Questioning the Quantum Graham Farmelo Parses a Takedown of the Most Successful Physics Theory Ever

COMMENT BOOKS & ARTS

A computer-generated artwork inspired by quantum mechanics.

PHYSICS Questioning the quantum Graham Farmelo parses a takedown of the most successful physics theory ever.

uantum mechanics is perhaps the most Smolin’s book is be described in the same way — he loved to

successful theory ever formulated. For in many ways ambi- debate philosophical matters with colleagues GETTY Qalmost 90 years, experimenters have tious. It goes right in a range of disciplines. Maxwell’s way of subjected it to rigorous tests, none of which back to square one, thinking had a profound impact on Albert has called its foundations into question. It introducing quantum Einstein, who might also be considered part is one of the triumphs of twentieth-century mechanics at a level natural philosopher, part theoretical physicist. science. The only problem with it, argues Lee basic enough for high- Like Einstein, Smolin is a philosophical Smolin in Einstein’s Unfinished Revolution, school science students ‘realist’ — someone who thinks that the real is that it is wrong. In this challenging book, to grasp. He points out world exists independently of our minds and he attempts to examine other options for a that the field gave a Einstein’s can be described by deterministic laws. These theory of the atomic world. truly revolutionary Unfinished enable us, in principle, to predict the future of Smolin is a theoretical physicist at the account of the atomic Revolution: The any particle if we have enough information Perimeter Institute in Waterloo, Canada, world, something that Search for What about it. This view of the world is incompat- and an outspoken critic of the direction his had proved impossible Lies Beyond the ible with the conventional interpretation of Quantum subject has taken over the past four dec- with the theories (ret- LEE SMOLIN quantum mechanics, in which key features ades. A fount of provocative ideas, he has rospectively labelled Penguin Press (2019) are unpredictability and the role of observers showcased them in several popular books, ‘classical’) that pre- in the outcome of experiments. Thus, Einstein including The Trouble with Physics (2006) ceded it. The mathematical structure of quan- never accepted that quantum mechanics was and Time Reborn (2013). He is perhaps best tum mechanics arrived before physicists were anything but an impressive placeholder for a known for his rejection of string theory, a able to interpret it, and Smolin gives a clear more fundamental theory conforming to his widely used framework for fundamental account of subsequent arguments about the realist credo. Smolin agrees. physics that he dismisses as misguided. nature of the theory, before finally setting out He conducts his search for other ways of Although Smolin’s spirited opposition to his own ideas. setting out quantum mechanics in language some mainstream developments in mod- For me, the book demonstrates that it is intelligible to a lay audience, with scarcely an ern physics irritates quite a few of his peers, best to regard Smolin as a natural philosopher, equation in sight. Smolin is a lucid exposi- I have a soft spot for him and anyone else most interested in reflecting on the funda- tor, capable of freshening up material that who is unafraid to question the standard way mental meanings of space, time, reality, exist- has been presented thousands of times. of doing things. As the journalist Malcolm ence and related topics. James Clerk Maxwell, Non-experts might, however, struggle as he Muggeridge observed: “Only dead fish swim leading nineteenth-century pioneer of the delves into some of the modern interpreta- with the stream.” theory of electricity and magnetism, might tions of quantum mechanics, only to dismiss

BOOKS & ARTS COMMENT

them. These include, for instance, the super- determinism approach of the theoretician Gerard ’t Hooft. Books in brief The book is, however, upbeat and, finally, optimistic. Unapologetically drawing Incredible Journeys on historical tradition and even modern David Barrie Hodder and Stoughton (2019) philosophy, Smolin proposes a new set of How does the blind Mexican cave fish (Astyanax mexicanus) navigate principles that applies to both quantum convoluted pools, or the tiny blackpoll warbler (Setophaga striata) fly mechanics and space-time. He then explores non-stop for 2,770 kilometres over open ocean? In this exhilarating how these principles might be realized as popular study, David Barrie reveals the roots of navigational prowess part of a fundamental theory of nature, — such as the adapted eye and biological clock of the desert ant although he stops short of supplying details Cataglyphis, which function as a compass oriented to the Sun, or of the implementation. the myriad species that use olfaction, Earth’s magnetism, sonar Smolin concludes with the implications of or cognitive mapping to find their way. The navigational nous of all this for our understanding of space and humans from astronauts to Indigenous peoples gets a look-in, too. time. He suggests that time is irreversible and fundamental, in the sense that the pro- cesses by which future events are produced Vanishing Ice from present ones are truly basic: they do not Vivien Gornitz Columbia University Press (2019) need to be explained in terms of more basic Whether it’s shrinking ice shelves in Antarctica or Greenland’s ideas. Space, however, is different. He argues destabilizing ice sheet, the cryosphere is in flux, and this solid that it emerges from something deeper. scientific primer by geologist Vivien Gornitz examines the human Yet it is far from clear whether Smolin’s costs. In the context of deep time, she explores dwindling glaciers, new methods allow space and time to be thawing permafrost and other shifts that are leading to buckled land, investigated effectively. In recent decades, diminished water supplies, serious sea-level rise and other impacts there have been many exciting advances in that, together with fiercer hurricanes, pose an existential threat that this subject, almost all made using standard must be fought with decarbonization and innovative adaptation. quantum mechanics and Einstein’s theory of A cogent analysis of this systemic, human-driven catastrophe. relativity. In my opinion, Smolin downplays the extraordinary success of this conserva- tive approach. It is the basis of modern quan- Ocean Outbreak tum field theory (a descendant of Maxwell’s Drew Harvell University of California Press (2019) theory of electricity and magnetism), which Abalone, corals, salmon and starfish: populations of these four accounts for the results of all subatomic marine animals are under siege from disease. The culprit, notes experiments, some of them to umpteen ecologist Drew Harvell in her succinct summation of two decades decimal places. Despite the impression that of research, is us — specifically, a confluence of ocean warming Smolin gives, modern theoretical physics is and acidification, dredging, oil extraction, overfishing and pollution. thriving, with potentially revolutionary ideas Harvell vividly recounts her work at the front line, studying die-offs about space and time emerging from a com- such as the past decade’s catastrophic starfish crash. Yet she is bination of the standard quantum mechanics hopeful, noting that policy change, with techniques such as plant and relativity theory taught in universities for biofiltration and phage therapy, could still turn this malign tide. generations. Maybe the upheaval in physics that Smolin yearns for is simply unnecessary. Rewarding as it is, I doubt Einstein’s The Dinosaurs Rediscovered Unfinished Revolution will convert many of Michael J. Benton Thames & Hudson (2019) Smolin’s critics. To do that, he will need to Palaeobiology is a field on fire with discoveries, such as China’s present his ideas more rigorously than he panoply of feathered dinosaurs and the titanic sauropod fossils could reasonably do in a popular book. recently excavated in Patagonia. With advances in technology, that One thing on which every physicist in upheaval has transformed the discipline from natural history to Smolin’s field can agree is that there is a testable science. In this illustrated update of dinosaur behaviour, crying need for more juicy clues from nature. cognition and locomotion, palaeontologist Michael Benton shows There have been no surprises concerning the how technologies such as scanning electron microscopy reveal inner workings of atoms for some 20 years. feather colour; 3D computer models indicate bone properties; and It is experimental results that will decide computation helps to build (and fell) evolutionary ‘trees’. whether Smolin is correct, or whether he protests too much. After all, although quantum mechanics might not satisfy the Eating the Sun philosophically minded, it has proved to be a Ella Frances Sanders Penguin (2019) completely dependable tool for physicists — With this pairing of witty illustrations and an open-weave narrative even those who have no interest in debates — strong on science but just this side of poetry — Ella Frances about its interpretation. ■ Sanders has penned a pocket-sized book vast in ambition. She distils phenomena, laws and principles, from heat, light and Earth’s Graham Farmelo is a fellow of Churchill gravitational pull on the Moon to Eigengrau, the greyness seen in College at the University of Cambridge, UK. perfect darkness. You find yourself constantly reframed (say, as His latest book is The Universe Speaks in stardust, the “remnants of burning giants”), and see the Universe Numbers. unpeeled to reveal the dance steps of electrons, the three hearts of a e-mail: [email protected] squid or the joys of noctilucent clouds. Barbara Kiser