Five hundred and twenty million years ago, in the Cambrian sea, there swam and crawled a bizarre array of animals. There was Opabinia, which carried on its head a veritable cluster of eyes, not to mention a huge anterior ‘sucker’. There was Anomalocaris, a swimming creature as large as a baby shark, equipped with two horrid grasping arms – jointed for all the world like those of a lobster – but with a body apparently as slick as a squid and weirdly flapped along its side. There were worms dusted with scales as dense as the down on a chick. Oddest of the oddities was Hallucigenia, a small, spindly, spiky thing, yet with tubular organs, and what may or may not have been a head. The Cambrian ocean swarmed with sea-going arthropods: jointed-legged animals, now familiar as lobsters and lice, beetles and bees, spiders and scorpions. Their original discoverer C.D. Walcott dubbed the commonest of these Cambrian beasts ‘lace crabs’: creatures as delicate and diaphanous as ostrich feathers, but crested in a way unlike any shrimp or woodlouse. And alongside this Marrella there were knobbly, prawn-like creatures and a dozen more puzzling or peculiar, like Sidneya inexpectans or Waptia. This was the world of the Burgess Shale, and all these creatures are known only from fossils preserved as subtle, silvery films laid out on slabs of dark shale.
Hallucigenia, Anomalocaris, Sidneya inexpectans – their Latin names alone betray the emotions of the original describers – for these animals were unexpected, anomalous hallucinations.
The Burgess Shale, and the insight its fossils provided into the early history of life, was made famous by Stephen Jay Gould in Wonderful Life (1989). Not that Gould himself first described any of these vanished animals: rather, he promulgated their importance to a world outside the hermetic palaeontological community – the Burgess Shale and its mysterious, extinct creatures were discovered in Western Canada as long ago as 1909. Simon Conway Morris was one of the scientists who did the hard work of interpreting the fossils. In the late Seventies and early Eighties he was noted for two things: at every symposium he presented some new oddity from among the ‘worms’ of the Burgess Shale; and he wore the most battered donkey jacket known to science. At that time there were reservations about the possibility of understanding such ancient and apparently peculiar fossils in relation to living animals, and Conway Morris pioneered the idea that the animals might include failed evolutionary experiments, designs that never prospered. I can recall the giggles that accompanied his revelation of Hallucigenia at a Christmas meeting of the Palaeontological Association – and he was the one who signalled its distinctiveness by christening it with that provocative name. Gould seized on the Burgess Shale as a demonstration that history might have been different if one, rather than another, animal had prospered. Who knows, had Hallucigenia been a fecund progenitor, maybe Man himself would never have arisen. And the design of these early animals was so original, so distinctive, that – he claimed – there were a larger number of fundamental designs in the Cambrian seas than there are living today (designs which might be called ‘phyla’ in the modern world): it was therefore possible to view life’s subsequent history as a loss of potential, a diminution in the variety of its architecture. It made a compelling story.
Something has happened since 1989, however. Conway Morris now treats Gould with contempt, even loathing. The best he allows him is a certain energy in his writings – or ‘perorations’, as he terms them. On Gould as evolutionist: ‘Again and again Gould has been seen to charge into battle … strangely immune to seemingly lethal lunges … he finally re-emerges … the dust and confusion die down. Gould announces to awestruck onlookers that our present understanding of evolutionary processes is dangerously deficient … We look beyond the exponent of doom and there standing in the sunlight is the edifice of evolutionary theory, little changed.’ (In the very next sentence, amusingly, we find Gould accused of blurring the ‘fine line between argument and rhetoric’.) What is astonishing now is that Gould himself treated Conway Morris (nearly always ‘Simon’) as the hero of Wonderful Life, as the most ‘brilliant’ and ‘original’ among the Cambridge scientists who described the Burgess Shale – a Nobel Prize was even mentioned. The way Conway Morris goes about biting the hand that once fed him would make a shoal of piranha seem decorous.
In The Crucible of Creation Conway Morris understands the significance of the Burgess Shale in a completely different way from Gould. The subtitle of Wonderful Life was ‘The Nature of History’, which makes it clear that, in the eyes of these two authors, the stakes are nothing less than the interpretation of the entire history of life. In the left corner, a representative of the fine, liberal Jewish intellectual tradition, from Cambridge (Mass): in the right corner (perhaps rather far to the right), of the Church and Cambridge (Cambs) establishment. So this is really a book about two professors fighting over one idea. Why, though, should a difference of opinion generate such heat on the part of Conway Morris? Here, the psychology of the protagonists becomes as important as the historical points at issue. For Gould’s interpretation in Wonderful Life was, at the time, also Conway Morris’s, as Gould so generously acknowledged. In truth, however, it was an interpretation that was already creaking.
What has happened over the last ten years is that the strange chimeras of the Burgess Shale – the ‘weird wonders’, as they were termed – became domesticated: they acquiesced more readily to interpretation. Theirs was a case comparable to the discovery of the platypus in Australia: an egg-laying mammal with a bill? Absurd. At first, biologists were sceptical of the existence of what subsequent research showed to be a primitive mammal. Eventually familiarity bred understanding, as it has with the Burgess animals. As Conway Morris now admits, he had interpreted Hallucigenia upside down: its strange tubular organs were not on its back – they were legs (another set was then discovered by Lars Ramsköld). Hallucigenia is now known to be related to the living velvet worm, Peripatus; not so much a hallucination as a puzzle to be solved. The same was true of Anomalocaris, which is now thought to be a primitive arthropod. Even Opabinia has been slotted into a reasonable evolutionary tree. So the Burgess animals were not new phyla, but fascinating glimpses into the early history of animals we know about – no less interesting, or odd, just more explicable. Conway Morris now fully accepts this view, and, like any reputable scientist, he is of course allowed to change his mind. What is peculiar about this book is that the casual reader, who knows nothing of the history of the research, would never guess from it that Conway Morris ever entertained views different from those he now holds. He has attempted to disown his past, and this in a book about ‘the nature of history’.
It is this selective amnesia which accounts for the passion of his disillusion with Gould, for Gould has preserved in the print of a bestseller ideas that Conway Morris (and indeed most of the scientific world) now repudiates. He is furious that his past misinterpretations have been so eloquently placed on record. He could have written an interesting account of paradigms shifting as the truth is approached. Instead, he has opted to obfuscate the past. One wonders how someone so pleasant, and even modest face to face, can so readily adopt such an olympian tone, spiked with such anger, once he takes up the pen. I thought at first that Conway Morris was merely forgetful, but as I read through the book with increasing amazement I realised that the exercise was as deliberate as it was detailed. The portrait of the past is doctored to serve the purpose of the present.
Conway Morris tries to achieve a compromise between the vernacular and the scholarly, by appending detailed, exhaustively referenced footnotes to a text which is variously humdrum or hubristic. The reader is continually pulled between text and footnotes, as between a pair of respectively naive and pedantic confidants seeking to monopolise your attention. The scholarship of the footnotes is excellent. As with a 19th-century Life of a Worthy, they are a bid for High Seriousness: had they been set in the same point size as the main text they would have taken up the major part of the book. It is also in the footnotes that the liveliest writing is to be found. Opinionated and sometimes outrageous, they frequently use the first person singular – the real Conway Morris. The only references omitted are any that might reveal his thinking in the Seventies and early Eighties. By contrast, the main text relies on an imperious ‘we’. The middle part of the book is a journey into the past in a hypothetical submersible (a time-travelling version of Jules Verne’s Nautilus), which gives the impression of having been written for some other purpose altogether. Gould’s original account of the animals was assuredly more riveting.
The Burgess Shale animals have now been supplemented by a range of new Cambrian discoveries – even earlier – from China and Greenland. It is clear that the Cambrian evolutionary ‘explosion’ went down to the very base of that time period. This suggests that there must have been a much extended period of ‘pre-explosive’ evolution and, as I write, this hunch has been confirmed by the discovery of tiny, Pre-Cambrian animal embryos in China.
Aside from the zoological interpretation of the animals, what, finally, is the difference between Gould and Conway Morris on ‘the nature of history’? Gould says that if history were rerun from the Cambrian, who is to say that the outcome might not have been different? The culling by extinction of one Burgess animal rather than another may have been a matter of chance, but might have a cascade of consequences – subsequent history could have taken another course. This is what is meant by ‘contingency’. Conway Morris says, contrariwise, that history would have been broadly similar whatever had been culled from the Cambrian – not identical, as if history were simply a deduction from the genome, but following a similar trajectory. He uses as an argument the observation, well known from palaeontology, that similar biological designs arise repeatedly in history in response to the demands of a life habit or habitat. The most familiar case is that of the tiger design, whereby sabre-toothed ‘cats’ arose on at least three occasions from unrelated ancestors. (There is not only more than one way to skin a cat – there is evidently more than one way to become a cat.) If one animal ancestor had not yielded the cat design, then another would have. This is not pure determinism, but the idea nonetheless retains a whiff of the Great Chain of Being. For mankind alone has access to transcendence. He does not say so in so many words, but one senses the pull of the divine in the Conway Morris version. The word ‘numinous’ appears in a footnote; how Richard Dawkins would shudder.
Do these differences in historical interpretation amount to anything more than the kinds of fiction which can be built around the idea that Hitler won the Second World War? What Gould called ‘re-running the tape of life’ is bound to be only notional – we can never actually do it. Is the whole debate no more than an intellectual party game? The answer is ‘no’, because important issues are involved, concerning the role of chance in history and the probability of consciousness ever arising.
Even if the radical reinterpretation of history that Gould purveyed proved unacceptable in its detail, many scientists accept that evolution has involved more than the endless fecundity of genes in perpetuating themselves. Consider the great extinction events. At the end of the Permian period (more than two hundred million years after the Burgess Shale), the variety of vertebrate life on land was horribly reduced – Lystro saurus and a few of its quadruped allies carried the genetic legacy that was to lead on to the Age of Dinosaurs and the Age of Mammals. The advantages at that time which secured the survival of one animal rather than another may have been largely to do with luck – the ability to store water, perhaps. There was no way of predicting these advantages in advance. It is hard to believe that had another, different animal taken Lystrosaurus’ place in the Permian, subsequent history would have been a simple replay. If a meteorite truly killed the dinosaurs 65 million years ago, this was not because dinosaurs were failures, but because another series of animals, including mammals, were gifted fortuitously with the art of survival. Just because, in an ecological sense, elephants are somewhat like herbivorous dinosaurs – or dolphins like ichthyosaurs – does not mean that the Age of Mammals is simply a furry duplication of the Age of Dinosaurs. The interaction between mammalian herbivore and mammalian carnivore has been as much a brain race as a brawn race. You cannot simply grow a giant brain in a dinosaur like Velociraptor: you have to reconstruct the skull. Consciousness is not a clever trick to be whipped up from any set of neurones like a soufflé from an egg.
Earth history – a whole confection of climate and sea-level changes, plate tectonics, and extraterrestrial events – has danced a pas de deux with life. The reductionist approach to evolution, especially the unscrambling of the genetics of development, has proved enormously successful in illuminating the ultimate basis for the transformation of one organ into another, or even one species into another: but these momentous discoveries do not explain the course of biological history. The description of a cast of characters alone does not determine the shape of a drama.