Manny Rayner's book reviews

Sometimes, things just don't work out the way you hope they will. Rand, knowing how much I liked Lee Smolin's The Trouble with Physics and Peter Woit's Not Even Wrong, asked if I was planning to look at this book. It seemed interesting, and I mailed Palgrave Macmillan to ask if I could get a review copy. They very kindly sent me one. I immediately started reading, and finished it in a few hours: but I'm afraid to say I'm disappointed.

I was hoping to get an updating and development of the themes in Smolin and Woit. As they plausibly argue, something is not right with modern physics. Theory doesn't connect properly with experiment, and there is too much pressure to work within the mainstream frameworks; the most obvious example of the malaise is string theory, which, so far at least, has miserably failed to deliver on its early promise. But although Unzicker and Jones are indeed covering similar territory, their treatment fails to impress. Smolin and Woit are experts, and these people aren't. I didn't want to prejudge the issue - as I saw a few weeks ago in Peter Byrne's The Many Worlds of Hugh Everett III, you don't have to be a physicist to write an interesting book about physics - but you do have to be acutely conscious of your limitations.

Byrne, who is a good investigative journalist, makes effective use of his talents and is wary about treading on the physicists' home turf: he quotes what they have to say, and he tries to interpret it, but he doesn't attempt to second-guess them. Unzicker and Jones storm in and tell you all the things they believe are wrong with early 21st century physics. This is an extremely hard act to pull off; it's quite possible that they are right some of the time, but their arguments came across as intemperate and unconvincing. In some cases, for instance when talking about string theory and the Strong Anthropic Principle, what they say amounts to little more than abuse. When details are provided, I felt, at the very least, that they were often quoting very selectively.

Let's look at some concrete examples. Two major themes are a pair of ideas stemming from Dirac: the "large number coincidences" (there is even an appendix describing them), and the hypothesis that the value of the gravitational constant G changes over time. Unzicker and Jones quote Dicke with approval more than once, but fail to mention that he gave a perfectly reasonable explanation of the large number coincidences in 1961, which is for instance quoted in Rees's Before the Beginning. They list Kragh's Higher Speculations in the bibliography, but do not mention that it contains a long chapter debunking the "varying G" hypothesis. Kragh is an acknowledged expert on Dirac, and I found his account compelling.

The discussion of "inflation" in the early universe, another main target, also seemed suspect. Yes, as Penrose and others have pointed out, the theory has hardly been proven yet, and there are important questions left to answer; but the reason why it's popular is not just peer pressure and groupthink, but also the fact that it currently seems to be the best way to address the "flatness" and "horizon" problems, which are indeed mentioned here. It is not true, as Unzicker and Jones claim, that there is no experimental evidence in its favor. Steinhardt and Turok, who are leading critics of inflation, quite rightly point out in their book Endless Universe that inflation made good predictions about the Cosmic Background Radiation which were validated by the WMAP data. Unzicker and Jones make a sort of admission about the key value of 0.96 found for the spectral tilt, but it is phrased in such an oblique way that I doubt I would have had any idea what they were talking about if I hadn't read Steinhardt and Turok first.

Perhaps the strangest part was the discussion of symmetry and group theory. For reasons I did not properly grasp, Unzicker and Jones hate these ideas, which are fundamental to modern physics. It is particularly odd that Woit's book, often quoted with approval, is one long hymn to the importance of group theory and representation theory; once again, this is never mentioned. I could not help wondering just how much of Woit they had actually read.

I don't want to give the impression that I disliked everything in the book. For example, I found the discussion of galaxy formation interesting; it made me want to read more on this subject, which I know little about. Unfortunately, the fact that I saw so many errors in the chapters where I did have reasonable background knowledge left me feeling unsure as to how seriously I should take their claims about the universe's large-scale structure.

In conclusion, I completely agree with Unzicker and Jones that skepticism is good and that Big Science is in trouble; but these points are all made better by Smolin, Woit and Penrose. If you haven't already done so, check them out.
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After posting the above review, I was contacted by one of the authors, Alexander Unzicker, who objected to my claim that I had found numerous errors in the book and demanded details. He was particularly reluctant to accept what I had written about his treatment of the large number coincidences, varying G and inflation.

Well: I am far from being an expert on these matters, but I have read a fair amount about them. It certainly doesn't seem unreasonable to me to describe many statements in Bankrupting Physics as errors, though I suppose one might call some of them extreme fringe theories advanced with little supporting evidence. Looking first at the large number coincidences and varying G, it seemed to me from reading the book that Unzicker was describing Dirac's theories, which were thoroughly debunked in the Kragh chapter I quoted. Unzicker now tells me that he is not in fact referring to Dirac's work, but rather to a variant theory, developed by himself, which is described in a paper he published in 2008.

There are several points one might make here. First, I do not think this is made very clear in the book, where it is easy to get the impression that the reference is to Dirac. Second, it seems presumptious to call a large part of the scientific community frauds and liars because they follow mainstream cosmology rather than this extremely obscure idea. And third, having looked at the paper in question, I do not understand what clear experimental predictions it makes which would allow it to be tested. If Unzicker is able to furnish such predictions, and they are confirmed by observation, I am sure people will treat his work with much more respect; so far, however, he does not seem to have done so.

Moving on to inflation, I will support my claim that it is unreasonable to say that there is no evidence in its favor; this evidence is by no means conclusive, but it seems quite wrong to say that it does not exist. Looking at a standard reference, Mukhanov's Foundations of Physical Cosmology (2005), I find the following passage on pp. 344-5:

Assuming a stage of cosmic acceleration - inflation - we are able to make robust predictions even in the absence of the actual inflationary scenario. The most important among them are:

i) the flatness of the universe

ii) Gaussian scalar metric perturbations with a slightly red-tilted spectrum

iii) long-wavelength gravitational waves.

The condition of flatness is not as "natural" as it might appear at first glance. We recall that Ω = 1 was strongly disfavored by observations not so long ago. If gravity were always an attractive force, it is absolutely unclear why the current value of Ω could not be, for instance, 0.01 or 0.2. Only inflation gives a natural justification for Ω = 1. The deuterium abundance clearly indicates that baryons cannot contribute more than a small percentage of the critical energy density. Therefore, inflation also predicts the existence of a dark component. (...) The current data on CMB fluctuations favor the critical density and, combined with the results from high-redshift supernovae, make it almost impossible to doubt the existence of dark matter and dark energy.

The predicted spectrum for the scalar perturbations is also in good agreement with the current data. However, the accuracy of the observations is not yet sufficient to determine a small spectral tilt.

I find this last sentence particularly interesting, given that measurements since then do in fact support the existence of spectral tilt.

It is easy to point out other passages in Bankrupting Physics which one could reasonably describe as errors or inconsistencies. Just looking at the last few chapters, we find for example on p. 195 a passage which invites us to compare Ptolemaic and Copernican astronomy, and comments that "The description of the data provided by epicycles wasn't that bad, but dozens of free parameters were necessary to accomplish this." - a strange statement, considering that Copernicus also used epicycles. On p. 209 there is a claim that "no one has the slightest clue" how to calculate the imbalance between matter and antimatter in the early universe; this is in reality a problem that has been studied in great detail, although it has not yet been solved. And on p. 231, we read that "modern theories, with their flamboyant extra dimensions, would have made [Einstein] queasy". In fact, Einstein did quite a lot of work on theories with more than four dimensions, even though he ended up deciding that they were unpromising.

In summary, it is very hard for an amateur to launch a convincing attack on Big Science, and Unzicker's book amply demonstrates that fact.