When the thirteen English colonies in North America became the United States of America in the 1770s, they possessed relatively few scientific institutions. However, by this time Americans enjoyed sufficient wealth and leisure to support fairly robust scientific communities in Philadelphia and Boston and moderately active ones in Charleston and New York. The most enterprising members of these communities worked closely with the major scientific centers of the Old World while at the same time developing intercolonial ties. Cultivators of natural history established an informal network of correspondents, and the American Philosophical Society, though essentially a Philadelphia institution, reached out to natural philosophers in every colony.

Charles Darwin’s primary goal in writing On the Origin of Species by Means of Natural Selection (1859) was to discredit what came to be known as creationism. Twelve years after publishing this book he explained that he had “had two distinct objects in view”: “firstly, to show that species had not been separately created, and secondly, that natural selection had been the chief agent of change.” Admitting that he may have exaggerated the power of natural selection, he took comfort in having at least “done good service in aiding to overthrow the dogma of separate creations” (Darwin 1871a, 1:146–47). Indeed, his primary scientific accomplishment was convincing his fellow naturalists that evolution was a fact of nature – and doing so within about fifteen years.

Despite believing that attributing the structure of animals to “the will of the Deity” was “utterly useless” scientifically (H. E. Gruber 1974, 417–18), Darwin did not himself entirely shun appeals to the Creator. Near the end of the Origin he wrote:

For the past century and a half no issue has dominated discussions of science and religion more than evolution. Indeed, many people see the creation-evolution debates as the central issue in the continuing controversy. And for good reason. More than a century after the scientific community had embraced organic evolution, many laypersons continued to scorn the notion of common descent. In the United States, where polls since the early 1980s have shown a steady 44-47 per cent of Americans subscribing to the statement that 'God created human beings pretty much in their present form at one time within the last 10,000 years or so', nearly two-thirds (65.5 per cent), including 63 per cent of college graduates, according to a 2005 Gallup poll, regarded creationism as definitely or probably true. As we shall see, such ideas have been spreading around the world. /Creation and Creationism / In 1929 an obscure biology teacher at a small church college in northern California self-published a book entitled Back to Creationism. This brief work, appearing just as the American anti-evolution movement of the 1920s was winding down, attracted little attention.

In 1991 John Hedley Brooke launched what I have dubbed the ‘complexity thesis’ in a review of his landmark book Science and religion: Some historical perspectives, the most important contribution to the historiography of the field since the appearance of Andrew Dickson White's History of the warfare of science with theology in Christendom nearly a century earlier. Avoiding the simplistic formulas of the past, Brooke revelled in the rich complexity and diversity of interplay between science and Christianity. He described a thoroughly entangled relationship, with religious beliefs not only providing ‘presupposition, sanction, even motivation for science’ but also regulating ‘discussions of method’ and playing ‘a selective role in the evaluation of rival theories’. As all right-thinking historians of science and religion now concede, he was correct. But he left many feeling emotionally and intellectually unsatisfied, because, to be blunt, Brooke's complexifying history seems to have little to recommend it besides its truth.

John Brooke is a self-described historical voyeur. ‘I like to stand back from the heated polemics’, he confesses, ‘and examine the enormous diversity and richness in the debate’. Fortunately for him he does not suffer this vice in isolation. Thus he has avoided the fate of many scholars who eschew notoriety for insight and accuracy. Not long ago one American intellectual suggested that ‘Historians who offer “multicausal explanations” – and use phrases like that – do not last, while those who discover the hidden wellspring of absolutely everything are imitated and attacked but never forgotten’.

Some years after writing his famous essay On the Origin of Species (1859), Charles Darwin noted that his primary goals had been to overthrow “the dogma of separate creations” and to establish natural selection as the primary, through far from exclusive, mechanism of change. Regarding the relative importance of these twin goals, he left no doubt. “Personally, of course, I care much about Natural Selection,” he confided to an American correspondent; “but that seems to me utterly unimportant, compared to the question of Creation or Modification.” Well into the twentieth century naturalists continued to debate the merits of natural selection, but since the early 1870s they have been describing the theory of common descent as an “ascertained fact.” The ultimate Darwinian heresy was thus the denial of common descent.

Despite the frequent claims of anti-evolutionists to the contrary, during the first quarter of the twentieth century about the only biologist of repute who rejected organic evolution was Albert Fleischmann (1862–1942), a respectable but relatively obscure German zoologist who taught for decades at the University of Erlangen in Bavaria. In 1901 he published a scientific critique of organic evolution, Die Descendenztheorie, in which he dismissed not only natural selection but also the notion of common descent. This gave him a unique reputation among biologists. As Vernon L. Kellogg noted in 1907, Fleischmann seemed to be “the only biologist of recognized position … who publicly declared a disbelief in the theory of descent.”