books and arts plained initial condition. Today, however, ing provide the key theoretical for why technological progress ON there is a ready explanation in the form of the element for computing will occur at such a pace ‘inflationary Universe’ scenario, involving a machines, he helped to that machine intelligence burst of frenetic expansion shortly after the build one of the first will surpass the human cosmic origin.Any pre-existing irregularities electronic computers, variety within a few would have been smoothed away by this in Manchester, UK, decades. abrupt and huge swelling of space. shortly after the On the principle This pleasing conclusion immediately Second World War. that no book is per- begs the question of what preceded inflation This book is the fect, I have to admit TIONAL PORTRAIT GALLERY, PORTRAIT LOND TIONAL and why it happened at all — which provides outgrowth of a to one small quib- NA a convenient jumping-off point for Greene workshop held in ble. Given Turing’s to embark on a discussion of the physics of Lausanne,Switzer- great interest in bio- unification.This is familiar territory for him, land, in June 2002 logical processes, as he is first and foremost a string theorist.He to honour the especially near the treats the reader to a review of the current ninetieth anniver- end of his life, and state of string/M theory, with digressions sary of Turing’s birth his pioneering work into a bewildering array of topics including on 23 June 1912. on what we now call higher dimensions, brane worlds, the holo- Turing’s work was so mathematical biology, graphic paradigm,teleportation,wormholes broad and deep that I was disappointed to and time travel. If I have a criticism of this another gathering this see only one of the 20 book, it is that it packs in so many challeng- year, to mark the fiftieth chapters devoted to that ing and abstract topics that it can leave the anniversary of his death,would aspect of his work.Of course,no reader’s mind reeling. Sensibly, Greene not be out of place. book can do everything, repeatedly cautions that most of the ideas he It is difficult to find the Machine architect: Alan Turing. and this short-changing of gallops across are extremely speculative and superlatives to describe biology in favour of com- are unlikely to be tested experimentally any the wonderful job the contributors to this puting is more of an opportunity than time soon. book have done. Every chapter is written in a problem. Nevertheless, a couple more The nature of space and time has exer- an expository fashion, demanding very little chapters on morphogenesis, artificial life and cised the minds of the world’s greatest scien- in the way of background knowledge from so on would have really made this book the tists and philosophers for centuries. Mostly any scientifically minded reader. The range definitive volume on Turing’s work and its they have regarded space and time as simply of topics is also impressive, with sections on implications. there — a given. Modern physics has shown Turing’s life and thoughts, the theory of I unreservedly recommend this book to that they are, in fact, things, just as particles computation and the Turing machine,artifi- anyone even slightly interested in the contin- of matter are things. The heady develop- cial intelligence and the Turing test, the uing role of Turing’s work in the develop- ments described in this book hold out the wartime Enigma code-breaking work and, ment of computer science in particular, and promise that we may one day explain how finally,forgotten ideas. ideas in general. Conference proceedings space and time have come to exist, and why Each section contains between two and rarely make for good reading and are gener- they possess the properties that they do. ■ seven chapters that explore themes ranging ally strange beasts to review. This volume is Paul Davies is at the Australian Centre for from what Turing might have thought about the exception that proves that rule. ■ Astrobiology, Macquarie University, Sydney, today’s work in ‘hypercomputation’ — a John L. Casti is at Complexica, Santa Fe, New South Wales 2109, Australia. His latest book field that explores information processing New Mexico 87505, USA, and the Institute for is How to Build a Time Machine. beyond the abilities of Turing machines — Monetary Economics, Vienna, Austria. to his ideas on thinking machines and robots. The book’s contributors are as ster- ling a collection of computer scientists, philosophers, engineers and historians as Touring artificial one could ever wish for, including logician In Newton’s long Martin Davis, philosophers Daniel Dennett minds and Jack Copeland, technologist Ray shadow Alan Turing: Life and Legacy of a Kurzweil and historian Andrew Hodges. From Newton to Hawking: A Great Thinker In her extremely entertaining chapter History of Cambridge University’s edited by Christof Teuscher “Alan’s Apple: Hacking the Turing Test”,the Lucasian Professors of Springer: 2004. 542pp.£46, $69.95, €59.95 Italian writer and theatre director Valeria Mathematics John L. Casti Patera creates a theatrical setting in which edited by Kevin Knox & Richard Noakes eminent figures in artificial intelligence meet Cambridge University Press: 2003. 512 pp. In 1999, Time magazine made Albert Ein- in a virtual plane to consider Turing’s ideas £27.50, $45 stein its ‘man of the century’ for the work on thinking machines. A staging of this Lewis Pyenson that changed our view of time and space. might be more interesting, intellectually at It’s difficult to argue too strenuously with least, than the rather dull play Breaking the For more than 300 years, Cambridge Uni- this choice. But when it comes to scientists Code that ran so successfully in London and versity’s Lucasian professors have promoted who have affected daily life, a far better New York some years back. the mathematical elaboration of nature’s choice would be Alan Turing, the British Two of the more provocative contribu- laws. The founder of the chair, Henry Lucas, mathematician turned computer scientist tions come from Davis, who argues against who was awarded an honorary MA by the whose invention in 1936 of what is now the ideas put forth by a number of university in 1636 and who represented called the Turing machine was the theoreti- researchers for transcending the Turing bar- Cambridge in both the Short and the Long cal backbone for every one of the zillions of rier in computation,and from Kurzweil,who Parliaments, filled a gap in his university by computers in use today. Not only did Tur- explains in detail his well-known arguments endowing a professorship in mathematics, 258 NATURE | VOL 428 | 18 MARCH 2004 | www.nature.com/nature © 2004 Nature Publishing Group books and arts Science in culture A weighty issue Eduardo Chillida’s sculptures are a form of ‘rebellion’ against Newton. WILDE/YSP J. Stefano Grillo Spanish artist Eduardo Chillida (1924–2002) used the name Gravitation for a major series of works that occupied him over a span of nearly 15 years — a clear suggestion that he shared some of the concerns of physical scientists. Indeed, Chillida himself once declared that he used “weight in his sculpture in order to rebel against Newton”. Was this simply a fashionably extravagant statement? No one would claim that Chillida’s sculptures and reliefs supersede Isaac Newton’s theory of gravitation in the sense that Einstein’s general theory of relativity does. Chillida’s aim was never to create a new quantitative model to compete with that of Newton. But his statement acquires signifi- cance when seen in terms of his work’s visual approach to the experience and understanding of nature. This approach consists, in the words of the Nobel-prizewinning poet Octavio Paz, of a “quali- tative physics”, springing from a “direct, dynamic and non-quantitative vision of reality”. Chillida’s works allow one to visually grasp phe- nomena such as weight, and even its opposite, weightlessness or levitation. He achieves this chiefly through his sense of form and of space. His rhythmically twisting shapes, often supported in ways that defy our visual expectations, seem to Up in the air: the floating form of De Música III challenges our visual expectations. possess a weight that is modulated by their form and is quite independent of the measurable prop- several months welding together the unsupported der Raum by the philosopher Martin Heidegger, erties of the piece. Thus Chillida’s great steel and horizontal sections to ensure that the joints were who was concerned throughout his life with concrete structures often appear to be floating in stable enough. the foundations of modern science and with the surrounding space, whereas the paper reliefs The importance of this visual and non-quantita- the question of whether the mathematical of his Gravitation series communicate a remark- tive way of experiencing reality has been stressed approach is the only valid way of understanding able sense of visual consistency. in recent years by the mathematician René Thom, physical reality. In the steel sculpture shown here, De Música III a Fields medallist and admirer of Chillida’s work. So despite Chillida’s declared rebellion against — one of 45 being exhibited at the Yorkshire Sculp- Thom noted that there are contexts in which newtonian physics, his work has been concerned ture Park in Wakefield, UK, until 4 May nuclear physicist Ernest Rutherford’s claim that with grasping the same phenomena in the natural (www.ysp.co.uk) — the horizontal structure hovers “qualitative is nothing but poor quantitative” world that have always interested scientists.