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:

Thomas Henry Huxley’s reaction to Darwin’s idea is understandable: “How extremely stupid of me not to have thought of that!” Darwin’s argument is not arcane. Why did we have to wait so long for an idea as simple and attractive as Darwin’s? An attempt to answer this question by means of a narrow set of influences is likely to produce an account that is, at best, impressionistic. However, that teleology played a leading role is widely accepted, as Darwin himself always recognized that the appearance of design is distinctive of the organic world, having been raised on the teleological argument of Archdeacon William Paley. And an important part of the conceptual network wherein Darwin found himself developed in antiquity. Classical thinkers erected much of the scaffolding with which evolutionists have had to work, framing the debate over teleology in important ways. Early cosmologists thought the idea of the world’s coming to be from nothing as unintelligible. Early teleologists thought getting order out of chaos, equally unsettling, akin to getting something from nothing.

The Early Cosmologists

Natural philosophy before Socrates can be said to concern the origin of the cosmos. The problem of origin, as one might call it, can be characterized in terms of the following three claims:

1. Coming to exist involves a transition from nonbeing to being.

2. Things come to exist.

3. Only that which has being can undergo a transition of any kind.

Darwin’s theory of evolution by natural selection required time for its operation. Darwin (1859, 287) knew that “it is highly important for us to gain some notion, however imperfect, of the lapse of years.” He needed some idea of the total amount of time available and the rate at which evolution took place, but he lacked data on both. Perhaps he was minded of the situation he faced when cataloging the world’s coral reefs and developing a theory for their origin, when he had to resort to unquantified phrases such as “slowly sinking” and “prolonged subsidence” (Darwin 1842c). For evolution, he had some relative data on roughly in which order certain taxa had evolved through geological time, but he also lacked detail here, especially with regard to the most recent parts of the geological record, and so he kept a close eye on the rates of appearance of domesticated varieties in relation to the archaeological record (Darwin 1868b). He became entangled with involved discussions on matters for which we now have far more complete data, but where his instincts were broadly correct. On the other hand, he and his contemporaries lacked information on the complexity and rapidity of geological changes (e.g., during the Quaternary period) which might well have made a substantial difference to how he formulated and presented his theory of evolution. In this chapter, I briefly discuss these aspects of how knowledge, or lack of it, influenced Darwin’s ideas.

The Age of the Earth

The first edition of On the Origin of Species (Darwin 1859) predates any significant attempt at a figure for the Earth’s age. Darwin’s ideas matured in the early years of scientific discussion of topics for which contemporary answers had been provided by the Bible, and interpretations of it (including the suggestion of Buckland [1836] that “millions and millions of years” might have passed between the Creation and the Mosaic narrative). Scientific rationale for understanding the age of Earth was, however, in its infancy (Dalrymple 1991), and Darwin was concerned that objections would be raised against his theory of evolution by natural selection on the grounds that Earth was not sufficiently old, although many geologists were apparently thinking of increasingly long periods of time since the origin of Earth (A. Geikie 1893).

Charles Robert Darwin was the epitome of the nineteenth-century natural philosopher by temperament and by training. Nevertheless, the ambit of his researches, which had roots that were firmly planted in the interwoven fields of chemistry, mineralogy, and geology, is quite extraordinary in the way that it came to encompass the physical and biological world that he inhabited (A. Geikie 1909; Judd 1909; Browne 1995; Herbert 2005).

Origins and Influences

Darwin was born into a comfortable and well-respected family in the county town of Shrewsbury. His father, Robert, a noted physician, astute businessman, and financier (Browne 1995), was not scholarly in an academic sense; however, Darwin’s grandfather Erasmus was a renowned intellect. Among Erasmus’s published works were geological as well as what we might now refer to as evolutionary interpretations. The Botanic Garden (E. Darwin 1791) reveals, especially in its “Philosophical Notes XV–XXIV” and “Geological Recapitulation,” that Erasmus was well versed in contemporary debates about minerals, rocks, and earth processes. He used this to make reasoned proposals about the formation of granites, lavas, coal, limestone, clays, and ironstone and envisaged a dynamic structure to the earth that was driven by a hot fluid interior (Herbert 1991). This “dynamic” perspective also resonated with his understanding of animal life: he understood (as did his approximate contemporary in Paris, Jean-Baptiste Lamarck) that change pervades the living world. For example, Erasmus used the term “evolution” but used it as a descriptor of growth (ontogeny): the changes in structure and appearance that occur during the lifetime of any individual as it develops on a trajectory from fertilized egg to adult. However, it is also clear that Erasmus perceived the possibility of plasticity of animal form and appearance over much longer periods of time. He used the example of the existence of purposeless or rudimentary features, such as the accessory toes seen in the feet of cattle and pigs, as suggestive that such animals formerly possessed fully functional toes but that they had become vestigial with the passage of time; and he proposed more forthright views on “transmutation” in his book Zoonomia (E. Darwin 1796).

Among the nations with a major scientific tradition in the nineteenth century, France certainly resisted the penetration of Darwin’s evolutionary ideas the most. Darwin himself observed this, in a letter he sent to the French anthropologist Armand de Quatrefages, ten years after the publication of the Origin of Species:

Some years later, Ernst Haeckel was more radical. In his popular book, The History of Creation, he insisted on the crucial role of Lamarck in the origins of evolutionary ideas, but observed that, despite this precedent, the French naturalists had simply ignored Darwin:

Darwin went public with his views on human evolution in The Descent of Man, and Selection in Relation to Sex (1871) and The Expression of the Emotions in Man and Animals (1872). By that time, he had been researching the subject on and off for decades, sometimes in unexpected directions. While on the Beagle, for example, he had met a surgeon who reported that the lice infesting Sandwich Islanders on his whaling ship were very distinctive and, furthermore, that when these lice crawled onto white men, the lice soon died. Darwin made a note about the story, adding: “If these facts were verified their interest would be great. – Man springing from one stock according his varieties having different parasites” (CUL DAR 31.315). That was in 1834, before Darwin believed that species evolve. He was nevertheless wondering how to connect the fact (as it seemed) that the human races, originating from a single stock, formed mere varieties within a single species, with the fact (as it seemed) that those races were so different physiologically as to sustain different species of lice. In 1844, and again in 1865, he quizzed England’s leading louse expert, Henry Denny, about it all – in the interim attempting to get Denny some lice from American blacks. In the Descent, Darwin cited Denny in a paragraph-long discussion of the matter. On the whole, Darwin judged, the facts about lice – and the surgeon’s observations had since been confirmed more generally – seemed to support the ranking of the different human races as distinct species (Darwin 1871a, 1:219–20; Radick and Steadman forthcoming).

Darwin and other nineteenth-century biologists found compelling evidence for biological evolution in the comparative study of living organisms, in their geographical distribution, and in the fossil remains of extinct organisms. In the Origin of Species, Darwin dedicates five chapters to the evidence for evolution: two chapters to the geological record, or, as we are more likely to say nowadays, to paleontology; two chapters to biogeography; and one chapter to comparative anatomy and embryology. Since Darwin’s time, the evidence from these sources has become stronger and more comprehensive, while biological disciplines that have emerged recently – genetics, biochemistry, ecology, animal behavior (ethology), neurobiology, and especially molecular biology – have supplied powerful additional evidence and detailed confirmation.

Darwin surely would have been pleased by the enormous accumulation of paleontological evidence, including the discovery of fossils of organisms intermediate between major groups, such as Archaeopteryx, intermediate between reptiles (dinosaurs) and birds, and Tiktaalik, intermediate between fish and tetrapods (Ahlberg and Clack 2006) and the numerous fossils and diverse species of hominins, intermediate between apes and Homo sapiens (e.g., Dalton 2006; T. D. White et al. 2006; Cela-Conde and Ayala 2007). But there are good reasons to believe that Darwin would have been most pleased and most impressed with the overwhelming evidence for evolution and precise information about evolutionary history provided by molecular biology, a source of evidence and document of history that Darwin could not have even imagined.

Disembarking from HMS Beagle on the lengthy inland expeditions that would prove so crucial for his subsequent evolutionary theorizing, Charles Darwin was conscious of the need to travel light. In the cramped quarters onboard, he had access to the ship’s “immense stock” of books, “upwards of 400 volumes!” that were ingeniously “stowed away in dry and secure places” in the poop cabin where Darwin worked and slept, and which included his own much-prized personal copies of Charles Lyell’s Principles of Geology (1830–33) and Alexander von Humboldt’s Personal Narrative of Travels to the Equinoctial Regions of the New Continent (1814–29). When on dry land among the immense vistas of South America, though, Darwin had to confine himself to just one book, and even then he was contravening Robert Fitzroy’s strict directive, “Books are never on any account to be taken out of the Vessel.” With the Beagle’s “complete library in miniature” comprising almost “all travels, & many natural history books,” Darwin’s choice of a travel reading was notable (Darwin 1985–, 1:553–54). As he recalled four decades later, “in my excursions during the voyage of the Beagle, when I could take only a single small volume, I always chose Milton.”

Paradise Lost (1667), which Darwin (2002, 48) observed was “my chief favourite,” was one of only three works of imaginative literature known to have been on board the Beagle, the others being Samuel Richardson’s sentimental epistolary novel The History of Sir Charles Grandison (1753) and Harriet Martineau’s didactic short stories Poor Laws and Paupers Illustrated (1833–34) (Darwin 1985–, 1:562–63, “Books on the Beagle”). In comparison, the shelves of the Beagle’s poop cabin groaned under the weight of more than one hundred titles on travel, geology, and natural history.

As explosive as was Darwin’s theory of evolution by natural selection in Britain, it initially received a cool response from American naturalists. This was partly because it did not engage the middle class in the United States the way it did in Britain, and partly because in the first half of the nineteenth century the United States was an intellectual and scientific backwater. Nonetheless, Darwin’s work served an important formative role in the establishment of the scientific enterprise in the United States.

Before and throughout the Darwinian revolution, science in the United States was a profoundly practical endeavor pursued primarily for its economic potential. In its emergence in the eighteenth, development in the nineteenth, and maturation in the twentieth century, American science was intricately bound to the development of new technologies and was justified almost entirely on its ability to generate practical economic, moral, or military benefits, especially when it was funded with public money. Tocqueville, the French political theorist who toured the United States about the same time that Darwin voyaged around South America, posited that Americans took up science “as a matter of business, and the only branch of it which is attended to is such as admits of an immediate practical application” (Tocqueville 2003, 65). American science thus contrasted sharply with the European scientific tradition in which science was generally pursued by wealthy gentlemen and usually for its own sake.

In 1991 Randolph Nesse and George C. Williams opened their classic article on “The Dawn of Darwinian Medicine” with the following assertion (Plates LI and LII):

The optimistic statement of the two pioneers of modern “Darwinian” or “evolutionary medicine” raises many questions. Was evolution indeed a foundation for biomedical science? Historians have traditionally located the foundations of modern medicine in clinical disciplines, anatomy, and physiology – or, from the institutional perspective, in the hospital, morgue, and the laboratory. Evolutionary and field studies do not figure in any of the major medical-historical accounts (Bynum 1994; Porter 1999; Cooter and Pickstone 2000). And, if evolutionary studies indeed gained new power to explain disease, why was Nesse and Williams’s “manifesto” published in the Quarterly Review of Biology, a journal with a traditional emphasis on evolution and, at the time of publication, edited by Williams himself, rather than in a medical journal. Why has evolutionary medicine remained marginalized from the medical community?

Certainly in the two decades following the publication of this article, a new field at the junction of evolutionary biology, molecular and developmental biology, genetics, epidemiology, and clinical medicine has gained in strength, with numerous articles, books, and first advances into medical school curricula (Nesse and Williams 1995; Stearns and Koella 2008; Gluckman, Beedle, and Hanson 2009). The appeal of evolutionary medicine is in providing a coherent framework to organize and explain facts about human biology and disease and in pointing out the importance of ultimate as well as proximal causation in understanding the human condition.

Charles Darwin is well known for his portrayal of the endless struggle in nature, the view that Tennyson immortalized as “nature red in tooth and claw” (Fig. 48.1). In addition to the fangs and claws of predators, Darwin’s “red view” also incorporated more subtle mortality factors, such as competition for food or mates, crowding, disease, parasitism, and climate flux (Plate XXXVII). Darwin detailed the central features of his red view in chapter 3 of Origin of Species (derived from chapter 5 of his unpublished “big species book”), entitled “The Struggle for Existence,” wherein he argued that the rate of population increase was so great that it regularly outstripped nature’s resources, compelling a constant struggle that had to be alleviated through a compensatory rate of death (Darwin 1859, 60–89; Darwin 1975, 172–212). Darwin proposed that the primary agent responsible for subduing this growth was “natural selection,” which drew upon the environment’s factors of mortality to eliminate the less favorable individuals and populations, thereby shaping the kinds and numbers of organisms found in nature. For Darwin, environment not only imposed the limits to growth but also applied the pressures to mold the population’s fitness. He explained that it was because of environmental “checks” that natural selection was “daily and hourly scrutinizing [for the] improvement of each organic being in relation to its organic and inorganic conditions of life” (Darwin 1859, 84). Environment, according to the red view, was an engine of “warfare” among and within species, or what his friend T. H. Huxley characterizes as a gladiatorial blood sport, in which “the creatures are fairly well treated and set to fight, where the strongest, the swiftest, and the cunningest live to fight another day” (T. H. Huxley 1894, 200; La Vergata 1990).