Wonderful Life: History according to Stephen Jay Gould

The late Stephen Jay Gould was one of the greatest popular science writers ever, and certainly one of the top three in evolutionary biology (the other two, as far as I’m concerned, being Thomas Henry Huxley and Richard Dawkins). For twenty-five years he wrote This View of Life for Natural History magazine, in which he examined the history of science and scientists, and tossed around scientific ideas in a way accessible to the general public. Basically, he was the most-recognized evolutionary biologist of his time, at least in America, and his influence still holds strong among non-biologists, and even among many biologists. He is renowned as the co-author of the punctuated equilibrium hypothesis, and argued for decades against various forms of “ultra-Darwinism” (his own term) that he thought were obscuring the proper “pluralist” version of evolutionary theory.

Wonderful Life was one of his few stand-alone books (most of his books were collections of his essays), and was, at least until the release of The Structure of Evolutionary Theory, his most influential work, and probably the clearest statement of his views on evolution and the nature of history, as well as of science in general. Certainly, it is far more readable than TSOET, and so will serve as the perfect book to review to give a glimpse into the phenomenon of Gould.

I must warn you, this is going to be a very lengthy review, and I must admit that this is because it concerns a subject that’s very dear to my heart. But it’s still not going to be anywhere near long enough to deal with so many topics in as much depth as they deserve. So if anybody’s unsatisfied with my treatment of anything in this review, I’ll be more than happy to post more in-depth discussions and link them to this review.

(I've just had a quick look at what I've written, and it's scary stuff. If you just want a light read, I won't blame you if you walk away now. Keep reading at your own risk.)

Okay, so let’s get down to it.

The book's title comes from the now-classic movie It’s a Wonderful Life, directed by Frank Capra, starring Jimmy Stewart as George Bailey, a man whose life seems to have hit rock bottom, and Henry Travers as Clarence Oddbody, an angel (second class) sent to prevent George committing suicide. Clarence accomplishes this by showing George how valuable his life really is, by showing him what the world would have been like if he hadn’t been around.

And this, in a nutshell, is what this book is all about – how small things (like George’s nonexistence) can deform the world.

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So what is this book all about?
In 1909, high in the Canadian Rockies (and now part of Canada’s Yoho National Park) Charles Doolittle Walcott discovered the wonder that is the Burgess Shale – exposed rock rich with the fossilized remains of early Cambrian life. The Burgess quarry, containing specimens from around 520 million years ago, is especially amazing in that even soft-bodied organisms have been preserved in it in large numbers, and in many cases their three-dimensional structure is still largely intact (fossilization tends to squash things down, leaving a 2-dimensional fossil picture, and metamorphosis tends to distort shapes of these fossils).

Walcott “shoehorned” (Gould’s term) all the Burgess organisms he got around to studying into existing animal groups, forcing them to fit into modern categories. Later, in the 1970’s and 1980’s, Harry Whittington, Simon Conway Morris and Derek Briggs took another, fuller and more thorough look at the Burgess organisms and began classifying them. What they found astonished them – many, perhaps most, of these invertebrates could not be traced to any known class, or even any known phylum! They were totally unlike any other animals known on earth since.

Wonderful Life is about this reinterpretation of the fauna of the Burgess shale, and its implications for evolutionary biology, history and science as a whole – at least, as Gould sees it.

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Gould’s 3 themes
Gould sets three aims for this book at the outset, and they are worth mentioning in his own words (as seen on page 24). Firstly, to chronicle “the intense intellectual drama behind…this reinterpretation”. Secondly, to develop a “statement about the nature of history and the awesome improbability of human evolution”. And, finally, to “grapple with the enigma of why such a fundamental program of research has been permitted to pass so invisibly before the public gaze”.

So how does he handle these three themes?

Theme 1: The Players
The first theme, that of intellectual biography, is Gould’s specialty, something he has handled countless times in his Natural History essays. The major difference here is that three quarters of his case studies were still alive, and Gould seems to think it in bad taste to do this kind of biography about a living target (at least, he thought so when Daniel Dennett did it of him in Darwin’s Dangerous Idea). But Gould brushes this concern aside by showing us how familiar he is with these people as people, as colleagues and personal acquaintances.

Gould’s reconstruction of Charles Doolittle Walcott’s life, work and views is as brilliant as any of the similar reconstructions he performed over the decades in his essays, but is, if anything, even more extensive. His description of the views which led Walcott to interpret (or “shoehorn”) the Burgess organisms the way he did is very convincing. As a historian of human nature, Gould is simply excellent.


Theme 2: The Meaning of the Play
So what does Stephen Jay Gould think the Burgess fauna can teach us?

Gould distills three main messages from the twisted bodies in the shale.

Firstly, he sees the Burgess organisms as strong evidence for a “Cambrian explosion”, a sudden arrival of animal types very different from what “gradualist” evolutionary views would lead us to expect. The appearance of all the known animal phyla (and many others besides) in the fossil record occur in a geologically brief span of time – which seems superficially to support Gould’s own punctuated equilibrium ideas (developed in conjunction with Niles Eldredge, the idea that most lineages experience no evolutionary change for most of their existence, and then experience geologically sudden evolutionary change).

There are many hypotheses to account for this Cambrian explosion, ranging from the idea that the apparent explosion of animal life is an artifact of the fossil record (perhaps the explosion only marks the sudden advent of hard, more easily fossilized parts) through the idea that the explosion, while real, still occurred over scores of millions of years and under ordinary gradualist (which probably doesn’t mean what you think it means, if you’re a non-biologist) evolutionary processes, to the view that the explosion was geologically practically instantaneous and governed by rules outside of the normal Darwinian selective process – the view Gould supports in this book.

There’s really no place to get into it here, but I support the intermediate view, for reasons that I feel are eminently defensible in terms of evolutionary theory and basic logic. Furthermore, all the actual evidence seems to support this view (molecular evidence, systematic studies, etc.).

Secondly, he sees in the Cambrian a period that is more diverse than any seen since. In the Cambrian, so the story goes, there were more phyla and classes than there are now. Over the ages, diversity may have increased at the species level, but at the highest levels of classification there has been a decrease in diversity. And since the higher levels represent intrinsically more diversity, diversity as a whole has decreased since the time of the Cambrian.

This is surely one of the stupidest ideas ever developed by a man of such intelligence.
It seems to be a basic misunderstanding of the way evolution works, not what you would expect from an evolutionist of Gould’s reputation.

Phyla are not real, concrete, definable objects. Phyla are constructs – names we give to groups of organisms that shared a common ancestor in the distant past, but more recently than they did with members of other phyla. Yes, this means that members of the same phylum tend to be more similar to each other than to other phyla, and will have similar “body plans” – after all, they only split from each other a short time ago (relatively speaking).

Importantly, the concept of phylum invokes evolutionary change through time, NOT fundamental body plans that came out of nowhere – or, at least, arose through unknown non-Darwinian processes – and constrained the possibilities of further evolution. [Yes, constraints are important, but I’m not getting into that here.]

Now take another look at Gould’s notion that there were more phyla in the Cambrian than there are now. Clearly, this is a meaningless idea. There were indeed lineages that went extinct without descendants surviving into the present, where we might have dignified them with a phylum of their own. But back then it’s doubtful that enough time had passed between the common ancestors of all the Burgess fauna to dignify them with separate phyla. When we say that a Burgess organism is so different as to merit its own phylum, we are looking at it with hindsight, with respect to modern organisms. The differences between these organisms must be judged by the actual differences between these organisms, not by their similarity to modern organisms.

The further back in time you look, the less likely it is that any particular organism will belong to a group (taxon) still extant today, a simple result of the fact that some groups go extinct, and the longer a group exists, the more diverse it’s likely to become (through speciation).

So there doesn’t seem to be anything to Gould’s idea of the Cambrian as a period of greater diversity than any time since.

Thirdly, Gould develops the idea of contingency from the story told by the Burgess fauna.

Contingency is similar to what we call chance, but not to be confused with randomness. True randomness is when things happen for absolutely no reason. Contingency is simply when causes and effects are so interrelated and manifold that slight changes lead to consequences that cannot be predicted. Applying this concept to history, Gould tells us that there is no single guiding principle behind life on earth (both in evolutionary terms and in terms of human history), and that a re-running of the Burgess tape (his metaphor) might see different groups going extinct, leading to a world in which, and this is the point of the book, we human beings might never have existed. We are here, he says, because our ancestors were lucky. For example, if the dinosaurs had never been wiped out by that meteor, our mammalian forebears would probably have remained little nocturnal things, and reptiles might still be the dominant land-dwelling vertebrates.

Now I’ve got no problem with the idea that history is complex and contingent. And I can see how a meteor strike is not dictated by biological laws. But that doesn’t mean that the extinction of lineages in the Cambrian was as arbitrary as that. There was surely some reason beyond luck that many lineages survived – perhaps they were simply better competitors in the game of life. There is no evidence to suggest that there was anything as non-selective as a rock from outer space involved.

But I love Gould’s argument that the extinction of Cambrian Bauplanne occurred as a result of non-Darwinian, non-adaptive rules – it’s just so silly. Basically, it goes as follows. The Burgess organisms are all so improbable and strange that he can’t see how any of them could have been better adapted than any other. In other words, because he can’t see any difference between their competitive abilities, there probably wasn’t any. Thus, rather than the extinctions being a result of interactions between the species, he sees them as being a result of random killing processes.

Now I admit that this is a slight caricature of Gould’s views. After all, most of the time he argues that his point is only that it’s possible that this is the way things happened, not that this must be what happened (though he employs lots of rhetoric to make it seem that it is the only sensible way it could have happened). And it is indeed possible that this is the case. But it’s not likely. And this sidesteps the whole scientific investigatory process. The point of adaptive, Darwinian explanations is that they can be tested. Gould professes that adaptationists just tell “just-so stories” about the possible evolutionary history that leads to the possession of certain traits – they are just constructing possible histories. Obviously Gould himself can’t really object to this – after all, this whole book is a just-so story, and he frequently made use of them in his Natural History column. What Gould objects to is the fact that an adaptive hypothesis can always be found, so even if one is tested and rejected, another one will probably be proposed in its place. This is valid criticism, but it doesn’t have mush to do with the Cambrian.

The idea of contingency is important, but not as important as Gould seems to be saying. Still, it’s one of the ideas in this book that provides extremely good food for thought, and I can’t really blame him for getting so carried away. He’s just trying to drum into our heads that we aren’t the ultimate goal of evolution.

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Theme 3: The Conspiracy
Gould finds the obvious explanation for the depth of ignorance about the wonders of early animal life as revealed by the Burgess Shale – people find it too boring and arcane to get excited about it – unsatisfying. And he has a point, because everybody has at least heard of quantum theory, which is about as arcane as science can get, while you would have been hard-pressed to find anybody – at least until this book was published – who had the slightest inkling about the mysteries of the Burgess Shale.

He finds the major cause of this neglect in a form of scientific chauvinism – the division of the natural sciences into the “hard” sciences (physics, chemistry, and their ilk) and the “soft” (biology and other “historical” sciences), with the implication that those that are “harder”, i.e. more like physics, are somehow more scientific and more important.

Gould rejects this idea as unworthy, saying it stems from a false view of science and knowledge. While it is true that the “hard” sciences are great at prediction, lend themselves to easily testable hypotheses with largely unambiguous experiments, this is because they deal with subject matter that can be treated as being largely ahistorical and unvaried. Such simple systems are easy to describe using a simple reductionist model, while complex organisms require a more integrated approach.

So how do I feel about all this?

Well, I do agree with Gould that biology handles systems far more complex than those handled in physics, and that our investigations are therefore handled in a different manner. I also believe that physics deals in a higher degree of certainty than biology tends to, and that decreasing uncertainty is the ultimate aim of science, and thus a measure of how scientific an investigation is. In other words, I side with physics as being more scientific than biology.

Biology is most scientific when it is most carefully explained, when cause and effect is teased apart and explanations are built up based on testable principles. Thus, I feel Gould’s appeal to contingency and luck as the main force of evolution to be a rejection of good scientific principles for something untestable, which by its very nature denies predictions and known causes.

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So why’d I give it three stars?
I’ve done a lot of complaining about the conclusions Gould draws from the Burgess fauna in this review. And I really object to the fact that anybody without experience in biology or geology is almost bound to agree with Gould’s erroneous conclusions, given the level of rhetoric he employs to get his point across. So why isn’t my rating a bit lower?

Well, basically it’s because this book is so brilliantly written. Fossil anatomy and reconstruction is not exactly the most exciting subject in the world (at least as far as most people are concerned), and Gould makes it all seem so interesting that you’ve got to give him credit. Also, it’s extremely thought-provoking, and gives an excellent idea of what it means to peer into the rocks of the past and try to understand what life was like back then. And Gould’s writing style is a thing of beauty, witty, personal, friendly and intelligent.