Farewell to Reality

by Jim Baggott

  What do the philosophers have to say about all this?

  Hmm. Another interesting question. We might have imagined that these rather striking developments in theoretical physics would have attracted a lot of interest from the philosophy community. After all, the fairy-tale physicists appear to be challenging the very definition of science, and this is something on which philosophers of science might have been expected to have a ready opinion.

  In fact, almost a century of intellectual endeavour and argumentation appears to have led the philosophers further and further away from a consensus on science and the scientific method. As Greek philosopher Stathis Psillos, an authority on scientific realism, commented in a personal note to me:

  I share your concerns [regarding] the [current] state of [the] philosophy of science. There is nothing like a consensus on scientific method, explanation, causation, laws and all other key concepts and issues in the philosophy of science. Actually, it seems that if there is anything like a growing tendency it is for pluralism. When it comes to the metaphysics of science, it seems the tendency is to go back to Aristotelianism — and here is where things go bizarre really, since the connection with the current scientific image of the world is thinner than ever.11

  In broad terms, the pluralism that Psillos mentions refers to the very different perspectives held by contemporary philosophers of science. Some, like Psillos himself, argue for a form of scientific realism. Others favour a form of post-positivist empiricism, retaining the negative attitude towards metaphysics and denying that scientific theories progress towards a literally true representation of an independently existing reality. The empiricist believes that the purpose of science is rather to provide us with theories that are adequate for the task of relating one set of facts to another. We should accept as true only what these theories have to say about those things that we can see directly for ourselves. But we should not believe that the unobservable entities that the theories describe (such as photons, quarks or electrons) are in themselves real and that the theories are literally true.

  Yet others argue that scientific theories are social constructions, that their interpretation and acceptance as ‘the truth’ are no more than conventions, achieved through consensus within the community of people engaged in scientific activity in any particular generation. For sure, these constructions might collectively offer a more reliable interpretation of nature than those afforded by superstition or religious mythology, but they are constructions nonetheless.

  Steven Weinberg was expressing exasperation with this state of affairs as early as 1993:

  This is not to deny all value to philosophy, much of which has nothing to do with science. I do not even mean to deny all value to the philosophy of science, which at its best seems to me a pleasing gloss on this history and discoveries of science. But we should not expect it to provide today’s scientists with any useful guidance about how to go about their work or about what they are likely to find.12

  Susskind goes even further. He believes that the guardians of science and scientific methodology are scientists, not philosophers:

  Good scientific methodology is not an abstract set of rules dictated by philosophers. It is conditioned by, and determined by, the science itself and the scientists who create the science. What may have constituted scientific proof for a particle physicist of the 1960s — namely the detection of an isolated particle — is inappropriate for a modern quark physicist who can never hope to remove and isolate a quark. Let’s not put the cart before the horse. Science is the horse that pulls the cart of philosophy.13

  Despite this wave of general negativity, if not outright hostility, towards philosophers, there are a few (rare) instances in which philosophers have deigned to pass judgement. For example, in September 2007, philosophers Nancy Cartwright and Roman Frigg provided a short commentary on string theory which was published in the British science monthly Physics World.

  In my view, Cartwright and Frigg were actually rather generous in their assessment of string theory’s ‘successes’, but they were quite clear about the theory’s lack of ‘progression’:

  The question of how progressive string theory is then becomes one of truth, and this brings us back to predictions. The more numerous, varied, precise and novel a theory’s successful predictions are, the more confidence we can have that the theory is true, or at least approximately true … That a theory describes the world correctly wherever we have checked provides good reason to expect that it will describe the world correctly where we have not checked. String theory’s failure to make testable predictions therefore leaves us with little reason to believe that it gives us a true picture.14

  I think it’s high time we heard a bit more from the philosophers. I’d be interested in their interpretation of the status of M-theory, the multiverse and the anthropic principle. A hostile reception can be pretty much guaranteed, but I believe it is vitally important that the guardianship of science and the scientific method should not be left solely in the hands of scientists, particularly those scientists with intellectual agendas of their own.

  Are we witnessing the end of physics?

  In the years building up to the end of the last millennium, a considerable stir was caused by a number of popular books declaring the ‘end’ of things. The trend may have begun with Francis Fukuyama’s The End of History and the Last Man, which was published in 1993. In 1996, John Horgan, then a staff writer at Scientific American, weighed in with The End of Science.

  Horgan took a generally pessimistic view, not just of physics and cosmology, but of philosophy, evolutionary biology, social science and neuroscience. The End of Science was generally rather destructive and unhelpful, which was a shame, because Horgan did have some really valuable points to make. He reserved particular ire for the state of contemporary physics:

  This is the fate of physics. The vast majority of physicists, those employed in industry and even academia, will continue to apply the knowledge they already have in hand — inventing more versatile lasers and superconductors and computing devices — without worrying about any underlying philosophical issues. A few diehards dedicated to truth rather than practicality will practice physics in a nonempirical, ironic mode, plumbing the magical realm of superstrings and other esoterica and fretting about the meaning of quantum mechanics. The conferences of these ironic physicists, whose disputes cannot be experimentally resolved, will become more and more like those of that bastion of literary criticism, the Modern Language Association.15

  In truth, we’ve been here before. Although entirely apocryphal,16 we shouldn’t let this get in the way of a neat story, and the story goes that in 1900,* the great British physicist Lord Kelvin famously declared to the British Association for the Advancement of Science that: ‘There is nothing new to be discovered in physics now. All that remains is more and more precise measurement.’17 What followed was a century of scientific discovery on an unprecedented scale.

  This tends to be the fate of any declaration that we’ve reached the end. Horgan’s claim that we’d reached the end of physics and cosmology was swiftly followed in 1998 by the announcement — to the considerable astonishment of theorists — that the expansion of the universe is actually accelerating. Leggett demonstrated that it was still possible to explore the meaning of quantum mechanics through experiment, and experiments were duly performed and reported in 2007.**

  And although Horgan might be tempted to dismiss the discovery of the electro-weak Higgs boson in 2012 (if this indeed is what it is) as something that was predicted nearly fifty years ago and so takes particle physics no further forward, the simple truth is that this is a particle we know relatively little about. If this is the Higgs boson, then there is much we still need to learn about its properties and behaviour. Now that we can make it, we have an opportunity to study it in great detail. There may yet be surprises in store.

  We’re far from the end of physics and cosmology. There is still a long way to go and we have a long list of
unanswered questions. But there is an inescapable consequence of the stage of maturity that physics has reached. Discoveries of significant new empirical facts are now very few and very far between. In the meantime, our Western scientific-technical culture has developed a seemingly insatiable appetite for instant gratification. We want answers now. Theorists need to attend conferences and publish papers this year. They (and we) don’t want to be kept waiting another two decades (three? five?) for the next discovery, the next big empirical fact.

  In this sense Horgan got it exactly right, although he might have emphasized that the most important psychological factor driving the development of what he called ‘ironic physics’ (and what I’ve called fairy-tale physics) is childish impatience.

  I think he also underestimated just how esoteric the esoterica would become.

  So, what do you want me to do about it?

  This is easily answered, and you’ll find I’m not very demanding. There are already some signs that the grip of the fairy-tale physicists may be weakening. Failed theories don’t get junked overnight. They tend to fade away none-too-gracefully, as theorists gradually realize that their time and energy may be more fruitfully spent on other things. The annual string theory conference, last held in June 2011, was less well attended than previous events, although this might have been simply because the cost of attending this conference (in Uppsala, Sweden) was quite high and videos of the talks were freely available online.18

  The absence of hard evidence from the LHC for sparticles and other phenomena tentatively ‘predicted’ by SUSY and superstring theories is greatly discouraging, despite the tendency of SUSY and string phenomenologists to put a brave face on things. My own feeling is that the interconnectedness of all the unjustified and untestable assumptions that have been deployed in the creation of fairy-tale physics will slowly but inevitably bring the whole structure down. Future theorists may look back at this period in the development of physics and wonder why so few thought to challenge the orthodoxy of the time. Didn’t we appreciate that something funny was going on?

  My hope is that in its exploration of what looks likely to be the electro-weak Higgs boson, the various detector collaborations at the LHC turn up some really puzzling new facts. No doubt the theorists will be quick to explain how any new facts are consistent with SUSY, M-theory or the multiverse, but I’m reasonably confident that common sense will ultimately prevail.

  In the meantime, we have to square up to the challenge posed by fairy-tale physics. And this is all I ask of you. Next time you pick up the latest best-selling popular science book, or tune into the latest science documentary on the radio or television, keep an open mind and try to maintain a healthy scepticism. By all means allow yourself to be entertained, but remember Hume’s quote above. What is the nature of the evidence in support of this theory? Does the theory make predictions of quantity or number, of matter of fact and existence? Do the theory’s predictions have the capability — even in principle — of being subject to observational or experimental test?

  Come to your own conclusions.

  * Any doubters might want to consult Charles Mackay’s Extraordinary Popular Delusions and the Madness of Crowds, first published in 1841. Among the economic Grand Delusions Mackay lists the Dutch tulip mania of the early seventeenth century and the South Sea Bubble of 1711-20. Thanks to Professor Steve Blundell for drawing this book to my attention.

  * In this case, social rather than physical reality — see my book A Beginner’s Guide to Reality.

  * There’s obviously something about the turning of centuries that brings out this kind of stuff.

  ** Although, in fairness, the experiments only served to deepen the mystery even further.

  Endnotes

  Quotes and other references to texts listed in the Bibliography are indicated by author surname, title (where necessary) and page number. Most of the Einstein quotes used in the chapter headings can be found in Alice Calaprice, The Ultimate Quotable Einstein (Princeton University Press, 2011). There are several references to articles posted on the online preprint archive arXiv, managed by Cornell University. These can be accessed by loading the arXiv home page —, http://arxiv.org/ — and typing the article identifier in the search window.

  Chapter 1: The Supreme Task

  1 Albert Einstein, ‘Motives for Research’, a speech delivered at Max Planck’s sixtieth birthday celebration, April 1918.

  2 Larry and Andy Wachowski, The Matrix: The Shooting Script, Newmarket Press, New York, 2001, p.38.

  3 Bernard d’Espagnat, Reality and the Physicist: Knowledge, Duration and the Quantum World, Cambridge University Press, 1989, p.115.

  4 From the 1978 essay ‘How to Build a Universe that Doesn’t Fall Apart Two Days Later’, included in the anthology I Hope I Shall Arrive Soon, edited by Mark Hurst and Paul Williams, Grafton Books, London, 1988. This quote appears on p.10.

  5 Heisenberg, p.46.

  6 Quoted in Maurice Solovine, Albert Einstein: Lettres à Maurice Solovine, Gauthier-Villars, Paris, 1956. This quote is reproduced in Fine, p.110.

  7 Hacking, p.23.

  8 Ian Sample, ‘What is this thing we call science? Here’s one definition …’, Guardian, 4 March 2009. www.guardian.co.uk/science/blog/2009/mar/03/science-definition-council-francis-bacon. More details can be found on the Science Council’s website: www.sciencecouncil.org/content/what-science.

  9 Jon Butterworth, ‘Told You So … Higgs Fails to Materialise’, Life and Physics, hosted by the Guardian, blog entry, 11 May 2011. www.guardian.co.uk/science/life-and-physics.

  10 Pierre Duhem, The Aim and Structure of Physical Theory, English translation of the second French edition of 1914 by Philip P. Wiener, Princeton University Press, 1954, p.145.

  11 Johannes Kepler, Astronomia Nova, Part II, Section 19, quoted in Koestler, pp. 326—7.

  12 Ibid., Part IV, Section 58, quoted in Koestler, p.338.

  13 Letter to Richard Bentley, quoted in Koestler, p.344. The letter appears to be undated but is a reply to one from Bentley dated 18 February 1693. Transcripts of both letters can be viewed online at The Newton Project, www.newtonproject.sussex.ac.uk.

  14 Russell, p.34.

  15 Ibid, p.35.

  Chapter 2: White Ambassadors of Morning

  1 Letter to Heinrich Zangger, 20 May 1912.

  2 Pink Floyd, Meddle, originally released on Harvest Records (an imprint of EMI), October 1971.

  3 Albert Einstein, Annalen der Physik, 17 (1905), p.133. English translation in Stachel, p.178.

  4 Following Planck, Einstein suggested that the energy (E) carried by an individual light quantum is proportional to its frequency (given by the Greek symbol nu, ν), according to E = hν, where h is Planck’s constant, the fundamental quantum of action in quantum mechanics. In many ways, this result rivals his most famous equation E = mc2, which we will encounter in Chapter 4.

  5 Quoted in Pais, Subtle is the Lord, p.382.

  6 Quoted by Aage Petersen in French and Kennedy, p.305.

  7 This is given as the quantum number multiplied by Planck’s constant h divided by 4π

  8 Letter to Max Born, 4 December 1926. Quoted in Pais, Subtle is the Lord, p.443.

  9 The two are related according to the equation λ = v/ν, where the Greek symbol lambda, λ, represents the wavelength, v is the phase velocity and ν is the frequency of the wave.

  10 The de Broglie relationship is written λ = h/p, where λ is the wavelength, h is Planck’s constant and p is the momentum.

  11 Heisenberg established that the uncertainty in position multiplied by the uncertainty in momentum must be greater than, or at least equal to, Planck’s constant h.

  12 Albert Einstein, Boris Podolsky, Nathan Rosen, Physical Review, 47, 1935, pp. 777—80. This paper is reproduced in Wheeler and Zurek, p.141.

  13 In Stefan Rozenthal (ed.), Niels Bohr: His Life and Work as Seen by his Friends and Colleagues, North-Holland, Amsterdam, 1967, pp. 114—36. An extract of this essay is reproduced i
n Wheeler and Zurek, pp. 137 and 142—3. This quote appears on p.142.

  14 Paul Dirac, interview with Niels Bohr, 17 November 1962, Archive for the History of Quantum Physics. Quoted in Beller, p.145.

  15 A. J. Leggett, Foundations of Physics, 33 (2003), pp. 1474—5.

  16 John Bell, Epistemological Letters, November 1975, pp. 2—6. This paper is reproduced in Bell, pp. 63—6. The quote appears on p.65.

  17 The expression 2.697±0.015 indicates the spread of experimental results around the mean value. The experiments produced results in the range 2.682 to 2.712, representing 68 per cent confidence limits or one standard deviation.

  18 See Xiao-song Ma, et al., arXiv: quant-ph/1205.3909v1, 17 May 2012.

  19 Why do all these experiments never quite achieve the precise quantum theory predictions? Because entangled quantum particles are easily ‘degraded’. Entangled particles which lose their correlation because of stray interactions or instrumental deficiencies will look, to all intents and purposes, as though they are locally real and will not contribute to a violation of the inequality being measured. The wavefunctions of such entangled particles have been prematurely collapsed.

  20 Niels Bohr, Physical Review, 48 (1935), pp. 696—702. This paper is reproduced in Wheeler and Zurek, pp. 145—51. The quote appears on p.145 (emphasis in the original).

  Chapter 3: The Construction of Mass

  1 Albert Einstein, Autobiographical Notes, 33 (1946).

  2 Remember, the number of different spin orientations is given by twice the spin quantum number plus 1. For s = ½, this gives 2 × ½ + 1, or two spin orientations.

  3 In fact, Einstein’s famous equation E = mc2 is an approximation of a more complex equation E2 = p2c2 + m2c4, where p is the momentum and m is the rest mass. In any relativistic treatment, energy must therefore enter as E2 and there will always be two sets of solutions, one with positive energy and one with ‘negative’ energy.