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No. 1 47

On Popper's Metaphysical Realism in Memory of Sir

by Keiichiro KAMINO

I Why on Realism

Professor Sir Karl Popper passed away on the 17th of September, 1994. As he was born on the 28th of July, 1902, he had rather a long life. The concern for a philosopher, however, would be whether his own would survive for a long after his death. Would Popper's philosophy still be some guide or some target of argument for future philosophers? I, who was once a student of his at L. S. E. more than thirty years ago, would like here to pay some homage to him by way of writing an obituary. Philosophically, however, in this essay I aim to clarify Popper's theory of realism, which I think might give us not only a better of his whole philosophy, but also a clue for a further step towards expanding our . Popper's attitude in doing philospohy is, as is well known, his critical rational ism, which is the attitude of solving problems by an appeal to , i.e. to clear and , but is entirely different from comprehensive . The distinction between and extreme or comprehensive rational ism, however, is not the I would like to discuss here.(1) I referred to his critical rationalism only to draw attention to the that for his philosophy the of is very basic. Without the concept of truth, he cannot criticise any knowledge or theory by saying that this or that theory is true or false. Besides, as his arguments of W3 show, knowledge, in our search for a better , has a fundamental importance. But 'knowledge is the search of truth' (S. B. W., p. 38). According to Popper, the proper way of expanding our knowledge is critical discussion. And this is the rational tradition in Western Europe. Modern epis temologists, as a matter of fact, have asked questions about the sources of our knowledge. But there is no ultimate source of our knowledge. The proper epis temological question is not one about the sources. We should rather ask whether the conjecture or hypothesis we have made is true. The question about the sources of our knowldege may be replaced by an entirely different question: 'How can we hope to detect and eliminate error?' And the proper answer to this is, he says, 'by criticising the theories and guesses of others and-if we can train ourselves to do so

* Setsunan University , Faculty of Business Administration and , 17-8, Ikeda naka-machi, Neyagawa, Osaka, 572, Japan.

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- by criticizing our own theories and guesses' (C. R., p. 26). We human have reached the stage that we can consciously detect and elimimate error. Other animals cannot criticise each other, for they have no lan guage of descriptive and argumentative or explanatory function (C. R., p. 135). So they have no knowledge such as human beings have, say scientific knowledge. The invention of descriptive human language containing true and false statements made a further step possible, a further invention: the invention of criticism. This permits us a conscious and critical pursuit of our errors. "This", he says, "is the decisive point. Here begins what is called...human knowledge. There is no knowledge without rational criticism, criticism in the service of the search for truth. Animals have no knowledge in this sense.... But what we call knowledge, and the most important type of knowledge, scientific knowledge, is dependent on rational criticism. This is, therefore, the decisive step that depends upon the invention of true or false statements. And this is the step, that, I suggest, lays the foundation for W3, for human culture." (S. B. W., pp. 21-2). Here, however, a problem arises. What is the logical structure of criticism? How can we hope to show that some theory is wrong? The answer Popper prepared for this is 'falsification'. The criterion of the scientific status of a theory is its , or refutability, or (C. R., p. 37). Of course, one of the cornerstones of his philosophy is his theory of falsifiability. This , however, presupposes the concept of truth, and leads to realism. For, although the mere adoption of the concept of truth does not necessarily mean the adoption of realism, but as his theory of truth is a correspondence theory of truth, which is based on Tarski's idea, Popper's position should at least, be very near to realism. Now I should like to discuss Popper's metaphysical realism. There are at least three types of argumrnt he offered for realism, namely, (1) metaphysical realism in his "Realim and the Aim of ", and in "Two Faces of Common sense", in "Objective Knowledge". (2) the explanation of the concept of which he produced in developing his theory about W1, W2, W3, in "The and Its Brain", and the explanation of his standpoint in " without a Knowing ", in "Objective Knowl edge". (3) the explanation of the concept 'real' in "Three Views concerning Human knowledge". I shall begin with (1).

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II Metaphysical Realism in Realism and the Aim of Science, and Objective Knowledge.

Popper says that he in metaphysical realism, and also that it is nowhere used to support any of the solutions proposed in L. Sc. D. In this he differs from idealists, or so he says (R. A. S., pp. 80-1). It is not one of the theses of L. Sc. D., nor does it anywhere play the part of a presupposition. And yet, it is very much there. It forms a kind of background that gives point to our search for truth (ibid., p. 81). Without an objective reality, there would be no point in our critical discussion aiming to get nearer to the truth. It is surely our task to attain to the world of objective reality, which is largely unknown. British empiricists such an Bacon, Hume, Mill, and Russell, according to Popper had the of practical and realistic. But their subjectivist epis temology confiicted with their realist . They upheld the theory that all knowledge is derived from sense experience, and equated 'is derived' either with 'is inductively derived' or with 'originated' (ibid.). This leads them to the that all knowledge is derived from sense experience, and that all knowledge is knowledge of what is going on in our . On this subjective basis, no objective theory can be built. Upon the idealist theory, the world becomes the totality of my , of my dreams. And so Popper rejects . It may well be that the doctrine that the world is my dreams is irrefutable, because it can deal with every objection as a dream. But, for a theory, irrefutability is not a , but a vice. The irrefutability of idealism is not its virtue. This, however, also applies to realsim. Realism is also irrefutable. Pop per says that from the irrefutability of idealism follows the non-demonstrability of realism, and vice versa. Both theories are non-demonstrable, and also irrefutable: they are metaphysical (ibid.). In spite of this, however, he contends that there is an all-important between them: metaphysical idealism is false, and metaphysical realsim is true. And thus he starts the defence of realism by way of criticising idealism, particularly by rejecting , which is, from the point of view of idealist or subjectivist, the strongest form of idealism, or so Popper says. This, however, I not discuss here. In any case, there are two why Popper thinks that the subjectivisit theory fails. (1) it naively assumes that all knowledge is subjective, and that we cannot speak of knowledge without a knower, and (2) what is traditionally its fundamental quention is misconceived. It always asks 'how do I know what I know', with its implied naive answer 'from , or sense-experience'. Against all this, he contends that scientific knowledge is not his knowledge. For, he says, he knows that there are many things which are known to science, but

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not to him. Or "I have some knowledge, which, whether it be scientific, or common sense, or some kind of personal knowledge, I know that it is not from observation", and so on. But I do not here enter into the details (cf. op. cit., •˜9). I now turn to the second argument for realism.

III The second type of argument for realism

The second type of the argument Popper propounds for realism, is found in the sections 4, and 10 of "The Self and Its Brain", and in chap. 3 of "Objective Knowledge". In his "The Self and Its Brain", Popper discusses briefly the use of the term ' real'. According to him, the most central use of the term 'real' is its use to characterise material things of ordinaary size-things which a baby can handle and (preferably) put into his mouth. From this, the usage of the term 'real' is extended, first, to bigger things-things which are too big for us to handle, like railway trains, houses, mountains, the earth and the stars, and also to ssmaller things-things like dust particles or mites. The behind this extention is that the entities which we conjecture to be real should be able to exert a causal effect upon the prima facie real things-that is, upon material things of ordinary size. Take the case of atoms or molecules, for example. Towards the end of the last century, people or even many physicists were sill reluctant to admit the of atoms, which were then invisible. "But atoms were widely admitted to exist after Einstein's theory of Brownian motion. Einstein proposed the well-testable theory that small particles suspended in a liquid (whose movements are visible through a micro-scope, and therefore 'real') moved as a result of the random impacts of the moving molecules of the liquid. He conjectured that the then still invisibly small molecules exerted causal effects upon those very small yet 'ordinary' real things. This provided good reasons for the reality of molecules, and then further of atoms". And so we extend the usage of the term 'real' to molecules, and then further to atoms. The existence of atoms, Popper remarks, became common knowledge also after the destruction of two populated cities by the artificial disintegration of atoms. Their disintegration caused observable effects, which are the of the existence of atoms. Of course, in our accepting a new fact as an evidence, there always occurs the subtle problem of deciding whether or not we may regard the fact as the evidence, and no evidence is decisive. The matter here is not quite straightforward. But Popper says that we seem to be inclined to accept something (whose existence has been conjectured) as actually existing if its existence is corroborated, for instance , by the discovery of effects that we would expect to find if it did exist. In any case, this -50- No. 1 On Popper's Metaphysical Realism 51 corroboration indicates, first, that somethig is there, and the fact of this corrobora tion must be explained by any future theory. Secondly, the corroboration indicates that the theory that involves the conjectured entities may be true, or may be near to the truth. With these reservations in mind, we may say that the things which causally act upon, or interact with, ordinary material things, can be tentatively regarded as real. In this way we can say that elementary particles, forces and fields really exist. And we see that real entities in Popper's sense, can be concrete or abstract in various degrees. Popper calls the physical world, the universe of physical entities, "World 1" or W1. So in this way, he, first, accepts the reality of W1. After the discussion of the reality of the things in W1 Popper now comes to discuss the reality of the world of conscious experience, or if I use his term, the reality of "World 2". Of course, he conjectures W2 to be real. But is W2 truly real? First he reminds us that dead matter seems to have more potentialities than merely to produce dead matter-life originated with the chemical synthesis of self-producing molecules, and then, after many stages, produced , and then in the end the human brain and the human mind. But how can we say that W2 is real? We should show that mental states interact with our bodies, which are among the of reality. Just as we conjecture that the entities of the physical world (including theoretical entities of course) are real, because they interact among one another, and therefore with material bodies, which are the paradigms of reality, so, if we show that mental states interact with our bodies, we are in a position in which we may conjecture those mental states to be real.(2) Interactionism, which is the theory that mental and physical states interact, seems to give a solution to this matter. And, indeed, there are many good examples which seem to establish the interaction. Popper assumes interactionism and quotes, for instance, the case of toothache, as a good example of a state that is both mental and physical. "If you have a bad toothache, it may become a strong reason for visiting your dentist, which involves a number of actions and of physical movement of your bodies." These are the physical effects of your toothache. But your action of visiting the dentisit may be regarded as somethig which was caused by your painful sensation and by your knowledge of an existing social institution, such as dentistry. All this is obvious, even trivial. But, as is well known, the reality of mental states has been denied by some phiqosophers. And the history of the mind-body problem since Descartes is notorious. Philosophers never come to agreement. The adoption of interactionism, Popper says, would have to be supported by a critical discussion of alternative views. This is a very philosophical attitude. In fact, the mind-body problem itself is philosophical, for here the concept of falsifiability is not of much use. Interactionism is a metaphysical theory. Here, as

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everywhere, complete understanding is not easy to achieve. And yet Popper still assumes interactionism, regarding it as a kind of research programme. Popper first accepts the existence of the physical world (W1), and then secondly accepts the world of mental states (W2), including states of and psychological dispositions and unconscious states. Now he proceeds to the third world, the world of the contents of thought, and of the products of the human mind, which he calls "W3". And he accepts this W3 as real, in the sense that the objects in this world interact with the entities that are by now already accepted as real. W3 is the world of the products of the human mind. Examples of W3 objects Popper enumerates are stories, explanatory myths, tools, scientific theories (whether true or false), scientific problems, social institutions, and works of art. Many of them exisit in the form of material bodies, and belong in a sense to both W1 and W3. W3 objects may induce men to produce other W3 objects, and, thereby, to act on W1. And interaction with W1-even indirect interaction-he regards as a decisive argument for calling a thing real. To sum up, Popper accepts the reality of W3 objects as well as that of W2 objects for the reason that they have causal interactions with W1 objects.

IV The concept of reality in "Three Views concerning Human Knowledge"

The third type of Popper's statement about the concept of reality is connected with his view concerning human knowledge. It is well known that he discusses the structure of human knowldge by way of comparing three views, namely , , and the 'third view', which is his view. Popper takes three points out of Galileo's thought. (1) The scientist aims at fi nding a true theory or description of the world, which shall also be an explanation of observable . (2) The scientist can succeed in finally establishing the truth of such theories beyond all doubt. (3) The best, the truly scientific theories describe the '' or the 'essential natures' of things-the which lie behind the appearances. And he says that he wishes to support (1), but not (2) and (3). The assertion (2) needs correction, and (3), which he calls essentialism, is mistaken, and leads to obscurantism. Instrumentalist philosophers also reject essentialism, but do so for a reason somewhat different from Popper's. They assert that explanation is not an aim of physical science, since physical science cannot discover 'the hidden of things'. They deny that a is a descriptive statement conjectured to be true (but possibly a false statement). Theories do not describe at all , they are mere instruments, -instruments for, say, prediction. From an instrumentalist point of view, what may appear as the growth of theoretical knowledge is merely the

-52- No. 1 On Popper's Metaphysical Realism 53 improvement of instruments. Popper contends that instrumentalism ignores the difference between scientific theories and technological computation rules, that it can give a perfect description of these rules but is quite unable to account for the difference between them and the theories, and that thus it collapses. One of the fundamental differences between scientific theories and computation rules is that theories are tested by attempts to refute them, while there is nothing strictly corresponding to this in the case of technological rules. If theories are refuted, then they will be abandoned. But for the instrumentalist purposes of practical applica tion, a theory may continue to be used even after its refutation. And so Popper asserts that by neglecting falsification, and stressing application, instrumentalism proves to be as obsucurantist a philosophy as essentialism. It is very clear that for Popper's position the concept of truth (and so of falsity) is of vital importance. Scientific theories are conjectures, which we cannot verify, but which we have to try to test as severely as possible. Along the line of his view about the of human knowledge, Popper advocates his concept of reality. Falsifications indicate the points where we have touched reality. Theories are our own inventions, but some of them can clash with reality. And when they do, we know that there is a reality. Now according to Popper's view here, we are led to take not only our ordinary world but also further which are described by further theories-theories of higher level of , of universality, and of testability-as equally real. All these are equally real aspects or layers of world. Indeed, he comments that if looking through a microscope we change its magnification, then we may see various completely different aspects or layers of the same thing, all equally real. He does not think that only the so-called primary qualities are real, but secondary qualities are not. He does not contrast the primary qualities of a body with its unreal apparent secondary qualities. Both kinds of qualities are equally real; and so are forces, and fields of forces, in spite of their undoubted hypothetical or conjectural character. For all this, however, Popper suggsets somehow paradoxically that, although in one sense of the word 'real' all these various levels are equally real, there is another yet closely related sense in which we might say that the higher and more conjectural levels are the more real ones (C. R., p. 116). These higher levels "are more real (more stable in intention, more permanent, though conjectural in character) in the sense in which a table, or a tree, or a star, is more real than any of its aspects." I am a bit uneasy about Popper's usage of the term 'reality' here, and I will come back to this later.(3) Popper of course admits that the conjectural or hypothetical character of our theories may be raised as the very reason why we should not ascribe reality to the world described by them. We should rather call only those states of affairs 'real'

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which are described by true statements. Conjecture may be false. And yet he takes the correspondence theory about the concept of truth that we should call a state of affairs 'real' if, and only if, the statement describing it is true. But Popper contends that it would be a great mistake to conclude from this that the of a theory i.e. its hypothetical character, diminishes in any way its implicit claim to describe something real. But I think that the assertion which claims the exis tence of the theoretical entities implied by a theory whose truth has not yet been decided has the same difficulty we have when we must decide the truth of the statement that there will be a sea-battle tomorrow. In any case, however, Popper claims that the testability of a theory implies its reality.

V Some discrepancy in Popper's statements about 'reality'

So far I have summarised Popper's three different expositions of his realsim. (A) Metaphysical realsim in his "Realism and the Aim of Science", (B) The explanation of the concept of reality to propound his theory of W1, W2, and W3 in his "The Self and Its Brain", (C) The explanation of the concept of 'real' in "Three Views concerning Human Knowledge". These arguments are fair, and I might have raised scarcely any objection to them, if they were put before me separately one by one on different occasions. I fi nd (A) cogent, except that it contains one statement saying that realism is true. I would very much like to agree with this statement.(4) I am afraid, however, I have no proof to establish the truth of the statement. And Popper too seems to have no proof, and of course he cannot, because metaphysical realsim is just metaphysical (neither verifiable nor falsifiable). He, in fact, just contends that it is true. And he rather chooses to reject idealism, than to vindicate realsim positively. (B) and (C) are good arguments indeed, taken by themselves. But I see some discrepancy between them, and I would like to say something about it. The argumnt in (B) is that, taking material things of ordinary size as the paradigms of real things, we can extend the usage of the term 'real' to entities which can exert some causal effects upon mechanical things of ordinary size. In (C), however, while Popper says that our ordinary world and the world discovered by the new scientific theories are equally real, he admits that there is a sense in which we might say that the higher and more conjectural levels are more real ones. This, I think, does not fit very well with he argument in (B), because (B) in the course of argument leads to the assertion that we need two kinds of explanation; one in terms of upward causal relation, and the other in terms of downward causal relation. On the other hand (C) mentions only one kind of exlanation (upward one).

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If I have to choose between (B) and (C), I would rather choose (B), because (B) was written later than (C), and also because (B) is a more comprehensive theory than (C). At the same time, however, I am not very happy with Popper's idea that material things and theoretical entities whose reality is supported only by some conjectural theory, though well-tested, have equal reality. This is something too paradoxical to accept. Well, I would gradly admit an equal reality both to an apple seen by my naked eye and to its images seen through microscopes. And I would rather contend that theoretical entities whose reality is supported only by some conjectural theory, should have 'so-to-say quasi-reality', but not that they should have equal reality with material things of W1. Popper indeed maintains that, although we take our idea of reality from material objects, this does not mean that material things are in any sense 'ultimate'. But he only claims this, and offers no argument. As his theory of explanation expounded in (C) is in connection with his idea of reality, the discrepancy in the idea of reality leads to a discrepancy in the exposition of his theory of explanation. As far as the arguments in (B) are concerned, I do recognise both the downward and the upward explanation as legitimate, for they have nothing to do with the levels of reality. (Though there may be some psycho logical matters in this way of understanding 'explanation'.) Popper says that explanation is a set of statements, explicans and explicandum, and explicandum can be logically deduced explicans. This leads necessarily neither to the upward explanation nor to the downward explanation, and has nothing to do with the levels of reality. But the scientific explanation he has in mind in (C) is upward only. Ordinary world things (explicandum) will be explained in terms of theoretical entities (science as explicans). And a scientific theory, which conjectures a deeper structure of ordinary material things, is surely an entity of W3. So although I have no particular objections to Popper's idea of explanation in (B), I feel somehow uneasy about the situation. Either in view of his idea in (C), I should have to reject the theory of the equal reality in (B), or in view of his theory of expalantion in (B) I should reject the theory of the levels of reality propounded in (C). The concept of 'deeper' level of explanation does not fit with the concept of the equality of reality. In this situation I would like to accept the arguments in (B) as Popper's view, as they are richer. But at the same time I should admit that it has some difficulties as well. For instance, his argument in favour of W3 is weak: it has not established its independence from W2. And also the mind-body problem has well-known difficulties, but upon whose solution the reality of W2 depends. And thirdly, the concept of , the key concept for the discussion of these difficulties, is in itself, as is well known, very problematic.

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VI Concluding Remarks

Popper's thery of W1, W2, and W3 may not be very popular. But I have some sympathy with it, because it seems to try and unite the two traditional philosphical arguments about realsim into one. In the history of philosophy, realism has two types of arguments which prima facie seem very different from each other. In medieval , the term 'realism' was used to refer, in opposition to , to the doctrine that universals have a real, objective existence. In , it is used for the view that material objects exist externally to, and independently from, us. In this sense, realsim is opposed to idealism. Now, realism in the medieval sense, I think, corresponds to Popper's idea of the reality of W3 while in the modern sense it is Popper's theory of W1. And so I find Popper's attempt to synthesize these two senses very interesting. And this is the reason why I would like to accept his argumrnt (B), in spite of its some weaknesses. The second reason why I would like to accept Popper's argument (B), is that I am interested in his way of thinking that a better world may be obtained by the shaping of new reality through knowledge. The psychological world W2 may be the products of problem-solving activities of living organisms. And his W3 is certainly the products of the human mind. The title of chapter 1 of his "In Search of a Better World" is 'Knowledge and the Shaping of Reality: the search for a better world'. This clearly expresses his intention in philosophical thinking. And I think that his intention is worth pursuing. If we admit the evolution from W1 to W3 via W2, and if we admit the reality of these three worlds, then we may be said to have some possibility to create a better world through our inventing new ideas. One of the great inventions of this kind is our social laws. Social laws are our conventions, man-made. (Indeed, Hume said that is convention.) And our lawful society is somehow more peaceful and securer than the 'natural state'. The possibility of our creating a better world by way of inventing new ideaas,of course, does not exclude the possibility of our failure and perishing. We can, however, on the theoretical level, discuss rationally, there fore critically the direction we should take, and we human beings may survive and create a better world, or ecological niche, letting theories be killed in place of human beings themselves. In this essay I write in a sympathetic rather than critical way. One of the reasons for this is that this paper is supposed to be a kind of obituary for Sir Karl Popper, but the other reason is that I feel some sympathy with his effort to make a philosophical synthesis. For I think, if I may borrow Kant's way of expressing an idea, that synthesis without analysis is obscure, but analysis without synthesis is vain. Popper, with sharp analyses on one hand, tried to comprechend the world synthetically, which is rather rare among present analytical philosophers. I hope

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Notes

(1) I have discussed this on another occasion. See my 'On Sir Karl Popper's Critical Rationalism', Vol. 8, No. 4, of this journal, March, 1994. (2) As a matter of fact, however, the history of the discussions on the mind-body problem since Descartes shows how difficult it is to establish interactionism or even any kind of dualism. But owing to the progress in neurophysiology in this century, we are in a better position than the past philosophers to defend causal between the mind and the body. (3) Anyway, this is related to his contention that these higher or deeper levels have in a sense more . (4) Popper's assertion that realism is true may reject the strategy to interpret his whole philosophy as a kind of . Any convention can never be true (or false). So his realism cannot be one of his conventions. Indeed, scientific knowledge is not mere conventions; and yet it is a of knowledge for him. I say this because there are actually some scholars who interpret Popper's philosophy as a kind of conven tionalism. And elsewhere I myself vindicated his critical rationalism along the line of conventionalism, because I take his critical rationalism not as any statement or theory, but an attitude. (see note (1) above). Critical rationalism can be a convention critical rationalsits can adopt. As far as my own interpretation is concerned, I would draw a distinction between the level of adopting critical rationalism and that of carrying out rational activities based on that decision.

References. Popper, Karl: Open Society and Its Enemies. (O.S. E.). : of Scientific Discovery.(L. Sc. D.). : Conjecturesand Refutations. (C.R.). : Realism and the Aim of Science.(R. A. S.). : ObjectiveKnowledge. (O. K.). : In Search of a Better World. (S.B. W.). Popper, Karl and John C. Eccles: The Self and Its Brain. (S.I. B.).

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