Science of Discworld III

Wallace certainly came close, for he was suffering from malaria when he composed his letter to Darwin. As a good socialist, Wallace had been taught not to trust the reasoning of Malthus, who had argued that the world’s ability to feed itself grew linearly, while the population grew exponentially – implying thateventually the population would win and there would be too little food to go round. Socialists believed that human ingenuity could postpone such an event indefinitely. But by the 1850s even socialists were beginning to view Malthus in a more favourable light; after all, the threat of overpopulation was a very good reason to promote contraception, which made excellent sense to every good socialist. Half-delirious with fever, Wallace thought about the rich variety of species he had encountered, wondered how that fitted in with Malthus, put two and two together, and realised that you could have selective breeding without the need for a breeder.
    As it turned out, he didn’t have quite the same view as Darwin. Wallace thought that the main selective pressure came from the struggle to survive in a hostile environment – drought, storm, flood, whatever. It was this struggle that removed unfit creatures from the breeding pool. Darwin had a rather blunter view of the selection mechanism: competition among the organisms themselves. It wasn’t quite ‘Nature red in tooth and claw’ as Tennyson had written in his In Memoriam of 1850, but the claws were unsheathed and there was a certain pinkness to the teeth. To Darwin, the environment set a background of limited resources, but it was the creatures themselves that selected each other for the chop when they competed for those resources. Wallace’s political leanings made him detect a purpose in natural selection: to ‘realise the ideal of a perfect man’. Darwin refused even to contemplate this kind of utopian hogwash.
    Wallace hadn’t mentioned publishing his theory, but Darwin now felt obliged to recommend it to him. At that point it looked as if Charles had compounded his Really Bad Idea, but for once the universe was kind. Lyell, searching for a compromise, suggested that the two men might agree to publish their discoveries simultaneously. Darwin was concerned that this might make it look as if he’d pinched Wallace’s theory, worried himself to distraction, and finally handed the negotiating over to Lyell and Hooker and washed his hands of it.
    Fortunately, Wallace was a true gentleman (the accident of breeding notwithstanding) and he agreed that it would be unfair to Darwin to do anything else. He hadn’t realised that Darwin had been working on exactly the same theory for many years, and he had no wish to steal such an eminent scientist’s thunder, perish the very thought. Darwin quickly put together a short version of his own work, and Hooker and Lyell got the two papers inserted into the schedule of the Linnaean Society, a relatively new association for natural history. The Society was about to shut up shop for the summer, but the council fitted in an extra meeting at the last minute, and the two papers were duly read to an audience of about thirty fellows.
    What did the fellows make of them? The President reported later that 1858 had been a rather dull year, not ‘marked by any of those striking discoveries which at once revolutionise, so to speak, our department of science’.
    No matter. Darwin’s fear of controversy was now irrelevant, because the cat was out of the bag, and there was no chance whatsoever that the beast could be stuffed back in. Yet, as it happened, the anticipated controversy didn’t quite materialise. The meeting of the Linnaean Society had been rushed, and the fellows had departed muttering vaguely under their breaths, feeling that they ought to be outraged by such blasphemous ideas … yet puzzled because the enormously respected (and respectable) Hooker and Lyell clearly felt that both papers had some merit.
    And the ideas struck home with some. In particular, the Vice-President promptly removed all mention of the fixity of species from a paper he was working on.
    Now that Darwin had been forced to put his head above the parapet, he would lose nothing by publishing the book that he had previously decided not to write, but had constantly been thinking about anyway. He had intended it to be a vast, multi-volumetreatise with extensive references to scientific literature, examining every aspect of his theory. It was going