Bowler, Peter. Darwin Deleted: Imagining a World without Darwin. Chicago: University of Chicago Press, 2013. 318pp. Cloth, $USD 22.89 ̶ It's a dark and stormy night in December 1832, and on the deck of the HMS Beagle a young Charles Darwinretches. He's washed overboard by a wave and never heard from again. Darwin Deletedasks what would have happened to the theory of evolution by natural selection in his absence (answer: delayed by about fifty years, with developmentalism considerably strengthened at the expense of "bean-bag genetics"), and whether there would have been "social Darwinism" (answer: known by a different name, obviously, yet just virulent as in our own timeline).
DarwinDeleted is a fascinating and daring book, full of interesting suggestions and alternatives. Peter Bowler is currently the English-speaking world's best-known historian of biology, and I can attest that its facts certainly check out. Yet facts cannot be the strong point of any counterfactual history. Darwin Deleted is chock-full of the conditional tense: "perhaps", "could have" and "might have" pepper the book. Does its speculative historical method work? That question is presumably the reason why this book is being reviewed in the Review of Metaphysics. On this matterthings get trickier.
Many historians turn up their noses at counterfactual history: in their view, once a work leaves facts behind and speculates about what might have occurred, it's no longer a history. But such hard-headedness about evidence - to paraphrase Steve Fuller–masks a naïveté about causation. Surely studies of history reveal larger patterns from which later scholars can learn? Otherwise historians are merely antiquarians writing for increasingly specialized audiences. Or indifferent ones.
Indeed evolution by natural selection is a promising case for a counterfactual study because it is a famous case of "simultaneous discovery." Alfred Russel Wallace came up with something similar in a malarial fever dream, impellingDarwin to publish sooner than he would have liked. This would seem to strengthen the realist view that phylogeny and the mechanism of natural selection are real phenomena awaiting discovery, not simply contingencies dependent upon cultural context.Darwin Deleted addressesthese points in its first and most important chapter, a chapter establishing the conceptual foundation upon which the rest of the book stands. And although I am eager for the counterfactual project to flourish, I must report that this foundation is somewhat unsatisfying.
The problem has nothing to do with realism or constructivism. Rather, it's that Darwin Deleted uses a linear, "horizontal", diachronic organization as the implicit model upon to set its counterfactual history. Most counterfactual historiesare set up this way, possibly because they tend to come from political and military realms whose outcomes depend on specific events. What would have happened next had Churchill negotiated with the Nazis in May 1940? Such timeline-oriented models also appear in the stories of popular culture: what would have happened nextto Bedford Falls had George Bailey never been born? But this arrangement creates two problems. One is its ceteris paribusassumption: one can speculate that that scenario X or Y or Z would have occurred had one single eventchanged – all other things being equal. But readersintuitively recognize that all other things are never equal, and their patience may betaxed by all of the conditionals. More seriously, a second problem is that a diachronic historical arrangement – a narrative - makes it all too easy to confuse chronology for cause – that is, since an earlier event happens before a later one, it must cause the later event. Although they give up the facts that historians treasure, then, diachronic counterfactual historiesstillseem to remain naïve about causation.
What if counterfactual histories instead discussed conditions of possibility? Such works might move "vertically," thinking about possible worlds, that is, relationships between historical factors in terms of the necessary, the contingent, and the impossible. Take, for instance, the evolutionary synthesis's view of species as gene pools, in which evolution is a process of trial and error where the proportion of adaptive mutations increase over time: such a view is not possible without natural selection. Natural selection would therefore seem to be necessary to the evolutionary synthesis. (Note that this model still does not tell us whether it specifically has to be discovered by Darwin or Wallace).
Despite this reservation, Darwin Deleted is extremelyimportant because it is above all a venture into a risky new kind of scholarly territory, and if only for this point alone Bowler is to be congratulated. Since Thomas Kuhn's Structure of Scientific Revolutions there has been a growing distance between historians of science on the one handand philosophers of science on the other. These two estranged groups of scholars should collaborate on counterfactual, speculative histories of science, for if such projects are to work they require far more careful thinking about historical causation. ̶ James Elwick, Science and Technology Studies Department, York University, Toronto