I call an experiment “crucial” when it makes possible a decisive choice between conflicting hypotheses. Joharmsen's selection for size and weight within pure lines of beans played a central role in the controversy over continuity or discontinuity in hereditary change, often known as the Biometrician-Mendelian controversy. The “crucial” effect of this experiment was not an instantaneous event, but an extended process of repeating similar experiments and discussing possible objections. It took years before Johannsen's claim about the genetic stability of pure (...) lines was accepted as conclusively demonstrated by the community of geneticists. The paper also argues that crucial experiments thus interpreted contradict certain ideas about the underdetermination of theories by facts and the theory-ladenness of facts which have been influential in recent history and sociology of science. The acceptance of stability in the pure lines did not rest on prior preference for continuity or discontinuity. And this fact permitted a final choice between the two theories. When such choice is characterized as “decisive” or “final”, this is not meant in an absolute philosophical sense. What we achive in these cases is highly reliable empirical knowledge. The philosophical possibility of drawing (almost) any conclusion in doubt should be distinguished from reasonable doubt in empirical science. (shrink)

The controversy between Biometricians and Mendelians has been called an inexplicable embarrassment since it revolved around the mistaken identification of Mendelian genetics with non-Darwinian saltationism, a mistake traced back to the non-Darwinian William Bateson, who introduced Mendelian analysis to British science. The following paper beings to unravel this standard account of the controversy by raising a simple question: Given that Bateson embraced evolution by natural selection and that he studied the causes of variation within a broadly Darwinian framework of (...) problems and questions, how are we to understand the claim that he was a non-Darwinian? A brief survey of possible responses to this question is followed by an alternative proposal: the controversy will be considered as a struggle among Darwinians about the future course of Darwinism. On this account, Darwin's own work led to the juncture at which Mendelians and Biometricians parted company, indeed, the Origin itself prepared the divergent methodological stances subsequently adopted by Bateson and his antagonists. The inexplicable embarrassment is dissolved through the parsimonious reconstruction of the profound substantive conflict between Biometricians and Mendelians as a chapter in the articulation and differentiation of the Darwinian research programme. (shrink)

Historiographical analyses of the development of genetics in the first decade of the 20th century have been to a great extent framed in the context of the Mendelian-Biometrician controversy. Much has been discussed on the nature, origin, development, and legacy of the controversy. However, such a framework is becoming less useful and fruitful. This paper challenges the traditional historiography framed by the Mendelian-Biometrician distinction. It argues that the Mendelian-Biometrician distinction fails to reflect the theoretical and methodological diversity in the controversy. (...) It also argues that that the Mendelian-Biometrician distinction is not helpful to make a full understanding of the development of genetics in the first decade of the twentieth century. (shrink)

It is far from obvious that outside of highly specialized domains such as commercial agriculture, the methodology of biometrics—quantitative comparisons over groups of organisms—should be of any use in today’s bioinformatically informed biological sciences. The methods in our biometric textbooks, such as regressions and principal components analysis, make assumptions of homogeneity that are incompatible with current understandings of the origins of developmental or evolutionary data in historically contingent processes, processes that might have come out otherwise; the appropriate statistical methods are (...) those suited to random walks, not normal distributions. A valid methodology would further require that especially close attention be paid to the difference between aspects of processes that are plastic, those that encode their own histories or biographies, and the very small fraction of quantifications that can usefully and realistically be modeled as varying by colored noise around a central tendency that itself has some quantitative meaning. This point of view—that only a vanishingly small fraction of the quantitative information borne by any living organism is worth quantifying—is illustrated by some data on a human birth defect, namely, fetal alcohol syndrome. In a suggestive metaphor, the biometrician is like the pilgrim in Friedrich’s painting Der Wanderer über dem Nebelmeer, uncertain as to whether to measure the mountains or the clouds. The mountains stand for contingent history, the clouds for the subset of the data most closely matching controlled experiments suitable for quantitative biometric summary. Biometrics applies to the clouds, not the mountains. The success of statistical methods comes at the expense of all the theories that we simultaneously hold to be true about the biological materials to which they both pertain. Biometrics is thus complementary to all of the emerging reductionist sciences of biological structure. (shrink)

The debate between the Mendelians and the (largely Darwinian) biometricians has been referred to by R. A. Fisher as ‘one of the most needless controversies in the history of science’ and by David Hull as ‘an explicable embarrassment’. The literature on this topic consists mainly of explaining why the controversy occurred and what factors prevented it from being resolved. Regrettably, little or no mention is made of the issues that figured in its resolution. This paper deals with the latter (...) topic and in doing so reorients the focus of the debate as one between Karl Pearson and R. A. Fisher rather than between the biometricians and the Mendelians. One reason for this reorientation is that Pearson's own work in 1904 and 1909 suggested that Mendelism and biometry could, to some extent, be made compatible, yet he remained steadfast in his rejection of Mendelism. The interesting question then is why Fisher, who was also a proponent of biometric methods, was able to synthesise the two traditions in a way that Pearson either could not or would not. My answer to this question involves an analysis of the ways in which different kinds of assumptions were used in modelling Mendelian populations. I argue that it is these assumptions, which lay behind the statistical techniques of Pearson and Fisher, that can be isolated as the source of Pearson's rejection of Mendelism and Fisher's success in the synthesis. (shrink)

This article discusses the work of George Udny Yule in relation to the evolutionary synthesis and the biometric-Mendelian debate. It has generally been claimed that (i.) in 1902, Yule put forth the first account showing that the competing biometric and Mendelian programs could be synthesized. Furthermore, (ii.) the scientific figures who should have been most interested in this thesis (the biometricians W. F. Raphael Weldon and Karl Pearson, and the Mendelian William Bateson) were too blinded by personal animosity towards (...) each other to appreciate Yule's proposal. This essay provides a detailed account of (i.), maintaining that Yule's 1902 proposal is better understood as a reduction, not a synthesis of the two programs. The results of this analysis are then used to evaluate (ii.), where I will instead argue that Bateson and the biometricians had good reasons to avoid endorsing Yule's account. (shrink)

Bernard Norton's research concentrated on the Biometrical school of Darwinism and the social implications of the hereditarian ideas that began to gain popularity in the closing years of the nineteenth century. In this article I want to look at the previous generation of evolutionists, the evolutionary morphologists against whom the Biometricians (and their great rivals, the early Mendelians) were reacting. Despite the prominence of evolutionary morphology in the post-Darwinian era, comparatively little historical work has been done on it. In (...) helping to fill this gap, I hope to honour Bernard Norton's memory by throwing light on a movement that forms a conceptual bridge linking the original Darwinian debate to the Biometrical – Mendelian controversy. I shall also argue that evolutionary morphology had ideological overtones that helped to shape the cultural environment within which the eugenics movement would emerge. Although originally a product of the Victorian faith in progress, evolutionary morphology seemed to confirm that exposure to an unstimulating environment led to degeneration. It thus fuelled the concern over racial degeneration which the supporters of eugenics would seek to allay through the application of their new hereditarian philosophy. (shrink)

Exploratory statistics represents the transformation of a realist theory of statistics held by early nineteenth-century astronomers into an empiricist theory of statistics held by biometricians at the turn of the twentieth century. This paper discusses four key ideas in empiricist thought that influenced the form exploratory statistics took: (1) Baconianism, (2) associationism, (3) the search for cognitive calculi, and (4) phenomenalism. Some limitations of and alternatives to exploratory statistics as a hypothesis-generating methodology are discussed.

One claim found in the received historiography of the biometrical school (comprised primarily of Francis Galton, Karl Pearson, and W. F. R. Weldon) is that one of the biometricians' great flaws was their inability to look past their population-focused, statistical, gradualist understanding of evolutionary change – which led, in part, to their ignoring developments in cellular biology around 1900. I will argue, on the contrary, that the work of the biometricians was, from its earliest days, fundamentally concerned with (...) connections between statistical patterns of inheritance and the underlying cellular features that gave rise to them. Such work remained current with contemporary knowledge of chromosomes, cytology, and development; in this article, I explore the first case. The biometricians were thus well positioned to understand the relationship between the patterns of Mendelian inheritance and the statistical distributions with which they primarily occupied themselves. Ignorance of this connection, then, is not the reason why they rejected Mendelism. Further, both Galton and Weldon – though each in their own unique way – decided to turn to biological detail as a way to better justify the generality of their statistical approaches to heredity. Perhaps paradoxically, then, for these biometricians, detail offered an approach to theoretical generality. (shrink)

Summary Long-standing claims have been made for nearly the entire twentieth century that the biometrician, Karl Pearson, and his colleague, W. F. R. Weldon, rejected Mendelism as a theory of inheritance. It is shown that at the end of the nineteenth century Pearson considered various theories of inheritance (including Francis Galton's law of ancestral heredity for characters underpinned by continuous variation), and by 1904 he ?accepted the fundamental idea of Mendel? as a theory of inheritance for discontinuous variation. Moreover, in (...) 1909, he suggested a synthesis of biometry and Mendelism. Despite the many attempts made by a number of geneticists (including R. A. Fisher in 1936) to use Pearson's chi-square (X 2, P) goodness-of-fit test on Mendel's data, which produced results that were ?too good to be true?, Weldon reached the same conclusion in 1902, but his results were never acknowledged. The geneticist and arch-rival of the biometricians, Williams Bateson, was instead exceptionally critical of this work and interpreted this as Weldon's rejection of Mendelism. Whilst scholarship on Mendel, by historians of science in the last 18 years, has led to a balanced perspective of Mendel, it is suggested that a better balanced and more rounded view of the hereditarian-statistical work of Pearson, Weldon, and the biometricians is long overdue. (shrink)

The bitterness and protracted character of the biometrician–Mendelian debate has long aroused the interest of historians of biology. In this paper, we focus on another and much less discussed facet of the controversy: competing interpretations of the inheritance of mental defect. Today, the views of the early Mendelians, such as Charles B. Davenport and Henry H. Goddard, are universally seen to be mistaken. Some historians assume that the Mendelians' errors were exposed by advances in the science of genetics. Others believe (...) that their mistakes could have been identified by contemporaries. Neither interpretation takes account of the fact that the lapses for which the Mendelian eugenicists are now notorious were, in fact, mostly identified at the time by the biometricians David Heron and Karl Pearson. In this paper we ask why their objections had so little impact. We think the answer illustrates an important general point about the social prerequisites for effective scientific critique. (shrink)

Why was Hensen unsuccesful in the quantification of ecological sampling? No aspect of plankton research itself seems to have hindered quantification; both collecting methods and taxonomy were sufficiently advanced. The reason is probably that at the time he began sampling, Hensen had to devise his own statistical methods for expressing the reproducibility and validity of samples. Hensen might have succeeded in this if he had overcome prevalent nineteenth-century attitudes toward randomness.The statistical literature of medicine and physics with which Hensen was (...) probably familiar gave methods for expressing reproducibility and for comparing differences between means of different sets of observations. For example, a student of Poisson writing on medical statistics advocated using Poisson's limit (standard error 2√2) to test the difference between two means56. Other authors suggested that differences between means were most meaningful if very large numbers of observations were used.57 In his laboratory subsampling, Hensen used the propable error as a limit about means. In this and other ways, he seems most indebted to the physicist Ernst Abbe for statistical methods.58 However, all the methodology available to Hensen had been developed for situations in which errors are a property of the measurement or sampling process, and not of the phenomena themselves. The available methods for measuring reproducibility were based on the assumption that differences from the average were small and that they tended to accumulate about the mean in a bell-shaped pattern. Hensen constantly reinvestigated the distribution of plankton numbers about the average using a different method each time. Westergaard points out that medical statisticians did not make such investigations with their biological data.59To a considerable extent, biological sampling problems forced development of theory because samples afforded the only information on a pattern in water or soil which could not be directly observed. The sampling methods of Laplace and the late nineteenth-century government statisticians contrasted strongly with Hensen's because, either through subjective knowledge of the population sampled or through censuses, they attempted to choose representative or typical samples.60 The high reproducibility and validity of representative sampling is attained by knowing more about a population than a biologist can ordinarily know. The uncertain reproducibility and validity of biological sampling spurred the development of formal sampling theory.A formal sampling theory developed only after change in the general intellectual attitude toward randomness, which was reflected in nineteenth-century statistics.61 The ninteenth-century attitude that randomness is not part of nature changed in the twentieth century to a view of randomness as a property of nature.62 The physicist's incorporation of randomness into physical models in response to this intellectual change late in the nineteenth-century is discussed by Bork.63 In biology, the change was initiated by the attention Darwin focused on morphological variation. The English biometricians — Francis Galton and W. F. R. Weldon, for example — were prominent in developing methods for the analysis of biological variation.64 Most pertinent to the development of sampling theory was Karl Pearson's use of frequency distributions as models of biological variation. In ecology, quantification was brought about by Ronald Fisher more than by anyone else; he incorporated randomness into sampling plans and built upon the methods developed earlier for analysis of individual variation. Fisher's use of random sampling allowed comparison between the sample collections and the collections expected from a model population of known patterning (calculated with a frequency distribution). This is a much more efficient method of determining the validity of a sample than Hensen's comparison of collections with a model uniform collection. Intellectual background and accumulated biological information caused Fisher to find variability where Hensen had seen uniformity.In summary, Victor Hensen became interested in fisheries research because of the economic importance of fishing to Germany. Hensen had considerable understanding of the prerequisites for valid sampling, but the value of his quantitative approach was limited by the general preconceptions shared by most nineteenth-century biologists. Through Hensen's efforts many other biologists were stimulated to undertake quantitative samples, even though the statistical methods for analyzing variation among populations developed only after methods for analyzing variation among individuals had been developed. *** DIRECT SUPPORT *** A8402011 00003. (shrink)

A prevalent narrative locates the discovery of the statistical phenomenon of regression to the mean in the work of Francis Galton. It is claimed that after 1885, Galton came to explain the fact that offspring deviated less from the mean value of the population than their parents did as a population-level statistical phenomenon and not as the result of the processes of inheritance. Arguing against this claim, we show that Galton did not explain regression towards mediocrity statistically, and did not (...) give up on his ideas regarding an inheritance process that caused offspring to revert to the mean. While the common narrative focuses almost exclusively on Galton’s statistics, our arguments emphasize the anthropological and biological questions that Galton addressed. Galton used regression towards mediocrity to support the claim that some biological types were more stable than others and hence were resistant to evolutionary change. This view had implications concerning both natural selection and eugenics. The statistical explanation attributed to Galton appeared later, during the biometrician-mutationist debate in the early 1900s. It was in the context of this debate and specifically by the biometricians, that the development of the statistical explanation was originally attributed to Galton. (shrink)

This essay introduces an anthropological practice that remains largely unexplored in the historical literature on racial science: biometrics. In the early twentieth century, biometricians analyzed skull measurements using novel statistical methods to demonstrate racial biological differences. Drawing on new archival material, the essay reveals how these biometric data practices challenged racist anthropology. Between 1934 and 1952, Geoffrey Morant, an expert on biometry and race in Karl Pearson’s Biometric Laboratory in London, mobilized biometry to debunk Nazi racial theories. He informed (...) the public about Nazism’s fallacies in The Races of Central Europe (1939) and his UNESCO pamphlet The Significance of Racial Differences (1952). Unlike anti-racism campaigners such as Ashley Montagu, however, Morant did not dismiss the biological reality of race in his fight against Nazi racism. The essay shows that the coexistence of anti-racist and racializing practices was not paradoxical but, rather, an important feature of the anthropological study of human variation in the twentieth century. (shrink)

The progress towards mathematization or, in a broader context, towards an increased “objectivity” is one of the main trends in the development of biological systematics in the past century. It is commonplace to start the history of numerical taxonomy with the works of R. R. Sokal and P. H. A. Sneath that in the 1960s laid the foundations of this school of taxonomy. In this article, I discuss the earliest research program in this field, developed in the 1920s by the (...) Russian entomologist and biometrician Eugen (Evgeniy Sergeevich) Smirnov. The theoretical and methodological grounds of this program are considered based on the published works of Smirnov as well as some archival sources. The influence of Smirnov’s evolutionary (mechano-Lamarckian) convictions on the development of this project of “exact systematics” is analyzed as well as the author’s attempts to establish a novel concept of “mathematical essentialism” in animal taxonomy. The probable causes of the failure of Smirnov’s project are viewed from both externalist and internalist perspectives, including the opposition to the use of quantitative methods in biology by some of the Lysenkoist ideologists in the USSR. A brief comparison of Smirnov’s research program with that developed 40 years later by Sokal and Sneath is provided. (shrink)

This article scrutinizes in detail much of the extant historiography on the controversy between biometricians and Mendelians, considering in particular how this controversy is related to the evolutionary synthesis. While the historiographic critique concentrates on William Provine’s standard account, it also extends to the proposal by Donald MacKenzie and Barry Barnes. What Provine and these sociologists of scientific knowledge have in common is a set of unquestioned assumptions about the nature of Darwinism, about William Bateson’s anti-Darwinism, and about the (...) very idea of an evolutionary “synthesis.” While these assumptions make for a compelling history of the synthesis, they engender an endemically asymmetrical perspective and bias historiography toward the mere confirmation of antecedent expectations, which renders the years from 1859 to 1929 an age of ignorance and misunderstanding. In contrast, a return to what was probably the original meaning of evolutionary “synthesis” allows for a symmetrical account. It yields an appreciation of the positive contributions made both by Mendelians and biometricians to the gradual development of Darwinism. The article concludes with a synopsis of this alternative account. (shrink)

This paper draws upon the history of scientific studies of inheritance in Mendel’s best-remembered model organism, the garden pea, as a source of two parables – one pessimistic, the other optimistic – on the challenges of data linkage in plants. The moral of the pessimistic parable, from the era of the biometrician-Mendelian controversy, is that the problem of theory-ladenness in data sets can be a major stumbling block to making new uses of old data. The moral of the optimistic parable, (...) from the long-run history of studies at the John Innes Centre of aberrant or “rogue” pea varieties, is that an excellent guarantor of the continued value of old data sets is the availability of the relevant physical materials – in the first instance, the plant seeds. (shrink)