L'universo Senza Stringhe: Fortuna Di Una Teoria E Turbamenti Della Scienza (2007) - Plot & Excerpts
Few aspects of theoretical physics capture the public imagination – but string theory, which states that the universe is composed of tiny, vibrating strings rather than point-like particles, certainly has. The theory has spawned dozens of popular books and even a three-hour PBS TV series. It continues to attract the attention of many of the brightest graduate students in theoretical physics, as well as the funding agencies that keep their research programs humming.Lee Smolin has a problem with that. Two problems, actually – first, that string theory may be wrong; and secondly, that the physics community, for a variety of reasons, is unwilling to admit it has chosen the wrong path.Smolin, a physicist based at the Perimeter Institute in Waterloo, lays out his argument in a bold and often audacious book that is clearly aimed at his physicist colleagues as well as the lay reader.His confrontational tone is clear from the first few pages, where he claims that fundamental physics has seen little progress since the 1970s – the first time since the late 18th century, he argues, that the wheels of progress have turned so slowly. Then, referring to string theory, he laments “a trend in which only one direction of research is well supported while other promising approaches are starved.”Having warned readers what lies ahead, he then gives a highly readable summary of 20th century physics, from Einstein’s theory of general relativity to quantum theory, along with major developments in particle physics. String theory, as Smolin explains, emerged as an attempt to unite Einstein’s theory with quantum theory, making it a candidate for a “unified theory,” the kind of framework needed to investigate extreme realms such as the inside of a black hole, or the earliest moments of the universe following the big bang.String theory has yet to make a concrete, testable prediction, but Smolin’s concerns run deeper. In a chapter titled “A Theory of Anything,” he says that the theory can no longer claim to provide a unique explanation for the laws of physics. Many string theorists, he points out, now believe that the theory “should be understood as a vast landscape of possible theories, each of which governs a different region of a multiple universe.”Some theorists, such as Stanford physicists Leonard Susskind and Andrei Linde, have suggested the multiple universes approach as a possible explanation for the “fine tuning” problem – the question of why so many of the universe’s physical parameters seem to be just right for life (or perhaps intelligence) to evolve.But for Smolin, a theory that can explain anything in fact explains nothing – this, in his view, is not how science is supposed to work. Those who postulate multiple universes to explain the physics that we observe, he says, are little better than supporters of “Intelligent Design,” who argue that some sort of intelligent being was responsible for our good fortune. Those multiple universes can’t be observed, Smolin reminds us, and postulating their existence doesn’t allow us to make specific predictions. Instead, he urges us to consider a third possibility – that there is “a so-far-unknown mechanism that will explain both the biofriendliness of our universe and make testable predictions by which it can be confirmed or falsified.”String theory, Smolin argues, “has failed to make any predictions by which it can be tested, and some of its proponents, rather than admitting that, are seeking to change the rules so that their theory will not need to pass the usual tests we impose on scientific ideas.”Smolin goes on to outline some of the alternatives to string theory, including loop quantum gravity, which he helped develop. (In loop quantum gravity, space and time are composed of indivisible, discrete units. In some calculations, those units have the properties of tiny loops – hence the name.) Smolin also turns his attention to other neglected approaches – the possibility that the supposed “constants” of physics may have changed over time, or that the Einstein’s equations for relativity may need modification.He concludes with a long list of things he doesn’t like about the way string theorists behave (though he stresses that he’s not picking on any individual scientist, and greatly respects the work of all those that he mentions). His larger beef is with the mentality of entire institutions, scientific associations, and funding agencies, all of which, he claims, foster “groupthink” and discourage innovative thinking.“More than at any time in the history of science,” Smolin writes, “the cards are stacked against the revolutionary.”Not every argument is convincing. The alleged lack of progress, for example, is surely subjective; the recent discovery that neutrinos have mass, and that the universe is accelerating, must count for something. And just how fast should science progress? The Greeks envisioned atoms some 2,000 years before we could measure their properties; who’s to say string theory isn’t a few decades (or more) ahead of its time?Ultimately, however, I don’t think Smolin’s aim is to disparage the efforts of string theorists. Rather, he wants all of us to take a more critical look at the way physics is done – a laudable goal, whether the universe is made of strings, loops, or something even stranger. (Adapted from a review I wrote for The Globe and Mail.) Although the actual science covered is quite arcane and might require the reader to have a really good grasp on the rigidly defined (or not so rigidly, the stuff is really intricate) concepts (which I probably haven't), Smolin succeeds in pointing out the flaws of string theory (essentially that it's not background-independent, i.e. it does not make any specific predictions about the the shape of the background (the number of dimensions and their shape etc.) which means that there are actually many different possible string theories with different configurations of those parameters that have so far not been convincingly shown to be the result of one overarching theory, and so on, it's really rather complicated). Most importantly though, Smolin illustrates the negative influence of the American model of academia: He shows that it discourages the exceptional thinkers that refuse to do science in the mainstream way by its selection mechanisms that mainly focus on financial prospects. Being an optimist, Smolin gives an outline how to overcome the institutional and sociological problems. Being a pessimist, I doubt that this proposal will have any real influence.
What do You think about L'universo Senza Stringhe: Fortuna Di Una Teoria E Turbamenti Della Scienza (2007)?
Great stuff, not only about the state of physics but also about the state of physicists themselves.
—Echo
For those of you who, like me, think string theorists have highjacked the physics academy.
—Blackcat
A nice overview of some of the issues surrounding modern Physics.
—APatel
Excellent book if you like quantum physics.
—Grace
