The dean of debunking (String Theory)

The dean of debunking
REVIEWED BY JOHN CORNWELL
In challenging string theory, Peter Woit is taking on the self-interest of the entire scientific establishment
NOT EVEN WRONG: The Failure of String Theory and the Continuing Challenge to Unify the Laws of Physics
by Peter Woit

Cape £18.99 pp290

What is the basic, unifying stuff of our universe? One philosopher in ancient Greece thought that everything was reducible to water; another plumped for air. Later, a philosopher called Democritus taught that the world is ultimately made up of tiny, eternal particles of varying weight known as “atoms”, which form and reform as nature undergoes its constant round of change, death and rebirth. Today, 2,500 years on, and after several great revolutions in modern physics, a large and expanding community of scientists believes that the basic stuff of our universe is “strings”. Hence “string theory”.

These are no ordinary strings. The physicists envisage tiny, vibrating, folding and elongating coils of energy, each 100 billion billion times smaller than the protons at the nucleus of an atom; so small,indeed, that they can be understood only in terms of extremely sophisticated mathematics impenetrable to all but an elite of specialists.

String theory, which nowadays dominates the research programmes and main funding of theoretical physics in many western universities (at a recent conference in Cambridge some 440 of them gathered to discuss their subject), was not so much discovered as invented in order to solve a vexing explanatory deficit. In the early 1970s, physicists announced the so-called “standard model” — a theory that seeks agreement between the contrasting realms of super-huge objects, such as stars and planets, (known as relativity) and the super-small realms of the subatomic (known as quantum). The standard model, however, failed to explain gravity. Enter string theory to rectify the problem. In its simplest terms, this complex set of notions claims 10 or 11 space dimensions (as opposed to the three of everyday human perception), and assumes a “landscape” of myriad elementary bundles of energy (strings) that interface not only with the universe we inhabit but a multiplicity of unseen and unknowable parallel universes.

But is string theory true? Peter Woit, a mathematician at Columbia University, has challenged the entire string-theory discipline by proclaiming that its topic is not a genuine theory at all and that many of its exponents do not understand the complex mathematics it employs. String theory, he avers, has become a form of science fiction. Hence his book’s title, Not Even Wrong: an epithet created by Wolfgang Pauli, an irascible early 20th-century German physicist. Pauli had three escalating levels of insult for colleagues he deemed to be talking nonsense: “Wrong!”, “Completely wrong!” and finally “Not even wrong!”. By which he meant that a proposal was so completely outside the scientific ballpark as not to merit the least consideration.

Woit’s book, highly readable, accessible and powerfully persuasive, is designed to give a short history of recent particle and theoretical physics. Ultimately he seeks not only to rattle but to dismantle the cage of the string theorists. What gives the book its searingly provocative edge, moreover, is the fact that Woit isn’t even a tenured professor, but a mere mathematics instructor specialising in computer systems. Yet he has formidable allies such as David Gross (the Nobel Llaureate theoretical physicist), Roger Penrose (the world-class mathematician) and Lee Smolin (the leading cosmologist), plus an accumulating constituency of other big-name supporters. Woit has taken on a group of the smartest minds in the world and told them that their intellectually imperial pretensions are naked. He has boldly published what many have thought but never dared to express so cogently, or at such length.

He grants that an explanation for gravity is usefully embedded in string theory, but he challenges its authenticity as proper science. In his view, string theory offers no foreseeable prospect of making predictions, a crucial criterion for any theory worthy of the name. Matching the theory with the way we see the world, he argues, depends on believing in sixseveral tiny unobserved spatial dimensions wrapped around each other. Hence there is an infinite number of possible choices as to how one would make predictions, and nobody knows how to determine which choice is correct. The objection invokes the late Karl Popper’s widely accepted definition of science. An explanation is scientific, according to Popper, only if it can be used to make predictions of a kind that can be falsified: in other words, can be checked to be right or wrong.

Woit’s second main objection is that string theory offers no possibility of producing experimental evidence. Even the proposed prodigiously expensive class of accelerators known as Superconducting Super Colliders (SSCs), he claims, would have failed to provide the merest clue as to whether the theory had merit. In the event, the SSCs fell victim to the hubris of physics. An infamous example is the one at Waxahachie, Texas. Budgeted at $11 billion, and designed to be 87km, it was cancelled by Congress in 1993 when $2 billion had been spent and 22km of tunnel constructed.

Woit’s most compelling accusation, however, is that the domination of string theory in universities has stifled progress in alternative research programmes within theoretical physics. As long as the leadership of the physics community refuses to accept that string theory is a “failed project”, he writes, “there is little likelihood of new ideas finding fertile ground in which to grow”.

Finally, and most devastatingly, he follows the lead of the science writer John Horgan, who suggested in his controversial book, The End of Science (1996), that, having reached their limit, some areas of science are in danger of becoming what he terms “ironic science”. In a passage of ultimate insult, Woit unpacks this notion further, suggesting that theoretical physics has become like the deconstructionist realms of literary criticism in the 1970s, which disappeared up its own fundament, “incapable of ever converging on the truth”.

Now that Woit has thrown a wild cat among the theoreticians, we can be sure that the ruffled string-theory advocates will be preparing a rebuttal. Woit, the humble maths instructor, has nothing to lose in terms of academic standing, but physics might have much to gain from his boldness. While his book tends to be negative, it may well shake up a community of scientists that has evidently become complacent if not entirely ossified in its thinking. If he can encourage string theorists to acknowledge the true difficulties of their discipline, and encourage young researchers to try neglected but promising alternatives, he will have succeeded in an important task.