Logik der Forschung, 1934 where, in section 79 (p. 252 of the English translation : The Logic of Scientific Discovery, 1959) I describe myself as a metaphysical realist. In those days I wrongly identified the limits of science with those of arguability. I later changed my mind and argued that non-testable (i.e. irrefutable) metaphysical theories may be rationally arguable. (See, for example, my paper « On the Status of Science and of Metaphysics », first published in 1958 and now in my Conjectures and refutation, 1963.) Added by: admin
Très intéressante autocritique dans la note. On connaît Popper pour son critère de scientificité. Est scientifique seulement ce qui est susceptible de réfutation et d’une théorie qui n’est pas scientifique, il n’y a rien à dire. Cela me fait penser au Wittgenstein du Tractatus : on ne peut parler que dans le langage que le Tractatus instaure et de ce qui n’est pas accessible à ce langage, on ne peut parler. Popper de même identifiait non scientifique et quelque chose comme l’ « indicible » de Wittgenstein.
Il a admis ensuite qu’il y avait quand même quelque chose à en dire. Cela conduit à penser qu’il y a, des théories scientifiques elles-mêmes, plus à dire que seulement qu’elles sont réfutables mais pas encore réfutées. Il y a un sens à parler positivement d'une théorie et Popper à écrit sur des critères de jugement plus fins que réfutée ou non. Added by: admin (2008-12-01 18:55:41)
|pp.40-41 (3) But even if we drop all arguments drawn from science, there remain the arguments from language. Any discussion of rea1ism, and especially all arguments against it, have to be formulated in some language. But human language is essentially descriptive ( and argumentative), and an unambiguous description is always realistic : it is of something — of some state of affairs which may be real or imaginary. Thus if the state of affairs is imaginary, then the description is simply false and its negation is a true description of reality, in Tarski’s sense. This does not logically refute idealism or solipsism; but it makes it at least irrelevant. Rationality, language, description, argument, are all about some reality, and they address themselves to an audience. All this presupposes realism. Of course, this argument for realism is logically no more conclusive than any other, because I may merely dream that I am using descriptive language and arguments ; but this argument for realism is nevertheless strong and rational. It is as strong as reason itself. Added by: admin|
|p.41 (4) To me, idealism appears absurd, for it also implies something like this : that it is my mind which creates this beautiful world. But I know I am not its Creator. After all, the famous remark « Beauty is in the eye of the beholder », though perhaps not an utterly stupid remark, means no more than that there is a problem of the appreciation of beauty. I know that the beauty of Rembrandt’s self-portraits is not in my eye, nor that of Bach’s Passions in my ear. On the contrary, I can establish to my satisfaction, by opening and closing my eyes and ears, that my eyes and ears are not good enough to take in all the beauty that is there. Moreover, there are people who are better judges — better able than I to appreciate the beauty of pictures and of music. Denying realism amounts to megalomania (the most widespread occupational disease of the professional philosopher). Added by: admin|
(5) Out of many other weighty though inconclusive arguments I wish to mention only one. It is this. If realism is true — more especially, something approaching scientific realism — then the reason for the impossibility of proving it is obvious. The reason is that our subjective knowledge, even perceptual knowledge, consists of dispositions to act, and is thus a kind of tentative adaptation to reality ; and that we are searchers, at best, and at any rate fallible. There is no guarantee against error. At the same time, the whole question of the truth and falsity of our opinions and theories clearly becomes pointless if there is no reality, only dreams or illusions.
To sum up, I propose to accept realism as the only sensible hypothesis — as a conjecture to which no sensible alternative has ever been offered. I do not wish to be dogmatic about this issue any more than about any other. But I think I know all the epistemological arguments — they are mainly subjectivist — which have been offered in favour of alternatives to realism, such as positivism, idealism, phenomenalism, phenomenology, and so on, and although I am not an enemy of the discussion of isms in philosophy, I regard all the philosophical arguments which (to my knowledge) have ever been offered in favour of my list of isms as clearly mistaken. Most of them are the result of the mistaken quest for certainty, or for secure foundations on which to build. And all of them are typical philosophers’ mistakes in the worst sense of this term : they are all derivatives of a mistaken though commonsensical theory of knowledge which does not stand up to any serious criticism. (Common sense typically breaks down when applied to itself ; see section I2 below.) Added by: admin