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)

Heredity has been dismissed as an insignificant object in Claude Bernard’s physiology, and the topic is usually ignored by historians. Yet, thirty years ago, Jean Gayon demonstrated that Bernard did elaborate on the subject. The present paper aims at reassessing the issue of heredity in Claude Bernard’s project of a “general physiology”. My first claim is that Bernard’s interest in heredity was linked to his ambitious goal of redefining general physiology in relation to morphology. In 1867, not only was morphology (...) included within experimental physiology, but it also theoretically grounded physiological investigations. By 1878, morphology and physiology were considered as completely independent sciences, and only the latter was perceived as suitable to experimentation. My second claim is that this reversal reflected the existence of two opposite attitudes towards heredity. In the late 1860s, Bernard was convinced that heredity would soon be accessible to experimental manipulation and that new species would be produced in the laboratory exactly like organic chemistry succeeded to do for raw bodies. Ten years later, he ascertained that this was impossible. My third claim is that Bernard was epistemologically ill-equipped to address the issue of heredity. Bernard was strongly committed to a general reasoning scheme that acknowledged only three categories: determining conditions, constant laws and phenomena. This scheme was a key factor in his successes as a physiologist who was able to capture new mechanisms in living bodies. Nonetheless, it also prevented him from understanding how time and history could be endowed with a causal action that cannot be reduced to timeless parameters. (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)

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)

This article shows how Lamarckism was essential in the birth of the French school of molecular biology. We argue that the concept of inheritance of acquired characters positively shaped debates surrounding bacteriophagy and lysogeny in the Pasteurian tradition during the interwar period. During this period the typical Lamarckian account of heredity treated it as the continuation of protoplasmic physiology in daughter cells. Félix d’Hérelle applied this conception to argue that there was only one species of bacteriophage and Jules Bordet applied (...) it to develop an account of bacteriophagy as a transmissible form of autolysis and to analyze the new phenomenon of lysogeny. In a long-standing controversy with Bordet, Eugène Wollman deployed a more morphological understanding of the inheritance of acquired characters, yielding a particulate, but still Lamarckian, account of lysogeny. We then turn to André Lwoff who, with several colleagues, completed Wollman’s research program from 1949 to 1953. We examine how he gradually set aside the Lamarckian background, finally removing inheritance of acquired characters from the resulting account of bacteriophagy and lysogeny. In the conclusion, we emphasize the complex dual role of Lamarckism as it moved from an assumed explanatory framework to a challenge that the nascent molecular biology had to overcome. (shrink)

La publication presque simultanée de L'Ordre biologique d'André Lwoff (1969), de La Logique du vivant de François Jacob (1970), du Hasard et la nécessité de Jacques Monod (1970) et les débats qui s'ensuivirent, ont constitué un moment fort de la vie intellectuelle française. Comme il serait difficile aujourd'hui d'imaginer des débats analogues, réunissant philosophes et scientifiques autour de questions aussi fondamentales que la nature de l'objectivité scientifique et l'explication des phénomènes vivants! Le contexte scientifique et culturel explique la genèse de (...) ces trois ouvrages et les réactions qui suivirent leur publication. Dès 1971, un bel article de Georges Canguilhem en soulignait les convergences. Ce livre montre qu'ils sont le fruit des avancées rapides survenues dans la description moléculaire des organismes vivants. L'impact de ces découvertes est d'autant plus important en France que les transformations précédentes des sciences du vivant, l'essor de la génétique et de la synthèse moderne dans les années1930 - nouvelle version de la théorie de l'évolution -, y étaient passées inaperçues. Ce recueil vise à rappeler, mais surtout à faire mieux comprendre, ce moment si riche - avec l'espoir secret d'y trouver des recettes pour réanimer une vie intellectuelle devenue aujourd'hui bien fade. (shrink)

That Jean Gayon never paid attention to Darwin’sDarwin, CharlespangenesisPangenesis might seem like an oddity given that natural selectionSelection and biological heredity were his primary focuses for decades. This lack of interest reveals Gayon’s specific methodological orientation: he aimed at producing rational reconstructionsRational reconstruction of the way a scientific hypothesisHypothesis entered experimentation and subsequently evolved within a specific theoretical pattern. Gayon’s most important achievements, Darwinism’sDarwinismStruggle for Survival (1998) in the first place, were all based on this “structuralist approachStructuralist approach (to history (...) of science)”, where philosophy of science provides a strong problematization and even shapes the historical narrative. I argue that LakatosLakatos, Imreand DuhemDuhem, Pierre were Gayon’s main inspirations, and that his work is thereby substantially different from both philosophy of biology andHistorical epistemology French historical epistemologyGayon, JeanOn historical epistemology. (shrink)