Terrestrial Thoughts, Extraterrestrial Science

There is a wonderful passage in Nietzsche’s Daybreak, about the ageing philosopher. ‘Subject to the illusion of a great moral renewal and rebirth, he passes judgment on the work and course of his life, as though it were only now that he had been endowed with clear sight.’ He ‘considers himself permitted to take things easier and to promulgate decrees rather than demonstrate’; and the inspiration of ‘ this feeling of well-being anti these confident judgments is not wisdom but weariness’.

The American philosopher Hilary Putnam, now in his sixties and with a lot of important and influential philosophy to his credit, shows in this collection of essays and occasional pieces that he is for the most part creditably resistant to the seductions of maturity. He does tell us occasionally about his place in the history of recent philosophy, but it is in a chatty and unpretentious style, which is present in most of the book. Many of the papers were clearly talks, and the cheery scattering of exclamation marks and amiable references to his colleagues give it the air of some personal and informal communication – letters home from a very bright pupil at a very philosophical school, perhaps – and not the self-congratulatory musings of late career.

Certainly it does not torment him, as it did Nietzsche’s ripe sage, that ‘he cannot be the last thinker.’ The sense is present all the time that philosophy and other creative activities continue, that nothing will look the same in a while, that none of us has the final word about anything. Decrees are, admirably, not promulgated from certainty. However, it must be said that they are sometimes promulgated from briskness, and some things go by a good deal too fast, particularly when Putnam calls on his authority in the philosophy of physics and mathematics. At one point an argument zooms through which is supposed to show that it makes a difference to the question of free will that physics is now indeterministic, the difference being that (after all) we are free. It is a version of a very old argument, and on the face of it no less awful than the other versions, but Putnam does not stay around to make it any more convincing; he seems, as he does on a number of large subjects, to be just visiting.

The collection covers a wide range, including the history of recent philosophy, the interpretation of literary texts, and a few political thoughts. There is a lot of overlap, and some areas are visited so briefly that even Putnam’s snaps have not come out too well. But most of the book is concerned with one very basic and important set of questions concerning the world, knowledge and values. The choice of the title, with its echo, perhaps shows less than total sensitivity to a painful history which, granted Putnam’s own political past, has some claims on his consideration: but it does well express the central subject of the book.

We have the idea that we live in a world that exists independently of us and our thoughts. This idea may be called realism. Almost everyone shares it, and even those whose philosophies seemingly deny it really accept it in some form – some literary theorists, for instance, who say that we can never compare our texts to ‘the world’ but only to other texts. (As a colleague in Berkeley said to me: tell that to the Veterans of Foreign Texts.) The question is, how much can be made of realism? How much theoretical weight can it be given?

Putnam thinks that it comes in just two basic forms. ‘Metaphysical realism’ is the view that we can conceive of the world in some way quite independent of our own theories and the terms in which we describe it, and raise the question whether our descriptions fit its real character – whether our descriptions correspond to the way it really is, the way it was before we got to it. This version of realism is indeed theoretically ambitious, but it is false or unintelligible. It suggests that we can, so to speak, get round behind our descriptions and see how they fit the world, and this makes no sense at all: any conception of the world we can use at all is one that is already expressed in terms that we understand, our terms. The world cannot describe itself for us.

So what is the idea of realism that, this side of insanity, we all share? Putnam calls it ‘internal realism’, and this, he says, while it is true and sensible, is entirely trivial. It yields such truths as that before there were human beings there were trees and rocks; that the English phrase ‘the sun’ refers to a certain star; that our theory that we live on a planet in the galactic system is true because we live on such a planet. Such formulae can express our scientific and other knowledge, but they give no general philosophical understanding of how our thoughts and words latch on to the world. As expressions of the idea that the world is independent of our thought, they exclude nothing except what the ordinary non-philosophical understanding would regard as mad – for instance, that there was no planet or sun until there were human beings to describe them.

‘Internal realism’ does not say much. All the same, there are, according to Putnam, some philosophical advantages in insisting on it. One is that it resists a certain kind of relativism, the theory that we cannot properly say ‘the sun is a star,’ but only ‘according to our way of looking at things, the sun is a star.’ Putnam conclusively disposes of this line, pressing the objection that if this is all we could say, we could not identify what it is that, according to our way of looking at things, we take to be true. He also shows, equally conclusively, that formulations in this relativistic style that have been popularised by Richard Rorty, in particular, simply tear themselves apart. If, as Rorty is fond of putting it, the correct description of the world (for us) is a matter of what we find it convenient to say, and if, as Rorty admits, we find it convenient to say that science discovers a world that is already there, there is simply no perspective from which Rorty can say, as he also does, that science does not really discover a world that is already there, but (more or less) invents it. These are excellent points: but when we look more closely at Putnam’s contrast between ‘metaphysical’ and ‘internal’ realism, we may begin to wonder how deeply he has assimilated them himself.

What exactly, first of all, have we rejected in rejecting metaphysical realism? Internal realism, after all, is not confined to banal remarks about banal objects. It can license banal remarks about less banal objects: if we believe that matter consists of certain types of particle, for instance, then we can say that what makes this true is that matter does consist of such particles, and that such particles are among the things that were there anyway, before our investigations. Metaphysical realism seems now to have added to all these acceptable banalities only a picture: a less acceptable picture, presumably, but also a very elusive one.

The issues become sharper, if we bring into the discussion a further idea: that some of our descriptions of the world are more local, or perspectival, or anthropocentric, than others. On the face of it, there should be something in this idea. I can say of the moon that it is a body of a certain shape with irregularities on its surface some of which, when illuminated by the sun, reflect more light than others. I can say that when so illuminated, it looks like a man’ s face. I can say that it looks like your Uncle Henry, indeed (icing this stale bun) that it looks amusingly, or strangely, or evocatively like him. These are all human descriptions of the same thing, but the understandings they call upon are increasingly parochial. On a larger scale, when Pascal said of the spaces of the universe that they were immense, that they were silent, and that they were terrifying, he spoke from an increasingly local perspective.

Applying the idea of such comparisons between the materials used in various descriptions, I brought into the discussion of these matters some years ago the notion of an account of the world that would be maximally independent of human peculiarities, the ideal of a description that could be used by any observer, even a non-human one, who was capable of investigating the world. I suggested that such a description might be said to express an ‘absolute conception’ of the world; and that it was such a conception that, as an ideal, science sought to achieve. The whole point of this was not to fall back into ‘metaphysical realism’, insofar as we can identify that illusion. If we use Putnam’s contrast, this idea belongs with ‘internal realism’. At the same time, however, it does not regard all the descriptions offered by humans as being on the same level. We can, I suggested, by a reflection within the resources of our human understanding, identify among our various descriptions of one and the same world some that, in order to be understood, make more demands on experience that is peculiarly human, and others that make less.

Putnam will have none of this, and in one piece in this book he works himself up into a state of extreme (though, happily, temporary) state of fury about these notions. His criticisms are a very ill-assorted lot. My view of them is doubtless skewed, but they all seem to me either to miss the point or at least to require more care in showing how they hit it. One uses a consideration which Putnam deploys in several places against various kinds of ‘realism’, that the world contains no fixed number of objects: asked whether a grove of five trees is one object, five, six, or what, there is no answer. But all this shows is the exceedingly well-known point that ‘object’ is not a concept under which you can count: there are, for instance, five trees. At a different level, he invokes conventional aspects of scientific description, or the relations of observers and observed in quantum theory: but he does not show how these aspects make the descriptions given by one kind of observer (in particular, human ones) local or perspectival in the relevant sense. If quantum mechanics presents these features, then it presents them to observers using a similar theory elsewhere in the universe. The ‘absolute conception’ is one that abstracts to the maximum degree from the peculiarities of any set of observers.

Of course, if extraterrestrial observers are doing well without any such theory, that raises another set of questions, about what we should think of quantum theory, as compared to their theory. Can we explain their theory in principle, or they ours? If so, we can understand, in terms of our conception of what science is, what is going on; if not, we shall be puzzled (we must remember that we have already made a lot of assumptions in supposing that these others are inquiring into the world, and successfully so). But on Putnam’s view of things, it looks as though there is no reason for puzzlement at all. Everything we say is equally what we say; his ‘internal’ realism has a distinctively human face. It looks as though there would be no more, and no less, reason to be puzzled if extraterrestrial physics were quite different from ours than if extraterrestrial fashions or food are.

It may be that Putnam can show that the idea of an ‘absolute conception’ is, as he claims, incoherent, but his breathless assault has not yet done so. I suspect that he is hostile to it because he wrongly thinks that it represents the return from the grave (just when you thought you were safe) of Metaphysical Realism. But to the extent that this horror can be clearly identified at all, this is a mistake. I did say that the idea of the ‘absolute conception’ could be used to give a sense to the contrast between ‘the world as it is in itself’ and ‘the world as it seems to us’. This, I believe, is a contrast that we need – in particular, when we explain the ambitions of science; and my aim was to explain what we might mean by this contrast, not from outside our conceptions, but in terms of reflections we can conduct within human life, the only place (needless to say) in which we can conduct them.

Putnam seems to say – though he does not address the question directly – that there is no sense in any such contrast at all, and, moreover, that science is not committed to it. He cheerfully says that it is mere dogmatism to suppose that even human scientific investigation will continue to converge on an agreed picture of the world; and he does not mean (as many might agree) that it is dogmatic to think that science will necessarily continue to succeed. He means that it might continue to succeed, but not by converging, or feeling the need to converge, on an agreed picture of the world. This seems to me a misunderstanding of what the scientific enterprise takes itself to be, precisely because it does not leave science with the conception that it is trying to tell us what the world is like.

Another thing that Putnam dislikes, and perhaps dislikes more than anything else, is a further suggestion, which I have also made, that there is an asymmetry in these respects between scientific and ethical thought. His aim on anything I have said in this area is even shakier: he goes on, a lot of the time, as though I aimed to distinguish facts from values as such (a traditional project which I explicitly reject), and as though I had to be a relativist (a necessity which I explicitly deny). Never mind. There are, Putnam and I agree, two important questions about these topics. First, do humans’ basic thoughts about our relation to the world – a world where we find ourselves, in the banal sense, and which we do not make – bear the same basic relations to that human endeavour which is scientific enquiry as they do to our ethical life? Second, does an understanding of scientific enquiry as finding out what the world is really like call on vacuous or false metaphysical images which modern philosophy should finally have left behind?

The message of Putnam’s book is that he says ‘yes’ to both these questions. The first affirmation may seem reassuring; rather less so, perhaps, when one reflects on the heroic paradox of the second. Whatever we eventually say about the first question (and it still seems to me that there are quite straightforward reasons for thinking that the relation of ethics to the world is very different from that of science), we should surely try to get rid of the paradoxical idea that we can only avoid metaphysical delusion by denying altogether that science is interested in what the world is really like (as opposed to the way it seems to us). Putnam is forced to this paradox, it seems to me, because of the very way in which he sets up his two kinds of realism in the first place.

In calling the acceptable and banal kind of realism ‘internal’, Putnam implies that the vital contrast is between a standpoint inside human experience, and one outside it. The outside standpoint is that which metaphysical realism tries to take. We cannot actually understand what the outside standpoint would be, and as a result, we find it hard to say what metaphysical realism would imply. We seem to have a boundary, but no conceivable idea of anything outside it. If we put it like this, however, and insist that the only standpoint is ‘inside’ human experience, we are still, in fact, using the idea of the boundary: we are claiming that there is a boundary, and that everything intelligible is on this side of it. Once we are stuck in that formulation, people who say such sensible things as that the world has certain characteristics which affect our experience – help to form our science, for instance – are read as trying to push the world and its characteristics back to the outside of this boundary.

But as Wittgenstein insisted, there is no such boundary – the very idea of it is unintelligible. Putnam says he agrees with Wittgenstein in this, and indeed Rorty says the same: but like Rorty, if less blatantly, Putnam is still guided by the ghosts that have supposedly been banished. An internal realism must be inside something, but what we have learned is that there is nothing for it to be inside. A distinction between metaphysical and internal realism makes sense only in terms of a diagram drawn by metaphysical realism itself. Once this lesson is properly learned, perhaps philosophers will be less anxious about saying what most people say, that the aim of science is to tell us what the world is like, as opposed to ways in which it seems (peculiarly) to us. Some may also think – it is certainly a separate question – that this is one of many ways in which science is different from ethics.