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In his Words essay “Owen's Parthian shot” (Nature 412, 123; 2001), Kevin Padian discusses a letter from Richard Owen to Spencer Walpole, a politically important member of the British Museum's Board of Trustees, shortly after Charles Darwin's death in 1882. Owen had been asked whether Darwin's scientific accomplishments merited a statue in the new museum. Owen, noting that the decision should be left to the museum's administrators, compared Darwin's singular contributions to biology to those of Copernicus to astronomy. He predicted that Darwin, like Copernicus, would have successors who would complete a fuller understanding of the concepts he had initiated.

Padian claims that in this post-mortem analysis and comparison, Owen was aiming “a Parthian shot at his rival in the guise of a tribute — a masterful and delicate duplicity”. Duplicity? Hardly. It was an analogy Owen frequently used. The letter reproduced in full in Padian's essay was in fact the last, as far as we know, in a series of four similar letters that began in 1877. In each of these, Owen uses the same analogy to restate figuratively the basic objections he had expressed when Darwin's Origin of Species was first published in 1859: that although natural selection is a valid mechanism to explain species diversification through time, it did not answer the more basic question of the origin of the inheritable individual differences subsequently “naturally selected” for survival in a surrounding and changing environment.

Without an answer to the problem of inherited variations, Owen believed that the origins of species were not fully understood. Darwin himself confessed: “Our ignorance of the laws of variation is profound.” With his copernican analogy, Owen was expressing his confidence that in the coming years, as with the heliocentric theory, Darwin's theory of evolution would find its own Galileos, Keplers and, finally, its Newton.

The twentieth century belonged to the geneticists, who shifted the field from the species level to that of the individual. Ironically, the 1908 meeting in Cambridge to celebrate darwinism provided a platform for the practititoners of the newly named science of genetics, led by William Bateson — those “snarling dogs”, complained one loyal darwinian — “to lower Darwin and elevate themselves”.

This meeting marked the beginning of the dominance of genetics, with its mutations and its mathematics, leading towards the productive evolutionary syntheses 30 years later.

Among that vast body of creative workers Darwin's work had spawned there were, and are, as Owen's analogy predicted, his Keplers, Galileos and perhaps a Newton.