Book review: Darwin Deleted by Peter J. Bowler

What if Charles Darwin had died on the Beagle voyage?

Hardly a far-fetched possibility. Some of Darwin’s family and friends thought the journey risky and tried to talk him out of it. Darwin was a lousy sailor, and the ship passed through severe storms; Darwin could easily have been swept overboard. Argentina was having a civil war while Darwin was there; he could’ve been shot. He could’ve caught some tropical disease, worse than the Chagas disease he’s widely believed to have contracted. Heck, when trying out the bolas used by Argentinian gauchos to hunt rheas, he tangled the legs of his own horse. The horse managed to stop without throwing him, and he and the gauchos had a good laugh. But it wouldn’t have been funny if the horse had gone down and he’d broken his neck.

In Darwin Deleted, eminent historian of evolutionary biology Peter Bowler asks what would’ve happened if, as was quite possible, Charles Darwin had died young. How would history have been different?

Darwin Deleted is what’s known as counterfactual history: trying to understand why history happened as it did by asking if or how things would’ve been different under some alternative scenario. The approach is most popular in military history (I once read a fun book of popular counterfactual histories that was heavy on military examples). The counterfactual method is controversial. Some historians argue that asking counterfactual questions is not only impossible in practice but meaningless in principle. But I suspect that, to scientific readers, the counterfactual method will seem a natural choice. As scientists, we’re taught that the best way to reveal causality is via manipulative experiments. Historians can’t run manipulative experiments, so the the best they can do is run the thought-experiment equivalent. Historians are the last people who should fall into the fallacy of post hoc ergo propter hoc (“after, therefore because”). Consideration of counterfactuals is a form of mental discipline that helps prevent you from falling into this trap. Plus, the counterfactual method is a close cousin to Stephen Jay Gould’s famous notion of “rewinding the tape of life” and playing it again. Gould was interested in whether things would come out differently starting from the same initial conditions, due to the accumulation of stochastic events. Here, Bowler discusses the likely consequences of a single stochastic event.

Of course, scientists also will be quick to wonder how to evaluate Bowler’s counterfactual claims. How can we tell if he’s right about what would’ve happened following Darwin’s early, untimely demise? We don’t have a time machine or a bunch of identical Earths, so can’t actually perform a controlled, replicated experiment. And we don’t know enough about history to build and validate a dynamical model that could then be tweaked to simulate alternative scenarios, analogous to what’s done with climate models. So the best we can do is engage in grounded speculation–plausible storytelling.

And while one could argue that plausible storytelling is all too easy–lots of quite different stories might all seem plausible–Bowler’s speculations are very well-grounded and so very plausible. Bowler knows a massive amount about Darwin and his times, and not just in Britain. One key line of evidence for Bowler’s arguments comes from his comparative approach. By looking at how evolutionary biology developed in countries like France and Germany, where Darwin’s ideas never gained much of a foothold or did so only in distorted form, we can get some insight into how evolutionary biology would’ve developed in the UK and the US if Darwin wasn’t around to propose his ideas.

Another key line of evidence comes from the fact that the idea of evolution by natural selection was highly controversial and remained so for decades. There were plenty of alternatives to evolution by natural selection that were widely-discussed at the time, so we have a good sense of what ideas would’ve been pursued instead, had natural selection never been proposed. Indeed, Bowler makes the case that natural selection was never an especially popular hypothesis even before it was nearly eclipsed in the late 19th century. Paleontologists and anatomists (as distinct from biogeographers) didn’t even share Darwin’s very modern sense that explaining adaptation was the key goal for evolutionary biology. For many biologists at the time, the key thing was to document the fact of evolution, to describe the tree of life. Interest in doing this was driven by many factors independent of Darwin, like Chambers’ Vestiges, discoveries of fossils, and comparative anatomy and embryology. From that perspective, adaptation of organisms to their local environments is an unimportant epiphenomenon–even a nuisance because it obscures what we’d now call phylogenetic signal and what many at the time would’ve called the evidence of nature’s purpose, God’s hidden plan. Part of what makes it possible to write a counterfactual history with Darwin deleted is that, in our world, Darwin’s ideas didn’t actually have as much influence as you might’ve thought.

Bowler’s counterfactual is a great vehicle for discussing all sorts of interesting issues in the history of evolutionary biology. For instance, Darwin’s idea of evolution by natural selection often is claimed to have been “in the air” in Britain at the time, on the grounds that Alfred Russel Wallace independently hit on the same basic idea. But on the other hand, Wallace’s original version of the idea was somewhat different than Darwin’s, and much less well-developed. His original 1858 paper, like Darwin’s, famously went unnoticed. And Wallace was poor, and poorly-connected. It’s hard to see his initial idea ever gaining a foothold in the absence of Darwin, given that Darwin was rich and well-connected and still struggled to get people to understand and agree with his ideas. Plus, Wallace’s own subsequent development was heavily influenced by reading Darwin, which is another strike against the notion that, if Darwin had died young, Wallace would’ve stepped neatly into his intellectual place.

The picture that emerges is of Darwin as a man decades ahead of his time in his thinking about the mechanisms of evolution, sending natural selection out into a world that wasn’t ready for it. Because of that, the so-called Darwinian revolution caused a big stir but didn’t actually greatly alter the course of science during Darwin’s lifetime. Teleological neo-Lamarckian theories accepted the fact of evolution but saw it as progressing in a directional manner towards a predetermined, higher goal, analogous to embryonic development. In the absence of Darwin, these ideas–which were much easier for scientists, clergy, and the lay public to understand and accept–would’ve dominated the field even more than they actually did. Insofar as biologists were interested in explaining adaptation, they’d have done so much as most of them actually did in our world–via appeal to Lamarck’s notion of the inheritance of acquired characters. Without Darwin, society at large, and the Christian religion in particular, would’ve had decades to get used to the idea of evolution in a (to them) relatively congenial form. So that, when natural selection was finally proposed, it would’ve been much more easily integrated into both science and society. Indeed, Bowler goes so far as to suggest that what we call the “Modern Synthesis” would’ve emerged earlier had Darwin died young! With the side benefit that the fundamentalist revival in the US would’ve ended up settling on other bogeymen to vilify (perhaps geologists, suggests Bowler), or at least viewing evolution as only one bogeyman among many. In other words, no Darwin, no creationism or intelligent design.

One really big idea under the surface here is the notion that scientific progress has a “natural pace” and can’t be accelerated by geniuses. I wish Bowler had talked a bit about whether he believes that’s generally true, because I found that a fascinating idea.

Don’t misunderstand, Bowler’s a Darwin fan–he’s absolutely not out to denigrate Darwin or downplay his importance. But he’s a historian’s historian, keen to scrape away all the accumulated myth-making by both Darwin fans and haters and get history right.

Bowler also spends a fair bit of time exonerating Darwin from the charges that eugenics, “social Darwinism”, and the Nazis are his fault. Bowler argues that, if anything, the influence ran the other way–from eugenical ideas into evolutionary biology, and that Darwin’s ideas actually slowed the progress of eugenics. No Darwin doesn’t mean no Final Solution. There’s valuable stuff here, in particular the discussion of how the meaning of “social Darwinism” has changed hugely over time. But some of this felt a little like Bowler settling scores with fringe-y nutters who arguably are best ignored.

There are all sorts of interesting tidbits in the book. For instance, Bowler suggests the two men whom he thinks would’ve finally developed the idea of natural selection in a world without Darwin, around 1900. One is hugely famous, the other is obscure. No, not Galton. No, not Spencer. Keep guessing… 🙂

I don’t know that I fully buy Bowler’s story, and not just because no historical counterfactual can ever be conclusively established. Like Marek Kohn, I wonder if the notion of natural selection would’ve been revolutionary no matter when it was proposed. But that’s a quibble, because even if that’s right you’ve still got a counterfactual picture in which evolutionary biology in more or less its modern form develops at about the same time it did in our world. I also wonder if teleology would’ve been harder to eradicate from evolutionary biology in Bowler’s counterfactual world. Bowler’s a fan of modern evo-devo (though not its most extreme, we-need-a-whole-new-evolutionary-synthesis manifestations). But I think Bowler sees rather more similarities between modern mainstream “evo-devo” and 19th century teleological thinking than there really are. And so I think he may be underrating the difficulty of incorporating natural selection into teleological evolutionism.

The first chapter gives a great roadmap and summary of the argument. And the whole book is clearly written, so I never felt like I was getting lost in the weeds and losing track of the main thread.

After reading the book, I found myself wondering about other counterfactuals. For instance, what if Darwin had worked up the courage to publish the Origin in, say, 1844, the same year Vestiges was published? That year Darwin expanded his 1842 sketch of his theory and the evidence for it into a longer (200 pages) sketch. My understanding is that, except for the “Principle of Divergence”, the 1844 sketch basically contains every big idea that would eventually be published in the Origin in 1859. So Darwin could’ve published something similar to the Origin in 1844 if he’d wanted to. That would’ve put Darwin so far ahead of his time that he would’ve been publishing simultaneously with the speculative tract that in our world prepared the ground for the Origin 15 years later. What would’ve been the consequences? For instance, would Darwin have been tarred with the same brush as the then-anonymous author of Vestiges was, derailing his career as a gentleman naturalist? Would a world in which Darwin published even further ahead of his time look like a world in which he’d never published at all because he died young?

If, like me and most other biologists, you only know the potted history of the development of evolutionary biology, or at best you’ve only read Ernst Mayr’s interpretation of that history, you’ll learn a lot from this book and have a lot of fun doing so. Even if you don’t buy the counterfactual approach, it’s an entertaining and accessible way to learn a lot about Darwin and his times. I highly recommend it.