Simon Conway Morris

LIFE'S SOLUTION

Inevitable Humans in a Lonely Universe

This book is in effect a counterblast to two popular and influential writers on evolution, Richard Dawkins and Stephen J. Gould, with whose views Conway Morris disagrees profoundly. In the case of Dawkins it is his militant atheism that Conway Morris dislikes. As for Gould, it is his claim that if the tape of life were rerun it is very unlikely that anything resembling humans would emerge. Conway Morris's view is that, given the right start, it is pretty well inevitable that intelligent life will appear and will almost certainly be quite similar to humans. But he also thinks that the right start is a pretty unlikely event, so we may in fact be unique in the galaxy or even the universe.

The book is certainly ambitious and wide-ranging. It starts at the very beginning, with the origin of life. In spite of much speculation we are still far from having an adequate theory of how this could have happened. And although some people maintain that the emergence of life is probably almost inevitable in the right circumstances, there is a lot of evidence to suggest that the development of complex life forms, as opposed to bacteria, requires very special conditions that are probably exceedingly rare. Planets exist in many solar systems apart from our own but most are probably unsuitable for any kind of advanced life.

Still, life did arise on earth and eventually gave rise to complex life forms, including us. Gould and those who think like him believe that the course of evolution might conceivably have taken any one of a huge number of paths, resulting in worlds that were completely unlike our own. In support of this, Gould made an extensive study of the famous Burgess Shale fossils and suggested that it was almost entirely due to chance that the vertebrate body plan eventually developed from among the varied forms that existed at the time. Conway Morris is an authority on the Burgess Shale and has reached diametrically opposite conclusions about what it signifies. His view is that evolution has been constrained to follow certain paths leading more or less inevitably to the development of intelligence, and the bulk of his book is a detailed explanation of why he believes this.

As Conway Morris realizes, his argument entails the risk that he might be taken for a "creation scientist". He is at pains to point out, in his preface, that this is not the case. He is, after all, Professor of Evolutionary Palaeobiology at Cambridge and a card-carrying Darwinian, who is fully signed up to the idea that evolution has been guided by natural selection. At the same time, he is convinced that evolution has "metaphysical implications", so one can understand why he needs to go out of his way to distance himself from Biblical literalists. He does seem to be treading a rather fine line here and I am not sure that he entirely manages to avoid crossing it at the end of his book.

His essential position is that evolution does not have a completely free hand in what it produces. "The number of evolutionary end points is limited: by no means everything is possible. [And] what is possible has usually been arrived at multiple times, meaning that the emergence of the various biological properties is effectively inevitable." Of all the possibilities that might in principle be realized, only a small subset has actually arisen. And this, he believes, is not just a local phenomenon on this earth but will be found to be true if any other planets harbouring advanced life are ever discovered.

In support of his thesis he provides a huge number of instances of convergent evolution—far too many to summarize here. They include the eye, which has evolved a considerable number of times from different starting points but has arrived at remarkably similar solutions. The same is true of other senses, including the familiar, such as hearing, and the more unusual, such as the electric sense organs of fishes. There are also interesting similarities in the brains of different groups of fishes that use electricity in this way. Convergences are also explored in the evolution of ants, birds, moles, and many other organisms. There is a good deal of discussion of the sophisticated agricultural technology possessed by some types of leaf-cutter ants, with its curious parallels to human agriculture (even in some cases the same risky dependence on monocultures).

But it is in the evolution of intelligence that is the real quarry for Conway Morris. The main groups exhibiting intelligence are the anthropoid apes, the elephant family, the cephalopods, and the whales and dolphins, although some birds, notably the New Caledonian crows, show behaviour as complex as that of any of the other groups. Conway Morris dwells on the degree of intelligent behaviour exemplified by these species and on convergences in the neurological basis for this behaviour.

When we come to the human level we seem to encounter a level of intelligence well above that of any of the other species on the planet, and we also find sophisticated language which appears to be unique to humans. But Conway Morris holds that the trend was moving in that direction in any case and he believes that, if we had not evolved to become bipedal and tool-using, another primate species would: "… from the present evolutionary perspective we are undeniably unique. Yet … if we had not arrived at sentience and called ourselves human, then probably sooner rather than later some other group would have done so, perhaps from within the primates, perhaps from further afield, even much further afield."

This claim is really the culmination of Conway Morris's argument; his purpose in writing was to reach this point. And in his concluding chapter (plus a postscript) we see why he wanted to arrive here. Chapter 11 has the title "Towards a theology of evolution?" and the question mark is not really needed. Much of this chapter is a sustained attack on the views of "ultra-Darwinists" such as Richard Dawkins and Edward O. Wilson and on what Conway Morris regards as their adherence to genetic determinism. In its place we should "ask ourselves what salient facts of evolution are congruent with a Creation."

At this point we get a frank recommendation (quoting an extended passage from Michael Polanyi's Personal Knowledge) to acknowledge the validity of the Book of Genesis. "The assumption that the world has some meaning which is linked to our own calling as the only morally responsible beings in the world, is an important example of the supernatural aspect of experience which Christian interpretations of the universe explore and develop." In other words, Conway Morris (citing Polanyi) is making an overt plea for Judaeo-Christian religion as a guide to what we should do and how we should think. And before long we he is citing C.S. Lewis and the "cosmic view" of G.K. Chesterton.

Here I part company with the author. Unless you believe in the uniqueness of the Judaeo-Christian revelation there seems to be no particular reason to prefer the Book of Genesis to Hindu or Buddhist cosmology (to name two possible alternatives). And ancient Chinese civilization produced a viable cosmology and mythology without a Creator God that satisfied a quarter of the world's population for millennia. Conway Morris does not even mention any of these rival mythologies.

At the end, therefore, this book turns out to be a polemical tract. But the maddening thing about it is that, if we leave the polemics aside, it contains a huge amount of fascinating information. The examples of convergence it provides are in many instances certainly astounding, even if others do appear to be somewhat trivial. And there is no doubt that Conway Morris is making a valid point: there is a question to be answered.

He touches only in passing on the notorious Anthropic Principle, which is an attempt to account for the astonishing fact that our very existence depends on the fine tuning of certain cosmological numbers [see Just Six Numbers, by Martin Rees]. In a sense, this book could be seen as a transposition of the Anthropic Principle to the biological level. Conway Morris quotes with approval the late Fred Hoyle's opinion that the Universe is a set-up job. And it can hardly be denied that the book provides an impressive array of evidence to support its author's contention.

At the same time, I still find myself wondering if the trend towards sentience and intelligence is as inevitable as we are told it is. Mind certainly took its time in arriving on the scene. The dinosaurs were around for a very long time but there does not seem to be any evidence that they went in much for developing intelligence; they seem to have focused on size more than anything. Are we to suppose that if the fatal meteor had not ended their career they would eventually have produced a civilization? (Though I suppose Conway Morris could point to his friend, the New Caledonian crow, as an intelligent descendant of the dinosaurs.)

It seems to me to be perfectly possible to maintain that intelligence is simply one manifestation of life and that it is only because we value it so highly that we are tempted to think it arises inevitably in evolution. Is this perhaps the ultimate anthropocentric illusion? I am not convinced that Conway Morris has adequately made a case for the view that it was in some sense the "purpose" of evolution to give rise to intelligence.

13 March 2005

For a different take on this subject see Improbable Destinies: How Predictable is Evolution?, by Jonathan B. Losos.

13 March 2005