to describe different physical situations canactually be mathematical equivalents. Thisconcept comes in handy when he tries to reconcile the apparent inconsistency in thethesis of this book — that great ideas driveprogress in science — to that in his previousbook, The Bit and the Pendulum (John Wiley,2000), which postulates that technologicaladvances drive scientific discovery. Althoughduality is not meant to imply that you can always have it both ways, in this casemaybe he can. ■

Marc Kamionkowski is in the Division of Physics,Mathematics and Astronomy, California Instituteof Technology, Pasadena, California 91125, USA.

A social activist in geneticsMaking Genes, Making Waves: A Social Activist in Science by Jon BeckwithHarvard University Press: 2002. 256 pp.$27.95, £18.50, 27.95 euros

Ute Deichmann

“Science was puzzle-solving — figuring outmathematical proofs or devising pathwaysfor the synthesis of complex organic com-pounds — it was fun.” The joys of doing science, first experienced in college, motivatedJon Beckwith to become a scientist — and toremain one. He is now professor of micro-biology and molecular genetics at HarvardMedical School. But literature, philosophyand social concerns have remained impor-tant to him throughout his scientific life. In1969, Beckwith was the first to isolate a singlegene from a chromosome (of the bacteriumEscherichia coli) and, two decades later, hisexperiments on protein secretion from cellsopened up new lines of research on theprocess of protein folding.

In this beautifully written autobiography,Beckwith explains these and his other scientific successes, as well as his failures. He vividly describes aspects of the “cultural revolution in science that molecular biologybrought with it”, epitomized by “iconoclasticand unchemist-like” Jim Watson, and majorpublic controversies about genetics in theUnited States from the 1960s. Beckwith isacquainted with various laboratories in theUnited States and Europe, and characterizesthe scientific styles of different individualsand groups. He was particularly fascinatedwith the French style of “daring leaps oflogic”, simple experiments that seemed toyield profound insights, and papers withpersuasive “elegant rhetorical strokes”, butlater realized that it did not represent theprocess of how discoveries actually takeplace. He amply depicts the human ele-ments, “the wrong turns, the surprises, the

flashes of intuition, even the passions thatdrive us in science”.

Beckwith’s growing enchantment withscience was mirrored by his growing concernfor its consequences. His social activism inscience grew out of a more general politicalradicalism in the 1950s and 1960s, stimu-lated especially by the civil-rights movementin the United States, the assassination ofMartin Luther King, and the turmoil over the Vietnam War. As a member of the actiongroup Science for the People, he was con-vinced that scientists have a special socialresponsibility, so he decided to help informthe public about the potential negative socialconsequences of genetic research. In 1969, in the same week that his famous paperabout the first isolation of a gene appeared in Nature (224, 768–774), Beckwith called a press conference aimed at raising publicawareness of the possible consequences ofgenetic manipulation.

This received huge international presscoverage and contributed to rising fears,even among fellow scientists, about the possible dangers of molecular-biologicalresearch. But Beckwith fails to mention thatmost of the scientists who called for a mora-torium on recombinant-DNA research in1973, Watson and Paul Berg among them,later considered this a mistake and the fearsunsubstantiated.

By contrast, Sydney Brenner, one of Beckwith’s scientific heroes, never believedthat scientists have a special social responsi-bility . In his autobiography, A Life in Science(BioMed Central, 2001), Brenner expressedthe opinion that, in order to act responsibly,one should not prevent the generation ofknowledge, but rather answer the following

question: “What are you doing with yourknowledge once you get it?” This, of course,presupposes the neutrality of science, whichBeckwith denies.

Beckwith’s activism was also an outcomeof his preoccupation with history. He real-ized that, in contrast to physicists, who hadopenly confronted their historical burden ofthe past, the atomic bomb, geneticists wereignorant of their own ‘atomic’ history —their role in the eugenics movement. Suspi-cious of genetic research that claimed toexplain antisocial behaviour, he launched acampaign against a study at Harvard MedicalSchool on the development of boys with anextra Y chromosome (XYY). Beckwith wasconcerned about the ethics of identifyingand studying these children, because manypeople still believed previous, seriouslyflawed scientific claims that linked this chromosomal aberration with criminalbehaviour. The Harvard researchers finallydecided to stop the screening. However, thiscampaign, because of the distrust it causedbetween the activists and faculty members,affected Beckwith’s life more than any other.

E. O. Wilson’s book Sociobiology: TheNew Synthesis (Harvard University Press,1975) presented a new theory about geneticprogrammes of behaviour in animals andhumans. It received wide media coverage. In their public attack on the theory, in whichthey said it was biologically determinist,Beckwith and his colleagues went as far as to associate Wilson and his theory withNazism. Whether the scientific evidence that Wilson presented was strong or weak,some of the attacks were blatantly unfair.Social activists in science have to showresponsibility, too.

In 1989 Beckwith joined the programmeto explore and anticipate the ethical, legaland social implications of the HumanGenome Project. The resulting public dis-cussion of this issue led to the passage of bills outlawing the practice in several USstates. At the time, the antagonism betweengenome scientists and activists seemed to beunbridgeable, which Beckwith interprets aspart of the long history of conflict betweenthe world of science and the humanities, asdescribed by C. P. Snow in his Two Cultures(Cambridge University Press, 1959). Today,bioethicists and genome scientists seem tohave begun to close this gap.

Beckwith’s account of social activism ingenetics implies that it arose from more thanan analysis of the possible dangers. It couldalso be predicted from scientists’ politicalinclinations: the same group of leftist scien-tists in the United States was critical of suchdifferent issues as recombinant DNA andgenetic theories of human behaviour. Thatmolecular biology attracted more critical and socially active scientists than did oldersciences such as chemistry does not meanthat molecular biology is intrinsically more

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Social conscience: Jon Beckwith was the first toisolate a gene, but warned of the risks of genetics.

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dangerous than chemistry. Indeed, chemistryhas its own ‘atomic’ history, which includeschemical warfare during the First World War,the use of Zyklon B in the Auschwitz concen-tration camp, and environmental disasters.

Beckwith has portrayed a fascinatingperiod in the history of modern biology and

of the interaction of science and society inthe Western world. Thanks to him and otheractivists, social injustices resulting from theapplication of genetics are now widely dis-cussed and, in democracies, meet with legalmeasures and regulation. In this book Beck-with, a committed scientist — and here he

has many predecessors — calls for greaterhumility about what science can and cannotaccomplish. This is a call that scientistswould do well to take seriously. ■

Ute Deichmann is at the Institute of Genetics,Cologne University, Weyertal 121, 50931 Cologne, Germany.

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The cut-and-paste carafeCaravaggio’s optical naturalism was a success in Rome in around 1600.Martin KempCaravaggio was a shocking painter. Or, rather, hiscompelling naturalism enthused a new breed ofpatrons and seduced young Roman artists, whilescandalizing the artistic establishment. Previously,painters had spent long years masteringperspective and anatomy. Now a youthfulprovincial from Lombardy was achievingstartling results without the necessary learning.

Caravaggio did not use drawings to map out perspectival forms within geometricallyconstructed spaces. Instead, he assembled vividlyilluminated items in shallow spaces against darkbackgrounds. His paintings appeared (like earlyphotographs in the nineteenth century) to beacts of nature, rather than art.

A typical reaction was that of Giovanni PietroBellori, who singled out a painting of the carafeof flowers which had first brought Caravaggio tothe attention of Cardinal Francesca Maria delMonte. The painter had miraculously captured“the transparencies of the water and…reflections of the window of a room, renderingthe flowers with the freshest dewdrops”. Theyoung arrivé was invited to join the cardinal’shousehold on the Palazzo Madama.

Caravaggio’s inaugural painting of this carafeis lost — but the motif became a set-piece incompositions involving pretty youths. It appearsin The Lutenist, the restored version of which willbe unveiled in Munich next month, and in twoversions of The Boy Bitten by a Lizard. No onehad previously come close to such scintillatingand convincing effects.

A window reflected on the left of the vessel ismirrored upside-down inside the right wall, as ifin a concave mirror. Cutting across this reflectionis a band of superficial glare, accompanied bysmaller smudges of brightness. The radiancecasts a glimmer across the water, and catches onthe shady plant stems. Four speckles of water onthe glass perform optical games that mirror thosein the carafe. The upper rim of water is brightwith captured light, while the foremost stemdrags it into a small peak, bearing witness tosurface tension.

How did he achieve such effects? We couldsay he looked hard. But other artists had lookedequally hard. To see simultaneously such effects of multiple reflection and refraction isimpossible. David Hockney has reasonablysuggested that Caravaggio had recourse to lens-

or mirror-based devices (see Nature 412, 860;2001). Giuseppe della Porta, in the 1589 editionof Natural Magic, described an apparatus thatcombined a lens and concave mirror to achieve“spectacles for my friends, who admired themwith great wonder and astonishment. Eventhough I gave them the explanations ofPhilosophy and Perspective they didn’t want to believe that these were natural things” (seeNature 417, 794; 2002).

A physical reconstruction of the optical set-up,commissioned by the owner and carried out bymyself and my colleagues, showed that the carafewas mounted more or less at a level with thecentre of the window to the left. In addition, asurprisingly high source of light — probablyfrom an aperture cut in the ceiling or high in thewall — accounts for the flare on the right wall ofthe vessel. Because the placing of the carafes inthe paintings with the youths is inconsistent withthis set-up, we can be sure that the carafe becamea cut-and-paste motif, replicated to satisfypatrons’ demands for something comparable to the lost painting.

We can understand why members of the delMonte circle were so excited by the newnaturalism. They were promoting sciences that

depended on new modes of observation, asadvocated in Tommaso Campanella’s PhilosophyExplicated According to the Senses (1591). Thecardinal, who was to become a staunch supporterof Galileo, was an enthusiastic practitioner ofalchemy (in its most experimental mode), andactively supported Ferdinando de’ Medici’sefforts to establish a glass-making industry inTuscany. Caravaggio, for his part, was closelyassociated with a leading figure in the mirrorbusiness in Rome.

In this conjoined context of observationalscience and ‘natural magic’, Caravaggio’s opticalnaturalism was bound to flourish, establishing asymbiotic relationship with the ideas of thosewho were forging new ways in instrumentalseeing, without his being overly concerned withtheir mathematical basis.Martin Kemp is in the Department of the History of Art, University of Oxford, Oxford OX1 2BE, UK.

The Lutenist can be seen at the Stille Welt:Italienische Stilleben aus drei Jahrhunderten in the Kunsthalle de Hypo-Kultyurstiftungexhibition in Munich from 6 December 2002 to 23 February 2003.

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Encore! The carafe of flowers on the left of The Lutenist appeared in several of Caravaggio’s paintings.

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