The scale of that intellectual achievement is so great that there might seem little room any more for the ‘natural miracles’ of an earlier age, or to ‘wonder’ whether there might after all be more than we can know. It would certainly require a truly Olympian perspective, capable of surveying the vast landscape of science, to recognise where and what the limits to its knowledge might be – and that would seem an impossibility. Yet it is not quite so, for while that landscape is indeed vast, and far beyond the comprehending of any individual, it is nonetheless sustained by three great unifying phenomena that impose order on the world – which on examination can tell us something very profound about science and the limits of its materialist explanations.
It is fruitless – always has been, always will be – to pose that most elementary of all questions: ‘Why is there something rather than nothing?’ The same however does not apply to the second and supplementary question: ‘Why, given there is something, are both the physical universe (and all that it contains) and all life (in its infinite diversity) so ordered?’ They should not be, for anything left to itself will tend towards chaos and disorder, as fires burn out and clocks run down – unless countered by a compensating force imposing order, restituting lost energy.
There are (to put it simply) three ‘forces for order’: first the force of gravity, as discovered by Sir Isaac Newton, the glue that binds the universe together; next the all-powerful genes strung out along the Double Helix, imposing the order of form, the shape, characteristics and attibutes unique to each of the millions of species of living things; and thirdly the human mind, that imposes the order of understanding on the natural world and our place within it. These three forces control or sustain all (or virtually all) phenomena in the universe, and stand proxy for the ‘vast landscape’ of science. Thus, if they are knowable scientifically as belonging to that materialist, second-order reality of the physics and chemistry of matter (where water is a combination of two molecules of hydrogen and one of oxygen), then by definition there is nothing in theory that science cannot know. But if they are not so knowable, one can only infer that they exert their effects through some other force that lies beyond the range of science and its methods to detect. We start with Sir Isaac Newton’s theory of gravity.
Isaac Newton, born in 1642 into a semi-literate sheep-farming family in rural Lincolnshire, was one of the tiny handful of supreme geniuses who have shaped the categories of human knowledge. From the time of Aristotle onwards, and for the best part of two thousand years, the regularity and order of the physical world was as it was because it was divinely ordained to be so: the punctual and undeviating sun, the movement of the planets across the heavens, the passage of the seasons and apples falling from trees. Newton’s genius was to realise that these and numerous other aspects of the physical world were all linked together by the hidden force of gravity.
Soon after graduating at the age of twenty-three from Cambridge University, Newton was compelled by an epidemic of bubonic plague to return to his home in Lincolnshire. There, over a period of just two years, he made a series of scientific discoveries that would not be equalled till Einstein, almost 250 years later. These included the nature of light and the mathematical method of differential calculus, with which it is possible to calculate the movement of the planets in their orbit. Newton’s most famous insight came when, sitting in his garden, he saw an apple fall from a tree. He ‘wondered’ whether the force of the earth’s gravity pulling the apple to the ground might reach still further, and hold the moon in its orbit around the earth.
Newton’s friend Dr William Stukeley would later record his reminiscences of that great moment.
After dinner, the weather being warm, we went into the garden and drank tea, under the shade of some apple trees, only he and myself. Amidst other discourse, he told me he was just in the same situation as when, formerly, the notion of gravitation came into his mind. It was occasioned by the fall of an apple, as he sat in a contemplative mood. Why should that apple always descend perpendicularly to the ground, thought he to himself? Why should it not go sideways or upwards, but constantly to the earth’s centre? Assuredly, the reason is, that the earth draws it. There must be a drawing power in matter … and if matter thus draws matter, it … must extend itself through the universe.
Newton’s ‘notion of gravitation’, of ‘matter drawing on matter’, would resolve the greatest conundrum of the movement of those heavenly bodies, why they remained in their stately orbits (the moon around the earth, the earth around the sun) rather than, as they should by rights, being impelled by their centrifugal force into the far depths of outer space. Newton, being a mathematical genius, calculated the strength of that countervailing force of gravity, showing it to be determined by the masses of the moon and earth, earth and sun respectively, multiplied together and divided by the distance between them, and so too throughout the entire universe. By the time Newton published his epic three-volume Principia Mathematica in 1697, describing the theory of gravity and the three laws of motion, he had transformed the divinely ordained physical world into which he was born into one governed by absolute and unchallengeable universal laws known to man, where everything was linked to everything else in a never-ending series of causes – all the way into the past and indefinitely into the future.
From the beginning, the force of gravity at the moment of the Big Bang imposed the necessary order on those billions of elementary particles, concentrating them into massive, heat-generating stars. Several thousand millions of years later, the same force of gravity would impose order on our solar system, concentrating 99 per cent of its matter within the sun to generate the prodigious amounts of energy, heat and light that would allow the emergence of life on earth. And anticipating the future? Newton’s friend, the Astronomer Royal Edmond Halley, used Newton’s laws to work out the elliptical orbit of the comet that bears his name and so predict its seventy-six-year cycle of return. Three hundred years later, NASA scientists would use those same laws to plot the trajectory of the first manned space flight to the moon. Newton’s laws can even predict when it will all end – in five thousand million years’ time (or thereabouts), when the prodigious energy generated by our sun will be exhausted, and our earth will perish.
As time has passed, so the explanatory power of Newton’s laws of gravity has grown ever wider, to touch virtually every aspect of human experience: the movement of the sun and stars (obviously), the waxing and waning of the moon, the ebb and flow of the tides, the contrasting climates of the Arctic Circle and the sand-swept desert, the cycle of the seasons, rain falling on the ground, the shape of mountains sculpted by the movement of glaciers, the flow of rivers towards the sea, the size of living things from whale to flea and indeed ourselves – for we could not be any bigger than we are without encountering the hazard, posed by gravity, of falling over.
Newton’s laws epitomise, to the highest degree, the explanatory power of science, through which for the first time we humans could comprehend the workings of that vast universe to which we belong. But, and it is a most extraordinary thing, three hundred years on, the means by which the powerful, invisible glue of gravity imposes order on the universe remains quite unknown. Consider, by analogy, a child whirling a ball attached to a string around its head, just as gravity holds the earth in its perpetual orbit around the sun. Here, the string (like gravity) counteracts the centrifugal force that would hurtle the ball (the earth) into a distant tree. But there is no string. Newton himself was only too well aware that there had to be some physical means by which gravity must exert its influence over hundreds, thousands, of millions of miles of empty space. It was, he wrote, ‘an absurdity that no thinking man can ever fall into’ to suppose that gravity ‘could act at a distance through a vacuum without the mediation of anything else, by which that action and force may be conveyed’.
Perhaps, he speculated, space was suffused by an invisible ‘ether’ composed of very small particles that repelled one another and by which the sun could hold the earth in its orbit – though this would mean that over a very long period the movement of the planets would gradually slow down through the