Paul P. Mealing

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Sunday, 13 September 2015

Physics, mathematics, the Universe - is Reason its raison d'être?

I’ve just read Paul Davies’ The Mind of God: Science & The Search for Ultimate Meaning, published in 1992, so a couple of decades old now. He wrote this as a follow-up to God and the New Physics, which I read some years ago. This book is more philosophical and tends to deal with cosmology and the laws of physics – it’s as much about epistemology and the history of science as about the science itself. Despite its age, it’s still very relevant, especially in regard to the relationship between science and religion and science and mathematics, both of which he discusses in some depth.

Davies is currently at The University of Arizona (along with Lawrence Krauss, who wrote A Universe from Nothing, amongst others), but at the time he wrote The Mind of God, Davies was living and working in Australia, where he wrote a number of books over a couple of decades. He was born and educated in England, so he’s lived on 3 continents.

Davies is often quoted out of context by Christian fundamentalists, giving the impression that he supports their views, but anyone who reads his books knows that’s far from the truth. When he first arrived in America, he was sometimes criticised on blogs for ‘promoting his own version of religion’, usually by people who had heard of him but never actually read him. From my experience of reading on the internet, religion is a sensitive topic in America on both sides of the religious divide, so unless your views are black or white you can be criticised by both sides. It’s worth noting that I’ve heard or read Richard Dawkins reference Davies on more than a few occasions, always with respect, even though Davies is not atheistic.

Davies declares his philosophical position very early on, which is definitely at odds with the generally held scientific point of view regarding where we stand in the scheme of things:

I belong to the group of scientists who do not subscribe to a conventional religion but nevertheless deny that the universe is a purposeless accident… I have come to the point of view that mind – i.e., conscious awareness of the world – is not a meaningless and incidental quirk of nature, but an absolute fundamental facet of reality. That is not to say that we are the purpose for which the universe exists. Far from it. I do, however, believe that we human beings are built into the scheme of things in a very basic way.

In a fashion, this is a formulation of the Strong Anthropic Principle, which most scientists, I expect, would eschew, but it’s one that I find appealing, much for the same reasons given by Davies. The Universe is such a complex phenomenon, its evolvement (thus far) culminating in the emergence of an intelligence able to fathom its own secrets at extreme scales of magnitude in both space and time. I’ve alluded to this ‘mystery’ in previous posts, so Davies’ philosophy appeals to me personally, and his book, in part, attempts to tackle this very topic.

Amongst other things, he gives a potted history of science from the ancients (especially the Greeks, but other cultures as well) and how it has largely replaced religion as the means to understand natural phenomena at all levels. This has resulted in a ‘God-of-the-Gaps’, where, epistemologically, scientific investigations and discoveries have gradually pushed God out of the picture. He also discusses the implications of a God existing outside of space and time actually creating a ‘beginning’. The idea of a God setting everything in motion (via the Big Bang) and then watching his creation evolve over billions of years like a wound up watch (Davies’ analogy) is no more appealing than the idea of a God who has to make adjustments or rewind it occasionally, to extend the metaphor.

In discussing how the scientific enterprise evolved, in particular how we search for the cause of events, reminded me of my own attraction to science from a very early age. Children are forever asking ‘why’ and ‘how’ questions – we have a natural inclination to wonder how things work – and by the time I’d reached my teens, I’d realised that science was the best means to pursue this.

Davies gives an example of Newton coming up with mathematical laws to explain gravity that not only provided a method to calculate projectiles on Earth but also the orbits of planets in the solar system. Brian Cox in a documentary on Gravity, wrote the equation down on a piece of paper, borrowing a pen from his cameraman, to demonstrate how simple it is. But Newton couldn’t explain why everything didn’t simply collapse in on itself and evoked God as the explanation for keeping the clockwork universe functioning. So Newton’s explanation of gravity, albeit a work of genius, didn’t go far enough.

Einstein then came up with his theory that gravity was a consequence of the curvature of space-time caused by mass, but, as Cox points out in his documentary, Einstein’s explanation doesn’t go far enough either, and there are still aspects of gravity we don’t understand, at the quantum level and in black holes where the laws of physics as we know them break down. As an aside, it’s the centenary year of Einstein publishing his General Theory of Relativity and I’ve just finished reading a book (The Road to Relativity by Hanoch Gutfreund and Jurgen Renn) which goes through the original manuscript page by page explaining Einstein’s creative process.

But back to Newton’s theory, I remember, in high school, trying to understand why acceleration in a gravitational field was the same irrespective of the mass of the body, and I could only resort to the mathematics to give me an answer, which didn’t seem satisfactory. I can also remember watching a light plane in flight over our house and seeing it side-slipping in the wind. In other words, the direction of the nose was slightly offset to its direction of travel to counter a side wind. I remember imagining the vectors at play and realising that I could work them out with basic trigonometry. It made me wonder for the first time, why did mathematics provide an answer and an explanation – what was the link between mathematics, a product of the mind, and a mechanical event, a consequence of the physical world?

I’ve written quite a lot on the topic of mathematics and its relationship to the laws of nature; Davies goes into this in some depth. It is worth quoting him on the subject, especially in regard to the often stated scepticism that the laws of nature only exist in our minds.

Sometimes it is argued that laws of nature, which are attempts to capture [nature’s] regularities systematically, are imposed on the world by our minds in order to make sense of it… I believe any suggestion that the laws of nature are similar projections of the human mind [to seeing animals in the constellations, for example] is absurd. The existence of regularities in nature are a mathematical objective fact… Without this assumption that the regularities are real, science is reduced to a meaningless charade.

He adds the caveat that the laws as written are ‘human inventions, but inventions designed to reflect, albeit imperfectly, actually existing properties of nature.’ Every scientist knows that our rendition of nature’s laws have inherent limitations, despite their accuracy and success, but quite often they provide new insights that we didn’t expect. Well known examples are Maxwell’s equations predicting electromagnetic waves and the constant speed of light, and Dirac’s equation predicting anti-matter. Most famously, Einstein’s special theory of relativity predicted the equivalence of energy and mass, which was demonstrated with the detonation of the atomic bomb. All these predictions were an unexpected consequence of the mathematics.

Referring back to Gutfreund’s and Renn’s book on Einstein’s search for a theory of gravity that went beyond Newton but was consistent with Newton, Einstein knew he had to find a mathematical description that not only fulfilled all his criteria regarding relativistic space-time and the equivalence of inertial and gravitational mass, but would also provide testable predictions like the bending of light near massive stellar objects (stars) and the precession of mercury’s orbit around the sun. We all know that Riemann’s non-Euclidian geometry gave him the mathematical formulation he needed and it’s been extraordinarily successful thus far, despite the limitations I mentioned earlier.

Davies covers quite a lot in his discussion on mathematics, including a very good exposition on Godel’s Incompleteness Theorem, Turing’s proof of infinite incomputable numbers, John Conway’s game of life with cellular automata and Von Neuman’s detailed investigation of self-replicating machines, which effectively foreshadowed the mechanics of biological life before DNA was discovered.

In the middle of all this, Davies makes an extraordinary claim, based on reasoning by Oxford mathematical physicist David Deutsch (the most vocal advocate for the many worlds interpretation of quantum mechanics and a leader in quantum computer development). Effectively, Deutsch argues that mathematics works in the real world (including electronic calculators and computers) not because of logic but because the physical world (via the laws of physics) is amenable to basic arithmetic: addition, subtraction etc. In other words, he’s basically saying that we only have mathematics because there are objects in our world that we can count. In effect, this is exactly what Davies says.

This is not the extraordinary claim. The extraordinary claim is that there may exist universes where mathematics, as we know it, doesn’t work, because there are no discrete objects. Davies extrapolates this to say that a problem that is incomputable with our mathematics may be computable with alternative mathematics that, I assume, is not based on counting. I have to confess I have issues with this.

To start from scratch, mathematics starts with numbers, which we all become acquainted with from an early age by counting objects. It’s a small step to get addition from counting but quite a large step to then abstract it from the real world, so the numbers only exist in our heads. Multiplication is simply adding something a number of times and subtraction is simply taking away something that was added so you get back to where you started. The same is true for division where you divide something you multiplied to go backwards in your calculation. In other words, subtraction and division are just the reverse operations for addition and multiplication respectively. Then you replace some of the numbers by letters as ‘unknowns’ and you suddenly have algebra. Now you’re doing mathematics.

The point I’d make, in reference to Davies’ claim, is that mathematics without numbers is not mathematics. And numbers may be to a different base or use different symbols, but they will all produce the same mathematics. I agree with Deutsch that mathematics is intrinsic to our world – none of us would do mathematics if it wasn’t. But I find the notion that there could hypothetically exist worlds where mathematics is not relevant or is not dependent on number, absurd, to use one of Davies’ favourite utterances.

Earlier in the book, Davies expresses scepticism at the idea that the laws of nature could arise with the universe – that they didn’t exist beforehand. In other words, he’s effectively arguing that they are transcendent. Since the laws are firmly based in mathematics, it’s hard to argue that the laws are transcendent but the mathematics is not.

I have enormous respect for Davies, and I wonder if I’m misrepresenting him. But this is what he said, albeit out of context:

Imagine a world in which the laws of physics were very different, possibly so different that discreet objects did not exist. Some of the mathematical operations that are computable in our world would not be so in this world, and vice versa.

Speaking of mathematical transcendence, he devotes almost an entire chapter to the underlying mystery of mathematics’ role in explicating natural phenomena through physics, with particular reference to mathematical Platonists like Kurt Godel, Eugene Wigner and Roger Penrose. But it’s a quote from Richard Feynman, who was not a Platonist as far as I know, that sums up the theme.

When you discover these things, you get the feeling that they were true before you found them. So you get the idea that somehow they existed somewhere… Well, in the case of physics we have double trouble. We come across these mathematical interrelationships but they apply to the universe, so the problem of where they are is doubly confusing… Those are philosophical questions that I don’t know how to answer.

Interestingly, in his later book, The Goldilocks Enigma (2006), Davies distances himself from mathematical Platonism and seems to espouse John Wheeler’s view that both the mathematics and the laws of nature emerged ‘higgledy-piggledy’ and are not transcendent. He also tackles the inherent conflict between the Strong Anthropic Principle, which he seems to support, and a non-teleological universe, which science virtually demands, but I’ll address that later.

Back to The Mind of God, he discusses in depth one of the paradigms of our age that the Universe can be totally understood by algorithms leading to the possibility that the Universe we live in is a Matrix-like computer simulation. Again, referring to The Goldilocks Enigma, he discounts this view as a variation on Intelligent Design. Towards the end of Mind of God, he discusses metaphysical, even mystical possibilities, but not as a replacement for science.

But one interesting point he makes, that I’ve never heard of before, was proposed by James Hartle and Murray Gellmann, who claim:

…that the existence of an approximately classical world, in which well-defined material objects exist in space, and in which there is a well-defined concept of time, requires special cosmic initial conditions.

In other words, they’re saying that the Universe would be a purely quantum world with everything in superpositional states (nothing would be fixed in space and time) were it not for ‘the special quantum state in which the universe originated.’ James Hartle developed with Stephen Hawking the Hawking-Hartle model of the Universe where time evolved out of a 4th dimension in a quantum big bang. It may be that Hartle’s and Gellmann’s conjecture is dependent on the veracity of that particular model. The link between the two ideas is only alluded to by Davies.

Apropos to the book’s title, Davies spends an entire chapter on ‘God’ arguments, in particular cosmological and ontological arguments that require a level of philosophical nous that, frankly, I don’t possess. Having said that, it became obvious to me that arguments for God are more dependent on subjective ‘feelings’ than rational requirements. After lengthy discussions on ‘necessary being’ and a ‘contingent universe’, and the tension if not outright contradiction the two ideas pose, Davies pretty well sums up the situation with this:

What seems to come through such analyses loud and clear is the fundamental incompatibility of a completely timeless, unchanging, necessary God with the notion of creativity in nature, with a universe that can change and evolve and bring forth the genuinely new…

In light of this, the only ‘God’ that makes sense to me is one that evolves like ‘Its’ creation and, in effect, is a consequence of it rather than its progenitor.

One of the points that Davies makes is how the Universe is not strictly deterministic or teleological, yet it allows for self-organisation and the evolvement of complexity; in essence, a freedom of evolvement without dictating it. I would call this pseudo-teleological and is completely consistent with both quantum and chaotic events, which dominate all natural phenomena from cosmological origins to the biological evolution of life.

This brings one back to the quote from Davies at the beginning of this discussion that the universe is not a meaningless accident. Inherent in the idea of meaningfulness is the necessary emergence of consciousness and its role as the prime source of reason. If not for reason the Universe would have no cognisance of its own existence and it would be truly ‘purposeless’ in every way. It is for this reason that people believe in God, in whatever guise they find him (or her, as the case may be). Because we can find reason in living our lives and use reason to understand the Universe, the idea that the Universe itself has no reason is difficult to reconcile.

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