Farewell to Reality (5 page)

So, neither verifiability nor falsifiability provides a sufficiently robust criterion for defining ‘science'. And yet history shows that some
theories have indeed been falsified and that others have been at least temporarily ‘verified', in the sense that they have passed all the tests that have been thrown at them so far.

It seems to me that the most important defining criterion is therefore the
testability
of the theory. Whether we seek to verify it or falsify it, and irrespective of what we actually do with the theory once we know the test results, to qualify as a scientific theory it should in principle be testable.

I want to be clear that the demand for testability in the sense that I'm using this term should not be interpreted as a demand for an immediate yes-no, right-wrong evaluation. Theories take time to develop properly, and may even be perceived to fail if subjected to tests before their concepts, limitations and rules of application are fully understood. Think of testability instead as more of a professional judgement than a simple one-time evaluation.

The Testability Principle demands that scientific theories be actually or potentially capable of providing tests against empirical facts. Isn't this rather loose? How can we tell if a novel theoretical structure has the
potential
for yielding predictions that can be tested? For sure, it would be a lot easier if this was all black and white. But I honestly don't think it's all that complicated. A theory which, despite considerable effort, shows absolutely no promise of progressing towards testability should not be regarded as a scientific theory. A theory that continually fails repeated tests is a failed theory.

The correspondence theory of truth

All this talk of verification and falsification implies that ‘truth' plays a central role in whatever we conclude passes for a scientific methodology. But according to the Reality Principle, the reality we seek to study is a metaphysical concept. The Theory Principle says that the common currency of scientific theories involves yet more metaphysics.

It seems obvious that concepts that start out as purely speculative cannot be considered to be true. By the same token, concepts accepted as true may later turn out to be false. Phlogiston was once believed to be a substance contained in all combustible materials, released when these materials burned. This is not what we believe today.

How should we reconcile all this with the idea of scientific truth?

What convinces us either way is, of course,
evidence
in the form of facts. Here, we anchor the idea of ‘truth' firmly to the idea of an empirical reality. A statement is true if, and only if, it corresponds to established facts about the real world derived from our perceptions or measurements.

This
correspondence theory
of truth implies that there can be no truth — no right or wrong — without reference to facts about the external world.
^*
True statements tell it like it really is. The correspondence theory is the natural choice of a realist.

We appreciate that scientific theories are imperfect in many ways and, as Russell noted, we cannot assume that what we regard as true today will necessarily be true tomorrow. But we can think of scientific theories as possessing a
verisimilitude,
a truth-likeness, which increases with each successive generation of scientific development.

Scientists are constantly refining and improving their theories, and as it makes no sense to develop new theories that are less useful than their predecessors, we might be prepared to accept that successive developments help take us closer and closer to ‘the truth' about empirical reality.

The correspondence theory shifts the burden from the meaning of ‘truth' to the meaning of ‘facts', which seems both logical and helpful.
Most often, scientists who claim to be in pursuit of the truth are actually in pursuit of the facts. An interesting and unexpected experimental result will prompt a flurry of activity in competing laboratories, as scientists rush to confirm or refute the facts and so establish the truth.

For example, on 4 July 2012, scientists at CERN declared that they had discovered a new particle ‘consistent' with the standard-model Higgs boson. Further research will be required to categorize fully its properties and behaviour. This research will establish empirical facts about the existence of a particle that was first hypothesized in 1964. If these facts emerge broadly as anticipated, we may conclude that the statement ‘the Higgs boson exists in nature' is true, in much the same way that ‘unicorns exist in nature' or ‘phlogiston exists in nature' are false.

The Copernican attitude

There is one final, critically important ingredient to consider. When scientists go about their business — observing, experimenting, theorizing, predicting, testing and so on — they tend to do so with a certain fixed attitude or mindset. It is this attitude that sets science apart, that lends it its ‘Spock-ness' and exposes it to occasional criticism as a soulless, somewhat inhuman enterprise.

Let me explain.

The purpose of an organized system of religion is to enable its followers to come to terms with their place in the universe, give meaning to their lives and offer moral instruction and comfort in times of need. Religion is all about ‘us'. It puts us at the centre of things, and
although not all religious systems necessarily claim that the external physical world is organized principally for our benefit, many do.

Science is very different. Scientists tend to assume that there is, in fact, nothing particularly special about ‘us'. We are not uniquely privileged observers of the universe we inhabit. We are not at the centre of everything. There is nothing special about the planet on which we exist. Or the rather average class G2 main-sequence star that gives us sunlight. Or the galaxy of between 200 and 400 billion stars in which our sun orbits, about two thirds or 25,000 light years from the centre. Or the 53 other galaxies which together with the Milky Way form the Local Group. Or the Virgo Supercluster of which the Local Group forms part. I could go on, but I think you've got the message.

This is the Copernican Principle.

The principle is misnamed insofar as Nicolaus Copernicus himself did not view his heliocentric model of the universe as necessarily undermining earth's unique position. What he offered was a technical improvement over the Ptolemaic system's obsession with convoluted structures constructed using epicycles. By putting the sun at the centre, the retrograde motions of the other planets in the solar system could be explained as apparent motions when observed from an orbiting (rather than stationary) earth. The planets don't really move backwards: they only appear to move backwards because we are also being transported around the sun.

But Copernicus sparked a revolution that was to shape the very nature of science itself. It became apparent that science works best when we remove ‘us' as the primary objective or purpose of the equations of reality.

Nearly five hundred years on, all the scientific evidence gathered thus far suggests that the Copernican Principle is justified. The evidence suggests rather strongly that we are not privileged: we are not at the centre of things. It points to the singular absence of an intelligent force, moving in mysterious ways to organize the world just for our benefit. As French mathematician and astronomer Pierre-Simon, marquis de Laplace, once advised Napoleon:
‘Je n'avais pas besoin de cette hypothèse-là
.'
^*

Now this has been a bit of a whirlwind tour through some aspects of the philosophy of science and scientific methodology. I hope it wasn't too much like hard work.

I've tried to be reasonable. This ‘working model' of science acknowledges that reality-in-itself is metaphysical, that the objects of scientific study are the shadows, the things-as-they-appear or things-as-they-are-measured. It accepts that the facts that scientists work with are not theory-neutral — they do not come completely free from contamination by theoretical concepts. It accepts that theories are in their turn populated by metaphysical concepts and mathematical abstractions and are derived by any method that works, from induction to the most extreme speculation. It acknowledges that theories can never be accepted as the ultimate truth. Instead, they are accepted as possessing a high truth-likeness or verisimilitude — they correspond to the facts. In this way they become part of the authorized version of empirical reality.

Finally, the model acknowledges the important role played by the Copernican attitude. Science works best when we resist the temptation to see ourselves as the primary objective or purpose of reality.

This is a bit more elaborate than the Science Council's definition. But this elaboration is more reflective of actual practice. It is necessary if we are to understand how fairy-tale physics is not only possible, but is able to thrive.

^*
Perhaps we've just lost the habit.

^*
Alas, it's not possible.

^*
That's a lot of trillions, which is why the Large Hadron Collider cost £5 billion to construct. By the way, an electron volt is the amount of energy a single negatively charged electron gains when accelerated through a one-volt electric field. A l00W light bulb burns energy at the rate of about 600 billion billion electron volts per second.

^**
ATLAS stands for A Toroidal LHC Apparatus. CMS stands for Compact Muon Solenoid.

^*
We'll look more closely at the search for the Higgs boson in Chapter 3.

^*
Although Copernicus had argued for a sun-centred planetary system, the debate was still raging in Kepler's time. Brahe himself argued for a system in which the planets orbit the sun, which, in turn, orbits a stationary earth.

^*
For a vivid account of some of the more extreme methods that scientists have used to make discoveries, see Michael Brooks,
Free Radical: The Secret Anarchy of Science
, (Profile Books, London, 2011).

^*
For a recent, highly readable tour through the abstract, see Giovanni Vignale,
Beautiful Invisible: Creativity, Imagination, and Theoretical Physics
, (Oxford University Press, 2011).

^*
Eddington was also selective with his data, with history rewarding his choices as ‘good judgement'.

^**
How you pronounce ‘Uranus' is entirely up to you. I'm old enough to be stuck with the pronunciation I learned at school: ‘your anus'. This does not make me titter, or blush, because I am no longer eight years old.

^*
There is an alternative
coherence
theory of truth which asserts that truth is determined by relations between statements rather than correspondence to external facts. We will return to this alternative interpretation of truth in Chapter 10.

^*
‘I had no need of that hypothesis.' From W. W. Rouse Ball,
A Short Account of the History of Mathematics
, (4
^th
edition, 1908).

Part I

The Authorized Version

2

White Ambassadors of Morning

Light, Quantum Theory and the Nature of Reality

The more success the quantum theory has, the sillier it looks. How non-physicists would scoff if they were able to follow the odd course of developments!

Albert Einstein
¹

Two years before they hit the stratosphere with
Dark Side of the Moon
in 1973, the British progressive rock band Pink Floyd released their sixth studio album, called
Meddle.
Side two is a single 23-minute-long track called ‘Echoes'.
^*
After a short, discordant nightmare sequence in the middle of the track, ‘Echoes' greets the morning with a return to harmony. Soft, gentle vocals declare: ‘And through the window in the wall, comes streaming in on sunlight wings, a million white ambassadors of morning.'
²