Jim Baggott has written a very good new book called Farewell to Reality that will soon come out here in the US. It is already out in the UK, where it is stirring up some debate, and perhaps the US will soon see something similar.
In the preface, Baggott explains that he was motivated to write the book by the experience of watching this BBC program, which featured a combination of serious science with revelations about how we’re all part of a cosmic hologram, there’s an infinity of parallel worlds, and various other examples of what he refers to as “fairy-tale” physics. In the last decade or so there have been a large number of such mass media efforts promoting highly dubious ideas about fundamental physics, and Baggott decided that in his next book he’d try and do something to counter this. I think he’s succeeded admirably: the BBC and other such organizations should atone for their sins by sending copies of the book to their viewers.
The book is divided into roughly two halves, with the first half a well-executed overview of the current state of our theories about fundamental physics, from quantum theory through the standard model and cosmology. It ends with a description of the outstanding problems left unsolved by our best theories, and a good summary of the current situation:
Several centuries of enormously successful physical science have given us a version of reality unsurpassed in the entire history of intellectual endeavour. With a very few exceptions, it explains every observation we have ever made and every experiment we have ever devised.
But the few exceptions happen to be very big ones. And there’s enough puzzle and mystery and more than enough of a sense of work in progress for us to be confident that this is not yet the final answer.
I think that’s extremely exciting…
… but there is no flashing illuminated sign saying “this way to the answer to all the puzzles”. And there is no single observation, no one experimental result, that help to point the way. We are virtually clueless.
With this background he turns to a detailed examination of the speculative ideas that have not worked out, but have dominated the field for the past 30-40 years (SUSY, GUTS, Superstring/M-theory, the multiverse). This is difficult material to do justice to, but Baggott does a good job of giving an explanation of these ideas that includes some understanding of the problems with them. He ends the book with this advice to the reader:
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… 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.
The thorniest problems that come up in this sort of discussion are essentially ones about the philosophy of science. What counts as evidence for a scientific theory? At what point does pursuit of speculative ideas that are going nowhere stop being legitimate science? One quickly realizes that naive ideas about the scientific method don’t capture how good science really works. Baggott devotes the first chapter of the book to an overview of his take on what the scientific method really is. In the end, this may be the most important issue here: will books and TV programs promoting the views of a narrow part of the scientific community that doesn’t want to admit failure end up discrediting the scientific endeavour? Some are all too willing to exploit the subtleties of good science to find a way to defend the indefensible, with the multiverse mania pointing to the all too real dangerous endpoint this can lead to.
Also today in the Guardian, there’s a debate between Baggott and Mike Duff. Duff characterizes the experimental situation of string theory as follows:
Definitive experimental tests will require that the theory also incorporate and improve upon the standard models of particle physics and cosmology. An impressive body of evidence in favour of this has accumulated, but it is still work in progress.
without giving an example of any sort of conceivable such experimental test. I think Duff is being highly misleading here, since the story of the last thirty years is not one of evidence for string theory unification accumulating, but the opposite: the more we learn about string theory, the less likely it seems that it can predict anything. One can argue that string theorists just need more time (Duff points to the idea of atoms arising back in 400BC, taking more than two millennia to come to fruition), but the problem with string theory is not that progress is slow but that it is negative.
On the question of TV programs like the one that motivated Baggott to write the book, even Duff won’t defend them, but blames the situation on journalists:
As for misrepresentation in the media, there will always be sensationalists and attention-seekers in any field, but in my (admittedly biased) opinion, the worst culprits are the journalists.
This is quite amusing coming from someone who (see here) had his university put out a press release claiming that he had made the first discovery of a way to test string theory. He advertises string theory as having found application in quantum information theory, a claim that I doubt is believed by any other string theorist or quantum information theorist. No, the worst culprits here are not journalists, whose mistake is often just that of taking seriously press releases from people like Mike Duff.
Duff invokes the same criticism made back in 2006 that “Sadly, many critics of string theory, having lost their case in the court of science, try to win it in the court of popular opinion.” He’s well aware though that string theorists are losing badly in the court of science (with US physics departments now hiring virtually no string theorists). String theory unification is an idea now discredited in the scientific community, but getting propped up by TV programs and prizes from Russian billionaires. I hope when Baggott’s book comes out in the US, we’ll see a more serious discussion of the issues that it raises.
Update: Duff is unhappy about Butterworth’s mild criticism of string theory, so has responded with a comment at the Guardian site that begins
”The concern arises if everyone makes the same wild guess, and the experiments to confirm or deny it are out of reach”.
is more-or-less what people said when theorists predicted the Higgs boson in 1964.
According to Duff, I guess, back in 1964 the situation was just like that of string theory, with the field experiencing what people were calling an unhealthy domination by the likes of Peter Higgs and others working on the Higgs mechanism. That’s a very odd take on the history, given that the work of Higgs and others was virtually ignored at the time.