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Science (a term in itself inoffensive and of indefinite meaning).

Joseph Conrad (1857–1924), The Secret Agent

That bright-eyed superstition known as infinite human progression.

Terry Eagleton, literary theorist and critic

1 | Life may be messy, but in the physical world there appears to be underlying order. Evidence of this order has encouraged scientists to believe in the existence of physical laws of nature. Why nature should have unifying features is a deep mystery. That physical laws of nature are ultimately reducible to mathematics is an even deeper mystery.¹

2 | The difference between the ways of science and the ways of other truth-seeking enterprises is that science has a method.

First find what you think might be a solution to a problem, then express it as a mathematical model, then test it.

David Deutsch, physicist

3 | In science, to look is not enough, there needs also to be intervention in order to affirm what it is that is being looked at. A testable theory is required, not just mere description, though a description is a start. A theory is proven for as long as it is confirmed in that repeatable process of measurement called experiment. Sometimes we improve our ability to measure and theories are further confirmed, and sometimes theories fail when examined more closely.

If the explanation of physical phenomena were evident in their appearance, empiricism would be true and there would be no need for science as we know it.

David Deutsch

‘We admit the existence of electricity, which we know othing about, why can’t there be a new force, still unknown which …’

‘When electricity was found,’ Levin quietly interrupted, ‘it was merely the discovery of a phenomenon, and it was not known where it came from or what it could do, and centuries passed before people thought of using it. The spiritualists on the contrary, began by saying that tables write to them, and spirits come to them, and only afterwards started saying it was an unknown force.’

Vronsky listened attentively to Levin, as he always listened, evidently interested in his words.

‘Yes, but the spiritualists say: now we don’t know what this force is, but the force exists, and these are the conditions under which it acts. Let the scientist find out what constitutes this force. No, I don’t see why it can’t be a force, if it …’

‘Because,’ Levin interrupted again, ‘with electricity, each time you rub resin against wool, a certain phenomenon manifests itself, while here it’s not the same each time, and therefore it’s not a natural phenomenon.’

…

‘I think,’ he continued, ‘that this attempt by spiritualists to explain their wonder by some new force is a most unfortunate one. They speak directly about spiritual force and want to subject it to material experiment.’

They were all waiting for him to finish, and he felt it.

‘And I think that you’d make an excellent medium,’ said Countess Nordston, ‘there’s something ecstatic in you.’

Leo Tolstoy, Anna Karenina

4 | The astronomer Nicolaus Copernicus (1473–1543) wondered if there might be some sort of inclination in matter that causes matter to be drawn to itself. But his was a vague poetic notion; it didn’t have what elevates Newton’s description – of what was later named gravity – to the level of theory. Newton writes in mathematics how the force works even as he fails to tell us what it is. Since it acts at a distance without any visible means of action, Newton’s gravity has no material existence, for which lack the theory was criticised by followers of Descartes, who believed that physical actions must result only from physical causes. But in physics mathematics trumps material means. The theory works, and that is enough, particularly when the theory is as encompassing as this one: explaining as it does both why an apple falls to earth and why the earth falls perpetually towards the sun.

A force without materiality looks indistinguishable from magic, but mathematics is what makes the reality of gravity testable. The lack of visible means was first criticised, then overlooked, and finally forgotten about.

If they don’t depend on true evidence, scientists are no better than gossips.

Penelope Fitzgerald (1916–2000), The Gate of Angels

5 | Science is an attempt to make knowledge collective. Science separates out from the world what can be repeated. Scientific experiments are repeatable (in theory at least) by anyone, ideally not just any competent human but any competent alien. Art is collective evidence of shared experience too, but science goes further; its knowledge means to be universal, not ‘merely’ human.

6 | Science searches for evidence of stability in the world out there. At one time we saw stability in the so-called fixed stars, until it was discovered that they are not fixed, just moving very slowly relative to each other, and only appear fixed because they are so far away. We used to think space and time were immutable, until Einstein showed otherwise. Today we begin to wonder if even the speed of light is a constant.

7 | Science organises the meaning of the world into what it is hoped are irreducible statements called the laws of nature, but every seemingly irreducible statement is doomed ultimately to be replaced by another attempt at the irreducible; and so science makes progress. There are no truly fundamental theories in science. Something more fundamental always comes along, eventually. ‘Fundamental’ theories are the theories that are currently most effective, but they are never complete. And never being truly fundamental, we cannot know if they are ever truly universal. In science, to understand more deeply is to get under what it is that is currently being stood on. What science stands on is continually being replaced by lower floors.

8 | Science has this particular strength, that theories are only overthrown when a new theory encompasses more phenomena than the previous theory encompassed. In this sense, old theories do not die, a new theory reveals the limits within which the old theory was, and still is, effective; but crucially the new theory goes beyond those boundaries into territory in which the old theory fails. Some scientists say that Newtonian physics was shown to be incorrect by Einstein’s theories of relativity, others that Einstein showed the limits within which Newton is true.

9 | Truth in science is a comparative entity: there is always the possibility of truer, but what is truer may sometimes – not always, by any means – look completely different from what was almost as true. In order to encompass all that has gone before, a new theory may – occasionally – be forced to do so by completely refashioning the nature of reality.

10 | Einstein twice had to rearrange the material world in order to satisfy the demands of mathematics. In order to take James Clerk Maxwell’s equations seriously – they describe electric and magnetic fields and their relationship to each other – he showed that it was necessary to change our thinking about what motion is. The invariant nature of light, he asserted, sets a limit on how fast things can move. In our everyday world we assume that however fast we travel, someone or something might conceivably travel faster; but this is not how things are, only how they appear to be at the relatively slow speeds (compared to the speed of light) of everyday human life. The classical world of Newtonian mechanics is limited, and Einstein shows where and why. No doubt Einstein’s assumption about light will prove to be an approximation too, but we do not yet understand how. When we do we will call it progress.

Einstein’s assumption upheaved time and space into a conjunction that Nabokov called ‘that hideous hybrid whose very hyphen looks phoney’. ‘Space-time’ more accurately describes the nature of reality than space and time taken separately. And yet, puzzlingly, we do not experience the space-time continuum. We believe we experience space and time separately. But since we do not have sense organs devoted to experiencing either space or time, perhaps what we experience comes from habit or is a delusion. In any case, all our best measurements show that space-time is a better approximation to reality than Newton’s theatre set in space and time.

In 1900, Max Planck solved a seemingly intractable problem in physics by breaking light into small packets. He effected a revolution in science even though he did not personally believe that these small packets – later named quanta – were anything more than a mathematical trick. Einstein took quanta seriously, and effectively invented quantum physics (aka quantum mechanics).

11 | The magnetic moment of an electron has been measured to eleven decimal places, and is still in agreement with what quantum mechanics predicts it should be. There is no guarantee that in the twelfth decimal place some new theory might not be required.

Astronomers have been monitoring the orbits of one double neutron star system – known as PSR 1916+16 – for around forty years. The emission of Einstein’s predicted gravitational waves from this system has been confirmed through a very gradual shortening of the star’s orbital period, and there has been agreement between the signals received from space and the overall prediction of Einstein’s theory to an astonishing fourteen decimal places.

Roger Penrose, mathematical physicist and philosopher

In the fifteenth decimal place, who knows?

12 | Finer measurement requires the invention of finer measuring instruments. Finer measurements lead to better theories. Out of better theories come subtler experiments. Progress is what results from the positive feedback of theory, experiment, and tool-making.

Very little in nature is detectable by unaided human senses. Most of what happens is too fast or too slow, too big or too small, or too remote, or hidden behind opaque barriers, or operates on principles too different from anything that influenced our evolution. But in some cases we can arrange for such phenomena to become perceptible, via scientific instruments.

David Deutsch

13 | Science goes in search of what is truer. If that means science goes in search of the truth, it does not logically follow that the truth exists, nor, if it does exist, that the truth can ever be reached. Even if we did believe that some ultimate truth exists, we can have no idea what it might look like.

14 | When Copernicus first wondered if the sun, and not the earth, was at the centre of things, he stumbled on what was to become a powerful driving force of the scientific method: that human beings do not occupy any position of privilege in the universe. Scientific progress is the attempt – repeated over and over again – to remove human beings from the centre of things. We are not at the centre of anything, is what the scientific method continually reminds us.

15 | The centre is a place of privileged perspective. If science is to find universal laws, then by their very nature universal laws cannot be privileged, or they would not be universal; and if they are not universal – no matter how grand they are – they are provincial.

16 | In order to uphold its own central tenet that humans are not at the centre of anything, the scientific method itself must be universal. It must have been discovered elsewhere by other intelligences across the universe. Science needs aliens. The more aliens the better. That no aliens have so far stepped forward might be seen as a blow to materialism.

We can be sure that any intelligent beings inhabiting those planets will measure the same inverse square law.

John Gribbin, science writer

It will be a great day in the history of science if we sometime discover a damp shadow elsewhere in the universe where a fungus has sprouted. And here we are, a gaudy efflorescence of consciousness, staggeringly improbable in light of everything we know of the reality that contains us.

Marilynne Robinson, Absence of Mind

17 | If aliens do not exist, the whole question of what kind of reality science describes is called into question. So long as aliens do not exist, what we are as humans in the universe remains an open question. So long as aliens do not exist, human beings are the aliens in the scientific woodpile.²

18 | There is nothing inevitable about the way the scientific method has developed on earth. Nor is it inevitable that human beings should have stumbled on the scientific method at all. Many civilisations have come and gone with very different cosmologies. And if not inevitable here, there may be many other worlds where there is sentient life but no scientific understanding. Presumably there are cosmologies out there, as there have been here on earth, that come at the universe from quite a different perspective. Why should other life forms care about intelligence most of all? They may have discovered other motors of the universe. Scientific progress is directly related to our ability to imagine what alien life might be.³

Our conceptual model of space and time has proven to be extremely successful – to such an extent that we may even find it difficult to imagine other ways of organising our thoughts and experience – but it isn’t logically inevitable.

Marilynne Robinson, novelist and essayist

[Theories] about the nature of the world become frameworks within which we live. And so they constrain what we think is possible, what we think is real.

Max Velmans, professor of psychology

19 | Scientific theories are frameworks that attempt to contain the world. But these frameworks are never more than detailed models, and a model is not the thing itself. Any knowledge about something is not the thing itself either. The only complete model of the universe would be the universe.

There is nothing more deceptive than an obvious fact.

Sir Arthur Conan Doyle (1859–1930), ‘The Boscombe Valley Mystery’

20 | Scientific facts are attached to theories that are part of a methodology that continually changes the limits within which they can be regarded as true. Facts are always embedded in theory, and theories come and go. There are no facts without theories. What we take to be facts may not be facts for other intelligent, questioning life forms. We can know the facts, but why they mean anything is another matter.

21 | It is far from clear that there are universal laws,⁴ but the pursuit of them has resulted in what we call progress, the outward and visible evidence of which is the material world we live in.

22 | The scientific fundamentalist takes home with him his belief that laws of nature actually exist. The more open-minded scientist understands that science is a kind of game whose rules only need apply in the laboratory or at the desk.

23 | Science is a mode of enquiry, not the last word. There are different world views, and they do not have to be commensurate, or agree with each other. And you don’t have to say one is better than another in all domains. But clearly if you want to build a rocket you will turn to physics, not theology.⁵

And why, after all, may not the world be so complex as to consist of many interpenetrating spheres of reality, which we can then approach … by using different conceptions and assuming different attitudes.

William James (1842–1910), The Varieties of Religious Experience

24 | There are new theories to come that are beyond the reach of current technologies and of our current imaginations. In order to make progress sometimes a technological leap will come first, as it did when the telescope turned from plaything into scientific measuring instrument. Sometimes experiment comes last of all, as it did when Einstein re-imagined gravity as the geometry of space-time. He spent ten years working out the mathematics, leaving it to others to prove by experiment that gravity was indeed how he conceived it to be. When Einstein was asked what his response would be if experiment were to prove his theory false, he said he would feel sorry for the dear Lord.

25 | Experiments are generally hard to perform and require determination. No one would perform an experiment without already having some idea of what they are looking for.

Every brilliant experiment, like every great work of art, begins with an act of the imagination.

Jonah Lehrer, writer

26 | For there to be progress in science there has to be some kind of understanding that comes in advance of the finding out: intuition. The history of science is necessarily full of instances in which insight comes first, ahead of proof in observation and theory. Where does, where can that insight come from? There must be various conduits of the truth if imagination sometimes gets there first.

In science the leap of imagination must be of the right kind and not too great a leap. Mediums and other sensitives also claim the ability to see ahead of the material evidence, but their methods fail when exposed to scientific, repetitive investigation. Their evidence is personal and anecdotal, not public and repeatable as science demands.

27 | On the radio I hear the announcer describe the discovery of new planetary system as ‘a rather wonderful poetic idea’. And why not?

28 | In a purely material world the immaterial is what we don’t yet understand materially; a dwindling pile in the to-do basket of science. If we wait too long the ink will have faded and the mystery will have become illegible. How long we are prepared to wait for material answers to material questions tests our faith.

We call the boat back in – Come in, number 87, your time’s up – only to find that the boat is too far out, and anyway, if we but knew it, the boat long ago rotted away and sank without trace.

29 | We don’t know what Nature is. There is that sifted-out part of Nature we call the material world, that ongoing conversation between science and the world, and then there is the world itself, in the largest sense, in which we are embedded. Most of us, most of the time, confuse the material world with the real world, whatever that is.

The scientific method sieves out the material world. The question is left open whether or not there will be anything left in the sieve afterwards, or indeed, if there is an afterwards. It seems increasingly likely that science may at best describe its own limitations, and not ‘everything’, as is sometimes predicted by its fundamentalists.

‘Freddy,⁶ I’m told that there are left-overs in the larder. Have you any idea what to do with left-overs?’

‘You don’t have to do anything with them. They’re left over from whatever was done to them before.’

His father smiled and sighed.

Penelope Fitzgerald, The Gate of Angels

30 | Materialism describes a world made out of logic and things that move. If it cannot be measured by a clock and a ruler, it lies outside scientific enquiry. That the whole world is capable of being measured requires faith, and there are days when my faith falters.