Steven Rose enjoys a tale of the anxious strategising behind a great idea
Charles Darwin's bicentenary has generated such an armada of books, conferences and TV programmes that it may be hard to find anything new to say. Nonetheless, Iain McCalman, an Australian cultural historian, has made a brave try.
Darwinian evolution by natural selection rests on three indisputable axioms: like breeds like, with minor variations; all organisms can produce more offspring than can survive to adulthood; the best adapted variants are the most likely to survive to reproduce in turn. Therefore, species change with time - that is, evolve.
There is nothing in these principles that Darwin could not have deduced from his observations of the English countryside, from his work with pigeon breeders, and from rereading Reverend Malthus, all of which he pursued assiduously. Furthermore, evolution was not a new idea; it had been a matter of common discussion among European biologists since the late 18th century.
Yet Darwin's evolutionary epiphany came during his five-year voyage as a naturalist on the Beagle, the small vessel chartered in 1831 to chart the waters and coastline of South America, New Zealand and Australia. Such expeditions had been a routine part of British Admiralty policy since the 17th century, and it had become common practice to include on board someone with expertise in the emerging sciences of geology and biology to identify novel species and collect specimens. Naturalists making these arduous trips would be, as Darwin was, exposed for the first time to an abundance of living forms alien to European eyes.
As a young man of means, Darwin travelled as a companion to the ship's captain. The more usual practice was to employ a suitable person directly, as happened on the slightly later voyages of two rather less wealthy young men. The self-made zoologist Thomas Huxley was later to become "Darwin's bulldog", a ferocious advocate of natural selection; the botanist Joseph Hooker was a scion of the Hookers who were for decades to direct the botanical gardens at Kew. The fourth member of Darwin's armada was Alfred Russel Wallace, who for many years eked out a living as a collector and seller of tropical specimens.
It was Wallace's independent formulation of the axioms of natural selection, sent by him to Darwin in 1858, that precipitated Darwin's long-ruminated publication of On the Origin of Species, as an abstract of the much longer book he had postponed writing for two decades.
The stories of all four men have been well told previously, so there is little new material here. What McCalman does is to link them together by way of their voyages. He provides an antipodean perspective on the time spent in Australia by Hooker, and especially by Huxley. As his subtitle suggests, McCalman is using the concept of an armada in a second sense: the alliance of three old sea salts, later to be joined by Wallace.
The "battle" was to make natural selection not just a theory, but a universally accepted mechanism for evolutionary change. When Darwin received Wallace's letter, seemingly establishing primacy in developing the theory, he summoned Hooker and Huxley to his country retreat, where the three anxiously strategised. Propriety demanded they acknowledge that Wallace had anticipated Darwin, whose heterodox ideas had been buried for decades in his notebooks. The solution was to publish short notes from Darwin and Wallace simultaneously and let Darwin work at full pelt on the "abstract" that was published as Origin a year later. Wallace seems to have taken it all in good part, but he remained an outsider, a Christian socialist who was never to accept that human intelligence could have evolved by entirely natural causes.
Rather like Wallace, McCalman knows he is an outsider to mainstream Darwin studies, but he tells his story well. It reads as a combination of Boy's Own travellers' tales stretching from the Amazon to Antarctica, and a scientific adventure as racy as any historical novel.
• Steven Rose's The 21st Century Brain is published by Vintage.
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