Since the 1990s, the terms “Lamarckism” and “Lamarckian” have seen a significant resurgence in biological publications. The discovery of new molecular mechanisms have been interpreted as evidence supporting the reality and efficiency of the inheritance of acquired characters, and thus the revival of Lamarckism. The present paper aims at giving a critical evaluation of such interpretations. I argue that two types of arguments allow to draw a clear distinction between the genuine Lamarckian concept of inheritance of acquired characters and transgenerational (...) epigenetic inheritance. The first concerns the explanandum of the processes under consideration: molecular mechanisms of transgenerational epigenetic inheritance are understood as evolved products of natural selection. This means that the kind of inheritance of acquired characters they might be responsible for is an obligatory emergent feature of evolution, whereas traditional Lamarckisms conceived the inheritance of acquired characters as a property inherent in living matter itself. The second argument concerns the explanans of the inheritance of acquired characters: in light of current knowledge, epigenetic mechanisms are not able to drive adaptive evolution by themselves. Emergent Lamarckian phenomena would be possible if and only if individual epigenetic variation allowed the inheritance of acquired characters to be a factor of unlimited change. This implies specific requirements for epigenetic variation, which I explicitly define and expand upon. I then show that given current knowledge, these requirements are not empirically grounded. (shrink)

In the years of the post-Darwinian debate, many American naturalists invoked the name of Lamarck to signal their belief in a purposive and anti-Darwinian view of evolution. Yet Weismann’s theory of germ-plasm continuity undermined the shared tenet of the neo-Lamarckian theories as well as the idea of the interchangeability between biological and social heredity. Edward Drinker Cope, the leader of the so-called “American School,” defended his neo-Lamarckian philosophy against every attempt to redefine the relationship between behavior, development, and heredity beyond (...) the epigenetic model of inheritance. This paper explores Cope’s late-career defense of neo-Lamarckism. Particular attention is dedicated to the debate he had with James Mark Baldwin before the publication of Baldwin’s own “A New Factor in Evolution”. I argue that Cope’s criticism was partly due to the fact that Baldwin’s theory of social heredity threatened Cope’s biologistic stance, as well as his attempt to preserve design in nature. This theoretical attitude had a remarkable impact on Baldwin’s arguments for the theory of organic selection. (shrink)

This essay attempts to describe the neo-Lamarckian atmosphere that was dominant in French biology for more than a century. Firstly, we demonstrate that there were not one but at least two French neo-Lamarckian traditions. This implies, therefore, that it is possible to propose a clear definition of a (neo) Lamarckian conception, and by using it, to distinguish these two traditions. We will see that these two conceptions were not dominant at the same time. The first French neo-Lamarckism (1879-1931) was structured (...) by a very mechanic view of natural processes. The main representatives of this first period were scientists such as Alfred Giard (1846-1908), Gaston Bonnier (1853-1922) and Félix Le Dantec (1869-1917). The second Lamarckism - much more vitalist in its inspiration - started to develop under the supervision of people such as Albert Vandel (1894-1980) and Pierre-Paul Grassé (1895-1985). Secondly, this essay suggests that the philosophical inclinations of these neo-Lamarckisms reactivated a very ancient and strong dichotomy of French thought. One part of this dichotomy is a material, physicalist tradition, which started with René Descartes but developed extensively during the 18th and 19th centuries. The other is a spiritual and vitalist reaction to the first one, which also had a very long history, though it is most closely associated with the work of Henri Bergson. Through Claude Bernard, the first neo-Lamarckians tried to construct a mechanical and determinist form of evolutionary theory which was, in effect, a Cartesian theory. The second wave of neo-Lamarckians wanted to reconsider the autonomy and reactivity of life forms, in contrast to purely physical systems. (shrink)

It is common to designate Lamarck and Lamarckism as the main historical references for conceptualizing the relationship between organisms and the environment. The Lamarckian principle of the inheritance of acquired characters is often considered to be the central aspect of the “environmentalism” developed in this lineage, up to recent debates concerning the possible Lamarckian origins of epigenetics. Rather than focusing only on heredity, this article will explore the materialist aspect of the Lamarckian conception of the environment, seeking to highlight that (...) the life-supporting function of physicochemical milieux was its cornerstone. Indeed, compared to the Darwinian conception of the environment, which focuses on interindividual and interspecific relationships in a given habitat, Lamarck’s emphasis on the dependencies of organisms on physicochemical environments appears to have given rise to a very active philosophical environmentalism. Studying the environmental Lamarckism of 19th-century philosophers and social scientists in France, Great Britain, and the United States, such as Comte, Quatrefages, Spencer, and Ward, I propose to analyze their contribution to the conceptualization of the environment. The social, moral, or psychological conceptions of human environments that proliferated in the second half of the 19th century deviated from Lamarck’s more material approach, but they were still referencing Lamarck. Examining the scope of their “Lamarckism,” this article seeks to highlight the common context of life sciences and social philosophy, in which the environment emerged as a central issue in the 19th century. (shrink)

Julian Huxley’s eclipse of Darwinism narrative has cast a long shadow over the historiography of evolutionary theory around the turn of the nineteenth century. It has done so by limiting who could be thought of as Darwinian. Peter Bowler used the eclipse to draw attention to previously understudied alternatives to Darwinism, but maintained the same flaw. In his research on the Non-Darwinian Revolution, he extended this problematic element even further back in time. This paper explores how late nineteenth-century neo-Darwinian conceptualizations (...) of Darwinism were later utilized by several advocates and detractors of the Modern Synthesis. John Beatty has shown how this continuity hinges at least partly on the perceived importance of the creativity of natural selection. The paper provides a more thorough look at Darwin’s two conflicting accounts of variation, ascribed to struggles in explaining quantitative versus qualitative characters. In doing so, it suggests that other forms of Darwinism persisted, in both the non-Darwinian revolution and eclipse periods, because of tension between contingency and creativity in Darwin’s own work. This tension is traced out from Darwin’s conceptions of variation into the work of Alfred Russel Wallace, Hugo de Vries, and Thomas Henry Huxley. Based on this, the eclipse narrative is criticized for not considering the meaning of Darwinism in different geographical locations. Britain and the United States showed few signs of an eclipse. Rather, the rise of German debates about Haeckel’s vision of Darwinism have been mistaken for a universal decline in support. (shrink)

William Keith Brooks was an American zoologist at Johns Hopkins University from 1876 until his death in 1908. Over the course of his career, Brooks staunchly defended Darwinism, arguing for the centrality of natural selection in evolutionary theory at a time when alternative theories, such as neo-Lamarckism, grew prominent in American biology. In his book The Law of Heredity, Brooks addressed problems raised by Darwin’s theory of pangenesis. In modifying and developing Darwin’s pangenesis, Brooks proposed a new theory of heredity (...) that sought to avoid the pitfalls of Darwin’s hypothesis. In so doing he strengthened Darwin’s theory of natural selection by undermining arguments for the inheritance of acquired characteristics. In later attacks on neo-Lamarckism, Brooks consistently defended Darwin’s theory of natural selection on logical grounds, continued to challenge the idea of the inheritance of acquired characteristics, and argued that natural selection best explained a wide range of adaptations. Finally, he critiqued Galton’s statistical view of heredity and argued that Galton had resurrected an outmoded typological concept of species, one which Darwin and other naturalists had shown to be incorrect. Brooks’s ideas resemble the “biological species concept” of the twentieth century, as developed by evolutionary biologist Ernst Mayr and others. The late-nineteenth century was not a period of total “eclipse” of Darwinism, as biologists and historians have hitherto seen it. Although the “Modern Synthesis” refers to the reconciliation of post-Mendelian genetics with evolution by natural selection, we might adjust our understanding of how the synthesis developed by seeing it as the culmination of a longer discussion that extends back to the late-nineteenth century. (shrink)