T. H. Morgan (1866–1945), the founder of the Drosophila research group in genetics that established the chromosome theory of Mendelian inheritance, has been described as a radical empiricist in the historical literature. His empiricism, furthermore, is supposed to have prejudiced him against certain scientific conclusions. This paper aims to show two things: first, that the sense in which the term empiricism has been used by scholars is too weak to be illuminating. It is necessary to distinguish between empiricism as an (...) epistemological position and the so-called methodological empiricism. I will argue that the way the latter has been presented cannot distinguish an empiricist methodology from a non-empiricist one. Second, I will show that T. H. Morgan was not an epistemological empiricist as this term is usually defined in philosophy. The reason is that he believed in the existence of genes as material entities when they were unobservable entities when they were unobservable entities introduced to account for the phenotypic ratios found in breeding experiments. These two points, of course, are interrelated. If we were to water down the meaning of empiricis, perhaps we could call Morgan an empiricist. But then we would also fail to distinguish empiricism from realism. (shrink)

Drosophila flies began to be used in the study of species evolution during the late 1930s. The geneticists Natasha Sivertzeva-Dobzhansky and Elizabeth Reed pioneered this work in the United States, and María Monclús conducted similar studies in Spain. The research they carried out with their husbands enabled Drosophila population genetics to take off and reveals a genealogy of women geneticists grounded in mutual inspiration. Their work also shows that women were present in population genetics from the beginning, although their contributions (...) have previously remained unacknowledged. The similarities between their research biographies also illustrate their position in a genealogy of partnerships working on Drosophila genetics. (shrink)

Laudan's thesis that conceptual problem solving is at least as important as empirical problem solving in scientific research is given support by a study of the relation between the chromosome theory and the Mendelian research program. It will be shown that there existed a conceptual tension between the chromosome theory and the Mendelian program. This tension was to be resolved by changing the constraints of the Mendelian program. The relation between the chromosome theory and the Mendelian program is shown to (...) be a good illustration of the influence of science itself on the rational standards governing scientific development. (shrink)

Early in his career Thomas Hunt Morgan was interested in embryology and dedicated his research to studying organisms that could regenerate. Widely regarded as a regeneration expert, Morgan was invited to deliver a series of lectures on the topic that he developed into a book, Regeneration (1901). In addition to presenting experimental work that he had conducted and supervised, Morgan also synthesized and critiqued a great deal of work by his peers and predecessors. This essay probes into the history of (...) regeneration studies by looking in depth at Regeneration and evaluating Morgan's contribution. Although famous for his work with fruit fly genetics, studying Regeneration illuminates Morgan's earlier scientific approach which emphasized the importance of studying a diversity of organisms. Surveying a broad range of regenerative phenomena allowed Morgan to institute a standard scientific terminology that continues to inform regeneration studies today. Most importantly, Morgan argued that regeneration was a fundamental aspect of the growth process and therefore should be accounted for within developmental theory. Establishing important similarities between regeneration and development allowed Morgan to make the case that regeneration could act as a model of development. The nature of the relationship between embryogenesis and regeneration remains an active area of research. (shrink)

Early in his career Thomas Hunt Morgan was interested in embryology and dedicated his research to studying organisms that could regenerate. Widely regarded as a regeneration expert, Morgan was invited to deliver a series of lectures on the topic that he developed into a book, Regeneration. In addition to presenting experimental work that he had conducted and supervised, Morgan also synthesized and critiqued a great deal of work by his peers and predecessors. This essay probes into the history of regeneration (...) studies by looking in depth at Regeneration and evaluating Morgan’s contribution. Although famous for his work with fruit fly genetics, studying Regeneration illuminates Morgan’s earlier scientific approach which emphasized the importance of studying a diversity of organisms. Surveying a broad range of regenerative phenomena allowed Morgan to institute a standard scientific terminology that continues to inform regeneration studies today. Most importantly, Morgan argued that regeneration was a fundamental aspect of the growth process and therefore should be accounted for within developmental theory. Establishing important similarities between regeneration and development allowed Morgan to make the case that regeneration could act as a model of development. The nature of the relationship between embryogenesis and regeneration remains an active area of research. (shrink)

In June 1909, scientists and dignitaries from 167 different countries gathered in Cambridge to celebrate the hundredth anniversary of Charles Darwin’s birth and the fiftieth anniversary of the publication of Origin of Species. The event was one of the most magnificent commemorations in the annals of science. Delegates gathered within the cloisters of Cambridge University not only to honor the “hero” of evolution but also to reassess the underpinnings of Darwinism at a critical juncture. With the mechanism of natural selection (...) increasingly under attack, evolutionary theory was in disarray. Against this backdrop, biologists weighed the impact of several new developments—the rediscovery of Mendel’s laws of heredity, de Vriesian mutation theory, and the linkage of sex‐cell division to the mechanism of heredity. The 1909 Darwin celebration thus represents a significant watershed in the history of modern biology that allows historians to assess the status of evolution prior to the advent of the chromosome theory of genetics. (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)

“The difficulty of discussion between people brought up in different frameworks is to be admitted,” Karl Popper writes. “But nothing is more fruitful than such a discussion; than the culture clash which has stimulated some of the greatest intellectual revolutions.”71 Certainly Kirby and Darwin were brought up in different cultures — Kirby with his Anglican-Tory orientation, Darwin with his Whig-liberal background — and certainly the clash generated some interesting theories; but it also resulted in the revival of Lamarck's discredited habit (...) theory, which took another century of careful experimentation to weed out. (shrink)

R. A. Fisher is perhaps best known for his influential theoretical contributions to the ‘Evolutionary Synthesis’ of the 1930s and 1940s in which biometry was reconciled with Mendelism. It is no accident, I believe, that when historians discuss the ‘Synthesis’, the names R. A. Fisher, Sewall Wright and J. B. S. Haldane are nearly always given in that order. Fisher's 1918 paper ‘The correlation between relatives on the supposition of Mendelian inheritance’ suggested that biometry, which emphasized the distribution of characters (...) based on continuous variation, and Mendelism, which emphasized discontinuous characters, were compatible and could be united to study evolutionary change. If one considered large numbers of discontinuous, Mendelian characters, then statistical biometrical analysis could be conducted. Thus, Fisher argued, biometry and Mendelism need not oppose each other. (shrink)

This paper has three principal aims: first, through a detailed analysis of the hypotheses and assumptions underlying Weismann’s and Morgan’s disagreement on the nature of animal regeneration, it seeks to readdress the imbalance in coverage of their discussion, providing, at the same time, a fascinating case-study for those interested in general issues related to controversies in science. Second, contrary to Morgan’s beliefs according to which Weismann employed a speculative and unempirical method of scientific investigation, the article shows that Weismann performed (...) experiments, made observations and proposed ‘undogmatic’ theories open to refutation. Third, through the reconstruction of Weismann’s and Morgan’s disagreement, this study illustrates how biology, during the very late nineteenth and early twentieth centuries, was undergoing important changes. I argue that this controversy clearly and convincingly demonstrates how some important epistemic assumptions became increasingly problematic for some members of the younger generations of biologists. At the end of my discussion I will also argue that Weismann and Morgan both had strong well-grounded arguments supporting their conclusions; for this reason I suggest a few factors (“taken-for-granted” beliefs or assumptions) that could explain why their disagreement was doomed to remain unresolved. In particular, I will analyze their diverse explicative interests, their different theoretical concerns and their distinct use of the available evidence. (shrink)

Laudan's thesis that conceptual problem solving is at least as important as empirical problem solving in scientific research is given support by a study of the relation between the chromosome theory and the Mendelian research program. It will be shown that there existed a conceptual tension between the chromosome theory and the Mendelian program. This tension was to be resolved by changing the constraints of the Mendelian program. The relation between the chromosome theory and the Mendelian program is shown to (...) be a good illustration of the influence of science itself on the rational standards governing scientific development. (shrink)

The concept of natural kind is center stage in the debates about scientific realism. Champions of scientific realism such as Richard Boyd hold that our most developed scientific theories allow us to “cut the world at its joints” (Boyd, 1981, 1984, 1991). In the long run we can disclose natural kinds as nature made them, though as science progresses improvements in theory allow us to revise the extension of natural kind terms.

This Ph.D. thesis provides a pilosophical account of the structure of the evolutionary synthesis of the 1930s and 40s. The first, more historical part analyses how classical genetics came to be integrated into evolutionary thinking, highlighting in particular the importance of chromosomal mapping of Drosophila strains collected in the wild by Dobzansky, but also the work of Goldschmidt, Sumners, Timofeeff-Ressovsky and others. The second, more philosophical part attempts to answer the question wherein the unity of the synthesis consisted. I argue (...) that it exemplifies a weak of form of explanatory unification. (shrink)