Jean Gayon

Dans la théorie contemporaine de l’évolution, trois sens classiques de la notion de hasard interviennent : la notion ordinaire de chance, la notion probabiliste de l’aléatoire, et la notion épistémologique de contingence relativement à un système théorique. Ces trois notions suffisent à définir le statut du hasard aux principaux niveaux du processus évolutif où l’on invoque communément des effets fortuits : mutations, dérive génétique, révolutions génétiques, changements écologiques, macroévolution. On se demande enfin si les divers sens du hasard rencontrés dans cette étude peuvent être ramenés à l’unité, et s’ils renvoient à un hasard subjectif ou à un hasard objectif. In the contemporary theory of evolution, three classical meanings of the notion of chance come into play : the ordinary meaning of chance, the probabilistic notion of randomness, and the epistemological notion of contingency with reference to a theoretical system. These three notions are sufficient in order to define the status of chance on the principal levels of the evolutive process where fortuitous effects are commonly invoked : mutations, genetic deviations, genetic revolutions, ecological changes, macroevolution. The question is raised, finally, whether the diverse meanings of chance considered in the present study may be brought to one, and whether they refer to a subjective form of chance or to an objective chance.

Did Darwin Write the Origin Backwards is Sober’s book that comes closest to history of science. Some reviews have expressed reservations about Sober’s inclination to subordinate historical accuracy to analytical clarity, and to contemporary discussions . My comments will be devoted to the kind of relationship that Sober entertains with history of science. I do not think that the author’s interest in history is superficial and instrumental.In the first section, I try to locate Sober’s book within ‘&HPS’ , a recent initiative that gathers a growing number of people willing to promote a new regime of interaction between philosophy and history of science. I will suggest that Sober offers an interesting way of developing this approach. The more critical second section is devoted to Sober’s first chapter, bearing on the relationship between the two main tenets of Darwin’s argument in the Origin—descent with modif ..