Weismann's ideas on species transmutation were first expressed in his famous debate with Moritz Wagner on the mechanism of speciation. Wagner suggested that the isolation of a colony from its original source is a preliminary and necessary factor for speciation. Weismann accepted a secondary, facilitating role for isolation, but argued that natural and sexual selection are the primary driving forces of species transmutation, and are always necessary and often sufficient causes for its occurrence. The debate with Wagner, which occurred between (...) 1868 and 1872 within the framework of Darwin's discussions of geographical distribution, was Weismann's first public battle over the mechanism of evolution. This paper, which offers the first comprehensive analysis of this debate, extends previous analyses and throws light on the underlying beliefs and motivations of these early evolutionists, focusing mainly on Weismann's views and showing his commitment to what he later called "the all sufficiency of Natural Selection." It led to the crystallization of his ideas on the central and essential role of selection, both natural and sexual, in all processes of evolution, and, already at this early stage in his theoretical thinking, was coupled with sophisticated and nuanced approach to biological organization. The paper also discusses Ernst Mayr's analysis of the debate and highlights aspects of Weismann's views that were overlooked by Mayr and were peripheral to the discussions of other historians of biology. (shrink)

This article considers the reception of British cytogeneticist C.D. Darlington's controversial 1932 book, Recent Advances in Cytology. Darlington's cytogenetic work, and the manner in which he made it relevant to evolutionary biology, marked an abrupt shift in the status and role of cytology in the life sciences. By focusing on Darlington's scientific method -- a stark departure from anti-theoretical, empirical reasoning to a theoretical and speculative approach based on deduction from genetic first principles -- the article characterises the relationships defining (...) the "disciplinary landscape" of the life sciences of the time, namely those between cytology, genetics, and evolutionary theory. (shrink)

Claude Bernard (1813–1878) and Emil du Bois-Reymond (1818–1896) rank as two of the most influential scientists of the nineteenth century. Renowned for their experiments, lectures, and writing, Bernard and du Bois-Reymond earned great prestige as professors of physiology in a time when Paris and Berlin reigned as capitals of science. Yet even though they were equals in every way, du Bois-Reymond’s reputation has fallen far more than Bernard’s. This essay compares aspects of the two men’s attitudes to philosophy, history, and (...) biology in an attempt to explain why Bernard remains the better known. The answer lies less in the value of du Bois-Reymond’s contributions than in the way that science is remembered in France and Germany. (shrink)

In 1920, Eugen Steinach and Paul Kammerer reported experiments showing that exposure to high temperatures altered the structure of the gonad and produced hyper-sexuality in "heat rats," presumably as a result of the increased production of sex hormones. Using Steinach's evidence that the gonad is a double gland with distinct sexual and generative functions, they used their findings to explain "racial" differences in the sexuality of indigenous tropical peoples and Europeans. The authors also reported that heat induced anatomical changes in (...) the interstitial cells of the gonad were inherited by the heat rats' descendants. Kammerer used this finding to link endocrinology to his long-standing interest in the inheritance of acquired characteristics. The heat rats supported his hypothesis that the interstitial cells of the double gland were the mechanism of somatic induction in the inheritance of acquired characteristics. The Steinach-Kammerer collaboration, Kammerer's use of Steinach's "puberty gland" to explain somatic induction, and his endocrine analysis of symbiosis reveal Paul Kammerer's late career attempt to integrate endocrinology and genetics with the political ideals of Austrian socialism. With them he developed a bioethics that challenged the growing reliance on race in eugenics and instead promoted cooperation over competition in evolution. I relate his attempt to the controversies surrounding the interstitial cells, to the status of extra-nuclear theories of heredity, and to Kammerer's commitment to Austromarxist social reforms during the interwar period. (shrink)

Bernard Norton's friends in the history of science have had many reasons for commemorating, with admiration and affection, not only his research and teaching but no less his conversation and his company. One of his most estimable traits was his refusal to beat about the bush in raising the questions he thought worthwhile pursuing. I still remember discoursing at Pittsburgh on Darwin's route to his theory of natural selection, and being asked at the end by Bernard what were Darwin's views (...) on heredity. I answered with the conventional waffle to the effect that the theory concerned the populational fate rather than the individual production and transmission of heritable variation, so that whatever views Darwin had on heredity had only a subsidiary place in his theorizing. Bernard was not fooled. ‘I would have thought’, he said, ‘that in order to understand anyone's theorising about evolution it would be necessary to look at his views on heredity’. (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)

As frequently pointed out in this discussion, one of the most characteristic features of Mayr's approach to the history of biology stems from the fact that he is dealing to a considerable degree with his own professional history. Furthermore, his main criterion for the selection of historical episodes is their relevance for modern biological theory. As W. F. Bynum and others have noted, the general impression of his reviewers is that “one of the towering figures of evolutionary biology has now (...) written a towering history of his discipline.”138 Bynum is here referring to The Growth of Biological Thought, but this observation holds equally true for Mayr's other historical writings: One must surely read this book [One Long Argument] not only for its content in itself, but for what it tells of its author. And certainly as one does so, one comes away full-handed. Many, if not all, of the disputes and controversies that have driven Mayr through his long intellectual life reappear, stated as forcefully and elegantly as ever.139Up to this point, most reviewers agree; the bone of contention is, rather, how to evaluate Mayr's historical work, considering this observation. The two related characteristics of his work-I will call them subjectivity and presentism-stand in opposition to a widespread approach in the history of science exemplified by Kuhn's suggestion that “insofar as possible..., the historian should set aside the science that he knows. His science should be learned from the textbooks and journals of the period he studies.”140 There are, however, historians who consider the close connection between Mayr and the subject matter of his historical studies to be an advantage.141On the other hand, it is assumed that the connection between past and present must result in a distortion of the historical truth and lead to a historiographical fallacy, commonly referred to as “Whig history”. Herbert Butterfield, who in 1931 gave the term its now generally accepted meaning, believed that “real historical understanding is not achieved by the subordination of the past to the present, but rather by our making the past our present and attempting to see life with the eyes of another century than our own”142. Unfortunately, Butterfield's definition of what he considers Whig history remains somewhat vague, and modern authors have emphasized what they consider most important. Butterfield's “subordination of the past to the present” is referred to in respect to the selection of subjects (there are more biographies of Charles Darwin than of, let's say, Louis Agassiz),143 to the evaluation of historical authors,144 or, more generally, to all kinds of histories “with one eye, so to speak, upon the present.”145 The underlying tendency of Whig historians is to produce a “historical account told from the viewpoint of those in power,”146 leading to a “glorification of the present.”147 It is obvious that Mayr's strongly presentist approach to the history of biology can be called Whiggish, if we apply the criteria of “selection” or “reference.” However, it might be worth mentioning that the program of writing a strictly historicist account of the history of science is challenged by various authors.148 For Mayr, it is not only legitimate but necessary to compare the present situation with the past. “Whiggish” is only the evaluation of an author in terms of our time.149I cannot discuss the Whit/anti-Whig controversy in any detail here, apart from saying that Mayr has defended himself rather extensively against the charges of being Whiggish.150 Nevertheless, it may be useful to touch on some of the criticisms that are predominant in reviews of his writings. First, we encounter the notion that historians can write a true and convincing historical account only if they have no personal interest or interpretation of their own; Mayr, on the other hand, because he “has such strong interpretations of his own, ... cannot possibly convince everyone that he is right about everything.”151 It makes one wonder, what historian has ever been able to convince everyone that he or she is right about everything? But apart from this peculiar idea, it unquestionably poses certain dangers if the subject matter of historical scrutiny and the author are identical. At the same time, this identity brings certain advantages with it, especially firsthand experiences of the period in discussion. Whether these personal memories ultimately result in a distorted picture of the past has to be decided in every particular instance. The notion that a scientific study can be conducted by a completely detached observer from a neutral standpoint has been shown to be impossible in physics, and it is also an illusion in historiography. The question is not whether, but which kind of interest are the underlying motivation for a historian. At this point, Mayr is ahead of his critics when he suggests that our understanding of the past always has a subjective component: The main reason, however, why histories are in constant need of revision is that at any given time they merely reflect the present state of understanding; they depend on how the author interpreted the current zeitgeist of biology and on his own conceptual framework and background. Thus, by necessity the writing of history is subjective and ephemeral.152Second, the temporal proximity between the event and the historical analysis makes difficulties inevitable and will finally result in certain false assessments. But this applies to all historians when they discuss recent problems, regardless of whether they are personally involved or not: As long as the battle between Darwinism and Lamarckism was raging, it was quite impossible to undertake an unbiased evaluation of Lamarck. ...[The] definite refutation of Lamarck's theory of evolutionary causation clears the air. We can now study him without bias and emotion and give him the attention that this major figure in the history of biology clearly deserves.153Third, Mayr is primarily interested in biological problems and not, for instance, historiographical, sociological, or psychological questions. Several authors have remarked that since the beginning of the professionalization of the history of science in the 1960s, a rift between two groups has developed, resulting from the heterogeneous professional backgrounds and interests of the people involved: the authors who were originally biologists and became interested in the history of their discipline only later on, and the authors who were trained as historians.154 Whereas the first group, the “biologists,” tend to be laymen in history proper, the “historians” are in most cases laymen in biology. Different professional backgrounds obviously shape the historical perspective in both groups, but neither approach is necessarily superior. The great number of important books in the history of biology written by “biologist” documents how valuable this point of view can be. On the other hand, it cannot be denied that the writings of biologists in the history of science tend to have a strong “internalist” tendency and often neglect the professional, cultural, and political context of science. Mayr's approach is that of a “biologist”; it is “internalist,” and typical for scientists who turn to the history of their discipline.I want to conclude my analysis with a quotation from a review by Douglas J. Futuyma, which gives a perceptive glimpse of Mayr's personality and style: One cannot help standing in awe of the germanic capacity for vast, allembracing synthesis: consider the lifelong devotion of Goethe to Faust, or Wagner's integration of the arts into a Gesamtkunstwerk in which all of human history and experience is wrought into epic myth. It is perhaps in this tradition that Ernst Mayr's The Growth of Biological Thought stands: a history of all of biology, a Ring des Nibelungen complete with leitmotivs such as the failures of reductionism, the struggle of biology for independence from physics, and the liberation of population thinking from the bounds of essentialism.155 Within this style of thinking Mayr has “to offer...nothing less than a vision of biology that places neodarwinian evolutionary theory firmly at the centre.”156 There may be other visions of biology, but few of them have as indefatigable and able representatives as Darwinism has in Ernst Mayr. (shrink)

In this essay I discuss the contents and the context of Italian zoologist and entomologist Carlo Emery’s discussion of the germ-plasm theory. August Weismann considered him one of his very few creditable supporters, and encouraged him to publish his theoretical reflections. In his Gedanken zur Descendenz- und Vererbungstheorie, which appeared between 1893 and 1903 as a series of five essays in the journal Biologisches Zentralblatt, Emery developed a very personal account, applying the concept of determinants to problems like atavism, sexual (...) dimorphism, speciation, geographical isolation, transmission of characters, and putting forward, as early as 1903, the idea of a genetic program. (shrink)