match the fluidity of human thought. Thisgives him the opportunity of writing withgreat clarity on logic and its useful but limit-ed role in computation. Devlin concludesthat a ‘soft’ form of mathematics might dothe trick. Unfortunately we never find outmuch about it: as Devlin himself admits, he isonly hoping this might be so.

Despite the qualities of these books, theymay be too ready to accept the lack ofprogress on the ‘thinking machine’ questionposed by Turing more than 60 years ago. Are

the hurdles better under-stood now? The first barri-er to progress comes fromthe word ‘machine’ in thecontext of ‘thinking’. It isgenerally assumed thatsuch a machine would be aconventional computerwhich, when given an

appropriate program, would behave in a wayakin to a thinking human. Unfortunatelymuch of the argument comes to a halt withthe functional emptiness of this model: the computer itself does nothing; some programmer must work out every step ofwhat the machine is to do.

By contrast, the brain is clearly a functionalmachine of a kind, as itdoes not rely on anythinglike a program. It is beau-tifully structured to bedriven by both evolvedstructure and learnedfunction, neither of

which may be available to a programmer.Understanding how this mechanism con-tributes to the experience of sensation andthought is top of the current agenda.

It helps that evolution and learning can be modelled and analysed in an appro-priate artificial domain: that of neural sys-

tems. Parallelism, adap-tation and modularity are needed to make realmachines work in emer-gent, seemingly intelli-gent ways. Models needthese self-organizing fea-tures. That the model-ling is often done on a

conventional computer is a red herring; theappropriateness of the model is important,not its box.

Another hurdle is the assumption thatthinking machines will work by performingendless manipulations of simple symbols atever-increasing speeds. The symbols of aneural machine, whether real or artificial, areneural firing patterns which are wonderfullyextravagant, rich, diverse and sufficientlyexpressive to be capable of directly support-ing subtle sensations that could distinguishbetween the thought of a good Burgundyand plonk, or between loving and liking. The

notion of the brain as a manipulator of parsi-monious symbols or, indeed, as some kind ofdata-processing machine is a customary butsterile starting point for a science of themechanics of thought.

Although both Casti and Devlin hint atthe possibility of evolving and adaptivemachines, they largely avoid the topic. Perhaps they do not wish to offend the manywho, over the past half century, have believedin the supremacy of an empty computingbox that begs for someone to tell it whatthinking is.Igor Aleksander is in the Neural SystemsEngineering Group, Imperial College, ExhibitionRoad, London SW7 2AZ, UK.

Change of mindMolecules of Emotion: Why You Feelthe Way You Feelby Candace B. PertScribner: 1997. Pp. 368. $25

Samuel H. Barondes

In 1970 Candace Pert was admitted to JohnsHopkins University as a graduate student in pharmacology, and soon began doctoralresearch in the laboratory of Solomon Snyder. By autumn 1972 she had helped todevelop the first practical binding assay for opiate receptors in brain homogenates,and this became the basis for studying the

interaction of these receptors with drugs andnatural ligands.

Three years later her work with Snyderhad earned her an independent position atthe “Palace” (her name for the NationalInstitutes of Health in Bethesda, Maryland),where she remained until 1987, publishingmore than 200 scientific papers, many ofwhich were very widely cited.

In 1978 Pert faced a great personal crisiswhen she learned that Snyder would receivethe Lasker Award for work on opiate recep-tors, along with John Hughes and HansKosterlitz, who had determined the struc-tures of two endogenous opiate peptides, theenkephalins. Believing she should have beenincluded among the winners, Pert made aformal protest that became public and wasrecounted in many places, including RobertKanigel’s Apprentice to Genius (1986) andJeff Goldberg’s Anatomy of a Scientific Dis-covery (1988). Now, in Molecules of Emotion,Pert retells the story from her point of view,and lets us know what she has been doingsince then.

Despite its subtitle, this book is essentiallya memoir. Interspersed throughout the first half are some discussions about neuro-peptides (Pert’s “molecules of emotion”),though even the endogenous opiate peptidesare considered in only a cursory way, andthere is no mention of a multitude of discov-eries about the structure and biology of opiate receptors that followed from Pert’s

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NATURE | VOL 391 | 22 JANUARY 1998 349

Captain Jacob Rowe’spatented diving enginewas the highlight of aremarkable salvageoperation to recover 17chests of specie from theDutch East IndiamanAdelaar, wrecked offBarra in the OuterHebrides, Scotland, in1728. The machine couldbe used — albeit withgreat discomfort — atdepths of up to 18metres. The Encyclopediaof Underwater andMaritime Archaeologyedited by James P.Delgado (Yale UniversityPress, $55) is a treasure-trove of informationabout the submergedpast. Its 500 pagesdescribe sites around theworld, the techniquesand tools of underwaterarchaeologists, ethicaland legal aspects, andimportant institutionsand individuals.

Hidden depths of underwater salvage

Haldane.

Schrödinger.

Turing.

seminal work.Molecules of Emotion is mostly about

Pert’s life in science, which she often dis-cusses with startling candour. She recounts,for example, how, late in 1975, she and a col-laborator betrayed a confidence by obtainingthe then unpublished structure ofenkephalin “from a secret source”, made thesynthetic peptide, and showed that it had ananalgesic effect when injected in the brain,aiming “to get it printed as close on the heelsof Hughes’s paper as possible”. With remark-able openness she traces her hunt for a treat-ment for AIDS to a voice she heard in 1985“echoing inside my own head! It was a strongmale voice that commanded: ‘You should do this!’ ”.

Following “the direction [that] had beendictated by a voice in my head while I stood ata podium in Maui”, Pert enlisted others tohelp her to design peptides that might blockthe attachment of an HIV envelope proteinto a receptor on T cells using a receptor-binding assay.

She quickly found a synthetic peptide —peptide T (for threonine) — that seemed towork. It so interested the “Second BiggestDrug Company on the Planet” that its repre-sentatives persuaded her to give up her tenured position at the National Insti-tutes of Health for a new laboratory theybuilt for her, called “Peptide Design”. But inlittle more than a year their support for thislaboratory was terminated, and “PeptideDesign became Peptide Demise”.

Devastated by this turn of events, and dis-heartened by the hostility with which herwork on peptide T was received by othersstudying HIV, Pert decided to withdrawfrom the intensely competitive arena of sci-ence, and to devote herself to the “newmodalities of personal healing”. She wassoon “earning a reputation... as a ‘body-mind’ scientist”, and the warm welcome shereceived when she spoke at the 1991 meetingof the American Association of HolisticMedicine made her “feel totally at home withthe new-paradigm crowd”.

Towards the end of the book she offersopinions and advice based on what she haslearned about holistic medicine, in a sectioncalled “Lifestyles of the Healthy, Whole andConscious: an Eight-Part Program”. There isalso an appendix: “Prevention-OrientedTips for Healthful, Blissful Living”.

This is not a run-of-the-mill autobiogra-phy of a scientist. As Pert says at the outset:“Perhaps my journey, intellectual as well asspiritual, can help other people on theirpaths”. Molecules of Emotion can certainlyserve that purpose, but the lessons drawnfrom it by many readers may be rather differ-ent from those drawn by Pert herself.Samuel H. Barondes is at the Center forNeurobiology and Psychiatry, University ofCalifornia at San Francisco, San Francisco,California 94143-0984, USA.

Worried to death?Culture of Fearby Frank FurediCassell: 1997. Pp. 224. £45, $70 (hbk);£11.99, $19.95 (pbk)

Haunted Housing: How Toxic ScareStories Are Spooking the Public Outof House and Homeby Cassandra Chrones MooreCato Institute: 1997. Pp. 274. $21.95 (hbk);$11.95 (pbk)

John Galloway

“All life,” Sam the Gonoph concluded in A Nice Price by Damon Runyon, “is six tofive against”. Of course, in the end we will all be dead. However, in the meantimewe would like the odds stacked as much aspossible in our favour. The authorities dotheir best by making, or trying to make, usanxious.

These two books attempt to describe whathappens when the “anxiety promoting”machinery takes on a life of its own. But theirstyles and standpoints are very different. InCulture of Fear, Frank Furedi’s thesis is thatanxiety has become the defining spirit of the age. The Zeitgeist fastens itself to anynatural disaster, accident, technologicaldevelopment, research finding or crime. Nomatter how slight a risk is involved or how fewpeople are affected, it turns them into causes.This brings them into the realm of public policy and, worse, to the attention of do-gooders and bureaucratic busybodies.

The book’s theme ambitiously suggeststhat the traditional moral forces in society arebeing replaced by ethical codes based on, ormasquerading as, safety. And finally, a reluc-tance to take risks leads to the blunting ofambition. A fear of falling kills the desire toclimb. It is an interesting although overstatedidea, and is rhetorical where it should be analytical.

For instance, Furedi seems angered by thefact that small events use up more of people’semotional energy than large ones that are tohim at least more worthy. A single teenagedeath from the drug Ecstasy matters more tous than the 100,000 deaths in the United King-dom each year from tobacco-related illnesses,or an outbreak of Ebola virus counts morethan pandemic diarrhoea.

Scientists traditionally find this incom-prehensible and call for the public to be better educated about the statistics of risk. Playwrights and novelists, of course,understand it perfectly well as the essence ofdramatic art. Certainly we in Britain prefertheatre to science. Look at our institutions,parliament, the monarchy, courts of law: allpure theatre. How else can you account forthe BSE/CJD phenomenon? A disease affect-ing a handful of people has led to the decima-tion of a major industry and international

squabbling, based on evidence that is com-prehensible to virtually no one.

All this begs the question of whether thepublic are really consumed with anxietyabout the state of the world. Or are we merely entertained by the passing show, expe-riencing emotion briefly and superficially?Public concern is often a creation of themedia. Good news is no news. Are we reallyworried about issues unless they have a directimpact on us? Jane Austen said it all about theBattle of Waterloo: “How dreadful that somany poor fellows have been killed and whata blessing one cares for none of them.”

In this respect it has been said that the suc-cess of one British newspaper can be ascribedto its ability to relate any story anywhere in theworld to its effect on the price of your house.This is Cassandra Chrones Moore’s tactic inHaunted Housing, in which she chooses aseries of scare stories connected with health— asbestos, radon, lead and electromagneticfields — which make the buying and selling ofhouses more difficult and sometimes impos-sible. She uses this as a device to explore theinterplay between the science, politics andeconomics of these public health issues and asa stick to beat the US regulatory agencies, suchas the Environmental Protection Agency, fortheir failure to deploy rational evidence-based policies.

Haunted Housing is both scholarly — wellresearched and argued — and well written.One of the insights it provides is an answer tothe question of how scientists know how greatis the health risk in our homes. The authorputs forward a convincing case that they donot, exposing the difficulties in extrapolatingfrom one set of circumstances to another, andshows the folly of using such extrapolations asany more than the most tentative basis forpublic policy.

An underlying theme in both books is thatscience is always telling us more than we wantto know, and less than we need to know to takeeffective action. Richard Feynman’s remarkthat science does not come with instructionsabout how to use it has never been more apt.Science has lit the fuse for the informationexplosion, which often prevents rationalargument because it becomes impossible,even for experts, to be entirely certain of theirsubject.

One of Furedi’s lines of argument is presumably that we have given up the certain-ty of faith for the uncertainty of science. As acounter, Moore points out the folly of faith inscientific findings that do not warrant it. Gov-ernments and their agencies are in the samepsychological bind as parents over-anxious toprotect their children from the pitfalls of liferather than letting them find out for them-selves. The only thing worse politically thandoing something is doing nothing.John Galloway is in the Team Development Unit,Eastman Dental Hospital, 256 Gray's Inn Road,London WC1X 8LD, UK.

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