The 'Cloudy and Fitful Quantum World'

JOHN POLKINGHORNE: TWO INTERVIEWS

Questions by Patrick Miles

2: THE 'CLOUDY AND FITFUL QUANTUM WORLD'

One of your best-known statements, from Exploring Reality (2005), is: 'It is clear that science has not demonstrated the causal closure of the natural world.' This seems perfectly reasonable, but is it a plea for the 'God of the gaps'?

I think that's a good question. You have to ask yourself, 'What's wrong with gaps?' There are various sorts of gaps. Some gaps are simply gaps of current ignorance: we don't understand this, we don't know how to do that. A God of those sort of gaps is no God at all. As knowledge advances, he fades away. But there are other gaps which are intrinsic, and some of them are intrinsic in the actual physical structure of the world as science has discovered it, and some of them are intrinsic for reasons connected with metaphysics, rather than science. Take the first ones: modern physics has discovered that there are intrinsic unpredictabilities present in physical processes – that is to say, unpredictabilities not due to the fact that we can't calculate accurately or measure precisely, they are just there!

I notice that several times in your most recent books you refer to quantum reality as 'cloudy', 'fitful', even 'veiled'.

Yes, we have lost the simple clarity of Newtonian physics. Quantum theory can calculate, for example, the probability of a radioactive nucleus decaying, but it cannot establish whether this particular one is going to decay in the next hour or so. And then there are gaps of principle involved in questions which go beyond science's self-limited power to answer. There are big questions. Perhaps the biggest of these metaphysical questions is Leibniz's great question, 'Why is there something rather than nothing?' Why does the world exist at all, and why do the laws of nature exist with the remarkable properties they have? We know that they have to take a very precise form, if the universe was to be capable of evolving carbon-based life; in fact just producing carbon requires the laws of nuclear physics to take a very specific quantitative form in relation to that.

Did God have any choice, then?

Well, Einstein said that when he went to heaven that was the first thing he was going to ask God! I think the answer is yes, God did. I mean, it's interesting at the end of Stephen Hawking's A Brief History of Time, when he's explaining all about the beautiful equations of nature and so on, he then asks the question he should have asked himself earlier: 'What is it that breathes fire into the equations and makes a universe for them to describe?' And I think God has chosen the world that we are able to describe in that sort of way.

I've read your Quantum Theory: A Very Short Introduction (2002) several times, and can see why Niels Bohr said that anyone who thought they fully understood quantum theory showed they hadn't begun to understand it. But you yourself explain that much of it is 'unpicturable' and many of its postulated particles haven't been 'observed directly in the laboratory'. So how empirical is quantum physics?

Very. The phenomena that we are trying to explain are carefully measured, and wonderfully accurately calculated. We know certain properties of electrons to an accuracy which represents the width of a human hair in relation to the distance between Los Angeles and New York, and that's pretty exact. We have the results, the 'phenomenology' as we physicists tend to call it, we know these are interesting things that go on in the world, they have these suggestive patterns about them. But how do they fit together? How are they consistent with each other? How can we actually use them to gain further understanding...to go beyond where we started? That's when we try to find a theory.

Clearly quantum theory is intensely mathematical. But if, according to Gödel's Theorem, we can't prove the consistency of axiomatised systems like mathematics, isn't quantum physics in danger of being self-verifying but not 'falsifiable', as Karl Popper required a truly scientific hypothesis to be?

I'm pretty critical of Popper's logic of scientific discovery. Falsifiability is a much trickier concept than he really conceded, at least in his original writings. You know, a famous example is: all swans are white, until you go to Australia and then see a black swan. But is it really a black swan? Or is it a long-necked duck? I think, ultimately, all physical theories – and in fact I think ultimately all human understandings of the nature of reality – have an element of commitment to a point of view which is not logically coercive.

But what worries me about quantum physics, string theory, or Hawking's stream of cosmological ideas, is that in the absence of empirical observations or falsifiability they seem more like metaphysics...

They are not simply unmotivated airy speculations. At the end of the day an appropriate degree of empirical accuracy is always going to be required. Dirac once said that it was more important to have beauty in your equations than to have them fit physical experiment. By that he didn't mean the fit didn't matter, but simply that if they didn't seem to match, the experiment might be wrong, or you might have made a mistake in the calculations. Particularly people working in fundamental physics are deeply impressed with the order of the world. Not only is it orderly but it is also beautifully ordered. The fundamental equations of physics are always found to be expressed in what mathematicians would recognise, and agree about, as being beautiful equations.

That is coming very close to the metaphysical statement of one of Dostoevsky's characters, that 'beauty will save the world'!

Maybe... There's something in the role of beauty. The sense of a beautiful equation is significant in physics, but we don't always have the right resources to find the beauty that might be lying behind it all.

I must say, as a layman I find it extraordinary that these very scientific chaps like Einstein or Schrödinger, studying a physical reality, have such fierce metaphysical and aesthetic emotions.

But everyone has a metaphysics. It simply means their world view – and we all have to have a world view. Somebody who tells you, for example, that there's nothing to do with reality other than what physics can tell you about it, hasn't learned that from his or her science. It's a metaphysical assumption. Important interpretative issues in quantum physics demand for their settlement not only physical insight, but metaphysical decision. It has turned out that there are both deterministic and indeterministic interpretations possible of quantum physics.

Turning now to your last two books, Quantum Physics and Theology: An Unexpected Kinship (2007) and Science and Religion in Quest of Truth (2011), I was very taken by the sets of parallel processes and concepts that you trace in them between science and theology – the dyads, as it were, of theoretical creativity/ christology from below and above; quark theory/humanity and divinity; phase transitions/miracles; quantum entanglement/Trinity, etc. These homologies, as you describe them, clearly do exist, but are you afraid of being thought to argue by analogy, which philosophers don't like?

Well, theologians are less reluctant about analogy. Aquinas' analogia entis (analogy of being) was a very important part of his theological thinking. The point is, when we have to talk about entities which have properties that are not part of our commonsense experience of the world, we have to make use of analogy to get some sort of grip on things. And of course, when you're thinking about analogies the interesting things are not only the things in common, but also the differences...

But isn't there a danger that your dyadic-homologous approach might suggest science and religion are essentially 'the same' – that Dawkins thinks science proves God doesn't exist, but Polkinghorne thinks science proves God does exist?

Well, that would be a mistake! It obviously isn't true. Analogy is not just an equation of identity. Science and religion are both similar and different in their approaches to truth. Putting it in the very simplest terms, science is concerned with an impersonal dimension of reality and has therefore to have recourse to repetition and experiment. And that doesn't exist in any form of personal knowledge, and least of all religious knowledge. So that's a very important dysanalogy from the start. But it doesn't mean there isn't motivated belief in these subjects.

I found that in both books you produced a convergence between science and theology that is very persuasive.

Well...convergence is perhaps too strong a word. I say it's consonance.

It seemed to me that, quite apart from their separate arguments, towards the ends of these two books you wanted to make summative statements about certain issues. One of these was physicists' Grand Unified Theories, or what is popularly known as 'The Theory of Everything'...

The Theory of Everything claim is just hubris.

You end the last two chapters of Quantum Physics and Theology by stressing that for you trinitarian theology is the true 'Theory of Everything'.

Well I think theology is the theory of everything because God is the ground of everything. It seems perfectly clear to me that science doesn't answer every question and therefore we have to seek other insights as well. It's not an argument that can be condensed into a sentence or two, but I believe that the most comprehensive way of understanding things is in terms of a theological view. For example, the beautiful equations and deep intelligibility of the physical world are understood as being a reflection of the mind of God. Theology really does have a 'scope' which enables it to be an integrating discipline. That's why I say I think the true theory of everything is theology. But of course that's not a knock-down argument.

I also thought it was courageous of you to end your last book, Science and Religion in Quest of Truth, with a section 'Other Faiths', which you clearly regard as a very important subject.

Yes, I think after the problem of suffering it's the biggest problem on the agenda and it will take a long time. Religions really matter to people and that's partly the source of their destructive influences as well as their fertility. It's a puzzling scene, because world religions are obviously all talking about the same dimension of human experience – the encounter with the sacred – but they do have very different things to say about it. Not just about strictly dogmatic matters, but even about human beings. To the Abrahamic faiths human beings are of unique and individual continuing significance. To our Hindu friends personality is recycled through reincarnation. And to our Buddhist friends, if I understand the doctrine of Anatta right, personal individuality is in fact an illusion which we eventually see through. Now those aren't three sets of people saying the same thing in culturally different ways, they are disagreeing. So there are serious and important problems there which need to be pursued and they're only beginning to be pursued, it seems to me. Nowadays, we can no longer dismiss our brothers and sisters in other faiths as being deluded people in far away countries who don't know very much. They're living down the street and we can see the integrity of their lives. So it's a pressing problem. And a lot of faiths are just beginning to talk to each other. Actually I think, in a small way, science can contribute to that. I've taken part in one or two projects in which people from different faiths and religions met together and discussed what they made of modern scientific discoveries, and that's a useful meeting point, I think.

Well, relating to that, perhaps my last question should be: Do you think there is anything positive that can be said for the great public God controversy of the past decade or so? Do you see any good coming out of it?

I think there's a little good coming out of it, but there's a lot to be regretted in the way in which the debate has been conducted. These are very important and difficult issues – the existence of God and so on – and actually in a back-handed sort of way people like Dawkins have done us a bit of a help by putting that question firmly back on the agenda. But they have not done any good to themselves or anybody else, in my opinion, by the way in which they've done so. Instead of entering into argument, they have just indulged in bluster and assertion.

Thank you, John. Very much.

Back to main page