origins & design 17:1 - eddie olson · are we alone? philosophical implications of the...

Gordon Mills and Dean Kenyon

The RNA World:A Critique

George Ayoub

On the Design of theVertebrate Retina

Phillip Johnson

Daniel Dennett’sDangerous Idea

Book Reviews,Literature Survey,News and Commentary

AN INTERDISCIPLINARY QUARTERLY

PUBLISHED BY ACCESS RESEARCH NETWORK

Volume 17Number 1

Winter 1996ISSN 0748-9919

$5.00 U.S.$6.00 Canada

Inside:


The RNA World:A Critique

George Ayoub

On the Design of theVertebrate Retina

Phillip Johnson


Plus

Book Reviews,Literature Survey,News and Commentary

Origins& DesignOrigins& Design

Origins& Design

Stephen C. MeyerDepartment of PhilosophyWhitworth College300 W. Hawthorne RoadSpokane, WA 99251-1502Voice: 509-466-1000, x4548E-mail: [email protected]

Michael Behe

Biochemistry

Lehigh University

Tom Bethell

Washington Correspondent

The American Spectator

John Angus Campbell

Speech and Rhetoric

University of Memphis

Kenneth de Jong

Linguistics

Indiana University

Michael Denton

Biochemistry

University of Otago

Brock Eide

Committee on Social Thought

University of Chicago

Doug Geivett

Philosophy

Talbot School of Theology

Loren Haarsma

Neurosciences

Tufts University

Brian Harper

Applied Mechanics

Ohio State University

Mark Hartwig

Social Sciences

Found. for Thought & Ethics

Phillip Johnson

School of Law

Univ. of Cal., Berkeley

Robert Kaita

Plasma Physics Laboratory

Princeton University

Dean Kenyon

Biology

S. F. State University

Ernst Lutz

Sr. Environ. Economist

The World Bank

J. P. Moreland

Philosophy

Talbot School of Theology

Bijan Nemati

Physics

University of Oklahoma

John Mark Reynolds

Philosophy

Biola University

Siegfried Scherer

Taxonomy/Molecular Evol.

Tech. University of Munich

Charles Thaxton

Chemistry

Prague, Czech Republic

Hubert Yockey

Inf. Theory/Molecular Biol.

Bel Air, Maryland

Stan Zygmunt

Physics and Astronomy

Valparaiso University

EDITORIAL ADVISORY BOARD

EDITOR

P.A. NelsonEditorial Office:600 Davis Street3rd Floor WestEvanston, IL 60201-4419Voice and Fax: 847-733-9417E-mail: [email protected]

ASSOCIATE EDITORS

William A. DembskiCenter for Interdisciplinary Studies66 Witherspoon Street #1000Princeton, NJ 08542-3226Voice: 609-497-1591E-mail:[email protected]

science • technology • societyarn access

research

network

Origins & Design (ISSN 0748-9919) is an interdisciplinary, peer-reviewed quarterly with two relatedgoals: (1) to examine theories of origins, their philosophical foundations, and their bearing onculture, and (2) to examine all aspects of the idea of design. Both “origins” and “design” areintellectual grounds on which theology, philosophy, and the natural sciences find themselves with anequal interest. Thus, the editors and the editorial board of Origins & Design are drawn from theseand other fields, and we welcome contributions from all interested persons.

Jonathan WellsMolecular and Cell Biology111A Stanley HallUniversity of CaliforniaBerkeley, CA 94720-3206Fax: 707-427-8703E-mail: [email protected]

PUBLICATIONS MANAGER

Edwin P. OlsonPremier PublicationsColorado Springs, CO

PUBLISHER

Dennis WagnerAccess ResearchNetwork(719) 633-1772

Access Research Network is a non-profit 501 (c) (3) organi-zation based in Colorado Springs, CO, providing accessibleinformation on science, technology, and society issues.

TO REACH ARN: You may contact us via Internet [email protected] to drop us a note, or to request moreinformation. We can also be contacted through the ARNweb site at: http://www.arn.org/arn

ORIGINS & DESIGN (ISSN 0748-9919) is pub-lished quarterly for $15 per year/$25.00 per year foreignby Access Research Network, P.O. Box 38069, ColoradoSprings, CO, 80937-8069. Second-class postage paid atColorado Springs, CO. POSTMASTER: Send addresschanges to Access Research Network, P.O. Box 38069,Colorado Springs, CO 80937-8069. Change of Address:Four to six weeks’ notice is required.

Please include old and new addresses, including zipcodes. Unsolicited material cannot be returned unlessaccompanied by sufficient return postage. Copyright ©1996 by Access Research Network.

All submissions including letters should be sent toP.A. Nelson, 600 Davis Street, 3rd Floor West, Evan-ston, IL 60201-4419.

For subscription membership informationplease see back cover.

Origins & DesignVolume 17, Number 1

Winter 1996

NEWS AND COMMENTNEWS AND COMMENTNEWS AND COMMENTNEWS AND COMMENTNEWS AND COMMENTARARARARARYYYYY 5 Colin Patterson Revisits His Famous

Question About EvolutionSince the late 1970s, the thinking of English paleontologist andsystematist Colin Patterson has been a focal point of controver-sy in biology and evolutionary theory. O & D reports onPatterson’s revisting of his famous question, “Can you tell meanything about evolution that is true?” and looks at highlightsof his published (and unpublished) work.

ARTICLESARTICLESARTICLESARTICLESARTICLES 9 The RNA World: A Critique


Within the past decade, the RNA World hypothesis – the ideathat life began with a self-replicating RNA molecule – hasmoved from intriguing speculation to widely-accepted theory.Yet behind the excitement lies a landscape of chemical difficul-ties which render the RNA World highly problematical.

19 On the Design of the Vertebrate RetinaGeorge Ayoub

It is widely argued by evolutionary biologists that the verte-brate retina is poorly designed, revealing the handiwork of theblind watchmaker, natural selection. However, this suboptimali-ty argument is exceedingly weak, ignoring the availableevidence about the actual structure and function of vertebrateeyes.

In This Issue:

AND ALSO:AND ALSO:AND ALSO:AND ALSO:AND ALSO: 4 Editorial

The editors bid farewell to Origins Research andwelcome you to Origins & Design, the newestjournal in a very old debate.

17 Literature SurveyLevinton on Kauffman; Penman rethinks cellstructure; Snyder illuminates Whewell; Sullivan andDawkins spar; and other selections.

31 ARN CatalogueBooks, videos, audio tapes, and study guides fromAccess Research Network.

BOOK REVIEWSBOOK REVIEWSBOOK REVIEWSBOOK REVIEWSBOOK REVIEWS23 Desmond

Huxley: The Devil’s Disciple. London: MichaelJoseph, 1994; 475 pp.

25 DaviesAre We Alone? Philosophical Implications of theDiscovery of Extraterrestrial Life. New York: BasicBooks, 1995; 160 pp.

27 DennettDarwin’s Dangerous Idea: Evolution and theMeanings of Life. New York: Simon and Schuster,1995; 586 pp.

4 ORIGINS & DESIGN 17:1 Winter 1996

Welcome to the first issue of Origins & Design, aninterdisciplinary journal dedicated to examining“theories of origins, their philosophical founda-

tions, and their bearing on culture,” and “all aspects of the ideaof design.” Origins & Design begins its existence as anadolescent, not a newborn. The reader will notice that this isVolume 17, number 1. Origins & Design represents thenatural growth and maturation of Origins Research, the na-tional college newspaper first published as an eight pagetabloid nearly twenty years ago. The publishers of OriginsResearch have wanted for some time to issue that publicationin a more permanent format, and to expand its content careful-ly under the guidance of an editorial board. It now seemstimely to move to full journal status as a quarterly.

Origins & Design will continue the editorial practices bywhich Origins Research was known: openness, encourage-ment of responsible dissent, and the free give-and-take ofviews on the science and philosophy of origins. “I dogmatiseand am contradicted,” said the great English lexicographer,poet, and essayist Samuel Johnson (1709-1784), “and in thisconflict of opinions and sentiments I find delight.” Takedelight in being contradicted? But Johnson could do so,comfortably, for he believed in the stability and power oftruth.

By encouraging a disciplined exchange of views on ori-gins, the editors and editorial board are persuaded that thetruth, which surely can take care of itself, will emerge, and thatscience, the growth of knowledge, and intellectual freedomwill thereby be served.

“Origins” covers a wide swath of ground. In that territory,one finds, for instance, Darwin’s On the Origin of Species, theNK models of Stuart Kauffman, the heated polemics of theUsenet group talk.origins, the anthropic principle, the book ofGenesis, the Cambrian explosion of animal body plans, DanielDennett’s musings about the motives of Stephen Jay Gould inDarwin’s Dangerous Idea, school board debates, the notion ofirreducible complexity – and so on. At its broadest, “origins”includes these and other topics, and the full list of competinganswers about how the universe and all its objects came to be.

Among those answers, Origins & Design takes as itsspecial interest the idea of “design.” Can there be a theory ofdesign – understood, very roughly, as intelligent causation –that serves as a proper explanation in the historical sciences?If so, what would the content of that theory be? Or mustscience adopt the principle of methodological naturalism, toavoid being swallowed up by a “God of the gaps?” These arequestions for which Origins & Design seeks answers. Weseek, moreover, criticism of the answers offered here. Thenotion of design (as a scientific explanation) does not lack forcritics, and we urge them to bring their arguments here forpublication. They will find a respectful audience, albeit anaudience that can be expected to dissent as sharply as it listenscarefully.

Welcome to An Evolving Publication

FROM THE EDITORS:

o

Origins & Design will be an interdisciplinary journal.Given the breadth of both “origins” and “design,” readers canexpect to see articles from fields as diverse as developmentalbiology, cosmology, philosophical theology, and paleontolo-gy. We intend to publish articles that are comprehensible,however, by a wide audience, while not sacrificing accuracyor depth.

In the 1980s, with the discovery of self-splicing RNAmolecules, or “ribozymes”, the hypothesis of an “RNAWorld” came to prominence: the view, as the January 1996

Scientific American reports, “that ribozymes might have beenthe precursors of modern DNA-based organisms.” And, with-in the past five years, molecular biologists have learned howto expand the catalytic repertoire of ribozymes to includenovel reactions. These and other developments have led manyto argue that the RNA World hypothesis provides the mostpromising avenue for reconstructing the origin of life.

Perhaps – but the road to the RNA World, if it ever existed,biochemists Gordon Mills and Dean Kenyon argue, is markedwith many obstacles. In their feature article, “The RNAWorld: A Critique,” Mills and Kenyon map those obstacles. Inan accompanying sidebar article, “What Do Ribozyme Engi-neering Experiments Really Tell Us About the Origin ofLife?” they argue that the intelligently-designed manipulationof RNA, far from supporting the naturalistic story for theorigin of life, in fact lends weight to a quite different design-based view. (Ribozyme engineering is certainly important toexpanding our knowledge of the properties of RNA. Itsrelevance to the naturalistic origin of life, Mills and Kenyoncontend, is another matter altogether.)

Our second feature article, “On the Design of the Verte-brate Retina,” by biologist George Ayoub, looks in detail atthe widely-cited claim that the vertebrate retina is “wiredbackwards.” No competent designer, many evolutionary biol-ogists argue, would build a light-receiving device that re-quired incoming photons to pass through several cell layersbefore they struck the photoreceptors – yet the vertebrateretina is just so structured. Stupid design, at best.

Not so fast, cautions Ayoub. In a careful analysis, Ayoublooks at the functional context of the retina, and demonstratesthat such suboptimality claims are facile.

This issue also features shorter articles, on the thinking ofEnglish paleontologist Colin Patterson (including a bibliogra-phy of “selected hits” from Patterson’s work), literature sur-veys, and book reviews.

Again: welcome. We hope to make Origins & Design thebest new journal in a very old debate, and look forward tohearing from you, our readers. E-mail or the regular variety:the Correspondence column is officially open.

Winter 1996 ORIGINS & DESIGN 17:1 5

Authoritative,” conveying “an im-pression of moody rebellious-ness,” and “habitually pessimis-

tic”–thus writer Tom Bethell describedthe paleontologist and systematist ColinPatterson, on first meeting him in 1983.1

Patterson, who works at the BritishMuseum of Natural History in London,is one of the leaders of the philosophy ofbiological systematics known as “trans-formed cladistics.” The public hubbubwhich surrounded “transformed” or“pattern” cladistics in the 1980s hasnow generally subsided, although theissues lying at the heart of the contro-versy have not. Indeed, Patterson hasrevisited those issues, which were cap-tured in large measure by a famousquestion he first posed nearly fifteenyears ago. “Can you tell me anythingabout evolution,” he asked his listeners,“any one thing, that is true?”

On November 5, 1981, Pattersongave a now infamous talk at the Amer-ican Museum of Natural History in NewYork, to the Systematics DiscussionGroup which met monthly at the muse-um. An unknown creationist in the au-dience secretly taped the talk, and atranscript was soon circulating as sam-izdat among creationists, and shortlythereafter among the scientific commu-nity at large.

The uncorrected transcript was plain-ly flawed–giving “Conbear” for “vonBaer,” for instance, and omitting thenames of well-known biologists–butenough of Patterson’s provocative pointscame through to ignite the firestormwhich followed. Patterson soon came infor heavy criticism from the evolution-ary community. The talk was much de-bated: what had he meant; was he sim-ply tweaking noses in New York; whatdid he really think about evolution?

ing theory (since its power toexplain was only verbal) but anantitheory, a void that had thefunction of knowledge but, asnaturalists increasingly came tofeel, conveyed none.’ Unfortu-nately, and unknown to me, therewas a creationist in my audiencewith a hidden tape recorder. Atranscript of my talk was pro-duced and circulated among cre-ationists, and the talk has sincebeen widely, and often inaccu-rately, quoted in creationist lit-erature. 2

But despite the inaccuracies, Patter-son’s central question about evolutioncame through unmistakably:

But one sentence from the talkwas accurately reproduced, andwas perhaps quoted more thanany other. The sentence was arhetorical question; I quote itfrom a creationist source(Johnson 1991, p.10): ‘Can youtell me anything about evolu-tion, any one thing that is true?’3

The question still matters, Pattersonargues, because evolution is still as-sumed to be the primary determinant ofphylogenetic reasoning. But Patterson’sagnosticism about evolution–expressedin 1981 as, “I had been working on thisstuff for twenty years, and there was notone thing I knew about it”–continuestoday.

Patterson describes that agnosticismby looking at patterns in molecular data.

At first, he notes, he thought he hadfound answers to his own question:

In 1981, I knew of no sensibleanswer to the question, but in the

As creationist writers trumpeted thespeech, Patterson retreated, understand-ably annoyed by the episode and thevoluminous correspondence he receivedin its wake.

In August 1993, at a SystematicsAssociation meeting in London, Patter-son revisited his 1981 talk; specifically,the bearing of evolution on the practiceand philosophy of systematics: order-ing the relationships of organisms. Inhis recollections (published last year;see the notes on p.7), Patterson describesthe background to the talk:

In November 1981, after an in-vitation from Donn Rosen [a fishsystematist at the AmericanMuseum, now deceased], I gavea talk to the Systematics Discus-sion Group in the AmericanMuseum of Natural History.Donn asked me to talk on ‘Evo-lutionism and Creationism’, andit happened that just one weekbefore my talk Ernst Mayr pub-lished a paper on systematics inScience (Mayr 1981). Mayrpointed out the deficiencies (inhis view) of cladistics and phe-netics, and noted that the ‘con-nection with evolutionary prin-ciples is exceedingly tenuous inmany recent cladistic writings.’For Mayr, classifications shouldincorporate such things as ‘in-ferences on selection pressures,shifts of adaptive zones, evolu-tionary rates, and rates of evolu-tionary divergence.’ Fired up byMayr’s paper, I gave a fairlyradical talk in New York, com-paring the effect of evolutionarytheory on systematics withGillespie’s (1979, p. 8) charac-terization of pre-Darwinian cre-ationism: ‘not a research gover-

NEWS AND COMMENTARY

Colin Patterson Revisits His FamousQuestion about Evolution


hierarchy.’ In the framework ofphylogenetic reconstruction andour current problems with it,another answer comes to mind:‘I know that evolution generateshomoplasy’ [or “convergence,”in the older jargon of systemat-ics]. In both cases, the answer isnot quite accurate. It would betruer to say, ‘I know that evolu-tion explains hierarchy’ or ‘Iknow that evolution explainshomoplasy.’ We must remem-ber the distinction between thecart–the explanation–and thehorse–the data. And where mod-els are introduced in phyloge-netic reconstruction, we shouldprefer models dictated by fea-tures of the data to models de-rived from explanatory theories. 6

Among the issues raised by Patter-son’s revisiting of his 1981 question,probably the most significant is how dowe know which patterns are real (andtherefore, actually need explaining)?“Transition bias is data,” he argues–butonly if one assumes the common de-scent of the gene sequences in question,meaning, in most cases, macroevolu-tion. For some design theorists, whodoubt that macroevolution is possible,sequence comparisons between diver-gent animal phyla (for instance) will notbe data showing a historical relation-ship from an unknown common ances-tor–a relationship requiring causal ex-planation. Rather, those data may re-flect any number of causes other thandescent.

Data–“facts” requiring explanation–emerge against a background of causalpossibility. Because they are highlyskeptical of the possibility of macro-evolution, some design theorists woulddeny that the systematic hierarchy isreal, in the same sense that the branch-ing pattern of an elm tree or the Haps-burg Dynasty is real, i.e., somethingextending through space and time.

Thus, they would seek a nominalistexplanation for the systematic hierar-chy (reflecting, perhaps, our desire toorganize data in bifurcating trees), andwould defend that by arguing that thetransformations required by macroevo-lution are probabilistically inaccessi-

ble. (Other design theorists would ac-cept the hierarchy as actual, of course, agenuine tree of life, but would arguethat the tree exists only because of adesigner’s intervention to make the nec-essary transitions between forms possi-ble.)

The real crunch between Pattersonand design theorists, however, arisesfrom the possibility of design. The pres-ence of cytochrome c in, say, echino-derms, and the same protein in humans,gives evolutionists an historical linkagebetween the two forms, even in theabsence of a theory of macroevolution,simply because high degrees of molec-ular similarity require a common cause.

For most methodological natural-ists, that can only be descent with mod-ification. 7

But suppose, as seems possible, thata designer employed the same cyto-chrome molecule in two distinct lineag-es (echinoderms and humans)? The usualnaturalist response holds while this iscertainly possible, any theory makingsuch predictions is empty. Assertionsabout the designer’s actions are uncon-strained, and would fit whatever dataturn up.

But that does not follow. A designerwho is free to employ the same mole-cules in constructing diverse organismsis not therefore an agent who acts capri-ciously. Furthermore, a design theoristwould locate the empirical content ofhis theory elsewhere, in those predic-tions which distinguish design from

ensuing decade I came to be-lieve that there were two things Iknew about evolution. First, thattransitions [purines, adenine (A)and guanine (G), mutating topurines, e.g., A —> G; or pyrim-idines, cytosine (C) and thymine(T), mutating to pyrimidines,e.g., T —> C] are more frequent-ly fixed than transversions[where a purine mutates to apyrimidine, or vice versa] andsecond, that at the level of DNA,the great majority of substitu-tions take place despite naturalselection rather than because ofit. 4

However, as Patterson continues, hecame to doubt whether in seeing thesepatterns he was grasping the process ofevolution:

...do transition bias and neu-tral substitution represent knowl-edge about evolution, or some-thing else? Further, and moregenerally, why should I, a mor-phologist, claim to know some-thing about molecular evolutionbut nothing of morphologicalevolution? 5

We must distinguish between pat-terns to be explained, Patterson urges,and the process theories by which weexplain those patterns–a distinctionfoundational to the “transformed cla-distic” perspective on systematics andphylogeny. The molecular patterns heobserved, Patterson believes, are thusonly data awaiting explanation.

“I therefore believe I was mistakenin thinking that I knew something aboutmolecular evolution,” he writes. “In-stead, I know (or have learned) some-thing about the properties of moleculardata, and those properties are amongstthe things that must be explained byevolutionary theory.”

Patterson concludes:

...I mentioned a question (‘Canyou tell me anything you knowabout evolution?’) that I haveput to various biologists, and ananswer that had been given: ‘Iknow that evolution generates

Now available onthe Internet!

Check out the new AccessResearch Network web site:

http://www.arn.org/arn

Z


naturalistic descent. It is the whole casefor design, taken broadly, that gives thetheory empirical content. 8

But the step to the possibility ofdesign, it seems, is a far longer stridethan the shorter step from certainty toagnosticism about evolution. One hopes,in any case, that Patterson will join thedebate, wherever he ends up standing.o

NOTES1. Tom Bethell, “Agnostic Evolutionists,”

Harpers 270 (1985): 49-61.

2. Colin Patterson, “Null or minimal mod-els,” in Models in Phylogeny Reconstruction,

eds. R.W. Scotland, D.J. Siebert, and D.M.Williams, Systematics Association SpecialVolume No. 52 (Oxford: Clarendon Press,1994), pp. 173-92; p. 174.

3. Ibid.

4. Ibid., p. 175.

5. Ibid.

6. Ibid., pp. 188-89.

7. Patterson, for instance, argues: “Conver-gence between molecular sequences is tooimprobable to occur, just as similarity be-tween sequences is improbable to be explainedexcept by common ancestry. Some might viewthis argument as viciously or vacuously circu-lar, but the same argument is routinely advo-cated in morphology....This is the argumentfrom complexity: if two structures are com-plex enough and similar in detail, probabilitydictates that they must be homologous rather

than convergent.” See C. Patterson, “Homol-ogy in Classical and Molecular Biology,”Molecular Biology and Evolution 5 (1988):603-625; p. 615. This argument, as with allarguments assuming naturalism, excludes in-telligent causation, which may yield indepen-dent similarities in the absence of any materialdescent. Doubtless all instances of Colin Patter-son’s handwritten signature, for example–ondocuments from bank checks to personal let-ters–are spatiotemporally distinct (i.e., not“descended” from other signatures), yet thesignatures themselves will be remarkably sim-ilar, having, as they do, a unitary cause inColin Patterson himself.

8. Stephen C. Meyer, “The MethodologicalEquivalence of Design and Descent: Can ThereBe A Scientific Theory of Creation?” in TheCreation Hypothesis, ed. J.P. Moreland(Downer’s Grove, Illinois: InterVarsity Press,1994), pp.67-112.

A Colin Patterson Sampler1977 Sunderland: ...How do you see that evolution

might explain the origin of fishes?Patterson: (Pause)Sunderland: Then you’d rather not say?Patterson: Ten years ago I’d have been per-fectly willing to tell you, but it so happens that Iknow someone who is working this problem forabout 15 years–the starfish end of it–the echino-derms. He believes that this development could betraced from the Cambrian with the echinoderms. Icould very easily refer you to his work and say thatI agree with him that fish are related to echino-derms, but I do not think it is obvious.

“Cladistics,” The Biologist 27: 234-240.A popular article, drafted as the “trans-

formed cladistics” controversy was growing to its height.“As the theory of cladistics has developed,” argued Patter-son (p. 239), “it has been realized that more and more ofthe evolutionary framework is inessential, and may bedropped. The chief symptom of this change is the signif-icance attached to nodes in cladistics. In Hennig’s book, asin all early works in cladistics, the nodes are taken torepresent ancestral species. This assumption has beenfound to be unnecessary, even misleading, and may bedropped.”

“Phylogenies and Fossils,” Systematic Zoology 29: 216-219.

More skepticism about fossils and phylogeny: “Tome, one of the most astonishing consequences of the furorover cladistics is the realization that the current accountof tetrapod evolution, shown in a thousand diagrams andeverywhere acknowledged as the centerpiece of histori-

“The Contribution of Paleontology to Te-leostean Phylogeny,” in Major Patterns of

Vertebrate Evolution, eds. M.K. Hecht, P.C. Goody, andB.M. Hecht (New York: Plenum Press, 1977), pp. 579-643.

A major, well-illustrated paper in Patterson’s special-ty, the systematics of fishes, which shows his developingskepticism about the value of evolutionary theory insystematics. Patterson compares the practices of pre-Darwinians, e.g., Agassiz, with post-Darwinians:

Where Agassiz refrained from linking the con-verging bases of his lineages (Fig. 1) since hebelieved that their junction ‘may only be sought inthe creative intelligence,’ the theory of evolutionallows a modern author to represent a hypotheti-cal ancestral group as having the same reality asany other major taxon. Yet the search for ances-tors of the teleosts has hardly been successful, forevery other major branch point in Figure 18 is alsooccupied by hypothetical forms or question-marks:these ancestors have no more reality than theabstract synapomorphy-bearers indicated by theopen circles in Figure 17.

Interview with Luther D. Sunderland,June 30, British Museum of Natural Histo-

ry, ERIC Document Reproduction Service microficheED 228 056 (available at most public libraries), pp.7-19.

Sunderland, late creationist activist (d. 1987), inter-viewed several paleontologists while preparing his bookDarwin’s Enigma. This interview is marked by a fairamount of miscommunication, but also by passages suchas the following:

1980

1979


cal biology, is a will-o’-the-wisp. For nowhere can onefind a clear statement of how and why the Recent groupsare interrelated, and the textbook stories are replete withphantoms–extinct, uncharacterizable groups giving riseone to another” (p. 217).

“Significance of Fossils in Determining Evo-lutionary Relationships,” Annual Review of

Ecology and Systematics 12: 195-223.Patterson’s classic, critical analysis of the role of

fossils in systematics: “...extinct paraphyletic groups [com-mon in neo-Darwinian phylogenies before the cladisticrevolution] seem to me to obscure rather than illuminaterelationships, for they exist not in nature but in the mindsof evolutionists. Such groups lead to a sterile inversion ofproblems of relationships, which come to depend not oncomparative analysis of what is accessible–the Recentbiota–but on juggling with what is inaccessible–unchar-acterizable abstractions from the fossil record” (p. 219).

“Morphological Characters and Homology,”in Problems of Phylogenetic Reconstruction,

eds. K.A. Joysey and A.E. Friday, Systematics Associa-tion Special Vol. No. 21 (New York: Academic Press), pp.21-74.

Perhaps the most widely-cited paper on homology of

the past two decades, where Patterson discusses five waysof defining homology (classical, evolutionary, phenetic,cladistic, and utilitarian), taking issue with “theevolutionists...for here I do expect disagreement” (p. 62).Patterson’s main complaint is with extinct, paraphyleticgroups, which typically play the role of “transitionalforms” in evolutionary reasoning. “Such groups,” Patter-son argued, “...are imagined by evolutionists, those mostcommitted to the confirmation of Darwin’s views. Thepower of this mystery, extinct paraphyletic groups as thesource of phylogeny, is shown by the fact that we stillhave no cladogram, or series of nested homologies, fortetrapods, the group in which phylogeny is supposed to bebest known” (p. 64).

“How does phylogeny differ from ontoge-ny?” in Development and Evolution, eds.

B.C. Goodwin, N. Holder and C. Wylie (Cambridge:Cambridge Univ. Press), pp. 1-31.

A discussion of the bearing of ontogenetic (develop-mental) data on phylogeny: “Phylogeny is generalisedtransformation, but we have no empirical experience ofphylogeny; the only transformations of which we haveempirical evidence are those of ontogeny” (p. 21).

“Homology in Classical and Molecular Bi-ology,” Molecular Biology and Evolution 5:

603-625.Patterson applies his 1982 analysis of homology (see

above) to molecular data. This paper is notable for itsclaim that, at the molecular level (unlike gross morphol-ogy), “there is no detected molecular equivalent of con-vergence–or of misleading similarity–except in the mosttrivial sense” (p. 618).

“Congruence Between Molecular and Mor-phological Phylogenies,” Annual Review of

Ecology and Systematics 24: 153-188. In a review writtenwith fellow British Museum staffers David Williams andChristopher Humphries, Patterson surveys the congru-ence – or lack thereof – between molecular and morpho-logical phylogenies. He and his co-authors conclude:

As morphologists with high hopes of molecularsystematics, we end this survey with our hopesdampened. Congruence between molecular phy-logenies is as elusive as it is in morphology and asit is between molecules and morphology....Partlybecause of morphology’s long history, congru-ence between morphological phylogenies is theexception rather than the rule. With molecularphylogenies, all generated within the last coupleof decades, the situation is little better. Many casesof incongruence between molecular phylogeniesare documented above; and when a consensus ofall trees within 1% of the shortest in a parsimonyanalysis is published...structure or resolution tendsto evaporate (p. 180).

1981

1983

1988

1993

Figure 1. A portion of Louis Agassiz’s 1844 “genealogy ofthe class of fishes,” reproduced from Patterson’s 1977 paperon teleostean phylogeny. The figure shows the geological(historical) distribution of various types of fishes. “Agassiz’sexample shows clearly,” Patterson writes (1977:580), “thatbelief in evolution is not necessary for the production of suchdiagrams: the information contained in these diagrams istherefore not necessarily concerned with evolution orphylogeny.”

1982


The RNA World:A CritiqueThe RNA World:A Critique

REVIEW ARTICLE

Gordon C. MillsDepartment of Human BiologicalChemistry and GeneticsUniversity of Texas Medical BranchGalveston, TX 77555

and

Dean KenyonDepartment of BiologySan Francisco State University1600 Holloway AvenueSan Francisco, CA 94132

INTRODUCTION

One of the earliest published suggestions that RNA-catalyzed RNA replication preceded and gave rise to thefirst DNA-based living cells was made by Carl Woese in1967, in his book The Genetic Code1. Similar suggestionswere made by Crick and Orgel2, for reasons that are notdifficult to grasp. Prior to the discovery of catalytic RNAs,proteins were considered by many to be the only organicmolecules in living matter that could function as catalysts.DNA carries the genetic information required for the syn-thesis of proteins. The replication and transcription of DNArequire a complex set of enzymes and other proteins. Howthen could the first living cells with DNA-based molecularbiology have originated by spontaneous chemical processeson the prebiotic Earth? Primordial DNA synthesis wouldhave required the presence of specific enzymes, but howcould these enzymes be synthesized without the geneticinformation in DNA and without RNA for translating that

ABSTRACT: According to the RNA World hypothe-sis, life began initially with self-replicating RNAmolecules, acting both as information-carrying tem-plates and as catalysts for a broad range of reac-tions. Support for the hypothesis is said to flowfrom recent discoveries in ribozyme engineering,where the catalytic repertoire of RNA has beenexpanded beyond its naturally-occurring activi-ties. However, the RNA World hypothesis rests onseveral problematic postulates: (1) that there was aprebiotic pool of beta-D-ribonucleotides, (2) thatbeta-D-ribonucleotides spontaneously form RNApolymers of the proper form, (3) that such RNApolymers, once formed, can replicate themselves,and (4) that self-replicating RNA would have allthe catalytic activities needed to sustain an organ-ism. These postulates are doubtful. Moreover, be-cause of necessary investigator interference, ri-bozyme engineering provides illusory support forthe RNA World hypothesis.


information into the amino acid se-quence of the protein enzymes? In otherwords, proteins are required for DNAsynthesis and DNA is required for pro-tein synthesis.

This classic “chicken-and-egg”problem made it immensely difficult toconceive of any plausible prebioticchemical pathway to the molecular bio-logical system. Certainly no such chem-ical pathway had beendemonstrated experi-mentally by the early1960s. So the suggestionthat RNA moleculesmight have formed thefirst self-replicatingchemical systems on theprimitive Earth seemeda natural one, given theunique properties ofthese substances.

They carry geneticinformation and (unlikeDNA) occur primarily assingle-stranded mole-cules that can assume agreat variety of tertiarystructures, and mighttherefore be capable ofcatalysis, in a mannersimilar to that of proteins.The problem of whichcame first, DNA or pro-teins, would then be re-solved.

S e l f - r e p l i c a t i n gRNA-based systemswould have arisen first,and DNA and proteinswould have been added later. But in theabsence of any direct demonstration ofRNA catalysis, this suggestion remainedonly an interesting possibility.

Then, in the early 1980s3, the dis-covery of self-splicing, catalytic RNAmolecules (in the ciliated protozoanTetrahymena thermophila), put molec-ular flesh on the speculative bones ofthe idea of an early evolutionary stagedominated by RNA. These catalyticRNA molecules have subsequently beentermed “ribozymes.” “One can contem-plate an RNA World,” wrote WalterGilbert in 1986, “containing only RNAmolecules that serve to catalyze the syn-

thesis of themselves.”4

The phrase “RNA World” stuck tothe general hypothesis, and has sincecome to denote the RNA-first, DNA-and-proteins-later scenario depicted inFigure 1. The long-standing “chicken-and egg” puzzle at the origin of lifeindeed appeared amenable to a solu-tion:

The primordial...conundrum —which came first, informationalpolynucleotides or functionalpolypeptides — was obviatedby the simple but elegant com-paction of both genetic informa-tion and catalytic function intothe same molecule.5

A second impetus to the RNA worldhypothesis came from the cluster oftechnical innovations now known gen-erally as ribozyme engineering. Natu-rally occuring RNA catalytic activitiesare actually restricted to a small set ofhighly specialized reactions, e.g., theprocessing of RNA transcripts primari-

ly in eukaryotic cells. However, ri-bozyme engineering, made possible bytechniques such as DNA sequencing, invitro transcription and the polymerasechain reaction [PCR]6, allow molecularbiologists to manipulate RNA to what-ever extent the molecule will allow.Thus, the catalytic repertoire of RNAcan be expanded beyond the naturallyoccurring activities — in the main, bytwo broad strategies of ribozyme engi-

neering.

One strategy involvesthe direct modification ofexisting species of ri-bozymes, to produce bet-ter or even novel catalysts.This has been called the“rational design” ap-proach. The other strategyemploys pools of short (of-ten 50-100 nucleotideunits) randomized RNAmolecules, which are sub-jected repeatedly to a se-lection process designed toenhance the concentrationof RNA molecules with thedesired functional activi-ty. The few selected mole-cules are then multiplied amillion-fold or more byusing the polymerase chainreaction, which uses acti-vated nucleotide precur-sors and enzymes. This hasbeen termed the “irratio-nal design” method.

Judging from theprogress in ribozyme en-gineering in recent years,

it seems likely that new and improvedtypes of RNA catalysts will be pro-duced in years ahead. Moreover, molec-ular biologists may discover additionalcatalytic roles of RNA in living cells,although the variety of such roles is notexpected to rival that of the proteinenzymes. Thus, one might expect thatthe RNA World hypothesis will contin-ue to have supporters.

Yet beyond the immediate fore-ground of RNA World excitement lies adisquieting landscape of chemical prob-lems, largely ignored in the recent liter-ature on ribozyme engineering. As re-searchers broaden their focus to include

Figure 1. A schematic representation of the RNA World (redrawn fromHirao and Ellington 1995), with time flowing from the top (earliest) tobottom (latest). The “progenote” is the last common ancestor of modernliving things. In this schema, “cellularization” may be seen as marking theorigin of life as self-replicating RNA molecules might otherwise havediffused into non-reproducing populations.


but rather as ex-tending ourknowledge of themolecular biolo-gy of the cell inimportant ways(see below).

The rele-vance of catalyt-ic RNA to theproblem of thenaturalistic ori-gin of life is,however, a dif-ferent matter entirely.

We take heart in noting that, despitethe frequent neglect in much of thepopular literature of the chemical diffi-culties of the RNA World scenario, manyof the scientists involved with that hy-pothesis are quite candid in their assess-ment of the problems associated with it.These are represented for instance bythe numerous contributors to The RNAWorld7. Since the RNA World hypoth-eses are so broad, we will attempt tobreak them down into somewhat nar-rower postulates. In this way one maysee more clearly some of the presuppo-sitions that are involved.

PROBLEMATIC CHEMICALPOSTULATES OF THE RNAWORLD SCENARIO

Beta-D-ribonucleotides (see Figure2) are compounds made up of a

purine (adenine or guanine) or a pyrim-idine (uracil or cytosine) linked to the1'-position of ribose in the beta-config-uration.

There is, in addition, a phosphategroup attached to the 5'-position of theribose. For the four different ribonucle-otides in this prebiotic scenario, therewould be hundreds of other possibleisomers.

But each of these four ribonucle-otides is built up of three components: a

the chemical plausibility of the RNAWorld itself, however7, these difficul-ties cannot be avoided.

Furthermore, the relevance of ri-bozyme engineering to naturalistic the-ories of the origin of life is doubtful atbest, primarily because of the necessityfor intelligent intervention in the syn-thesis of the randomized RNA; thenagain in the selection of a few function-al RNA molecules out of that mixture;then, finally, in the amplification ofthose few functional RNA molecules[see box, pages 15-16, “What Do Ri-bozyme Engineering Experiments Re-ally Tell Us About the Origin of Life?”].

Hubert Yockey, borrowing a meta-phor from Jonathan Swift, suggests thatcurrent origin-of-life research, includ-ing the RNA World hypothesis, floatsimprobably in mid-air like the roof of ahouse built by an architect of the GrandAcademy of Lagado. This savant hadcontrived a method of building housesby beginning at the roof and workingdownwards. “The architect pointed outthat among the advantages of this pro-cedure,” Yockey notes8, “was that oncethe roof was in place [before the walls orfoundation] the rest of the constructioncould proceed quickly and without in-terruption by weather.” That “roof” —consisting in this instance of tiles whichrepresent the catalytic activities of RNA— may look solid to those believers inthe existence of a prebiotic RNA World.But is the roof really solid? Is it support-ed by walls and a foundation?

Once one peers over the edge of theroof to look beneath, we shall argue, theimplausibility of the theoretical struc-ture as a whole is inescapable. In whatfollows, we present the key postulatesor presuppositions on which the RNAWorld hypothesis must rest (see Figure2). Each represents an unsolved chemi-cal problem, in every case well-knownto origin-of-life researchers. Unfortu-nately, in many articles on the RNAWorld, these problems are often col-lapsed into the “prebiotic soup” and“self-assembly” phases of the scenario,and receive no discussion. We suggestthat new discoveries about the catalyticactivities of RNA should be seen forwhat they really are: not elucidatingprebiotic processes on the early Earth,

purine or pyrimidine, a sugar (ribose),and phosphate. It is highly unlikely thatany of the necessary subunits wouldhave accumulated in any more than traceamounts on the primitive Earth. Con-sider ribose. The proposed prebioticpathway leading to this sugar, the for-mose reaction, is especially problemat-ic9. If various nitrogenous substancesthought to have been present in theprimitive ocean are included in the reac-tion mixture, the reaction would notproceed. The nitrogenous substancesreact with formaldehyde, the intermedi-ates in the pathways to sugars, and withsugars themselves to form non-biolog-ical materials10. Furthermore, as Stan-ley Miller and his colleagues recentlyreported, “ribose and other sugars havesuprisingly short half-lives for decom-position at neutral pH, making it veryunlikely that sugars were available asprebiotic reagents.”11

Or consider adenine. Reaction path-ways proposed for the prebiotic synthe-sis of this building block start with HCNin alkaline (pH 9.2) solutions ofNH

4OH.12 These reactions give small

yields of adenine (e.g., 0.04%) and oth-er nitrogenous bases provided the HCNconcentration is greater than 0.01 M.However, the reaction mixtures containa great variety of nitrogenous substanc-es that would interfere with the formosereaction. Therefore, the conditions pro-posed for the prebiotic synthesis of pu-rines and pyrimidines are clearly in-compatible with those proposed for thesynthesis of ribose. Moreover, adenineis susceptible to deamination and ring-opening reactions (with half-lives ofabout 80 years and 200 years respec-tively at 37º C and neutral pH), makingits prebiotic accumulation highly im-

1. There was a prebiotic pool of beta-D-ribonucleotides.

2. Beta-D-ribonucleotides spontaneously form polymerslinked together by 3�,5�-phosphodiester linkages.

3. A polynucleotide of RNA, once formed, would havethe ability to replicate itself.

4. Self-replicating RNA molecules would have all thecatalytic activities necessary to sustain a ribo-or-ganism.

POSTULATE 1:There was a prebiotic pool ofbeta-D-ribonucleotides.

Table 1. Key Chemical Postulates of the RNA World Scenario


probable13. This makes it difficult to seehow any appreciable quantities of nu-cleosides and nucleotides could haveaccumulated on the primitive Earth. Ifthe key components of nucleotides (thecorrect purines and pyrimidines, ribose,and phosphate) were not present, thepossibility of obtaining a pool of thefour beta-D-ribonucleotides with cor-rect linkages would be remote indeed.

If this postulate, the first and mostcrucial assumption, is not valid, howev-er, then the entire hypothesis of an RNAWorld formed by natural processes be-comes meaningless.

Joyce and Orgel discuss candidly theproblems with this postulate14. They

note that nucleotides do not link unlessthere is some type of activation of thephosphate group. The only effectiveactivating groups for the nucleotidephosphate group (imidazolides, etc.),however, are those that are totally im-plausible in any prebiotic scenario. Inliving organisms today, adenosine-5'-triphosphate (ATP) is used for activa-tion of nucleoside phosphate groups, butATP would not be available for prebiot-ic syntheses. Joyce and Orgel note thepossible use of minerals for polymeriza-tion reactions, but then express theirdoubts about this possibility15:

Whenever a problem in prebiot-ic synthesis seems intractable, itis possible to postulate the exist-ence of a mineral that catalyzesthe reaction...such claims can-not easily be refuted.

In other words, if one postulates anunknown mineral catalyst that is notreadily testable, it is difficult to refutethe hypothesis.

Joyce and Orgel then note that ifthere were activation of the phosphate

vated nucleotides to a randomensemble of polynucleotide se-quences, a subset of which hadthe ability to replicate. It seemsto be implicit that such sequenc-es replicate themselves but, forwhatever reason, do not repli-cate unrelated neighbors.17

They refer to this as a component of“The Molecular Biologists Dream,” anddiscuss the difficulties inherent in sucha view. In order for a stable populationof self-replicating RNA molecules toarise — a prerequisite for further evolu-tion — the RNA molecules must be ableto replicate themselves with high fidel-

ity, or the sequence specificity whichmakes self-replication possible at allwill be lost. While “it is difficult to statewith certainty the minimum possiblesize of an RNA replicase ribozyme,”Joyce and Orgel note, it seems unlikelythat a structure with fewer than 40 nu-cleotides would be sufficient. Suppose,then, that “there is some 50-mer [RNAmolecule of 50 nucleotides length],”Joyce and Orgel speculate, that “repli-cates with 90% fidelity. ... Would sucha molecule be expected to occur withina population of random RNAs?”

Perhaps: but one such self-replicat-ing molecule will not suffice.

“Unless the molecule can literallycopy itself,” Joyce and Orgel note, “thatis, act simultaneously as both templateand catalyst, it must encounter anothercopy of itself that it can use as a tem-

group, the primary polymer productwould have 5', 5'-pyrophosphate link-ages; secondarily 2', 5'-phosphodiesterlinkages — while the desired 3',5'-phos-phodiester linkages would be much lessabundant. However, all RNA knowntoday has only 3',5'-phosphodiester link-ages, and any other linkages would alterthe three-dimensional structure and pos-sibilities for function as a template or acatalyst.

Even waiving these obstacles, andallowing for minute amounts of oligor-ibonucleotides, these molecules wouldhave been rendered ineffective at vari-ous stages in their growth by addingincorrect nucle-otides, or by re-acting with themyriads of othersubstances like-ly to have beenpresent. More-over, the RNAmolecules wouldhave been con-tinuously de-graded by spon-taneous hydroly-sis and other de-structive pro-cesses operatingon the primitiveEarth16.

In brief, anymovement in the direction of an RNAWorld on a realistically-modeled earlyEarth would have been continuouslysuppressed by destructive cross-reac-tions.

The difficulty with this postulate isevident in the following quotation

from Joyce and Orgel:

...it is assumed...that a magic cat-alyst existed to convert the acti-

Figure 2. A dinucleotide of two adenines, showing adenine, thesugar D-ribose, and phosphoric acid.

POSTULATE 2:Beta-D-ribonucleotidesspontaneously form polymerslinked together by 3', 5'-phosphodiester linkages (i.e.,they link to form molecules ofRNA; see Figure 2).

POSTULATE 3:A polyribonucleotide (i.e., RNAmolecule), once formed, wouldhave the catalytic activity toreplicate itself, and a populationof such self-replicatingmolecules could arise.


plate.” Copying any given RNA in itsvicinity will lead to an error catastro-phe, as the population of RNAs willdecay into a collection of random se-quences. But to find another copy ofitself, the self-replicating RNA wouldneed (Joyce and Orgel calculate) a li-brary of RNA that “far exceeds the massof the earth.”18

In the face of these difficulties, theyadvise, one must reject

the myth of a self-replicatingRNA molecule that arose de novofrom a soup of random polynu-cleotides. Not only is such a no-tion unrealistic in light of ourcurrent understanding of prebi-otic chemistry, but it shouldstrain the credulity of even anoptimist’s view of RNA’s cata-lytic potential. If you doubt this,ask yourself whether you believethat a replicase ribozyme wouldarise in a solution containingnucleoside 5'-diphosphates andpolynucleotide phosphorylase!19

S.A. Benner et al. note20:

...one is forced to conclude thatthe last ribo-organism had a rel-atively complex metabolism thatincluded oxidation and reduc-tion reactions, aldol and Claisoncondensations, transmethyla-tions, porphyrin biosynthesis,and an energy metabolism basedon nucleoside phosphates, allcatalyzed by riboenzymes...Itshould be noted that this recon-struction cannot be weakenedwithout losing much of the log-ical and explanatory force of theRNA World model.

Although Benner et al. speak of thelast “ribo-organism,” surely the firstribo-organism would have required near-ly all of the same metabolic capabilities

in order to survive. It is also apparentthat the scenario of Benner et al. wouldsurely include enclosing the ribozymeswithin a membrane with the ability totransport ions and organic moleculesacross that membrane.

Anyone who is familiar with bio-chemistry would recognize that it wouldtake hundreds of different ribozymes,each with a particular catalytic activity,to carry out the metabolic processesdescribed above. It should also be ap-parent that most of these metabolic ca-pabilities would have to be functionalwithin a short period of time (certainlynot hundreds of years), in the samemicroscopic region, or the ribo-organ-ism would never survive.

When one recognizes that catalyticactivities of RNA are just as dependentupon specific sequences of nucleotidesin RNA21 as protein enzymes are ofamino acid sequences, then the proba-bility of postulate 4 being valid is seento be vanishingly small.

Benner et al. note that the diversecatalytic properties of enzymes oftenrequire coenzymes or prosthetic groups.They mention particularly the iron-por-phyrin, heme, and pyridoxal, but haveno suggestion how these (and other co-enzymes) could have functioned in thecatalytic activities of early RNA mole-cules.

The other unproven assumption ofpostulate 4 is that RNA molecules ini-tially had all of these suggested catalyt-ic activities, but nearly all of these activ-ities have been subsequently lost. RNAmolecules with catalytic activity thatare known today predominantly havenuclease or nucleotidyl transferase ac-tivity with some minimal esterase acti-tivy22. There is no solid evidence thatRNA molecules ever had the broad rangeof catalytic activities suggested by Ben-ner et al., even though a number of theauthors of The RNA World speak ofpresent-day RNA molecules as beingvestiges of that early RNA World.

CONCLUSION

We have more to learn about RNA,both in vivo (as used by organisms) andin vitro, in terms of its chemistry gener-

ally and functional properties in partic-ular. RNA is a remarkable molecule.

The RNA World hypothesis is an-other matter. We see no grounds forconsidering it established, or even prom-ising, except perhaps on the objection-able philosophical grounds of philo-sophical naturalism (and its operationaloffspring, methodological naturalism),according to which the best naturalistichypothesis is perforce the hypothesis tobe accepted. We consider that historicalbiology should be open to all empiricalpossibilities, including design — andsee the molecular biological system oforganisms, of which RNA is so stun-ning a part, as exemplars of design.

We find ourselves, however, dis-tinctly in the minority of biologists. Ifdesign exists at all, it is a matter ofsubjective intuition, the majority of ourcolleagues would claim, asserting withscience writer George Johnson that “thepoint of science is...to explain the worldthrough natural law.”23

We would put the point rather dif-ferently. The point of science is to ex-plain the world, through natural laws orwhatever other causes best account forthe phenomena at hand.

Philosopher of science StephenMeyer captures the point well:

The (historical) question thatmust be asked about biologicalorigins is not “Which material-istic scenario will prove ade-quate?” but “How did life as weknow it actually arise on earth?”Since one of the logically appro-priate answers to this latter ques-tion is that “Life was designedby an intelligent agent that exist-ed before the advent of humans,”I believe it is anti-intellectual toexclude the “design hypothesis”without consideration of all theevidence, including the mostcurrent evidence, that would sup-port it.24

Detecting design is not a matter ofsubjective intuition.25 To see design as areal causal possibility, however, onemust break free of the constraints ofnaturalism. o

POSTULATE 4:Self-replicating RNA moleculeswould have all of the catalyticactivities necessary to sustain aribo-organism.


DARWINISM ONTRIALVideo Study Guide

Darwinism on TrialLecture at UC Irvine

Book � Video

Video Study Guide

See page 31 for ordering information

Excellent study series coveringProfessor Phillip Johnson�s 1992lecture at UC Irvine. In his lecture,Professor Johnson explains howambiguous terminology, faultyassumptions, and questionablerules for reasoning have trans-formed a scientific theory whichexplains minor evolutionarychange into a dogmatic naturalis-tic religion.

Study guide features teachingresources, video transcript, andoverhead masters. An outstandingresearch aid for both teachers andstudents.

Now Available:NOTES

1. Carl Woese, The Genetic Code (New York:Harper and Row, 1967).

2. F.H.C. Crick, “The origin of the geneticcode,” J. Mol. Biol. 38 (1968): 367-379; L.E.Orgel, “Evolution of the genetic apparatus,” J.Mol. Biol. 38 (1968): 381-393.

3. K. Kruger, P.J. Grabowski, A.J. Zaug, J.Sands, D.E. Gottschling, and T.R. Cech, “Self-Splicing RNA: Autoexcision and Autocycliza-tion of the Ribosomal RNA Intervening Se-quence of Tetrahymena,” Cell 31 (1982): 147-157.

4. Walter Gilbert, “The RNA World,” Nature319 (1986): 618.

5. I. Hirao and A.D. Ellington, “Re-creatingthe RNA World,” Current Biology 5 (1995):1017-1022; p. 1017.

6. Mullis, K.B. and Faloona, “Specific syn-thesis of DNA in vitro via a polymerase cata-lyzed chain reaction,” Methods Enzymol 155(1987): 335-350.

7. G. Joyce, “RNA evolution and the originsof life,” Nature 338 (1989): 217-224; T.J. Gib-son and A.I. Lamond, “Metabolic complexityin the RNA World and implications for theorigin of protein synthesis,” J. Mol. Evol. 30(1990): 7-15; G.F. Joyce and L.E. Orgel, “Pros-pects for understanding the origin of the RNAWorld,” in The RNA World, eds. R.F. Gestelandand J.F. Atkins (Cold Spring Harbor, NY: ColdSpring Harbor Laboratory Press, 1993), pp. 1-25.

8. H.P. Yockey, “Information in bits andbytes: reply to Lifson’s Review of InformationTheory and Molecular Biology,” BioEssays 17(1995): 85-88; p. 87.

9. R. Shapiro, “The improbability of prebiot-ic nucleic acid synthesis,” Origins of Life 14(1984): 565-570; R. Shapiro, “Prebiotic ribosesynthesis: a critical analysis,” Origins of Life18 (1988): 71-85.

10. Recently it has been shown that reactionmixtures containing dilute glycoaldehyde phos-phate and formaldehyde or glyceraldehyde-2-phophate will generate reasonably high yieldsof ribose 2,4-diphosphate and a few other sugarphosphates in less amounts. See D. Muller, S.Pitsch, A. Kittaka, E. Wagner, C.E. Wintner,and A. Eschenmoser, “Chemie von alpha-ami-nonitrilen. Aldomerisierung von glykoaldehy-dphosphat zu racemischen hexose-2,4,6-triph-osphaten und (in gegenwart von formaldehyd)racemischen pentose 2,4-diphophaten:rac.allose-2,4,6-triphosphat und rac.-ribose-2,4,-diphosphat sind die reaktionshauptpro-duckte. Helv. Chim. Acta 73 (1990): 1410-1468; Joyce and Orgel, ibid. However, if thesereactions are not also run in the presence ofamines and other nitrogenous compounds (i.e.,in chemical mixtures of the complexity pro-posed for the “prebiotic soup”), their relevancyto the origin of life is problematical.

11. Rosa Larralde, Michael P. Robertson,

Study Kit, includes Video (V002), Book(B001), and Study guide (B010)

Item #V002SK $39.95

and Stanley L. Miller, “Rates of decompositionof ribose and other sugars: Implications forchemical evolution,” Proc. Natl. Acad. Sci.USA 92 (1995): 8158-8160. The ribose half-lives are very short, Larralde et al. report: 73minutes at pH 7.0 and 100º C and 44 years at pH7.0 and Oº C.

12. J.P. Ferris, P.C. Joshi, E.H. Edelson, andJ.G. Lawless, “HCN: a plausible source ofpurines, pyrimidines and amino acids on theprimitive Earth,” J. Mol. Evol. 11 (1978): 293-311.

13. R. Shapiro, “The prebiotic role of ade-nine: a critical analysis,” Origins of Life and theEvolution of the Biosphere 25 (1995): 83-98.

14. Joyce and Orgel, ibid.

15. Ibid., p.4

16. C. Thaxton, W. Bradley, and R. Olsen,The Mystery of Life’s Origin (New York: Philo-sophical Library, 1984).

17. Joyce and Orgel, ibid., p.7.

18. Ibid., p.11.

19. Ibid, p.13.

20. S.A. Benner, M.A. Cohen, G.H. Gonnet,D.B. Berkowitz, and K.P. Johnsson, “Readingthe Palimpest: Contemporary Biochemical Data

and the RNA World,” in The RNA World, eds.R.F. Gesteland and J.F. Atkins (Cold SpringHarbor, NY: Cold Spring Harbor LaboratoryPress, 1993), pp. 27-70; p. 57.

21. T.R. Cech, “Mechanism and Structure ofa Catalytic RNA Molecule,” in 40 Years of theDouble Helix, The Robert A. Welch Founda-tion 37th Conference on Chemical Research,1993, pp. 91-110; see also T.R. Cech, “Struc-ture and Mechanism of the Large CatalyticRNAs: Group I and Group II Introns and Ribo-nuclease P,” in The RNA World, eds. R.F.Gesteland and J.F. Atkins (Cold Spring Harbor,NY: Cold Spring Harbor Laboratory Press,1993), pp. 239-269.

22. Ibid.

23. George Johnson, Fire in the Mind: Sci-ence, Faith, and the Search for Order (NewYork: Alfred A. Knopf, 1995), p. 314.

24. Stephen C. Meyer, “Laws, Causes, andFacts,” in Darwinism: Science or Philosophy,eds. J. Buell and V. Hearn (Richardson, Texas:Foundation for Thought and Ethics, 1994),p.34.

25. See William A. Dembski, “The DesignInference: Eliminating Chance Through SmallProbabilities,” unpublished Ph.D. dissertation,1995, Department of Philosophy, University ofIllinois-Chicago Circle.


a recent ribozyme engineering experiment4) accumulate onthe early earth? How, for that matter, did any RNA accumu-late?

Here an analogy may be helpful. Suppose you learn abouta blackjack player who routinely beats the casinos in LasVegas. You would not be impressed to find that the casinoshad inexplicably made an exception for this person. Theyallowed him to fill parking lots, stadiums, and indeed the opendesert around Las Vegas with millions of dealers who eachdealt thousands of hands. The player monitored these millionsof dealers electronically. Whenever a good hand turned up, hewould play that hand, and ignore all the others.

Is that winning at blackjack? Not at all. The player con-trives to “win” only by violating the actual rules of the game.In the case of prebiotic chemistry, the actual rules of the gamegovern the formation of RNA molecules without the help ofbiochemists. And, according to those rules (see discussion ofpostulates 1-4, main text, and below), RNA does not arisefrom its chemical constituents except (a) in organisms, and (b)in laboratories where intelligent organisms synthesize it.

The “randomization” and “selection” steps in ribozymeengineering, therefore, have no realistic prebiotic analogues.Ribozyme engineering, where RNA is necessarily synthe-sized by intelligent agents is, truly, engineering — in the full,“intelligent design required” sense of that term.

Nothing conveys this better than reading the Methodsand Materials section of any ribozyme engineeringpaper. There, one will encounter biologically-derived

reagents such as DNA and RNA polymerases, automatedDNA synthesizing machines — e.g., the Biosearch 8750programmable DNA synthesizer5 — purified ribonucleosidetriphosphates, and various experimental tricks needed to helpreactions along. In one notable experiment, for instance, doneby RNA World researchers David Bartel and Jack Szostak, itwas found that the pools of randomized RNA precipitated —that is, formed large, tangled, useless networks of molecules:

Incubation of the pool RNA...led to rapid and extensiveaggregation; more than half of the pool RNA precipitatedwhen incubated for 90 minutes at 37º C in high concentra-tions of Mg2+ and monovalent ions...and precipitation waseven more rapid at higher temperatures. It appears thatconditions that favor RNA intramolecular structure alsostabilize intermolecular interactions; as molecules findregions of complementarity with more than one othermolecule, RNA networks form and eventually become toolarge to remain in solution.6

How to solve the problem? Tie the RNA molecules downto something:

Are biochemists now routinely recreating the RNAWorld in vitro, and discovering the ease with whichfunctional sequences arise from random pools of nu-

cleotides? Many commentators appear to endorse this view.Ichiro Hirao and Andrew Ellington, for instance, two RNAWorld researchers at Indiana University, write:

The intersection of the discovery of ribozymes with thedevelopment of techniques for nucleic acid amplificationallowed models of molecular evolution to be recapitulatedin a test tube.1

On this view, in vitro ribozyme engineering provides a plau-sible and realistic model or experimental recapitulation ofactual prebiotic processes. Thus, “selection” from “randompools of RNA sequences” in ribozyme engineering experi-ments is held to be strongly analogous to critical prebioticconditions that led to RNA-based organisms. Ekland et al., forinstance, argue that in vitro selection of novel ribozymessuggests

that even the most complex natural ribozymes, such asribonuclease P and the group I and II self-splicing intronscould have arisen in one step from long random sequences,and that complex ribozymes may have played an importantrole early in the RNA World.2

But are these experiments genuinely relevant to the prebioticproblems to be solved? We argue that they are not. In vitroRNA selection does not demonstrate that complex ribozymescould have arisen naturally in a prebiotic soup, because the invitro experimental conditions are wholly unrealistic, revealingat every turn the fingerprints of intervening intelligence. RNAWorld researchers have taken their own engineering of ri-bozymes as analogous to plausible prebiotic processes, whenin fact the two situations are profoundly different. Indeed,aspects of ribozyme engineering, together with other lines ofevidence, support a very different view of biological originsfrom that advocated by RNA World researchers.

Ribozyme engineering involves two broad experimentalstrategies.3 The “rational design” approach modifies existingtypes of ribozymes to produce better or even novel RNAcatalysts. The “irrational design” approach, on the other hand,uses pools of partially randomized RNA molecules, which arescreened — “selected” — for functional activity of a desiredsort. Those molecules catalyzing the desired reaction are thenused as the basis for the next round of “evolution.” Thisrandomization-selection process may be repeated several times,to yield increasingly faster RNA catalysts.

These experiments certainly add to our knowledge of RNAchemistry. A simple question directly illuminates the doubtfulrelevance of these experiments to prebiotic chemistry, howev-er. How did pools of 1015 RNA molecules (to cite a value from

What Do Ribozyme Engineering ExperimentsWhat Do Ribozyme Engineering ExperimentsWhat Do Ribozyme Engineering ExperimentsWhat Do Ribozyme Engineering ExperimentsWhat Do Ribozyme Engineering ExperimentsReally TReally TReally TReally TReally Tell Us About the Origin of Life?ell Us About the Origin of Life?ell Us About the Origin of Life?ell Us About the Origin of Life?ell Us About the Origin of Life?


To minimize the prob-lem of RNA aggrega-tion, we immobilizedthe pool of RNA mole-cules on agarosebeads before the ad-dition of Mg2+.7

A clever move —“once tethered to theagarose,” Bartel andSzostak report, “the poolmolecules could not dif-fuse and form intermo-lecular reactions, andcould therefore be safe-ly incubated”8 — butthis is not a trick the primordial soup would be likely todiscover on its own. And, on occasion, the prebiotic unrealityof ribozyme engineering breaks through even to its supporters.“It is difficult to believe,” writes RNA World researcherSteven Benner, of ETH Zurich, “that larger pools of randomRNA emerged spontaneously without the gentle coaxing of agraduate student desiring a completed dissertation.”9

Indeed, an important parallel exists between these proce-dures and prebiotic simulation (i.e., chemical evolution) ex-periments. As Thaxton et al. have pointed out, the degree ofinvestigator interference in chemical evolution experimentsincreases as the subject of the experiments gets closer to themolecular genetic system.10In experiments simulating the prim-itive atmosphere the interference is minimal. The apparatus isfilled with the starting gases, turned on, and left alone untilproducts are analyzed.

But in experiments designed to simulate the prebioticformation of biopolymers the investigator may use unrealisticreaction conditions (e.g., high concentrations of a few purereagents) and/or change the conditions during the experimentto enhance the yields of desired products. This intelligentmanipulation of the experimental conditions (to guide thereactions to the desired results) is most apparent in simulationsof prebiotic polynucleotide synthesis. The reason why increas-ingly large doses of investigator influence are required is thatif the chemical processes are “left to themselves” they wouldnot produce the desired result, in fact, would go away from theliving state, not toward it.

The continuity between the increasing role of investigatorinfluence in prebiotic simulation experiments and the recentuse of rational design and in vitro selection procedures toproduce novel ribozymes lends support, not to the naturalisticbut to the intelligent design view of biological origins. Thepowerful selection processes used in ribozyme engineering areof course unlikely to have occurred spontaneously (unassisted,without the input of intelligent design) on the prebiotic Earth.It will be argued that similar though much weaker selectiveprocesses must have occurred in the evolving RNA World.Over the hundreds of millions of years thought to have beenavailable, these chemical selective processes resulted in a richvariety of ribozymes (most of which have long since disap-

peared from even thesimplest organisms al-though a few survive ineukaryotes).

But it is very diffi-cult to see how the mereextension of time wouldrender a chemical evo-lution process moreprobable when everypresumed stage of theprocess (assuming itcould spontaneouslyadvance at all beyondits earliest stages) wouldhave been powerfully

hindered or suppressed by the natural chemical tendencies ofthe reacting substances and by the preponderance of destruc-tive forces in the natural environment.

We can see that research in one context (ribozyme engi-neering) with its particular presuppositions and goals in mindand with results presumably providing insights into one puta-tive process of origins has in fact provided powerful additionalevidence for a very different view. This has occurred preciselybecause the procedures used in research on RNA catalysisreinforce the notion that intelligent design is required toproduce molecular species that would not form due to thenatural chemical tendencies of the reacting substances them-selves, even over vast stretches of time.

– Gordon Mills and Dean Kenyon

NOTES

1. Ichiro Hirao and Andrew D. Ellington, “Re-creating the RNAWorld,” Current Biology 5 (1995): 1017-1022; p. 1017.

2. Eric H. Ekland, Jack W. Szostak, David P. Bartel, “StructurallyComplex and Highly Active RNA Ligases Derived from Random RNASequences,” Science 269 (1995): 364-370; p. 369.

3. R.R. Breaker and G.F. Joyce, “Inventing and improving ribozymefunction: rational design versus iterative selective methods,” Trends inBiochemistry 12 (1994): 268-275.

4. Ekland et al., p. 364.

5. Rachel Green and Jack W. Szostak, “Selection of a Ribozyme ThatFunctions as a Superior Template in a Self-Copying Reaction,” Science258 (1992): 1910-1915; p. 1914; see also Niles Lehman and Gerald F.Joyce, “Evolution in vitro: analysis of a lineage of ribozymes,” CurrentBiology 3 (1993): 723-734 (oligodeoxynucleotides “were prepared onan automated DNA synthesizer” [p. 732]).

6. David P. Bartel and Jack W. Szostak, “Isolation of New Ri-bozymes from a Large Pool of Random Sequences, “ Science 261(1993): 1411-1418; p. 1412.

7. Ibid.

8. Ibid.

9. Steven A. Benner, “Catalysis: Design Versus Selection,” Science261 (1993): 1402-1403; p. 1403.

10. Charles Thaxton, Walter Bradley, and Roger Olsen, The Mysteryof Life’s Origin (New York: Philosophical Library, 1984), pp. 99-112.

o

� The intelligent synthesis of RNA molecules, using biologically-derivedreagents (e.g., RNA polymerases)

� Experimental materials are artificially simplified sets of pure reagents(i.e., interfering substances likely to be present on the early Earth areexcluded)

� Products are shielded from destructive forces that would have acted onthe early Earth (such as heat, hydrolysis, UV radiation)

� RNA molecules are amplified using the polymerase chain reaction (PCR),a process with no realistic prebiotic analogue

Some Elements of the Prebiotic Unreality of Ribozyme


again, you may be looking down a blindalley, poised on the edge of chaos” (p.577).

WHEWELL ON GOD ANDKNOWLEDGE

Laura J. Snyder, “It’s All Necessarily So:William Whewell on Scientific Truth,”Studies in the History and Philosophy ofScience 25 (1994): 785-807.

Snyder (Philosophy, Johns Hopkins)takes up William Whewell’s “antitheti-cal” philosophy of science, so-called“for its attempt to combine seeminglyopposed empirical and a priori ele-ments” (p. 785). Whewell (1794-1866)was a mathematician, astronomer, andMaster of Trinity College, Cambridge,but is perhaps best known as among thefirst rank of English philosophers andhistorians of science in the mid 19thcentury. Snyder argues that one canmake sense of Whewell’s “antithetical”epistemology only by looking to itstheological foundation. “...without prop-erly understand-ing the role ofWhewell’s theol-ogy,” she notes,“it is impossibleto understand notonly Whewell’snotion of neces-sary truth, butalso his resolu-tion of the ulti-mate problem ofhis epistemolo-gy” (p. 795). Whewell anchored hisunderstanding of knowledge on God’sauthorship of the world. “On his view,”Snyder writes, “we are able to haveknowledge of the world because theFundamental Ideas which are used toorganize our sciences resemble the Ideasused by God in his creation of the phys-ical world.”

“The fact that this is so is no coinci-dence: God has created our minds suchthat ‘they can and must agree with theworld.’ God intends that we can haveknowledge of the physical world, and

LITERATURE SURVEYZEN BIOLOGY?

Jeffrey Levinton, “Life in the TangledLane,” a review of Stuart Kauffman, TheOrigins of Order, Evolution 49 (1995):575-577.

In this review of Kauffman’s mag-num opus, Levinton (Ecology and Evo-lution, SUNY Stony Brook) is cheerful-ly skeptical. “Kauffman’s model,” hewrites, “is at once pervasive, explainingeverything. But equally, it explains whywe may never be able to explain any-thing in particular, which makes it comepretty close to Zen” (p. 575). Levinton

argues thatwhile “verypowerful,”Kauffman’scentral theo-ry–the NKmodel ofrugged fit-ness land-s c a p e s – i svastly over-e x t e n d e d ,into “greatleaps” and“ s o a r i n gflights of ex-citing andp r o b a b l yfanciful dis-course” (p.576). Thedata neededto test Kauff-

man’s ideas, Levinton worries, are notat hand. “At the morphological level sofamiliar to organismal biologists,” hewrites, “we know essentially nothingabout the role of complexity, even if somany choose to write about the subjectat length. I suppose that this degree ofconfusion is why one can see promi-nently featured within the same jour-nals one-parameter-tells-it-all optimalmodels along side of some prosody tothe pervasiveness of contingency in evo-lutionary history. We are still in thedark, which leaves lots of room fornearly boundless assertion” (p. 577). InThe Origins of Order, Levinton con-cludes, “you may see the future. Then

this is possible only through the use ofIdeas which resemble those that wereused in creating theworld....the Divineorigin of both ourIdeas and our worldis what enablesWhewell to claimthat axioms know-able a priori fromthe meanings of ourIdeas are informa-tive about the em-pirical world, and nec-essarily true of it” (p. 796).

SULLIVAN VS. DAWKINS

Lucy G. Sullivan, “Myth, metaphor andhypothesis: how anthropomorphism de-feats science,” Phil. Trans. R. Soc. Lond.B 349 (1995): 215-218; and RichardDawkins, “Reply to Lucy Sullivan,” Phil.Trans. R. Soc. Lond. B. 349 (1995): 219-224.

A print debate between RichardDawkins and an Australian critic ofDawkins’s theory of the “selfish gene.”Ms. Sullivan, the critic, complains thatDawkins’s writings have led to “a pro-liferation of pseudo-theories, who claimon our attention lies more in the realm ofliterature than of science” (p. 215).Dawkins, for his part, argues that Sulli-van “unfortunately demonstrates thatshe has never read The Selfish Gene,never read Darwin,” and has misunder-stood what she has read, leading to a“complete, root and branch, catastroph-ic misunderstanding of Darwin’s cen-tral idea of natural selection” (p. 219).

THE FORCE OF PREDICTIONS

Stephen G. Brush, “Prediction and Theo-ry Evaluation in Physics and Astrono-my,” in No Truth Except in the Details,eds. A.J. Kox and D.M. Siegel (Dor-drecht: Kluwer Academic Publishers,1995), pp. 299-318.

Historian and philosopher of sci-ence Stephen Brush (University of


Maryland) has long been studying whathe terms “the dynamics of theory-changein science.” In this article, he presentsseveral case studies (e.g., the Big Bangvs. steady-state cosmology, the originof the Moon, gravitational light bend-ing, and Hannes Alven’s plasma phys-ics) to examine the impact of predic-tions on theory acceptance. Brush con-cludes that confirmed predictions pro-vide “corroboration” of a hypothesis,but only in the minimalist sense of sci-entists voting with their publications(so to speak). Corroboration “merelymakes it more reasonable to pursue thathypothesis than one that has not beencorroborated,” and thus “there was asignificant increase in pub-lications on the the-ory [i.e., those theo-ries in the case stud-ies] that led to theprediction” (p. 314).Brush also stresses,however, that “if one’sbasic assumptions andmethod are considered unacceptable byother scientists, no amount of empiricalconfirmation will force them to acceptit. I say this not as a criticism of thescientific community, but simply as afact about science which many philoso-phers of science ignore” (p. 307).

HALDANE AND RELIGION

Gordon McOuat and Mary P. Winsor,“J.B.S. Haldane’s Darwinism in its reli-gious context,” British Journal for theHistory of Science 28 (1995): 227-31.

English biologist and science writerJ.B.S. Haldane (1892-1964) was one ofthe founders of the neo-Darwinian syn-thesis.

This article describes how his role“as an opponent of orthodox religion”(p. 228) was central to Haldane’s de-fense of evolution in general, and natu-ral selection in particular. “Clearly,”McOuat and Winsor write, “Haldanebelieved that if could make natural se-lection more credible to his fellow biol-ogists, he would be striking a blow inthe war between science and religion.Haldane always loved a good fight” (p.231).

cytoskeletal structure can “illuminatethat most vexing and refractory of puz-zles–the nature and location of the ge-nomic instructions dictating the form ofcells, tissue, and, ultimately, organisms”(p. 5251). In this review, Penman (amember of the NationalAcademy of Sciencesand cell biologist atMIT) urges thatconventionalelectronic mi-croscopy hasmisled biologists,because it fails to reveal “mostof cells’ architectural components.” Thisis critical, Penman is persuaded, to un-derstanding the open questions sur-rounding the specification of biologicalform: “Form and structure are not natu-ral subjects for biochemistry that, in themacroscopic world, deals with scalarquantities–i.e., amounts, rates, etc.Building the complex designs glimpsedin any anatomy or physiology text re-quires, at the very least, instructionsthat are vectorial–i.e., that specify di-rection and place. These instructionsare encoded somewhere–it seems verylikely that they reside in the heavilytranscribed but “non-protein coding”DNA. Building staggeringly complexorgans–e.g., brains or kidneys–by sim-ply specifying the constituent proteincomponents (as suggested by the moreextreme formulations of molecular bi-ology that genes are simply proteins) is

unlikely. Such a strategywould be tantamount to try-

ing to specify a bridge oran edifice by merely giv-

ing a list of parts. Indeed,Gray’s Anatomy, seen with

an engineer’s eye, suggests thatthe complexity of the instruction setsfor mammalian morphology requirelarge regions of the genome: very likelymuch of most of the currently ignored,non-protein coding, 90% (or more) ofthe genome. I suspect that future cellscientists will marvel at the density andingenuity of genome instructions forstructure while wondering how we couldoverlook them for so long” (p. 5257).o

RECOGNIZING NEWTON

B.J.T. Dobbs, “Newton as Final Causeand First Mover,” Isis 85 (1994): 633-643.

Until her death in 1994, Betty Dobbswas Professor of History at the Univer-sity of California, Davis. In this lecture,she evaluates the distortions of scientif-ic histories, which may lead us to seethinkers of the past, such as Newton, inour own image. “...we unconsciouslyassume that their thought patterns werefundamentally just like ours. Then welook at them a little more closely anddiscover to our astonishment that our

intellectual ancestors arenot like us at all: theydo not see the fullimplications of theirown work; theyrefuse to believe

things that are now soobviously true; they

have metaphysical andreligious commitments that they shouldhave known were unnecessary for astudy of nature; horror of horrors, theytake seriously such misbegotten notionsas astrology, alchemy, magic, the musicof the spheres, divine providence, andsalvation history” (p. 640). Newton’ssystem, Dobbs argues, “was very quick-ly coopted by the very -isms he fought,and adjusted to suit them. He camedown to us as coopted, an Enlighten-ment figure without parallel whocould not possibly have beenconcerned with alchemy or-with establishing the exist-ence and providence of aprovidential God” (p. 643).

THE ARCHITECTURE OFCELLS

Sheldon Penman, “Rethinking cell struc-ture,” Proceedings of the National Acad-emy of Sciences USA 92 (1995): 5251-57.

While his ideas of a complex cellu-lar matrix are controversial (see, e.g.,Science 268 [1995]: 1564-65), SheldonPenman doesn’t apologize for them.Current cell biology is stuck on “solu-tion biochemistry,” he argues. Whenthe field awakens, however, it will turnto “cell architecture,” and realize that


George AyoubDepartment of BiologyWestmont CollegeSanta Barbara, CA 93108-1099

ABSTRACT: It has been commonlyclaimed that the vertebrate eye is func-tionally suboptimal, because photore-ceptors in the retina are oriented awayfrom incoming light. However, there areexcellent functional reasons for verte-brate photoreceptors to be oriented asthey are. Photoreceptor structure andfunction is maintained by a critical tis-sue, the retinal pigment epithelium(RPE), which recycles photopigments,removes spent outer segments of thephotoreceptors, provides an opaque lay-er to absorb excess light, and performsadditional functions. These aspects ofthe structure and function of the verte-brate eye have been ignored in evolu-tionary arguments about suboptimali-ty, yet they are essential for understand-ing how the eye works.

EditorialIntroduction: APopular Argument

It has been widely argued in boththe technical (Thwaites 1984,

Williams 1992) and popular evolu-tionary literature (Diamond 1985,Dawkins 1986, Miller 1994) thatthe vertebrate eye is poorly de-signed. “In fact it is stupidly de-signed,” writes the influential neo-Darwinian theorist George Will-iams, “because it embodies manyfunctionally arbitrary or maladap-tive features” (1992:73). Chiefamong these features, Williamsclaims (1992:72), is the inversion ofthe retina.

“The retina is upside down,” he

ANALYSIS AND PERSPECTIVE

On the Design of the Vertebrate Retina

writes. “The rods and cones are thebottom layer, and light reaches themonly after passing through the nervesand blood vessels.” These struc-tures, claims UCLA evolutionarybiologist Jared Diamond (1985:91)

aren’t located behind the photo-receptors, where any sensible en-gineer would have put them, butout in front of them, where theyscreen some of the incominglight. A camera designer whocommitted such a blunder wouldbe fired immediately.

The capstone of this argument isheld to be the cephalopod (squidand octopus) retina, which is puta-tively “wired correctly,” with its pho-toreceptors facing towards the light,and with its nerves “neatly tuckedaway behind the photoreceptor lay-er” (Miller 1994:30; see also Dia-mond 1985:91 and Williams1992:74). The cephalopods, it issaid, got it right.In considering this argument, wemay dispense immediately with op-timality comparisons between ceph-

Figure 1. Horizontal cross-section of a high vertebrate eye. A critical tissue omitted fromevolutionary discussions of the optimality of the retina is the retinal pigment epithelium(RPE); see Figure 2. (Figure redrawn from R. Adler and D. Farber, The Retina [NewYork: Academic Press, 1986], p.3)


alopod (invertebrate) and vertebrateretina designs. None of the authorscited above provides any evidencethat the cephalopod retina is func-tionally superior to the vertebrateretina: a claim that, in any case,seems unreasonable on its face.Would hundreds of thousands ofvertebrate species –in a great variety ofterrestrial, marine,and aerial environ-ments – really seebetter with a visualsystem used by ahandful of exclu-sively marine verte-brates? In the ab-sence of any rigor-ous comparative ev-idence, all claimsthat the cephalopodretina is functional-ly superior to the ver-tebrate retina remainentirely conjectural.In short, there is noreason to believethem.But we should con-sider a more basicpoint. Why refer tothe cephalopod reti-na at all? The claimthat the cephalapodsgot it right assumesthat the vertebratesdid not, and that thelatter are making thebest of a bad situa-tion – but, of course,it remains to be dem-onstrated that, infact, the vertebrateretina is suboptimal.

And this has notbeen demonstrated:not by the authors cited above, norby other evolutionary biologists.“One of the difficulties with thehypothesis of optimality,” note Farn-sworth and Niklas (1995:355), “isthe availability of observations totest it.” That goes as well for hypoth-eses of suboptimality, as exempli-fied by the evolutionary literatureon the vertebrate retina. The biolog-

ical world is full of puzzling sys-tems. While it is not readily appar-ent why vertebrate photoreceptorsface away from the light, nor whyother cell layers intervene, a goodmany things in science are not ap-parent at first glance. We need tolook more deeply.

In this case, we need not look far.There are excellent functional rea-sons for vertebrate photoreceptorsto be oriented as they are. Theseaspects of retinal structure and func-tion have been ignored in evolu-tionary arguments about subopti-mality, yet they are essential forunderstanding how the eye works.

– The editors

The Structure of theVertebrate Retina

First, some anatomy. Figure 1 depictsa vertebrate eye in cross section.

Light passes first through the cornea,the primary focussing element, thenthrough the iris, which controls how

much light will en-ter the eye, and last-ly, through the lens,which provides theadjustable focus-sing element. Thelight, now adjustedfor intensity, is fo-cused onto the thintissue lining theback of the eye: theretina.

The retina (seeFigure 2) comprisescells from the cen-tral nervous system(CNS), and convertsor transduces lightinto electrical sig-nals, the “medium”of the CNS. A high-ly complex tissue,the retina containscells of several dif-ferent types:

Photorecep-tors (the rodsand cones, la-belled as “R”and “C” in Fig.2) which actual-ly convert thelight energyinto an electri-cal signal.These are thefirst cells direct-ly involved in

communicating informationwithin the visual system, send-ing signals via a chemical syn-apse to:The Bipolar Cells (B in figure),the second order cells in the ret-ina; the bipolar cells synapseonto:The Ganglion Cells (G in fig-ure), at the inner surface of theretina; these cells have axons

Figure 2. The adult vertebrate retina. In this representation, light enters from thebottom of the diagram (i.e., at the vitreal border). The main cell types are rods(R), cones (C), horizontal cells (H), bipolar cells (B), amacrine cells (A), andganglion cells (G). At the top of the figure is the RPE. Its finger-like cellularprocesses interact with the photoreceptors. (Figure redrawn from R. Adler and D.Farber, The Retina [New York: Academic Press, 1986], p.5.)


which travel together from theeye, exiting via the optic disk,and forming the optic nerve enroute to the brain.The Amacrine Cells (A in fig-ure) mediate lateral interactions,transmitting information be-tween adjacent bipolar cells andganglion cells; and the horizon-tal cells (H in figure) which com-municate laterally in the outerretina.

Now observe the path of light inFigure 2. The light must pass firstthrough all the auxiliary cells beforearriving at the photoreceptors — whichat first glance hardly seems sensible. Ifthe design problem to be solved by anyeye is forming a maximally accurateimage of the world, then degrading thelight before it reaches the “businessend” of the photoreceptors seems self-evidently a poor solution. “This isequivalent to placing a thin diffusingscreen directly over the film in yourcamera; it can only degrade the qualityof the image” (Goldsmith 1990: 286).

And that is where evolutionary ac-counts leave the story.

The Critical Role of theRetinal PigmentedEpithelium (RPE)

But there is much more to be said.Lying directly behind the retina is

an epithelial tissue which maintains thephotoreceptors (see Fig. 2). This tissue,called the retinal pigmented epithelium(hereafter, RPE), is critical to the devel-opment and function of the retina. In-deed, volumes have been dedicated tounderstanding the role of the RPE (see,for instance, Steinberg 1985, Zinn andMarmor 1979), because when it mal-functions, the eye as a whole malfunc-tions.

1. Regenerating photoreceptive pig-ments

When light strikes a photoreceptor,it sets in motion a chain of molecularevents which eventually culminate informing an image in the brain. Here,

let’s focus on just the first characters inthe story.

The first player on stage is the pho-tosensitive molecule rhodopsin.Rhodopsin consists of a protein, opsin,and another molecule, 11-cis-retinal.Found at the distal ends of the photore-ceptors — the portion closest to theRPE, called the outer segment — rhodop-sin is embedded in membranous discs.[An important note about some poten-tially confusing terminology. The“business end” of the photoreceptorcell, where the membranous discs occur,is called the outer segment. In verte-brates, however, this segment is actual-ly inner, i.e., at the back of the retina,pointing in towards the center of theorganism.] When light strikes rhodop-sin, the energy changes the shape of itsmolecular component 11-cis-retinal,into an all-trans conformation, a processcalled isomerization. This conforma-tional change in retinal starts a complexcascade of reactions in several othermolecules, causing the hyperpolariza-tion (or shift in electrical charge) of theouter segment membrane. Moleculartransmitters then carry this electricalsignal from the synapse at the photore-ceptor’s base to the next neurons, thehorizontal cells and bipolar cells —thus beginning the process by which wesee.

This process depends critically onthe isomerization of 11- cis-retinal. Eachphoton of light striking a photoreceptorcan isomerize retinal, and since manybillions of photons constantly strikethe eye, retinal must be replaced regu-larly to maintain the cycle, and overallphotoreceptor function. That job of re-placement falls to the RPE. The RPEcells collect the used retinal from thephotoreceptors, and employ vitamin Ato make fresh retinal, transporting itback to the photoreceptors (Bridges1989; Hewitt and Adler 1994).

2. Recycling of photoreceptive mate-rial

Next on the list of RPE responsibil-ities is a related function: recycling theused outer segments. Outer segmentmembranes are very active, and thusmust be continually replaced.

Each day, new outer segment mem-brane grows at the base of the outersegment (where it intersects with theinner segment, the cell region contain-ing the nucleus), adding to the length ofthe photoreceptor. As the outer segmentlengthens from its base, its distal end —the oldest membrane — sheds in seg-ments. These segments are picked up bythe RPE, which phagocytizes the mate-rial, recycling all of the moleculespresent (Bok and Young 1979).

Thus, spent photoreceptive mem-branes are removed from the opticalpath, to be replaced by new material.This process, which goes on continual-ly, maintains the high sensitivity of thephotoreceptors (Bok 1994).

3. Absorption of excess light

In addition to these active functions, theRPE also has an important passive role. Be-cause it is heavily pigmented, it forms anopaque screen behind the optical path of thephotoreceptors.

It thus absorbs light which is notcollected by the photoreceptors, lightwhich would otherwise decrease theresolution of images. This absorptiveproperty of the RPE is important tomaintaining high visual acuity.

This brief summary does not ex-haust the functions of the RPE. Note, forinstance, that the RPE “is required forthe normal development of the eye”(Raymond and Jackson 1995), a func-tion that, while not directly related tovision, certainly undergirds the verypossibility of seeing at all. In short:

Considering the diverse func-tions of the RPE cells...there isno doubt that the integrity of theRPE metabolic machinery is es-sential for the normal function-ing of the outer retina. Becauseof the nature of these interac-tions, it is essential that the RPEand photoreceptors be in closeproximity for normal retinalfunction (Hewitt and Adler1994: 67).There are excellent reasons for ver-

tebrate photoreceptors to be oriented asthey are.


A Thought Experiment

But still: there sits a blind spot ineach retina. To be sure, the blind

spots are displaced laterally from eachother, so that “with both eyes open, wecan see everything in the visual field”(Williams 1992: 73), as one eye seeswhat the other does not. However, wecan imagine situations where thiswouldn’t work:

Our retinal blind spots rarelycause any difficulty, but rarelyis not the same as never. As Imomentarily cover one eye toward off an insect, an importantevent might be focused on theblind spot of the other (Williams1992: 73).

So, as a thought experiment, let’s fixthe blind spot. We will start by turningthe photoreceptors around, so their wir-ing isn’t in the way.

We have eliminated the blind spot,providing slightly better sight in oneportion of the eye. Now, however, theblood vessels and RPE, needed to main-tain the photoreceptors, must be locatedon the inner side of the retina, betweenit and the lens. This places a large cap-illary bed (containing many red bloodcells) and an epithelial tissue in the pathof the light, significantly degrading thevisual information passing to the pho-toreceptors.

Furthermore, since the photoreceptorscontinually shed material from their outersegments, dumping this opaque waste in thepath of the light would greatly diminish theamount of light reaching the photoreceptors.Our proposed change also reduces the qualityof the light, by refracting it with the opaquepieces of shed outer segment membrane.

We might imagine simply placingthe RPE at the back of the retina, but thisraises the problem of how to dispose ofspent outer segment membranes, so thatthe photoreceptors can be quickly re-generated. Or, perhaps, we could sur-round each photoreceptor cell by RPEcells, but this would need increase thespace between the photoreceptors, thusdecreasing the resolution of vision.

These design changes may force tem-poral or spatial decrements in vision.

Are these improvements? Hardly;indeed, our thought experiment has tak-en the vertebrate eye rapidly downhill.In trying to eliminate the blind spot, wehave generated a host of new and moresevere functional problems to solve.Our “repair” seems far worse than theapparent flaw we wanted to fix.

Conclusion

The vertebrate retina provides an ex-cellent example of functional —

though non-intuitive — design. Thedesign of the retina is responsible for itshigh acuity and sensitivity. It is simplyuntrue that the retina is demonstrablysuboptimal, nor is it easy to conceivehow it might be modified without sig-nificantly decreasing its function.

References

Bok, D. 1994. Retinal photoreceptor discshedding and pigment epithelium phago-cytosis. In S.J. Ryan, ed., Retina, 2nded., Volume 1: Basic Science & InheritedRetinal Disease (St. Louis: Mosby), pp.58-71.

Bok, D. and Young, R.W. 1979. PhagocyticProperties of the Retinal Pigment Epithe-lium. In The Retinal Pigment Epithelium,eds. K.M. Zinn and M.F. Marmor (Cam-bridge, MA: Harvard University Press),pp. 148-174.

Bridges, C.D.B. 1989. Distribution of retinalisomerase in vertebrate eyes and its emer-gence during retinal development. VisionResearch 12: 1711-1717.

Dawkins, R. 1986. The Blind Watchmaker.New York: W.W. Norton.

Diamond, J. 1985. Voyage of the OverloadedArk. Discover, June, pp. 82-92.

Farnsworth, K.D. and Niklas, K.J. 1995.Theories of optimization, form and func-tion in branching architecture of plants.Functional Ecology 9:355-363.

Goldsmith, T.H. 1990. Optimization, Con-straint, and History in the Evolution ofEyes. Quarterly Review of Biology 65:281-322.

Hewitt, A.T. and Adler, R. 1994. The retinalpigment epithelium and interphotorecep-tor matrix: Structure and specialized func-tions. In S.J. Ryan, ed., Retina, 2nd ed.,

Volume 1: Basic Science & InheritedRetinal Disease (St. Louis: Mosby), pp.58-71.

Miller, R.F. 1994. The physiology and mor-phology of the vertebrate retina. In S.J.Ryan, ed., Retina, 2nd ed., Volume 1:Basic Science & Inherited Retinal Dis-ease (St. Louis: Mosby), pp. 58-71.

Raymond, S.M. and Jackson, I.J. 1995. Theretinal pigment epithelium is required forthe maintenance of the mouse neuralretina. Current Biology 5: 1286-1295.

Steinberg, R.H. 1985. Interactions betweenthe retinal pigment epithelium and theneural retina. Documenta Opthalmolo-gia 60:327-346.

Thwaites, W. 1992. Design: Can we see thehand of evolution in the things it haswrought? In Evolutionists Confront Cre-ationists, Proceedings of the 63rd Annu-al Meeting of the Pacific Division, AAAS,Volume 1, part 3 (San Francisco: PacificDivision, AAAS), pp. 206-213.

Williams, G.C. 1992. Natural Selection: Do-mains, Levels, and Challenges. Oxford:Oxford University Press.

Zinn, K.M., and Marmor, M.F. 1979. TheRetinal Pigment Epithelium. Cambridge,MA: Harvard University Press.

See page 31 for orderinginformation

Report by Alabama TextbookCommittee MemberNorris AndersonItem # B020 $5.00

NorrisAnderson

Education orIndoctrination?Analysis ofScienceTextbooks inAlabama

Education orIndoctrination?

Analysis of Textbooksin Alabama

Just Released:Just Released:Just Released:Just Released:Just Released:

After a careful analysis of all the sciencetextbooks submitted to the textbook com-mittee in Alabama, the State approved theinsertion of a disclaimer in the beginning ofeach book explaining to the students, par-ents, and teachers that evolution is a theoryand should not be taught as fact. This re-port by Textbook Committee Member,Norris Anderson, carefully documents thenumerous problems with all the popularscience texts that prompted this action. Acopy of the textbook insert is included inthe appendix.


The Bulldog’s Life:Part I

Huxley: The Devil’s DiscipleAdrian DesmondLondon: Michael Joseph, 1994; 475 pp.

But even leaving Mr. Darwin’s viewsaside,” wrote Thomas Henry Hux-

ley in 1863, in Man’s Place in Nature,“the whole analogy of natural opera-tions furnishes so complete and crush-ing an argument against the interven-tion of any but what are termed second-ary causes, in the production of thephenomena of the universe; that, in theview of the intimate relations betweenMan and the rest of the living world; andbetween the forces exerted by the latterand all other forces, I can see no excusefor doubting that all are co-ordinatedterms of Nature’s great progression,from the formless to the formed–fromthe organic to the inorganic–from blindforce to conscious will and intellect.”

High Victorian prose, but the mes-sage is plain. Even if Darwin werewrong, argued Huxley, science ought tobe wholly naturalistic. Nothing but sec-ondary causes–natural laws–has actedin the history of “Nature’s great pro-gression.” Indeed, after digesting Adri-an Desmond’s fascinating and highlyreadable biography of Huxley, one canplausibly assert that while Huxley mayhave been Darwin’s disciple (a point onwhich Desmond provides some contra-dictory evidence), he was unquestion-ably, and foremost, an apostle of natu-ralism.

Thomas Henry Huxley was born in1825, above a butcher’s shop in Ealing,a village just to the west of London. Hisfather was a failed schoolmaster whomoved his family north to Coventry in1835, where he unsuccessfully ran asavings bank for the local artisans. Ap-prenticed to a Coventry doctor at 13,Huxley was largely self-taught, a pro-cess which continued after he went toLondon in 1841 to study medicine atCharing Cross Hospital. (As a profes-

sion, medicine in early Victorian En-gland had little or nothing of the scien-tific and social cachet it now possessesin the United States. It was a knock-about trade, whose practitioners wereoften social and intellectual radicals.)Perpetually in debt, Huxley kept a pun-ishing, self-imposed schedule of study,winning academic awards (e.g., the goldmedal for anatomy and physiology fromUniversity College) for his efforts–butlittle else.

Compelled by circumstances, Hux-ley joined Her Majesty’s Naval Servicein 1846, as an assistant surgeon, andwas assigned to the HMS Rattlesnake, asurveying ship ordered to “secure North-ern Australia for British settlement.” Inpractice, Huxley’s duties included col-lecting and dissecting marine specimens,and describing generally the flora andfauna the Rattlesnake would encounter.He made the best of the opportunity. Bythe time he returned to England in 1850,Huxley had published several papers onmarine invertebrates, and found him-

self with a reputation as an up-and-coming young naturalist. Yet his pro-fessional situation was essentially un-changed:

Still he was hungry. Still he seethedabout the lack of paid openings [forscientists]. Science should be a sal-aried meritocracy, not a dabblingground for the foppish aristocracy.‘I am sick of writing, weary of long-ing. The difficulties of obtaining adecent position in England...seemto me greater than ever they were.’It was a cri de coeur... ‘To attempt tolive by any scientific pursuit is afarce...A man of science may earngreat distinction–great reputation–but not bread. He will get invita-tions to all sorts of dinners & con-versaziones, but not enough incometo pay his cab hire’ (p. 161).

Huxley’s letters to his fiancee Net-tie during this period (1850-1855; sheremained where he had met her, in Aus-tralia, awaiting word that he was finan-

Reason in the Balance:The Case AgainstNaturalism in Science,Law, & EducationPhillip E. JohnsonInterVarsity Press, 1995245 pages, $19.95

According to Naturalism, God has no place in law, science, or the schools.Naturalistic thinking rules the intellectual world, including the public schools, theuniversities, and the elite of the legal profession.

But is naturalism itself beyond question? Few among the cultural elite have dareddoubt it. Now comes Phillip Johnson, Berkeley law professor and former clerk tothe U.S. Supreme Court, set to take on the “intellectual superstitions”of the day.

After this book, the culture wars may never be the same again.

To order see form on page 31, Item #B018

BOOK REVIEWS


cially secure) are a wrenching record ofhis struggle to make his chosen profes-sion of science pay for itself; which atlast suceeded in doing by obtaining aposition in 1855 as a lecturer in theGovernment School of Mines.

Other appointments followed, andfrom there on Huxley marched to thehead of the emerging professional classof “scientists,” crowned (Desmond ar-gues) by Huxley’s election to the Pres-idency of the British Association for theAdvancement of Science in 1870.

There Desmond ends his story, to becontinued in a second volume. Huxley,increasingly influential, lived for an-other quarter century (d. 1895), and anactive period it was. But one is gratefulfor the incomplete story Des-mond does tell.

It bears directly on currentcontroversies, and is filled withrich ironies of history.

In casting his support for Dar-win, for instance, Huxley actu-ally lent his pugilistic weightonly to the most general view ofevolution advanced by the re-cluse of Downe, while disagree-ing with Darwin on many im-portant details.

As Desmond repeatedlynotes, it was the underlying nat-uralism that really mattered toHuxley:

Huxley was exuberantly en-dorsing the naturalism of Dar-win’s vision, not the fine pointsof his theory. Nothing was saidof Darwin’s infinitesimal variations,each selected for its adaptive ad-vantage. Nor did Huxley mentionthat his own belief in large-scalemutations, his Ancon sheep [bredfor short legs], actually negatedthem. Or that the Home Countriesrabbits which happily overran theAustralian outback belied Darwin’svaunted adaptation. Then again,until spaniels and greyhounds re-fused to cross he considered Dar-win’s analogy between domesticbreeds and wild speciesincomplete....Huxley’s bravura per-

friends. His fossil papers left not theslightest hint that he was Darwin’sbulldog. In Edinburgh’s museum hehad found more labyrinthodontsmixed with the fish; that they weremistaken for one another shouldhave suggested something to Dar-win’s right-hand man. But no. Heused Anthracosaurus to show thatamphibians had passed through pro-digious periods unchanged. It wasthe greatest irony that those closestto Darwin could not give him thefossil back-up he needed... (p. 303)

As the English translator of the anti-Darwinian embryologist Karl Ernst vonBaer (1792-1876), Huxley had learnedto think of living things as falling intofundamentally distinct groups–“the ver-

tebrates, molluscs, starfish andinsects”–that could not be unit-ed in any sort of evolutionarychain, for “each [was] based ona unique archetypal plan” (p.191). Until quite late in hisfriendship with Darwin, thisvision of organisms persisted.As Desmond argues,

In fact Huxley did not think interms of origins at all. Geom-etry, not genealogy, fascinat-ed him: the surreal beauty ofnature’s secret architecture.Species were not to be ex-plained historically, by messymutations and supposed pro-gression. They had to be ap-preciated as abstract anatom-ical patterns....fish, reptiles,birds and mammals were allequidistant from the abstractvertebrate type. Molluscs hadtheir distinct sphere, as did

coelenterates. And with the spheresunconnected no trilobite could illic-itly jump the gap to call itself a fish(p. 223).

Desmond argues that it was the force-ful impact of Ernst Haeckel’s “phyloge-netic” system of classification that fi-nally converted Huxley, moving him“to connect his ancient lung-bearingCrossopterygian fish with the first lab-yrinthodont amphibians–in other words,to show how fish grew limbs and slith-ered out of the water” (p. 355). Hux-ley’s reasons for so doing are philo-

formance was in support of Dar-win’s evolutionary naturalism, notthe minutiae of his mechanism. Dar-win had created a new nature fornew professionals (p. 262).

Huxley’s dogged opposition to anyplace for theology (or teleological ex-planation) in science set him to arguingpositions which, from our post- Dar-winian perspective, we are more accus-tomed to seeing in the mouths of cre-ationists. If Robert Chambers’s anony-mously published Vestiges of the Natu-ral History of Creation was a theisticaccount of the progressive developmentof living things, then, as Huxley savage-ly reviewed the tenth edition of thebook, he would prove that organismschanged little over their fossil history,

in no particular direction. Stasis, notprogressive change, was the rule. In1862, Huxley’s address to the Geologi-cal Society

had nothing to do with Darwinism.Huxley did not try to trace newts andlungfish back to their common De-vonian ancestor. Instead of concen-trating on origins, he harped on thesharks’ and crocodiles’ long un-changing history. He could not shakehis ten-year-old belief that the fossilrecord showed no progress. ...Hux-ley’s claws risked maiming his

“Eohippus and Eohomo,” reproduction of a sketch by T.H.Huxley, drawn in 1876 at the Yale Peabody Museum during ameeting between Huxley and the American paleontologist O.C.Marsh.


sophically interesting. It was “more prof-itable to go wrong,” he argued (presum-ably, to go wrong means to connect asrelated by descent what are, in fact,unrelated forms), “than to stand still”–meaning, one supposes, to admit thatthe evolutionary puzzle at hand couldnot be solved by the available evidence.

But Huxley’s diffidence about natu-ral selection was lifelong. As he becamea central figure in British science, hescrupulously separated “evolution” from“Darwinism,” which he took to mean“natural selection.” As the historianJames Moore (co-author with Desmondof the recent biography Darwin) ob-serves,

Natural selection was of such littleconsequence that in a famous essaycelebrating “the coming of age ofthe Origin of Species,” Huxley couldomit even to allude to the theory.“The first thing seems to me to drivethe fact of evolution into people’sheads,” he excused himself to Dar-win; “when that is once safe, therest will come easy.”

Huxley “never fully subscribed” tonatural selection, Moore notes–“al-though he held that its nonteleologicalnaturalism represented ‘the fundamen-tal principles of a scientific conceptionof the universe.’”

That conception, and its careful pro-tection, was the prize Huxley saw worthstruggling for–and it is that intellectualheritage (now, of course, the generalpresumption of naturalism) in whichdebates about origins still occur. WhileHuxley viewed Comte’s positivism as asham religion–“Catholicism minusChristianity,” he dubbed it–he was in-deed a positivist (in our sense) in hisunderstanding of knowledge. But whatlabel should he wear?

What could he call himself? He wasshifting power to an elite whose au-thority rested in right reasoning, notmythical realities. He had alreadydropped the ‘Unknowable’ as thelast remnant of idolatry....he cameup with ‘Agnostic.’ It was anotherpitch for his professionals. Itswitched the emphasis to the scien-tific method and its sensual limita-

tions. Agnosticism was made for themoment....He could also lecture theclergy with clean hands. He por-trayed agnosticism not as a rival‘creed,’ but as a method of inquiry.The sciences, he told the YoungMen’s Christian Association, ‘areneither Christian, nor Unchristian,but are Extra-christian’, in a word,‘unsectarian’ (p. 374).

Nearly any official pronouncementfrom nearly any scientific society in ourday, on the topic of origins, will echothis theme. One must makes one’s peacewith naturalism, for it is the way ofscience (which is itself the way of knowl-edge). If theology has a place, Huxleyargued, it was in the “deeps of man’snature,” as a matter of subjective judg-ment. But any theology or philosophythat connected God directly to the ob-jects of nature had been vanquished, hethought:

...Genesis, the ‘old traditions’, theincarnations of god, Disraeli’s an-gels–‘theology’ in a word–that wasa debased branch of history, ame-nable to test, indeed tested and foundwanting. As such, science had no‘intention of signing a treaty of peacewith her old opponent, nor of beingcontent with anything short of abso-lute victory and uncontrolled domi-nation over the whole realm of theintellect’ (pp. 331-332).

And thus we come down to 1995,where debates are raging anew over thescope of naturalism. One wonders whatHuxley would make of them, a centuryafter his death. It is fairly certain hisremarks would be sharp and to the point–but perhaps, one hopes, on the side ofentertaining the possibility that natural-ism had failed to fulfill its grand prom-ise.

Desmond’s biography is well worthreading. It brims with affection for itsprickly subject, and his times, and throwsfresh light on the emergence of natural-ism as the prevailing philosophy of sci-ence in the 19th century, and in our ownday.

– P.A. Nelson

What Would Real LittleGreen Men Tell UsAbout Evolution–AndGod?

Are We Alone?Philosophical Implications of theDiscovery of ExtraterrestrialLife.Paul DaviesNew York: Basic Books, 1995;160 pp.

They need not belittle, of course,

nor green, nor, forthat matter, come inmore than one sex:indeed (with apolo-gies to most episodesof Star Trek), theyprobably wouldn’trecognizably be“men” at all. But extraterrestrial intelli-gent life would need to be intelligent–meaning, operationally, able to manip-ulate electromagnetic radiation to carrysignals.

“This is necessary,” argues PaulDavies in his new book Are We Alone?Philosophical Implications of the Dis-covery of Extraterrestrial Life (NewYork: Basic Books, 1995, 160 pp.), “be-cause radio contact with aliens is possi-ble only if the aliens are intelligentenough to possess the necessary tech-nology” (p. 89). Should that message bereceived by our radio telescopes, itseffect, Davies argues, could only bemomentous:

There is little doubt that even thediscovery of a single extraterrestri-al microbe, if it could be shown tohave evolved independently of lifeon Earth, would drastically alterour world view and change our so-ciety as profoundly as the Coperni-can and Darwinian revolutions. Itcould truly be described as the great-est scientific discovery of all time. Inthe more extreme case of the detec-tion of an alien message, the likelyeffects on mankind would be awe-some (p. xii).


The effect would be awesome,Davies continues, because in an impor-tant sense it would refute the Darwinianrevolution of the 19th century. In AreWe Alone?, Davies makes his case forthis conclusion. It’s a case with severalbyways and tangents, and skeptics ob-serve that the religious implicationsDavies wants to draw are weakly sup-ported by his case, a criticism whichilluminates the philosophical vaguenessof concepts such as “contingency,” “de-terminism,” “randomness,” “progress,”or its absence, all of which play keyroles in the positions Davies attacks,and in his own speculations.

Despite its tangents, however–orperhaps because of them!–Davies’ bookis well worth reading. As the first scien-tifically-trained winner of the Temple-ton Prize for advancements in religion(1995), Davies shows an acute and ad-mirable appreciation for the larger philo-sophical implications of origins theo-ries. Furthermore, he understands theshortcomings of conventional evolu-tionary explanations. Take, for instance,the origin of life:

The main reason why the origin oflife is such a puzzle is because thespontaneous appearance of suchelaborate and organized complexi-ty seems so improbable. In the pre-vious chapter I described the Mill-er-Urey experiment, which succeed-ed in generating some of the build-ing blocks of life. However, the levelof complexity of a real organism isenormously greater than that of mereamino acids. Furthermore, it is notjust a matter of degree. Simplyachieving a high level of complexityper se will not do. The complexityneeded involves certain specificchemical forms and reactions: arandom complex network of reac-tions is unlikely to yield life (p. 27).

This passage, which echoes the no-tion of specified complexity employedby design theorists (see, e.g., Thaxton etal., The Mystery of Life’s Origin [NewYork: Philosophical Library, 1984],131), is followed a few pages later by acareful analysis of the real probabilitybounds set by cosmology. In brief, inthe cosmic gamble for the origin of lifeone can spin the wheel (or reach into the

urn) only a finite number of times, be-cause the pool of opportunities is notinexhaustible:

Even if the universe is spatiallyinfinite, and contains an infinity ofgalaxies, we can only even see afinite subset of them. Therefore, iflife is a random accident of infini-tesimal probability, then it is almostcertain that there is no other lifewithin our particle horizon at thisepoch, even though (assuming theCopernican Principle) there may beinfinitely many inhabited planets inthe universe as a whole....We cannow see why, if the odds against therandom formation of life are so great,there is little to be gained by widen-ing the trial space from planet Earthto all Earth-like planets and thenappealing to the panspermia hypoth-esis. Because no object may travelfaster than light, no micro-organ-ism may reach Earth from beyondour particle horizon.

Hence the trials that are relevant tolife on Earth must be restricted tothe 1010 or so galaxies within theobservable portion of the universe.These galaxies may contain a totalof, say, 1019 Earth-like planets. Butfaced with odds of 1040,000 to 1against, multiplying the trial rate by1019 has a negligible effect on theoutcome (pp. 32-33).

These (and other) passages in AreWe Alone? make the book appealing todesign theorists looking for thinkingoutside the usual boundaries. But otherpassages, and in fact the main thrust ofthe book, will be disappointing.

Davies recognizes that a theory ofintelligent causation need not commitone to invoking “miracles,” meaningevents which transgress known regular-ities of nature; i.e., “design” does notipso facto violate any natural laws:

...We can contrive to produce high-ly non-random processes (such asunusual card sequences) withoutviolating any laws of physics, sopresumably a purposeful Deity couldalso do this.

Yet he immediately reverts to meth-odological naturalism:

Nevertheless, it is the job of thescientist to try to explain the worldwithout supernatural purposivemanipulation, and a number of sci-entific responses have been made tothe problem of the enormous oddsdiscussed above (p. 29).

The solution Davies favors?

The laws of physics have the re-markable property that they encour-age matter and energy to evolvespontaneously from simple intialstates towards highly complex states(such as living or conscious sys-tems). This general self-organizingtendency in nature suggests that theemergence of life is a universal phe-nomenon, rather than a miracle or ahighly improbable accident. ...Evi-dently stupid matter has a sort ofinnate ability to organize itself.There are many, many other exam-ples in nature....we can imagine avery long sequence of such self-or-ganizing steps in which inert mattergoes in at the top and mind comesout at the bottom. That is, if weaccept that mind is an emergentphenomenon requiring a certaincritical level of complexity, we canimagine that level of complexity be-ing achieved, given long enough,and given the inherent self-organiz-ing tendencies that we find in matterand energy (pp. 102-103).

Yet the examples of “emergent phe-nomena” that Davies offers are eitherirrelevant–the “wetness” of water, andthe arrow of time (his illustration of thelatter is molecules of perfume diffusingin a closed room)–or beg the question.

Davies says that life itself is an emer-gent phenomenon, arising “only whenmatter reaches a certain level of com-plexity” (p. 100). True enough, but call-ing a phenomenon “emergent” or “self-organizing” hardly engages the ques-tion of how the necessary level of com-plexity is reached. Life and conscious-ness emerge when the conditions areright, as they must be, argues Davies,but he fails entirely to specify thoseconditions, beyond arguing that some-


how they were built into the universefrom the start, as a “sort of ‘law ofincreasing organixed complexity’” (p.105).

Well, as the famous street-wise equa-tion tells us, ill-defined laws of thatvariety plus 65 cents = a cup of coffee.To say that life, intelligence, and con-sciousness are inevitable, never mindthe details, is not to solve the problem oftheir emergence, any more than sayingthat they are the accidental products ofa cosmic roulette (a view Davies strong-ly rejects).

Davies’ words have a high-sound-ing ring:

I conclude...that consciousness, farfrom being a trivial accident, is afundamental feature of the universe,a natural product of the outworkingof the laws of nature to which theyare connected in a deep and stillmysterious way. (p. 128)

It is unclear, however, aside fromtantalizing but vague adjectives like“deep” and “mysterious,” how this real-ly differs from Darwinism, either of theclassical variety or later fillips. StephenGould, for instance, argues that he fullyexpects intelligent life to exist else-where in the universe (see his interviewwith John Horgan, “Escaping in a Cloudof Ink,” Scientific American August1995, pp. 37-41). Writing in the NewYork Times (12 July 1995, p. B4), criticRichard Bernstein scratches his headabout significance of Davies’ dissent:

What remains elusive...is why this“cosmic connection” is contrary toDarwinian law. If random variationand natural selection produced con-sciousness on earth, why would thesame random variations not occurelsewhere in a universe with billionsof other planets? If it did occur else-where, one could believe in extra-terrerstrial life without ditching or-thodox Darwinian thought, and with-out recourse to a mystical, semi-religious concept that makes us feelconnected to something really big.

Thus, E.T., should he ever turn upwith his glowing finger, would appar-ently both refute and support Darwin-

ism. One must say “apparently,” for thekey terms in this dispute–contingency,determinism, and the like–are too ill-defined to rule out empirical possibili-ties. One wants a gutsier and more pre-cise metaphysics from Davies than heprovides.

– P.A. Nelson


Darwin’s Dangerous Idea: Evolu-tion and the Meanings of Life.Daniel C. DennettNew York: Simon & Schuster,1995; 586 pp.

Daniel Den-nett’s fertile

imagination iscaptivated by thevery dangerousidea that the neo-Darwinian theoryof biological evo-lution should be-come the basis forwhat amounts toan established state religion of scientif-ic materialism. Dennett takes the scien-tific part of his thesis from the innercircle of contemporary Darwinian theo-rists: William Hamilton, John MaynardSmith, George C. Williams, and thebrilliant popularizer Richard Dawkins.When Dennett describes the big ideaemanating from this circle as danger-ous, he does not mean that it is danger-ous only to religious fundamentalists.The persons whom he accuses of flinch-ing when faced with the full implica-tions of Darwinism are scientists andphilosophers of the highest standing:Noam Chomsky, Roger Penrose, JerryFodor, John Searle, and especiallyStephen Jay Gould.

UNIVERSAL ACID

Each one of these very secular think-ers supposedly tries, as the simple reli-gious folk do, to limit the all-embracing

logic of Darwinism. Dennett describesDarwinism as a “universal acid; it eatsthrough just about every traditional con-cept and leaves in its wake a revolution-ized world-view.” One thinker afteranother has tried unsuccessfully to findsome way to contain this universal acid,to protect something from its corrosivepower.

Why? First let’s see what the idea is.

Dennett begins the account with JohnLocke’s late seventeenth-century EssayConcerning Human Understanding,where Locke answers the question,“Which came first, mind or matter?”Locke’s answer was that mind had tocome first, because “it is impossible toconceive that ever bare incogitativematter should produce a thinking intel-ligent Being.” David Hume mountedsome powerful skeptical argumentsagainst this mind-first principle, but inthe end he couldn’t come up with a solidalternative.

Darwin did not set out to overturnthe mind-first picture of reality, but todo something much more modest: toexplain the origin of biological species,and the wonderful adaptations that en-able those species to survive and repro-duce in diverse ways.

WITHOUT THE AID OF MIND

The answer Darwin came up withwas that these adaptations, which hadseemed to be intelligently designed, areactually products of a mindless processcalled natural selection. Dennett saysthat what Darwin offered the world, inphilosophical terms, was “a scheme forcreating Design out of Chaos withoutthe aid of Mind.” When the Darwinianoutlook became accepted throughoutthe scientific world, the stage was setfor a much broader philosophical revo-lution. Dennett explains that

Darwin’s idea had been born as ananswer to questions in biology, butit threatened to leak out, offeringanswers–welcome or not–to ques-tions in cosmology (going in onedirection) and psychology (going inthe other direction). If [the cause ofdesign in biology] could be a mind-less, algorithmic process of evolu-


tion, why couldn’t that whole pro-cess itself be the product of evolu-tion, and so forth all the way down?And if mindless evolution could ac-count for the breathtakingly cleverartifacts of the biosphere, how couldthe products of our own “real” mindsbe exempt from an evolutionary ex-planation? Darwin’s idea thus alsothreatened to spread all the way up,dissolving the illusion of our ownauthorship, our own divine spark ofcreativity and understanding.

CRANES, NOT SKYHOOKS

The metaphysical reversal was socomplete that it soon became as un-thinkable within science to credit anybiological feature to a designer as it hadpreviously been unthinkable to do with-out the designer. Whenever seeminglyinsuperable problems were encoun-tered–the genetic mechanism, the hu-man mind, the ultimate origin of life–biologists were confident that a solutionof the Darwinian kind would be found.To be sure, the cause of materialistreductionism was sometimes set backby “greedy reductionists” like the be-haviorist B.F. Skinner, who tried to ex-plain human behavior as a direct conse-quence of material forces. The catchymetaphor Dennett employs to describethe difference between the greedy andgood kinds of reductionism is “cranes,not skyhooks.” The origin of (say) thehuman mind must be attributed to someprocess firmly anchored on the solidground of materialism and natural se-lection (a crane), and not to a mystery ormiracle (skyhook), but this does notmean that human behavior or mentalactivity can be understood directly onthe basis of material concepts like stim-ulus and response or natural selection.

Although many aspects of evolu-tionary theory remain controversial,Dennett asserts confidently that the over-all success of Darwinism-in-principlehas been so smashing that the basicprogram–all the way up and all the waydown–is established beyond question.And yet the resistance continues.

Some of it comes from religiouspeople, who want to preserve some rolefor a creator. Dennett just brushes asidethe outright creationists, but takes more

pains to refute those who would say thatGod is the author of the laws of nature,including that marvelous evolutionaryprocess that does all the designing. TheDarwinian alternative to a Lawgiver atthe beginning of the universe is to post-pone the beginning indefinitely by hy-pothesizing something like an eternalsystem of evolution at the level of uni-verses.

For example, the physicist Lee Smo-lin has proposed that black holes are ineffect the birthplaces of offspring uni-verses, in which the fundamental phys-ical constants would differ slightly fromthose in the parent universe. Since thoseuniverses that happened to have themost black holes would leave the most“offspring,” the basic Darwinian con-cepts of mutation and differential repro-duction could be extended to cosmolo-gy.

Dennett contends that whether thisor any other model is testable, at leastcosmic Darwinism relies on the samekind of thinking that has been success-ful in scientific fields like biology wheretesting is possible, and that is enough tomake it preferable to an alternative thatbrings in a skyhook. He does not at-tempt to explain the origin of the cosmicevolutionary process. It’s just mutatinguniverses all the way down.

RESISTANCE TO DARWINISM

Much of the resistance to Darwin-ism “all the way up” comes from scien-tists and philosophers who deny thecapacity of natural selection to producespecifically human mental qualities likethe capacity for language. Foremostamong these is Noam Chomsky, founderof modern linguistics, who describes acomplex language program seemingly“hard-wired” into the human brain,which has no real analogy in the animalworld and for which there is no veryplausible story of step-by-step evolu-tion through adaptive intermediateforms. Chomsky readily accepts evolu-tionary naturalism in principle, but (sup-ported by Stephen Jay Gould) he re-gards Darwinian selection as no morethan a place holder for a true explana-tion of the human language capacitywhich has not yet been found.

To true-believing Darwinists likeRichard Dawkins and Daniel Dennett,all such objections are fundamentallymisconceived. The more intricately “de-signed” a feature appears to be, themore certain it is to have been construct-ed by natural selection–because there isno alternative way of producing designwithout resorting to impossible sky-hooks. Even in the toughest cases, whereplausible Darwinian hypotheses are hardto imagine and impossible to confirm, aDarwinian solution simply has to be outthere waiting to be found. The alterna-tive to natural selection is either God orchance. The former is outside of sci-ence, and also apparently outside thecontemplation of Gould or Chomsky;the latter is no solution at all. Once youunderstand the dimensions of the prob-lem, and the philosophical constraintswithin which it must be solved, Darwin-ism is practically true by definition–regardless of the evidence.

I call this a very interesting situa-tion. Within science the Darwinian view-point clearly occupies the high ground,because nobody has come up with analternative for explaining Design thatdoes not invoke an unacceptable pre-existing Mind. (Dennett easily refutessuch hype-induced notions as that aphysics of self-organizing systems fromthe Santa Fe Institute is in the process ofreplacing Darwinism.) But the rulers ofthis impregnable citadel are worriedbecause not everybody believes that theircitadel is impregnable. They are trou-bled not only by polls showing that theAmerican public still overwhelminglyfavors some version of supernatural cre-ation, but also by the tendency of prom-inent scientists to accept Darwinism-in-principle, but to dispute the applicabil-ity of the theory to specific problems,usually the problems about which theyare best qualified to speak.

DARWINISM AS A CREATIONSTORY

Dennett thinks that the dissenterseither fail to understand the logic ofDarwinism or shrink from embracingits full metaphysical implications. I pre-fer another explanation: Darwinism is alot stronger as philosophy than it is asempirical science. If you aren’t willingto challenge the underlying premise of


scientific materialism, you are stuckwith Darwinism-in-principle as a cre-ation story until you find somethingbetter, and it doesn’t seem that there isanything better. Once you get past theuncontroversial examples of microevo-lution, however, such as finch beak vari-ations, peppered moth coloring, andselective breeding, all certainty dissolvesin speculation and controversy. Nobodyreally knows how life originated, wherethe animal phyla came from, or hownatural selection could have producedthe qualities of the human mind. Inge-nious hypothetical scenarios for the evo-lution of complex adaptations are pre-sented to the public virtually as fact, butskeptics within science derisively callthem “just-so” stories, because they canneither be tested experimentally norsupported by fossil histories.

Many scientists who swear fealty toDarwinism on philosophical groundsput it aside when they get down toscientific practice. A good example isNiles Eldredge, a paleontologist whocollaborated with Stephen Jay Gould inthe famous papers advocating that evo-lution proceeds by “punctuated equilib-ria,” meaning long changeless periodswhich are occasionally interrupted bythe abrupt appearance of new forms.

“Punk eek” was widely interpretedat first as an implied endorsement of amacromutational alternative to Darwin-ian gradualism, a misunderstanding thatled scornful Darwinists to dismiss theidea as “evolution by jerks,” but bothGould and Eldredge insisted that theunseen process of change was Darwin-ian. Eldredge in particular is so deter-mined to wash away the taint of heresythat he has taken to describing himselfas a “knee-jerk neo-Darwinian,” a labelthat seems both to protest too much andto imply a willingness to overlook dis-confirming evidence.

On the other hand, Eldredge rejectswhat he calls “ultra-Darwinism,” theposition of Dawkins and Dennett, ongrounds that obscurely imply rejectionof the very factor that makes Darwin’sidea dangerous, the claim that naturalselection has sufficient creative powerto account for design. For example, hewrites in his 1994 book ReinventingDarwin that ultra-Darwinians are guilty

of “physics envy” because they “seek totransform natural selection from a sim-ple form of record keeping...to a moredynamic, active force that molds andshapes organic form as time goes by.”Eldredge has no philosophical problemwith atheistic materialism; his ambiva-lence stems entirely from the embar-rassingly un-Darwinian fossil record,as described in this typical paragraph:

No wonder paleontologists shiedaway from evolution for so long. Itnever seems to happen. Assiduouscollecting up cliff faces yields zig-zags, minor oscillations, and the veryoccasional slight accumulation ofchange–over millions of years, at arate too slow to account for all theprodigious change that has occurredin evolutionary history. When we dosee the introduction of evolutionarynovelty, it usually shows up with abang, and often with no firm evi-dence that the fossils did not evolveelsewhere! Evolution cannot forev-er be going on somewhere else. Yetthat’s how the fossil record hasstruck many a forlorn paleontolo-gist looking to learn something aboutevolution.

Whatever is motivating Eldredge togive all that fervent lip-service to Dar-winism, it obviously is not anything hehas discovered as a paleontologist. Infact the real problem is understood byeveryone, although it has to be dis-cussed in guarded terms. What paleon-tologists fear is not the scientific conse-quences of disowning Darwinism butthe political consequences. They fear itmight lead to a takeover of governmentby religious fundamentalists who wouldshut off the funding.

There are paleontologists who aremore supportive of Darwinism than El-dredge, just as there are other eminentscientists who are more explicit in in-sisting that the neo-Darwinian varietyof evolution is valid only at the “micro”level. Regardless of the number or sta-tus of the skeptics, the usual scientificpractice is to retain a paradigm, howev-er shaky, until somebody provides abetter one. I will assume arguendo thatthis “best we’ve got” policy is justifi-able within science itself. The questionI want to pursue is whether non-scien-

tists have some legal, moral, or intellec-tual obligation to accept Darwinism asabsolutely true, especially when the the-ory is encountering so many difficultieswith the evidence. The issue comes upin many important contexts; here aretwo examples.

First, consider the situation of Chris-tian parents, not necessarily fundamen-talists, who suspect that the term “evo-lution” drips with atheistic implications.The whole point of Dennett’s thesis isthat the parents are dead right about theimplications, and that science educatorswho deny this are either misinformed orlying. Do parents then have a right toprotect their children from indoctrina-tion in atheism, and even to insist thatthe public schools include in the sciencecurriculum a fair review of the argu-ments against the atheistic claim thatunintelligent natural processes are ourtrue creator? Dennett cannot be ac-cused of avoiding the religious libertyissue, or of burying it in tactful circum-locutions. He proposes that theistic reli-gion should continue to exist only in“cultural zoos,” and he says this directlyto religious parents:

If you insist on teaching your chil-dren falsehoods— that the earth isflat, that “Man” is not a product ofevolution by natural selection—thenyou must expect, at the very least,that those of us who have freedom ofspeech will feel free to describe yourteachings as the spreading of false-hoods, and will attempt to demon-strate this to your children at ourearliest opportunity. Our future well-being–the well-being of all of us onthe planet–depends on the educa-tion of our descendants.

Of course it is not freedom of speechthat worries the parents, but the powerof atheistic materialists to use publiceducation for indoctrination, while ex-cluding any other view as “religion.” Ifyou want to know how such threatssound to Christian parents, try imagin-ing what would happen if some promi-nent Christian fundamentalist addressedsimilar language to Jewish parents.Would we think the Jewish parents un-reasonable if they interpreted “at thevery least” to imply that young childrenmay be forcibly removed from the homes


of recalcitrant parents, and that thosemetaphorical cultural zoos may one daybe enclosed by real barbed wire? Strongmeasures might seem justified if thewell-being of everyone on the planetdepends upon protecting children fromthe falsehoods their parents want to tellthem.

I will pass over the legal issues raisedby this program of forced religious con-version because the intellectual issuesare even more interesting. Granted thatDarwinism is the reigning paradigm inbiology, is there some rule in the aca-demic world which requires non-scien-tists to accept Darwinian principles whenthey write about, say, philosophy orethics? My Berkeley colleague JohnSearle thinks so. In the first chapter ofhis recent book on The Construction ofSocial Reality, Searle states that it isnecessary “to make some substantivepresuppositions about how the world isin fact in order that we can even pose thequestions we are trying to answer (abouthow other aspects of reality are sociallyconstructed).” According to Searle, “twofeatures of our conception of reality arenot up for grabs. They are not, so tospeak, optional for us as citizens of thelate twentieth and early twenty-first cen-tury.” The two compulsory theories arethat the world consists entirely of theentities that physicists call particles, andthat living systems (including humansand their minds) evolved by naturalselection.

SOCIALLY CONSTRUCTEDDOCTRINES

I think that Searle undermines hiswhole project by virtually ordering hisreaders not to notice that scientific ma-terialism and Darwinism are themselvessocially constructed doctrines ratherthan objective facts. Scientists assumematerialism because they define theirenterprise as a search for the best mate-rialist theories, and this culturally-driv-en methodological choice is not evenevidence, let alone proof, that the worldreally does consist only of particles. Asan explanation for design in biology,Darwinism is perfectly secure when it isregarded as a deduction from material-ism, but remarkably insecure when it issubjected to empirical testing.

Given that what we most respectabout science is its fidelity to the princi-ple that empirical testing is what reallymatters, why should philosophers allowscientists to tell them that they mustaccept assumptions that don’t pass theempirical test?

Searle is a particularly poignant ex-ample, because he is famous for defend-ing the independence of the mind againstthe onslaught of the materialist “strongAI” program, and also for defendingtraditional academic standards againstthe corrosive relativism of the fact/val-ue distinction. He is so skillful in argu-ment that he almost holds his own evenafter leaping gratuitously into a pool ofuniversal acid, but why accept the dis-advantage? Searle could seize the highground if he began by proposing thatany true metaphysical theory must ac-count for two essential truths whichmaterialism cannot accommodate: first,that mind is more than matter; and sec-ond, that such things as truth, beauty,and goodness really do exist even ifmost people do not know how to recog-nize them. Scientific materialists wouldanswer that they proved long ago, or aregoing to prove at some time in the fu-

ture, that materialism is true. They arebluffing.

DREAMS OF WORLDCONQUEST

Science is a wonderful thing in itsplace. Because science is so successfulin its own territory, however, scientistsand their allied philosophers sometimesget bemused by dreams of world con-quest. Paul Feyerabend put it best: “Sci-entists are not content with running theirown playpens in accordance with whatthey regard as the rules of the scientificmethod, they want to universalize thoserules, they want them to become part ofsociety at large, and they use everymeans at their disposal–argument, pro-paganda, pressure tactics, intimidation,lobbying–to achieve their aims.” Sam-uel Johnson gave the best answer to thisabsurd imperialism. “A cow is a verygood animal in the field; but we turn herout of a garden.”

– Phillip E. Johnson

First Published in The New Criteri-on for October 1995. Reprinted by per-mission.

Can Science Know the Mind of God?Lecture at Princeton UniversityApprox. 2 hoursItem V008 $19.95

“If we really want to know the mind of God,” PhillipJohnson asks his audience at Princeton University, “shouldwe not start by assuming that God has a mind? That behindthe world we live in, there’s not matter in mindless motion,not meaningless combinations of matter, not just genesstriving to produce more genes, but a mind, that the worldis the product of a mind. And if we want to understandhow human beings can be searchers after objective truth, isit not best to understand them as beings who are producedby a mind, who are created in the image of a mind, which is itselfa source of absolute truth – the source of objective truth?”

With truth, understanding, and reason in the balance, PhillipJohnson makes a persuasive case for the reality of the mind of Godarguing against the naive idea that all reality can be explained interms of purely physical and material causes. His lecture isthought-provoking. The questions and answers that follow reflectintellectual discourse at its best!

Can Science Knowthe Mind of God?

A New Video from Phillip Johnson:

Please use form onopposite page to order.


Please order by indicating item numbers below and returning completed form to:

Access Research Network, P.O. Box 38069,Colorado Springs, CO 80937-8069

name

address

city state zip

phone

item qty. cost

shipping

subtotal

totalenclosed

BooksBooksBooksBooksBooks • T T T T Tapes apes apes apes apes • Videos Videos Videos Videos Videos

Books

Darwin on TrialPhillip E. JohnsonIntervarsity Press, 1993, 195 pages Item# B001 10.95

Evolution as Dogma: The Establishment of NaturalismPhillip E. JohnsonHaughton Publishing, 1990, 37 pages Item# B002 3.95

Evolution: A Theory in CrisisMichael DentonAdler and Adler, 1986, 368 pages Item# B003 19.95

The Mystery of Life�s Origin: Reassesing Current TheoriesCharles B. Thaxton, Walter L. Bradley, and Roger L. OlsenLewis and Stanley (FTE), 1984, 228 pages Item# B004 15.95

Of Pandas and PeoplePercival Davis and Dean H. KenyonHaughton, 1993,189 pages, hardback Item# B005 19.95

The Natural Limits to Biological ChangeLayne P. Lester and Raymond G. BohlinProbe Ministries, 1984, 207 pages Item# B006 9.95

Teaching Science in a Climate of ControversyDavid Price, John L. Wiester, and Walter R. HearnAmerican Scientific Affiliation, 1993,paperback Item# B007 6.95

Trial and Error: The American Controversy over Creation and EvolutionEdward J. LarsonOxford University Press, 1989, 243 pages Item# B008 9.95

Bones of Contention: Controversies in the Search for Human OriginsRoger LewinSimon and Schuster, 1988, 348 pages Item# B009 10.95

Invitation to Conflict: A Retrospective Look at the California Science FrameworkMark Hartwig and Paul NelsonAccess Research Network, 1992, 43 pages Item# B010 4.95

The Creation Hypothesis: Scientific Evidence for an Intelligent DesignerJ. P. Moreland, EditorInterVarsity Press, 1994, 335 pages Item# B016 12.95

Darwinism: Science or Philosophy?Proceedings of SMU SymposiumJohn Buell, Virginia Hearn, eds.Foundation for Thought and Ethics, 1994, 227 pages Item# B017 37.50

Reason in the BalanceThe Case Against Naturalism in Science, Law, & EducationPhillip E. JohnsonInterVarsity Press, 1995, 245 pages Item# B018 19.95

Darwinism on Trial Video Study GuideAccess Research Network, 1995, 85 pages Item# B019 10.00

Education or Indoctrination?Analysis of Science Textbooks in AlabamaNorris AndersonAccess Research Network Network, 1996, 32 pages Item# B020 5.00

Audio Tapes

What is Evolution and Why Does It Matter?Professor Phillip E. Johnson, Dec. 1991 Item# C001 5.00

Darwin on Trial (2 tape set)Professor Phillip E. Johnson, Oct. 1992 Item# C002 10.00

Phillip Johnson Interview by Joseph Busey, SCPKBLF Talkshow, Aug. 1992 Item# C003 5.00

National Public Radio Debate; Phillip Johnson with Eugenie ScottNPR, Oct. 1993 Item# C004 5.00

Phillip Johnson and Eugenie Scott (2 tape set)Wisconsin Public Radio, Aug. 1992 Item# C005 10.00

Focal Point Lectureship, EV FreePhillip E. Johnson, Nov. 1992 Item# C006 15.00

Trinity Founders LecturesPhillip E. Johnson Item# C007 5.00

Video Tapes

Darwinism on Trial: Phillip Johnson at UC Irvine1992, 1 hr. 45 min. Item# V002 19.95

Darwinism on Trial Study KitIncludes: UC Irvine Video lecture (V002), Darwin on Trial book (B001), and Video Study Guide (B019)

Item# V002SK 39.95

Darwinism: Science or Philosophy: Phillip Johnson at UC Santa Barbara1993, approx. 2 hrs. Item# V003 19.95

Darwinism: Science or Naturalistic PhilosophyDebate at Stanford University with William Provine and Phillip Johnson1994, approx. 2 hrs. Item# V004 19.95

Focus on Darwinism: An Interview with Phillip E. Johnson1993, approx. 45 min. Item# V001 19.95

Focus on Darwinism: An Interview with Michael Denton1993, 40 minutes Item# V005 19.95

Focus on Darwinism: An Interview with Dean Kenyon1993, approx. 30 minutes Item# V006 19.95

Dean Kenyon: Focus on the Origin of Life1993, approx. 30 minutes Item# V007 19.95

Can Science Know the Mind of God?Lecture at Princeton University1996, approx. 2 hrs. Item# V008 19.95

Please enclose check or money order payable to ARN Books;Shipping: U.S. First Class: 2.00 per item, U.S. Next Day: 5.00 per item (10.00 min.),Foreign Surface: add 20% of total order, Foreign Air: add 35% of total order.

Full product descriptions and ordering information can also befound on the ARN web site: http://www.arn.org/arn see back cover for information on subscribing to Origins & Design

Name

Address

City State Zip

Phone

Access Research Network is a tax-exempt organization. All membership donations that exceed the fair market value of the servicesprovided are tax-deductible. Please make checks or money orders payable (in U.S. funds) to Access Research Network and mail to:

Access Research NetworkP.O. Box 38069

Colorado Springs, CO 80937-8069

Non-Profit Org.U.S. Postage

PAIDPermit No. 745

Colorado SpringsColorado

Origins & DesignAccess Research NetworkP.O. Box 38069Colorado Springs, CO 80937-8069

Address Correction RequestedReturn Postage Guaranteed

ACCESS RESEARCH NETWORK 1996

q Regular Subscriber: I would like a regular subscription to Origins & Design (4X/yr) for $15/year

q Foreign Subscriber: Add $10 per subscription:$25/year

q Donation: Enclosed is a tax-deductible donation in the amount of $ _______________________

TOTAL ENCLOSED (check or money order): ________________________

origins & design 17:1 - eddie olson · are we alone? philosophical implications of the...

Documents