On the morning of June 18, 1858, Charles Darwin opened a letter from a naturalist named Alfred Russel Wallace and felt the ground shift beneath him. Wallace, working independently in the Malay Archipelago, had arrived at a theory of natural selection so close to Darwin's own that Darwin wrote to his friend Charles Lyell in a state of near despair, saying that all his originality would be smashed. He had been working on his theory for twenty years, accumulating evidence with characteristic patience and caution, aware of what it would mean when it was finally published and in no hurry to face the consequences. Now, a letter from a remote island had forced his hand. What followed was one of the more delicate negotiations in the history of science. Lyell and Joseph Hooker arranged for papers by both Darwin and Wallace to be read jointly at the Linnean Society, establishing the simultaneous but independent discovery of the principle. Darwin spent the next thirteen months writing what he called an abstract of the larger work he had planned, and On the Origin of Species was published in November 1859. The first edition sold out on the day it was released. Wallace, to his considerable credit, spent the rest of his life insisting that Darwin deserved the greater recognition. Darwin spent the rest of his life worrying that he had not given Wallace enough.
English naturalist Charles Darwin (1809–1882) laid the foundations of evolutionary biology through the process of natural selection, which he outlined in On the Origin of Species with an accumulation of evidence and a clarity of argument that transformed not only biology but the broader landscape of human thought. The idea that all living species share common ancestors, shaped over vast stretches of time by variation and selection, was not merely a scientific hypothesis. It was a reorientation of humanity's understanding of its own place in nature, with consequences for philosophy, theology, psychology, and the social sciences that continue to unfold today.
Yet the history of that idea is considerably more complex than the familiar story of a solitary genius and his dangerous book. How evolutionary thinking developed before Darwin, how it was received and transformed after him, and how the science has continued to evolve in ways that both confirm and complicate his original vision, are questions that require a historian as much as a biologist. Peter J. Bowler, Professor Emeritus of the history of science at Queen's University Belfast and the author of numerous works on the history of evolutionary theory and environmental sciences, has spent his career mapping exactly this terrain, bringing to it both scholarly rigor and a genuine feel for how ideas move through time and culture.
In the conversation that follows, Bowler guides us into the full history of evolutionary thought, illuminating the debates, the misconceptions, and the continuing vitality of an idea that began with a letter from a remote island and has never stopped reshaping how we understand life, including our own.
Charles Carlini: You’ve been writing about Charles Darwin and the development of Darwinism for many years, and you were the President of the British Society for the History of Science between 2004 and 2006. Could you explain what the term “Darwinism” really refers to? What is the difference between Darwinism and evolutionism?
Peter J. Bowler: It’s easier to begin with “evolutionism,” which refers to any theory that explains the origin of the animals and plant species we see around us in terms of a natural process by which previous forms (some of which have left their remains in the fossil record) changed into the modern ones. Conventionally, it’s assumed that the process operated continuously throughout the history of life on Earth so that we are all ultimately derived from the first living things. How those first forms of life arose is a different problem, and one we haven’t solved yet.
“Darwinism” is a particular explanation of how evolution occurred. In its most basic form, it proposes a mechanism of change called natural selection, but more broadly, it focuses attention on how species adapt to changes in their environment and rejects any suggestion that there are built-in trends forcing evolution in particular directions, e.g., a progressive trend. For Darwinists, progress is always a by-product of adaptation, and most adaptive changes are not progressive in any meaningful sense—some are even degenerative, as in the evolution of parasites.
Natural selection looks to the variation among individuals within a population as its raw material (now known to result from genetic mutation). Variations are produced without regard to how the species lives, but if, by chance, one variant/mutation is better adapted to the environment, it will breed more successfully, while any that are maladaptive will be weeded out. Over many generations, this will change the species' genetic makeup, making it better adapted overall. But that’s only “better” in that one environment—if the conditions change, the species will change again.
CC: The bulk of your research and publication addresses not only Darwin but also the history of early 20th-century environmental science as a whole. What first drew you to this field? Why do you believe this is an important subject to study, and what can we learn from examining the development of science in this period?
PJB: I have to confess that I wrote my big book on the environmental sciences only because I was offered a generous advance by the publisher to contribute to the series they were planning to introduce general readers to the history of science. It took me way beyond the areas I normally work in, so I learned to think more widely about how different areas of science link together. I also got to work with the editor of the series, the late Roy Porter, who taught me a lot about writing at this level. Since then, my interests have moved off in different directions, including the study of science and religion, so I haven’t really been keeping up with detailed work in the history of ecology. But I do still think it’s vital for us to think more carefully about the environment and how we study and exploit it. Most people think ecology is something to do with back-to-nature environmentalism, but in fact, it’s a collection of scientific disciplines that study the environment. They have no necessary connection to any ideological position, although, of course, they are used by environmentalists and their opponents. Looking at history helps us sort out these relationships by showing how they emerged.
CC: You note in the introduction to Charles Darwin: The Man and His Influence that Darwin was not the only person with views on evolution in the early 19th century, and that his theory of evolution was not the only one at the time. Could you briefly summarize who some of the other leading evolutionists were? How did their contributions impact the development of evolutionary theory?
PJB: Charles Darwin certainly wasn’t the first evolutionist, although he played a major role in getting the idea generally accepted and proposed the mechanism (natural selection) that modern biologists have adopted. Around 1800, two important figures promoted the general idea of evolution—the French naturalist J. B. Lamarck and Darwin’s own grandfather, Erasmus Darwin. They thought the process worked by adding up the effects of the individual animals’ efforts to cope with the environment, the so-called “acquired characters” (for example, the blacksmith’s bulging muscles). This process became known as Lamarckism and later formed one of the main alternatives to natural selection (even Charles Darwin accepted it as a subsidiary mechanism). Only in the early 20th century did the emergence of genetics show that acquired characters cannot be inherited.
CC: Evolution and Darwinism are primarily considered matters of biology, but you note in your History of an Idea that other scientific fields had an impact as well. How did new developments in geology and paleontology support Darwin’s theory of evolution?
PJB: You can’t have a theory of evolution unless you think the earth is immensely old, so in that sense, the emergence of geology as a science was a vital prerequisite. Darwin was also strongly influenced by the geologist Charles Lyell, who insisted that all changes on the earth’s surface are slow and gradual, not catastrophic. Lyell was interested in how animals and plants migrate around the earth as conditions change. That was how Darwin came to study biogeography, most obviously in the Galapagos Islands, as a clue to how evolution works. He saw how representatives of a single species, such as the finches, had diversified into several forms once they were transported to the separate islands in the group.
Fossils were also important for showing that living forms had changed over Earth’s history. But they weren’t really crucial for Darwin because he realized that most species have not left fossil remains, so the few that have been found don’t always offer us a detailed picture of how the evolution of a particular group has occurred. Biogeography was much more important for him.
CC: Darwin was and remains a controversial figure, with (primarily American) fundamentalist groups today still resisting the theory of evolution. You state early in The Man and His Influence that “the resulting debates reveal that even today most ordinary people still do not understand the basic principles upon which Darwin’s theory is based. What do you believe can be done to foster understanding of Darwin’s work and evolutionism as a whole? Is the creationism vs. evolution debate a healthy one, or is it distracting from the real issue?
PJB: There are certainly a lot of misunderstandings about Darwinism, some deliberately fostered by the creationists. For instance, many people think the primary evidence for evolution is the fossil record, which allows creationists to point to gaps and say it doesn’t work (although discoveries are constantly filling those gaps). People don’t remember that it was the geographical distribution of animals and birds that Darwin studied during the Beagle voyage that first led him to doubt the fixity of species.
There is also a common tendency to identify evolution with progress, although Darwinism holds that the driving force of change is adaptation, with progress to higher states as a rare byproduct. But explaining this only makes some people’s problems worse, because the theory implies that there was nothing inevitable about the emergence of the human race—we are not the intended goal of evolution. There are many liberal religious thinkers who are prepared to accept the general idea of evolution, but find it hard to live with the idea that we are not its goal. They accept that when the Bible speaks of “creation,” we should realize it was written for people who could not have understood anything like the modern scientific picture of the earth’s history, so the text of Genesis shouldn’t be taken literally. But even so, if God created us indirectly through evolution, His purpose would have to be manifest in the process. It’s very difficult (although not impossible) to see natural selection as an agent of divine purpose. Hence, the enthusiasm for Intelligent Design, although that position simply gives up on the hope of any scientifically verifiable explanation.
Fundamentalism poses a different problem altogether. For those who think the text of the Bible has to be taken literally, the whole scientific picture of the past—not just evolutionism—has to be false. Young-earth creationism insists that the Earth is only a few thousand years old. I sometimes wonder why these people bother to attack Darwinism in detail, because if they could establish their position on Earth's history, any form of evolution would be inconceivable. They pretend their alternative is scientifically viable, but they cherry-pick a few things that fit their viewpoint, deflecting attention from all the evidence that doesn't. Their tactics are partly responsible for the public's ignorance of the evidence on the evolutionists’ side.
One interesting development is the emergence of Islamic fundamentalism, which also rejects evolutionism because it’s inconsistent with the creation story in the Koran. Worrying at one level, but the skeptics can now ask the fundamentalists to get their act together and decide which sacred text we’re supposed to take literally.
CC: The first edition of Evolution: The History of an Idea was originally published in 1989, and in the first chapter, you state that “Whatever the success of evolution theory in science, the cultural phase of the Darwinian revolution has not yet reached its conclusion.” Almost 25 years later, do you think this is still true? How has the Darwinian revolution progressed culturally since then, and if that progress remains unfinished, how do you see it ending?
PJB: Obviously, to the extent that there is still massive religious opposition to evolutionism, the comments I made back in 1989 about the revolution not being completed are still valid. As long as there are people who feel they have to take an ancient text literally to maintain their faith, the scientific view of Earth's history will remain a source of controversy.
CC: One of the major shifts in the Darwinian revolution happened long after Darwin himself had died, with the rediscovery of genetics and trait inheritance in the early 20th century. Culturally speaking, was the union of Darwin’s theories with those of Gregor Mendel helpful for the Darwinian movement? Did people find the idea of evolution easier to accept once genetics entered the picture?
PJB: The emergence of genetics certainly boosted the credibility of Darwinism by supplying a credible mechanism of variation and heredity. But it didn’t do that immediately, and the early geneticists rejected the idea that selection removed harmful mutations. They were, however, opposed to rival theories such as Lamarckism (the idea that acquired characters can be imprinted on genes), and by the 1930s, it was recognized that selection acting on mutations provided the best explanation of adaptive evolution. To the extent that everyone now realizes the importance of genes, Darwinism becomes more plausible. Natural selection explains the constant emergence of bacteria resistant to antibiotics, a major problem in modern medicine. But the creationists don’t seem interested—to them, they’re just different bugs that have no relevance to the emergence of new species.
CC: Darwin’s theories have had not only religious implications, but also political ones, with some groups applying the concept of natural selection to economics and class struggle. To what extent did this political argument impact the cultural battle over Darwinism and evolutionism as they applied to science? How might Darwin himself have viewed the idea of “Social Darwinism?”
PJB: Most historians accept that Darwin drew some inspiration for his theory of natural selection from the competitive free-market society in which he lived—individuals jockey for position and the losers face serious difficulties. But he didn’t endorse the view that we should encourage ruthless behavior, because he knew we had evolved as social creatures and had acquired cooperative instincts, which are the source of our moral values. His theory was nevertheless used to “justify” various ideologies of social conflict, which were called “social Darwinism.” But his theory cannot have been the direct inspiration for these ideologies because they are mutually inconsistent. Some social Darwinists applauded individual competition (free-market capitalism), some opted for national rivalry (militarism), and others for racial struggle (imperialism and colonialism). Darwin was passionately opposed to slavery and held that the human races are all closely related—the claim that the races are separate species with distinct origins was more often supported by creationists and non-Darwinian evolutionists.
CC: Many of Darwin’s pro-evolution followers, including “Darwin’s bulldog” Thomas Huxley, actually rejected Darwin’s theory of natural selection. Why was this? What were their objections to natural selection as a cause of evolution?
PJB: Huxley was a staunch defender of “Darwinism” when the term was still used to denote the general idea of evolution, but he didn’t think natural selection could be a complete explanation because he doubted that adaptation was the most crucial factor. He thought that some form of internal, biological process shaped the variations that appear and hence the route that evolution can take. It can’t be totally non-adaptive, but the routes open to it are constrained by the available variations. Modern proponents of evolutionary developmental biology (evo-devo) adopt a somewhat similar position. Some non-Darwinian evolutionists opted for the Lamarckian theory of the inheritance of acquired characters. In its most basic form, that was disproved by genetics, but modern epigenetic studies suggest that processes superficially similar to Lamarckism may play a role.
CC: Your publications have done a great deal to clarify the development of Darwinism. What are some common misconceptions or inaccuracies you’ve encountered about Darwin’s life and the rise of Darwinism, whether in academia or the public?
PJB: The points I’ve just made illustrate one common misconception—evolutionism isn’t a static, all-or-nothing explanation like creationism. All scientific theories evolve as discoveries are made, and evolutionism is no exception. Creationists claim that because evolutionists are constantly “changing their minds,” it can’t be a proper explanation, but one that just shows how little they understand science. Their approach, especially in its Young Earth version, does have an absolutely predetermined structure into which all the evidence must be fitted—however much twisting that takes. Scientific biologists do research, and if what they discover suggests something new, they incorporate that into the theory. The new ideas don’t overthrow Darwinism; they modify and extend it.
We’ve already covered some other misconceptions. One is the idea that evolution is a theory, more or less, based solely on the fossil record. Fossils are important, and more discoveries are constantly being made that help us see how life evolved, but there are lots of other lines of evidence, including the biogeographical work that so inspired Darwin.
Another popular misunderstanding is the belief that Darwinism is a theory of inevitable progress. Evolution is best represented as a branching tree, not a ladder, and each branch is evolving in its own way. Most adaptive changes are not progressive in any absolute sense, and some are degenerative (as in parasites) or lead to dead ends where the species cannot respond to further environmental changes. Human beings cannot be the goal of evolution because we’re just the end product of one branch, and there was no guarantee that intelligent, self-aware creatures would evolve at any point. So evolutionism offers no real guide to future progress—that’s up to us to decide. I realize how hard this vision of the human situation is for many to accept, but pretending that we’ve been given a privileged status by some mysterious Creator doesn’t really help, especially as those who believe in this Creator don’t seem to be able to agree on what He’s really like or which ancient story actually tells us about His purposes.
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