The work of Gregor Mendel was rediscovered and fused with natural selection to make for adequate evolutionary understanding. The key figure in England, working as a mechanist, was R. A. Fisher. In America, the key figure was Sewall Wright, working as an organicist. In England, E. B. Ford provided empirical evidence. In America, the Russian-born Theodosius Dobzhansky did likewise.

This chapter engages two clusters of long-run, big-picture issues. One concerns relations between art and nature. Aristotle’s views on this were challenged in the late seventeenth century by Robert Boyle in defending the new mechanical philosophy. Darwin is aligned with neither Aristotle nor Boyle; nor with German Romantic philosophers, such as Schelling. The agrarian contexts of Darwin’s science, and its alignments with agrarian rather than industrial forms of capitalism, illuminate Darwin’s views, including his natural theological views, of art-nature relations. A second cluster of issues concerns the role of the selection analogy in later controversies about natural selection, notably involving Alfred Russel Wallace and Francis Galton in the nineteenth century, and Ronald Fisher and Sewall Wright in the twentieth century. We stress that Darwin’s theorising is sometimes ancient in its resources and sometimes modern, which is not surprising given the intellectual life he was leading. His analogical argument belongs in the science classroom not because it is up-to-date but precisely because, like all science, it is of its time.

Several high-profile evolutionary biologists in the twentieth century were committed organicists. Conrad H. Waddington, the British geneticist was one, trying to simulate Lamarckian processes through orthodox genetical approaches. Another was the well-known American paleontologist and scientific popularizer Stephen Jay Gould, who promoted morphology over adaptation. And a third was the founding populational geneticist, American Sewall Wright. He argued that random processes, genetic drift, could and would lead to major adaptive breakthroughs. Philosophers likewise embrace organicism, including the British John Dupré and the American philosophers Jerry Fodor and Thomas Nagel. Nagel in particular has been highly critical of Darwinian theory, thinking it to be crude materialism masquerading as science. Expectedly, the Darwinian mechanists have struck back, confirming the suspicion that we have paradigm differences at stake. The two sides, mechanism and organicism, defend their positions with alternative reasons. For the mechanists, the triumphs of their approach trumps all. The double helix is a popular example in support of mechanism. For the organicists, the special place of humans trumps all. We are superior and no further argument is needed.