Monday, 28 August 2006

Not Even Wrong?

I've recently read this book by Peter Woit and can recommend it as an (partial) evaluation of the String Theory programme. Woit's argument is that String Theory has not lived up to the hype of its greatest proponents and that 20 years of continued work have not lead to the breakthroughs which would warrant the dominant position it has in high energy and gravitational physics departments.

A String Theorist, with whom I spoke about the book, was quick to affirm that he himself did not think strings were going to be the fundamental theory, but rather the techniques developed by string theory has actually be useful for conventional QCD. So even if the strong claims, by a minority of String Theorists it was stressed, were mostly hype, he reiterated the argument, "It's the only game in town". Whether this is a compelling argument is not clear to me but Lee Smolin, who has worked in String Theory, would disagree, citing several different approaches to unification in his book which also is critical of the present domination of the String Theory.

I think it's an exciting time to be a physicist despite the apparent stagnation of fundamental particle physics. We are only beginning to plumb the depths of complexity of many-body physics. Quantum computation and information is an example of where whole avenues of phenomena were waiting to be discovered, despite all the work on quantum theory and the foundation of its mathematical principles. Though it's not inventing "new" physics, we are discovering surprising things about the connections between established sub-fields of science. Looking further out, new astronomical observations are raising more questions than they answer, dark matter, the cosmological constant, gamma ray bursts etc. The opportunity to discover important insights is not simply confined to String/M/Brane Theory.

Perpetual Dreams

Yet another claim of free energy, this time due to magnets. And yet again, the media report these claims without critical examination. Of course it isn't the job a newspaper to analyse the scientific aspects in great depth, but a bit of meta-analysis may have been useful to apply to all such non-mainstream claims (from the Guardian article):

And they are so confident that they have thrown down the gauntlet to the scientific community in a bid to prove that they have rewritten the laws of physics. Last week, frustrated that they couldn't persuade scientists to take their work seriously, McCarthy, Walshe and the other 28 shareholders of Steorn, a privately owned technology research company, took out a full-page advertisement in the Economist. In it, they called upon scientists to form a 12-member jury to decide whether their free-energy system is real, hoaxed, imagined or incorrectly well-intentioned.

The problem is that extraordinary claims require extraordinary evidence, and that the burden of proof in such a case is really on the side of those making such claims. When modern physics, within its long-established borders, has been so successful and consistent, coming up with a perpetual motion machine would seem to be extremely unlikely.

According to McCarthy and Walshe, the marketing manager, there have been no fewer than eight independent validations of their work conducted by electrical engineers and academics "with multiple PhDs" from world-class universities.

The fact that conventional physics is so successful and consistent, any credible evidence that the inventors' claims were true would have any true physicist to drop everything they were working on, and instantly switch to studying such a violation of all known laws of physics. They are claiming up to 4 times as much (mechanical) energy as they are putting in. A signature of free energy this large would be absolutely unmissable. Why haven't we seen anything run? They need only hook up one of their devices via a generator to the electricity grid and start making money.

Of course, the whole affair is running along the usual lines for a fringe claim. Conventionally, if a scientist makes a great discovery, after filing the necessary patents of course, they will disclose the set-up and techniques required to reproduce those results by independent researchers. If others are able to reproduce the results or confirm the observations, then one can have more confidence in the validity of the original claims. However, the inventors of this latest affair are, "seeking a jury of twelve qualified experimental physicists to define the tests required, the test centres to be used, monitor the analysis and then publish the results." This strike me as very odd. Science is not about testing black boxes. Without access to the inside of the black box and an attempt to understand its properties, the whole thing looks especially dubious. Why are their white papers restricted to registered academic users of their web-site and potential jurists? Why not post them on the arXiv like every other working physicist? The papers, here and here, claiming an anti-gravity effect above rotating High Tc superconducting discs were posted there (not that I find these claims credible either).

Even the Pons and Fleischmann affair was conducted slightly more openly. Other researchers tried to reproduce the experimental set-up but failed to obtain convincing data. Even then, the manner in which th original "results" were announced, the supposed signatures of fusion, and the ultimate lack of firm confirmation by anyone else has lead to cold fusion dying away. The supposed mechanism of cold fusion was at the extreme boundary of known physics, ultimately beyond it, but at least it was not totally inconsistent with what we know (just a extremely inconsistent).

It isn't up to the physics community to take up any "challenge", the challenge is for the inventors to back up their claims with proper disclosure for a truly scientific evaluation. Until that is done, the whole business cannot be taken seriously.