darwinian account is incomplete and has tobe supplemented in one way or another by a‘special’ action on the part of a ‘creator’.

This lasting hostility to the account ofevolution that is more or less universallyaccepted in the scientific community has deeproots in the USA. Two factors are frequentlyinvoked to explain this hostility: the literalistinterpretation of scripture observed by sig-nificant segments of the earlier immigrantpopulation; and resentment to the stringentexclusion of religion from a public education.Evolution has evidently become a lightningrod at this point for much broader dis-contents. The persistent attempts over thepast half-century to restrict the teaching of evolution in the public schools or to supplement it with a ‘creation’ alternativehave kept the issue alive, and have keptlocal school boards on edge (as recently as2001 in Ohio).

To allow ‘creation’ to be presented as analternative to evolution in a state-supportedschool, it would have to be construed as science according to numerous US courtrulings, and this has proved a major barrierto creationist efforts to modify school curricula. Still, varieties of ‘creation-science’that make no overt appeal to Genesis havebeen devised. In spite of a rather decisivedefeat of such efforts by a Federal judge inArkansas in 1981, in the early 1990s a newinitiative took shape under the banner of‘intelligent design’ (ID). Although un-orthodox by darwinian standards, ID claimedto be properly scientific, arguing that anintelligent cause, very different from darwin-ian natural selection, had to have played arole in the origin of species.

There was an obvious echo here of thenatural theology of the 17th to 19th centuriesthat had been displaced by Darwin, whichargued that numerous examples of adaptationcould only be due to the work of a design-ing Intelligence. The new proponents of IDare making a broadly similar claim, but thistime calibrated to the darwinian challenge.

Robert Pennock’s compendious (800 page)anthology does ample justice to the oftenacrimonious debate that has ensued over thelast decade. He has aimed at completeness ofcoverage of a controversy that has, at timesat least, reached a level of complexity andhence of philosophical interest that was quiteabsent in earlier stages of the 20th centurydebate. Critics of the ID arguments out-number their defenders in Pennock’s booktwo to one, and the editor makes no secretof his own allegiance. But he has taken painsto see that the proponents of ID are fairly

represented. The anthology makes livelyreading, with no holds barred in argumentand counter-argument, at times perhaps a bit too free on the darwinian side in hurlingepithets like ‘country bumpkin’ or the dismissive ‘neo-creo’.

The ID argument takes two forms. One –associated in particular with the biochemistMichael Behe – points to the ‘irreduciblecomplexity’ of certain molecular structuresand processes in living organisms, such ascilia or blood-clotting. These could not, heargues, have come about through naturalselection in the gradualist way that darwin-ian explanations require. There had to havebeen a shaping intelligence at work. In theabsence of even a single structural com-ponent or step in the complex process, thefunction would cease (hence ‘irreducible’).The argument resembles some of the firstcriticisms of Darwin’s theory on thegrounds that complex organs such as the eyeor complex behavior such as flying couldnot possibly have come to be in gradualsteps, with each one providing an adaptiveadvantage. Behe’s argument is more focused,this time on the newly appreciated complex-ities of cell biology, and has evoked severalkinds of response: from scientists, whochallenge his claim that a darwinian ex-planation is impossible; from philosophers,who want to know how the design alterna-tive is supposed to work; and from generalcritics, who point out that the argument cannot be purely scientific because it willhave to take into consideration the likeli-hood of there being an Intelligence of therequisite sort available.

A probability theorist, William Dembski,put forward the second and rather differentargument for ID. He proposed an algorithmto identify the mark of intelligence in theshaping of a feature of the natural world. It operates as a filter, first excluding the possibility that law-like natural process isresponsible, then excluding the possibilityof chance at work, leaving (he claims) onlyintelligence as the remaining alternative.Drawing on one of the many senses of thatchameleon term ‘information’, he defines a notion of ‘specified complexity’ that is an infallible indication (he believes) ofintelligence at work.

His work has evoked a veritable cascadeof objections, most of them represented inPennock’s anthology. One of the most tellingis that Dembski never really clarifies whereexactly the appearance of ‘complex specifiedinformation’ of the kind that would signalthe work of an intelligent agent is located in

the evolutionary process. Unlike Behe’sargument, which is tightly localized in cellbiology, it would seem that Dembski’s ap-proach involves the special action of a shapingintelligence at every step in evolution wherea new or improved adaptation appeared.

The intervention of well-known philoso-phers of religion like Alvin Plantinga on theside of ID can be understood, in part at least,as a reaction to those who, like RichardDawkins and Daniel Dennett, take the suc-cesses of evolutionary theory to make acompelling case for atheism. Not surpris-ingly, this evokes the predictable responsefrom some defenders of religion at least: anattack on claims to potential completenessof the neo-darwinian form of explanation.This enrages darwinian scientists, who viewthis as an attack on science itself. And so theemotion-laden dialectic winds on, each sideconfirmed in its convictions by the extremesof the other. Pennock’s book defines, as noother so far has, the present state of play.

Ernan McMullin

The Progress of Experiment:Science and Therapeutic Reformin the United States, 1900–1990by Harry M. MarksCambridge University Press, 2000.US$21.00 (271 pages) ISBN 0 521 78561 8

The 20th century witnessed a transformationin the development and assessment of medicaltreatments. Disillusioned with the ineffective-ness of treatments available at the beginningof the century, some doctors had becometherapeutic nihilists. As Sir William Oslerput it in 1903: ‘The young physician startslife with twenty drugs for each disease, andthe old physician ends life with one drug fortwenty diseases.’ By mid-century, however,a few dramatically effective treatments hadbeen discovered – insulin for diabetes,sulphonamides and antibiotics for infections,ergometrine for staunching haemorrhage

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after childbirth, and blood transfusion areexamples.

During the second half of the century, theoptimism resulting from discovering a few‘magic bullets’ with strikingly beneficialeffects became somewhat tempered. Althoughthere was a massive increase in new pharma-ceutical products, surgical operations, medical devices and other ways of treatingpatients, any beneficial effects of most ofthese tended to be modest. Furthermore, itbecame clear that therapeutic innovationscould do harm as well as good, nowheremore dramatically than in the tragic epidemicof disabling malformations of children born towomen who had been prescribed thalidomideduring pregnancy.

The thalidomide disaster gave furtherimpetus to longstanding calls to strengthensystems for assessing the effects of drugs,both before and after they were licensed foruse. By the end of the century, legislationhad been introduced in many countriesrequiring that applications for licences fornew drugs be supported by evidence fromcontrolled experiments, and that arrange-ments be put in place for post-licensing surveillance for adverse effects.

Harry Marks’ book on science and thera-peutic reform in the USA during the 20thcentury is the best available account of theprogress of clinical experiment available, andnobody seriously interested in the topic canafford not to read it. The book is a detailed,intensively researched and very readableaccount.

The first part of the book is an account oftherapeutic research in the USA before WorldWar II. The most interesting theme within thissection is the relationships between thera-peutic reformers in the medical profession,the pharmaceutical industry and government.Some officers of the American MedicalAssociation (AMA) had a longstandinginterest in therapeutic reform, but felt thatthe evaluation of new medicinal products wasproperly a job for the federal government.When efforts failed to secure federal control,George Simmons, then general manager ofthe AMA and editor of its journal (JAMA),suggested that the AMA create a body, sub-sidized by pharmaceutical manufacturers’fees, to analyse the quality and compositionof new drugs. A Council on Pharmacy andChemistry was duly constituted in 1905.

Predictably, the relationship between thereformers on the Council and industry wasnot exactly cosy, unchecked commercialismbeing seen by the reformers as ‘debauchingmedical journals’. But the influence of the

medical scientists on the Council on theirpractitioner colleagues was also problematic.As Marks puts it:

For reformers what distinguished the man of

science from other medical practitioners was

not that he possessed the truth about diagnosis

and treatment, but that he renounced false

complacency. Recognizing the limits of one’s

knowledge was of equal importance to having

a supply of it in the first instance. Putatively

men of science, practicing physicians were

eligible and expected to join its community.

But to the practicing physician, concerned with

accommodating (and keeping) his patients,

arriving at the truth was a problem best left to

others. The practice of medicine may have

been, in the ideology of the era, more than a

mere business but it was a business no less.

(p. 40)

In spite of its problematic relationship withindustry and frontline practitioners, theCouncil nevertheless had an importantinfluence. The standards of evidence itarticulated eventually formed the basis offederal drug regulation in the 1930s and1940s. By mid-century, most of the featuresof the well controlled clinical experiment aswe know it today had evolved.

The progress of experiment during thesecond half of the 20th century is dealt within the second part of Marks’ book, which issubtitled ‘the triumph of statistics’. The firstchapter in this part is entitled ‘Managingchance: statistics and therapeutic experiments,1950–1960’. It refers to ‘the extraordinarysocial success and intellectual influence ofstatistics in contemporary medicine’, but itdoes not make sufficiently clear that thereare three different ways that chance can beconceived of as being ‘managed’ in treatmentcomparisons.

First, chance can be used deliberately –using random assignment – to generate un-biased comparison groups. Random assign-ment is the only distinguishing feature common to all randomized clinical trials(RCTs), but the RCT was not, as suggestedby Marks and some other writers, ‘an extension of the statistician R.A. Fisher’sideas about experimental design’. Examplesof clinicians taking steps to generate unbiasedcomparison groups antedate the post war riseof medical statistics by at least a century(see www.jameslindlibrary.org), and thesepioneers deserve recognition.

Two other ways in which chance can be‘managed’ are by increasing sample sizes,in order to reduce the play of chance; and by

taking account of the possibility that theplay of chance may account for observeddifferences between comparison groups. Inprospect, statistics can thus help to clarifywhat size of experiment is needed to rule out,with specified levels of confidence, effectsof specified magnitude; and, in retrospect, oncompletion of the experiment, to interpretthe results obtained.

Although the situation began to improvetowards the end of the period covered inMarks’ book, most reports of controlled trials, even now, show little evidence thatthese important statistical issues are appre-ciated by clinical investigators. In particular,sample sizes studied are generally much toosmall to offer a chance of detecting treatmenteffects of a plausible magnitude on outcomeslikely to be of interest to patients. As a conse-quence, clinical research remains bedevilledby false negative and selectively publishedfalse positive results. Statistics will indeedhave triumphed when this sorry state ofaffairs has been addressed more generallythan is the case so far.

Iain Chalmers

Agnes Mary Clerke and the Riseof Astrophysicsby Mary T. BrückCambridge University Press, 2002. £35.00 (275 pages, 23 half-tone figures) ISBN 0 521 80844 8

Mary Brück describes Agnes Clerke’s firstand most important work, her PopularHistory of Astronomy during the NineteenthCentury, as ‘remarkable for its extraordinarythoroughness’. These words could equallywell be applied to the present book, an accountof Clerke’s family background, life and work,based on an exhaustive examination of whatmust be all the known sources available.The result is impressive.

As the story unfolds, the shy, somewhatelusive personality of this notable chronicler

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