Inferring and Explaining

77 t 2 0 as the best explanations. Some controversy questions, not about the overall theory, but about remains, however, regarding t 3 0 . Most grant that the details. Darwin wrote On the Origin of Species natural selection does result in species change, in ignorance of genetics, population biology, and but some question whether it is the primary molecular biology. It is quite remarkable that cause.Tis kind of controversy, rather than call- these revolutions, rather than undercutting his ing evolution into question, is precisely what theories, actually over time came to add further healthy science is all about. Tere do remain support. exerCIses 1. Darwin marshaled a lot of evidence in support of descent with modifcation—e 2 through e 6 . If you had to make his case using just one of these categories of data, which would you choose? Why? 2. Can you think of any rival explanations to t 1 0 , t 2 0 , or t 3 0 ? darwIn and Common desCent QuIz eIght The quiz for this chapter is to write a short (no more than three pages) paper on Darwin’s two theories. Your paper should do three things. It should carefully explain Darwin’s theory of common descent (or descent with modifcation). It should then explain what natural selec- tion is. Finally, it should use the tools of inference to the best explanation (the IBE recipe) to critically assess the quality of Darwin’s evidence for the frst part of his “one long argument,” the theory of descent with modifcation . Notes 1 Charles Darwin, On the Origin of Species (Cambridge, MA: Harvard University Press, 1964), 1. 2 Darwin, 484. 3 Darwin, 312. 4 Darwin, 411. 5 Darwin, 479. 6 Ernst Mayr, Te Growth of Biological Tought (Cam- bridge, MA: Harvard University Press, 1982), 446. 7 Darwin, Origin of Species , 306–7. 8 Darwin, 338. 9 Darwin, 434. 10 Darwin, 434. 11 Darwin, 442–43. 12 Darwin, 442. 13 Quoted in Mayr, Growth of Biological Tought , 474. 14 See John Maynard Smith, Shaping Life: Genes, Embryos, and Evolution (New Haven, CT: Yale Uni- versity Press, 1998). 15 Richard Swinburne, Te Evolution of the Soul (Oxford: Oxford University Press, 1997), 1. 16 Darwin, Origin of Species , 3. 17 See Daniel C. Dennett, Darwin’s Dangerous Idea (New York: Simon & Schuster, 1995); and Mayr, Growth of Biological Tought . 18 Mayr, Growth of Biological Tought , 479. 19 Darwin, Origin of Species , 63. 20 Mayr, Growth of Biological Tought , 479. 21 Mayr, 480. 22 Mayr, 480. 23 Mayr, 480. 24 Darwin, Origin of Species , 61. 25 Mayr, Growth of Biological Tought , 480. 26 Mayr, 480. 27 Mayr, 480. 28 Mayr, 480.