Darwin's ideas on variation, heredity, and development differ significantly from twentieth-century views. First, Darwin held that environmental changes, acting either on the reproductive organs or the body, were necessary to generate variation. Second, heredity was a developmental, not a transmissional, process; variation was a change in the developmental process of change. An analysis of Darwin's elaboration and modification of these two positions from his early notebooks (1836-1844) to the last edition of the /Variation of Animals and Plants Under Domestication/ (1875) (...) complements previous Darwin scholarship on these issues. Included in this analysis is a description of the way Darwin employed the distinction between transmission and development, as well as the conceptual relationship he saw between heredity and variation. This paper is part of a larger project comparing commitments regarding variation during the latter half of the nineteenth century. (shrink)

Comparison of the six editions of the Origin of Species reveals a definite change in Darwin's propounded theory.Although the tone of the statements seems to become more positive in later editions, the change of thought indicates a certain inability of the original theory to stand up to criticism.

References in Darwin’s Origin of Species to competition between units of selection at and above the level of individual organisms are enumerated. In many cases these references clearly speak of natural selection and do not support the view that Darwin thought selection only occurred at the level of the individual organism. Darwin did see organismal selection as the main process by which varieties were created but he also espoused what is here termed community and varietal selection. He saw no essential (...) difference between varieties and species and the references show that he also believed that selection could operate at the species level. (shrink)

This essay examines the relation of Darwin's orchids book to a central persuasive flaw in theOrigin: Its inability to give variation sufficient “presence” to break the hold of “design” in the mind of the reader. Darwin characterized the orchids book as “a flank movement on the enemy”; this essay identifies the “enemy” as Paley's natural theology and the “flank” as thetopoi, maxims, and habits of perception that led Darwin's colleagues and contemporaries to see design in nature. Moreover, this essay examines (...) three aspects of rhetorical timing pertinent toOrchids - time askairos, time as adequate duration, and time as transformation - and then relates those features to Robert Cox's Heideggerian logic of repetition, disavowal, and transcendence. The essay concludes with implications of the tactical and temporal aspects of Darwin's reasoning for understanding both the logic of science and of Darwin as a rhetorical artist. (shrink)

A great deal is known about the technical issues surrounding the introduction of Hugo De Vries's mutation theory and the subsequent development of the modern genetical theory of natural selection. But so far little has been done to relate these events to the wider issues of the time. This article suggests that extra-scientific factors played a significant role, and substantiates this by comparing De Vries's respect for the original Darwinian spirit with Thomas Hunt Morgan's use of the mutation theory as (...) part of an attack on the whole philosophy of Darwinism. In particular, it is argued that Morgan's attitude was dictated by his moral objections to the picture of a world dominated by struggle. (shrink)

Historians of science generally consider that Darwinism has played an important part in the birth of scientific ecology. Now most 19th century seminal works of the new discipline have been elaborated within a Lamarckian framework. The source of this paradox lies in the double-content of the adaptation concept, considered as a static phenomenon by the ecologists and as a dynamic process by the evolutionists. Although closely related nowadays, as shown by modern evolutionary ecology, the problematics of the fields of research (...) at issue were initially separated. (shrink)