When Darwin’s publisher John Murray consulted a colleague on Darwin’s manuscript of The Descent of Man, and Selection in Relation to Sex, the response he received was that ‘the arguments in the sheets you have sent me appear to me to be little better than drivel’ (Browne [2021], p. 14). Fortunately, this did not deter Murray from going ahead with publication. In the 150 years since, the ideas Darwin expressed in those pages have had a multitude of scientific, moral, and political lives. Some, like sexual selection, were neglected for many years and their significance not appreciated until much later. Others, like those on racial difference, lived longer than they ought to have. Regardless, the influence of Descent is evident in contemporary thinking about evolution, humanity, and society.

In Sex, Gender, Ethics and the Darwinian Evolution of Mankind, Michel Veuille brings together an impressive range of philosophical, historical, and biological perspectives on Descent and its legacies. The work of the late historian and philosopher of biology Jean Gayon demonstrated so clearly the fruitful complementarity of history and philosophy in understanding Darwin and Darwinism. This volume, dedicated to his memory, is a fitting continuation and should be of interest to historians and philosophers of biology alike. In the following discussion, I group the chapters according to the title’s topics of sex, gender, and ethics, beginning with the topic of sex and sexual selection.

The second part of Darwin’s The Descent of Man is devoted to elaborating on the process of sexual selection, an idea that he had introduced in The Origin of Species. As defined by Darwin ([1871], p. 256), sexual selection ‘depends on the advantage which certain individuals have over other individuals of the same sex and species, in exclusive relation to reproduction’. While natural selection concerns the ‘struggle for existence’, sexual selection concerns mating success—competition between individuals of the same sex for mating opportunities, or preferences of individuals of one sex for mating with certain individuals of the other sex. These processes of sexual selection can produce traits that do not contribute to individual survival, and may even hinder it—including some of the most impressive and beautiful traits across the natural world, like oversized antlers, elaborate plumage, and intricate courtship displays. Darwin’s basic insights are fundamental to sexual selection research today.

Appropriately then, several chapters in this volume explore Darwin’s account of sexual selection and its legacies. Jean Gayon, among his many contributions to the study of Darwin, wrote insightfully on Darwin’s distinction between natural and sexual selection, and the divergence between Darwin and Wallace on this issue (for example, Gayon [2010]). Acknowledgment of this comes in the form of a reprinted excerpt of an interview with Gayon that provides an overview of these issues (chapter 5). Jonathan Hodge (chapter 4) provides an exploration of Darwin’s analogical reasoning with regards to the contrast between natural and sexual selection (another examination of Darwin’s reasoning, this time in identifying Africa as the birthplace of humanity, comes in Jorge Martínez Contreras’s contribution in chapter 12).

Contributions by Alan Grafen and Hugh Desmond provide further demonstrations of the fruitfulness of understanding Darwin for contemporary evolutionary theory. Grafen’s longstanding formal Darwinism project has worked to provide mathematical foundations for Darwin’s argument that natural selection leads to the appearance of design. In this volume, Grafen (chapter 6) teases out the underlying logic of Darwin’s account of sexual selection and considers how this might be distinguished from natural selection mathematically. Desmond (chapter 7), concerned with organismal agency and the appreciation of beauty, also begins from Darwin. According to Desmond, Darwin should be read as holding the intuition that female mate choice, at least in some species, involves a real aesthetic sense—an appreciation for beauty in itself, not just because (for example) it triggers pleasure. Desmond then provides a compelling argument in support of Darwin’s intuition through a journey into the empirical evidence for the dynamic preference structure of peahens.

The volume also tackles the topic of sex through a variety of perspectives on the puzzle of the evolution of sex ratios. Why do most species have roughly even numbers of males and females? This isn’t a question that can be straightforwardly answered in terms of natural selection on individuals, and Darwin himself recognized this and grasped for solutions. Darwin attempted an answer in the first edition of The Descent of Man—in monogamous species, an excess of one sex will lead to more individuals of that sex failing to mate. So, parents that produce offspring of the less common sex will have more productive offspring. If sex determination is inherited, then in the aggregate natural selection will tend towards equal sex ratios. In the second edition, Darwin ([1874], p. 260) retracted this theory, replacing the passage with a discussion of the empirical evidence of sex ratios in humans and the concession that the puzzle of equal sex ratios is ‘so intricate that it is safer to leave its solution for the future’. Why did Darwin lose faith in his previous theory? The significance of Darwin’s retraction is under-discussed; the volume remedies this, placing three different perspectives on the retraction in conversation with one another.

Elliot Sober (chapter 9) provides two hypotheses for the mystery of Darwin’s retraction: Darwin might have come to appreciate that even sex ratios evolved prior to monogamy, following phylogenetic reasoning to undermine the theory that monogamy results in even sex ratios; or perhaps Darwin began to doubt his initial focus on ‘excess’ individuals rather than average effects. For Veuille (chapter 11), the retraction can be explained in terms of a contradiction Darwin faced with his initial theory when up against his (now known to be flawed) assumptions about heredity. Or perhaps the retraction is no mystery at all: Andre Ariew (chapter 10) suggests that the retraction was a result of Darwin putting his theory to the test. While in the first edition Darwin relied on thought experiments, empirical data on sex ratios in human populations failed to provide conclusive evidence.

Turning next to the subject of ethics, contributions in this volume address two broad dimensions: Darwin’s own theory of the evolution of morality (and its relevance to contemporary moral philosophy), and the implications of Darwinism for questions of equality and human rights. On the former, Hayley Clatterbuck (chapter 2) provides an intriguing reconstruction of Darwin’s theory of morality, and the ways in which Darwin’s view conflicts with contemporary evolutionary debunking arguments. Darwin’s ethical vision might also have relevance for exploration of moral virtues: Eric Charmetant (chapter 3) examines Darwin’s philosophical influences to unpack his notion of virtue, and suggests resonances with Aristotelian virtues.

The racism and sexism in Darwin’s own thinking have been well documented. In the opening chapter to the volume, Michael Ruse (chapter 1) outlines how Darwin’s own views on race, gender, and homosexuality are reflective of his Christian education and the mores of Victorian society—and how Darwin’s own theory set the stage for radically different thinking on those same topics. The legacies of Darwinism in terms of the expanding circle of moral regard and the idea of universal human rights is explored further later in the volume. Gregory Radick (chapter 14) traces shifts from Darwin’s conception of humankind as united by common ancestry but also characterized by racial hierarchy, to Darwinism’s twentieth century transformation into a means to underwrite racial equality while distancing humans from non-human animals, to the twenty-first century expansion of the moral circle in Peter Singer’s articulation of speciesism.

The volume address not only the moral and political legacies of the Darwinian vision of humanity, but also its scientific legacies embodied in a range of Darwinian approaches to human behaviour, society, and culture. The final two chapters in the volume focus on contemporary Darwinian frameworks for the social sciences, examining evolutionary psychology and cultural evolution as two research programmes that have taken up the mantle of Darwinism in differing ways. Both Philippe Huneman’s and Agathe du Crest’s contributions (chapters 15 and 16, respectively) outline key differences between evolutionary psychology and cultural evolution. Both chapters compare cultural evolution favourably to evolutionary psychology, highlighting problems with central assumptions of evolutionary psychology (particularly the ‘Santa Barbara school’ epitomized by the work of John Tooby and Leda Cosmides)—problems that cultural evolution apparently avoids. Many of these insights will not be novel to those who are familiar with many long-standing critiques of this kind of evolutionary psychology (Buller [2006]; Rose and Rose [2010]; Smith [2020]). But we might also call into question the overall impression these chapters give of the relative superiority of cultural evolution over evolutionary psychology for understanding human societies. For one, critiques of cultural evolution are left out of the discussions (for example, Fracchia and Lewontin [1999]; Ingold [2007]; Chellappoo [2022]; Valković [2024]). Also, while the multiplicity of approaches within cultural evolution is acknowledged in these chapters, the focus on the Tooby and Cosmides approach ignores the diversity of work within evolutionary psychology that relaxes some of its most problematic assumptions (Burke [2014]). Nevertheless, the exploration of the legacies of The Descent in contemporary evolutionary approaches to culture provides an interesting complement to the rest of the volume.

Du Crest (chapter 16) brings in feminist critiques to highlight the limitations of evolutionary psychology in relation to its treatment of putative differences between men and women—a welcome engagement with Darwinian perspectives on gender`. As one of the three topics in the title of the volume, gender receives little attention in comparison to sex and ethics. While coming in at the edges of discussions in many of the contributions, gender does not appear as a central focus. The notable exception is Claudine Cohen’s fascinating exploration of Darwin’s views of gender relations and the legacies of Descent in feminist archaeology (chapter 13). Cohen highlights how traditional ideology that takes male superiority as a given coloured Darwin’s understanding, while at the same time his account of gender differences as arising from sexual selection makes these differences the outcomes of a ‘process’ and not a ‘predestination’. These tensions are present in the varying ways that Darwin’s ideas have been taken up: while evolved gender differences have been interpreted by some in deterministic and reductive terms, attention to contingency and variation in evolutionary processes can undermine grand narratives or myths in search of the ‘natural origins’ of gender. The history of the relationships between Darwinism and feminism is complex (Deutscher [2004]; Hamlin [2014]), and further examination of the impacts of Descent on questions of gender and feminism would have been a valuable addition to the volume.

Many of the contributions in the volume ably demonstrate how historical investigation can enrich philosophical analysis—from examining and reconstructing Darwin’s reasoning, to tracing the trajectories of Darwinian thought, to exploring what revisiting Darwin can do to illuminate current philosophical debates. The result is a wide-ranging and thought-provoking examination of various aspects of Darwin’s thinking in Descent, and its impact on our understanding of the natural and social world.

Azita Chellappoo
The Open University
azita.chellappoo@open.ac.uk

References

Browne, J. [2021]: ‘Introduction’, in J. DeSilva (ed.), A Most Interesting Problem: What Darwin’s Descent of Man Got Right and Wrong about Human Evolution, Princeton, NJ: Princeton University Press, pp. 1–23.

Buller, D. J. [2006]: Adapting Minds: Evolutionary Psychology and the Persistent Quest for Human Nature, Cambridge, MA: MIT press.

Burke, D. [2014]: ‘Why Isn’t Everyone an Evolutionary Psychologist?’, Frontiers in Psychology, 5, available at .

Chellappoo, A. [2022]: ‘When Can Cultural Selection Explain Adaptation?’, Biology and Philosophy, 37, available at doi.org/10.1007/s10539-021-09831-0.

Darwin, C. [1871]: Descent of Man, 1st ed., London: Murray.

Darwin, C. [1874]: Descent of Man, 2nd ed., London: Murray.

Deutscher, P. [2004]: ‘The Descent of Man and the Evolution of Woman’, Hypatia, 19, pp. 35–55.

Fracchia, J. and Lewontin, R. C. [1999]: ‘Does Culture Evolve?’, History and Theory, 38, pp. 52–78.

Gayon, J. [2010]: ‘Sexual Selection: Another Darwinian Process’, Comptes Rendus. Biologies, 333, pp. 134–44.

Hamlin, K. A. [2014]: From Eve to Evolution: Darwin, Science, and Women’s Rights in Gilded Age America, Chicago, IL: University of Chicago Press.

Ingold, T. [2007]: ‘The Trouble with “Evolutionary Biology”’, Anthropology Today, 23, pp. 13–17.

Rose, H. and Rose, S. [2010]: Alas Poor Darwin: Arguments against Evolutionary Psychology, London: Vintage.

Smith, S. E. [2020]: ‘Is Evolutionary Psychology Possible?’, Biological Theory, 15, pp. 39–49.

Valković, M. [2024]: ‘Ontological and Methodological Limitations of Certain Cultural Evolution Approaches’, Philosophy of the Social Sciences, 54, pp. 279–301.