Not Even Wrong: The Failure of String Theory and the Continuing Challenge to Unify the Laws of Physics [Hardcover]

Apart from the fact that Peter Woit has every right (even obligation) to publish a view dissenting from the received wisdom, the fact that the representatives of that received wisdom are so hostile to such a lucid, balanced and well-written description of the current state of String Theory (or should that be "String Hypothesis"?) is a good sign that he is onto something.

Several decades ago I was awarded a modest degree in Mathematics and Physics from a very good Physics faculty at Manchester University (attending lectures in the Rutherford Building gave one a sense of time travel). Far too modest a degree to allow an academic career, but enough to give a lifetime of interest and curiosity in these matters. I have read pretty much every popular book mentioned by Woit and, in an attempt to understand even a little more about string theory than the vague ideas provided by these simpler books (not to mention Brian Green's computer generated graphics) I have recently finished the massive task of reading Penrose's "The Road to Reality".

I made it to the end (skipping all the equations except one; the one which I along with everyone else on the planet born since Einstein already knows) not because I understood much of what I was reading but because I thought I might be rewarded with some understanding of what it was all about. No chance.

So when I found this book by Woit once more hope triumphed over experience and I ordered it immediately.

What I want to do is thank Woit for providing the best book on the subject (from the viewpoint of the non-practitioner) that I have ever seen or read. Obviously, as a teacher, he understands how to explain things that are not self-evident truths. And he does it with wit and intelligence.

I can't say I now understand String Theory, but I am a lot closer to understanding what it is that it is trying to describe.

So, thank you Peter Woit.

Before I begin, let me point out that my PhD supervisor was Barton Zwiebach, a leading string theorist and author of the recently published 'A First Course in String Theory'.

It is certainly true that string theory is by far the most beautiful and complex physical theory that man has ever contemplated, so that it is hardly surprising to find so many talented young researchers drawn to it. It is also one of the very few theories currently under serious investigation as a possible 'theory of everything', with the potential to unify gravity and the standard model. There was a time long ago when string theory was thought (or rather, hoped) to be a single unique theory, but the current proliferation of string vacua (the 'landscape') and the consequent complete lack of predictiveness should, for any reasonable-minded person, dash any hope of it being the 'theory of everything'. Rather, the huge number of manually tunable parameters make it a 'theory of almost anything'. Indeed, given any particular universe you can imagine, the chances are that there is a string theory (or more likely, lots of them), which describe it. To still hold on to the vain and distant hope that maybe, just maybe, there is some deep, as yet unknown, underlying symmetry principle which will somehow manage to pick out our particular universe as the only possible one out of the infinite number of possible stringy universes, goes far beyond wishful thinking - it is an exercise in self-delusion. Unfortunately, "all that glitters is not gold" - mathematical beauty in and of itself simply does not imply correctness.

Of course string theory should continue to be studied, but the physics establishment must be in a state of crisis when an extraordinarily disproportionate number of people are investigating a model which potentially has nothing useful to say about the real physical world. Time, money and effort are surely better spent elsewhere.

Even though it may leave a bitter taste in the mouths of the more fanatical string theory advocates, Woit's book is an important and indeed necessary contribution. For the sake of scientific advancement we would do well to take note of the issues he raises.

Peter Woit is interested in finding a final theory that produces predictions, and the purpose of this book is to investigate mainstream ideas and some alternatives. Lee Smolin comments that Not Even Wrong 'is a courageous and necessary book that should spark a debate about the future of theoretical physics', while Roger Penrose's states: 'The hold that string theory has ... is very remarkable, considering the lack of any observational support ... Woit supplies the first thorough and detailed analysis...'

Woit acknowledges on page xi that most stringers are 'not likely to be very happy with this book.'

Chapter 1 begins with Winston Churchill's advice in war, the version I'm familiar with being simply: 'Never surrender!' But should this advice advice apply to speculative mainstream ideas?

Woit discusses this in the context of stringy speculators. They too will never surrender: too much depends on their speculations. Surrender will mean loss of prestige, power, control of arXiv.org, journals, etc.

Chapter 2 briefly defines (in words) state-vectors and Hamiltonians and then gives a history of experimental particle physics.

Chapter 3 explains (in words and illustrations) quantum theory, symmetry groups, Lie algebra unitary group U(1), representation theory, Weyl's theory, symmetry unitary groups SU(2), special orthagonal group SO(3) and its relationship to SU(2) by rotations, particle spin, all in historical context.

Chapter 4 explains the history of quantum field theory from the inconsistency of Schroedinger's quantum mechanics with relativity, through Dirac's equation that solves the problem and predicts spin, antimatter and the electron's magnetic moment. Woit briefly discusses renormalization, which is physically understood by the polarization of Dirac's sea of virtual charge created by the strong field around a real particle. The polarized charge tends to shield out most of the charge as seen at large distances or in low energy collisions. Renormalization is required because there must some kind of cutoff (reason unknown) that prevents the entire vacuum being polarized by a single real charge, but Woit does give the detailed history which makes at least the mathematical side of the problem crystal clear to the layman.

Chapter 5 is gauge symmetry and gauge theories. Woit explains Weyl tried to unify gravity and electromagnetism by extending the general covariance of general relativity (general covariance is the property whereby covariant laws of nature don't depend on either the velocity or acceleration of the observer) into a new symmetry principle of gauge invariance, giving Maxwell's equations. Einstein immediately found experimental objections to Weyl, so that closed down that speculation. However Weyl later introduced the maths of spinor fields. Woit introduces the Yang-Mills weak force isospin symmetry SU(2), noting that the name derives from isotopes (where the experimental data comes from).

Chapter 6 is the Standard Model. This is what you're buying the book for. Chapter 7 explains the successes of the Standard Model in experimental particle physics. Chapter 8 lists the few outstanding problems of the Standard Model like gravity and, 'Why does the vacuum state break the electro-weak gauge symmetry? If the origin of this really is a Higgs field, then at least two new parameters are needed ... One [only] is determined by the observed properties of the electro-weak interactions ... This is why the Standard Model predicts the existence of a Higgs particle, but does not predict its mass.'

The first 101 pages, just described, are worth the price of the book. Chapter 9 onwards sadly gets into the boring and useless stringy speculations: Kaluza-Klein 5 dimensional unification, supersymmetry, supergravity. Sense is restored from page 120 with lattice gauge theory in quantum chromodynamics, which makes predictions that are tested. Woit explains that Witten made the decisive breakthroughs which allowed calculations to be made using the current algebra model of pions.

Page 180 gives Feynman's published statement about superstring theory:

'nonsense ... not calculating anything ... maybe there's a way of wrapping up six of the dimensions. Yes, that's possible mathematically, but why not seven? When they write down an equation, the EQUATION should decide how many of these things get wrapped up, not the desire to agree with experiment ... So the fact that it might disagree with experiment is very tenuous, it doesn't produce anything; it has to be excused most of the time.'

Feynman added: 'String theorists don't make predictions, they make excuses.'

The next hundred pages explains boring stringy pseudo science dominating the media with hype. I pray for the day when it will be possible for Woit to bring out a new edition renamed 'Not Wrong!', with those last 100 pages replaced by a discussion of naturally checkable theory, hopefully something from Lee Smolin or someone. Overall, this is the best book I've ever read.

Page 227 describes the some silly attacks on Woit by string theorists:

'... some superstring theorists have chosen to attack me personally [via the Not Even Wrong weblog comments section] ... One of the more excitable of such superstring theorists, a Harvard faculty member, [commented] that those who criticised the funding of superstring theory were terrorists who deserved to be eliminated by the United States military.'

Woit spent the years 1984-7 as a postdoc at Stony Brook, during which the 'first superstring revolution' took place (the one where either 10 or 26 dimensions seemed likely). By 1987, superstring theory had closed down most of the opportunities for investigators interested in understanding the Standard Model in 4 dimensions. Like Feynman, Woit considered it premature to introduce extra dimensions merely in order to address speculation about graviton and unification guesses. If the introduction of extra dimensions was addressing an experimentally fact, then that would be science. Similarly it would be science if a speculation have a checkable, definite prediction.

However, to invent a speculation about extra dimensions merely in order to justify other speculation about gravitons and unification of forces, without a checkable connection to reality, is not physics.