In summary, then, this discussion indicates one of the ways in which Simpson participated in the “modern evolutionary synthesis” by focusing on his developing concept of the species. In particular, we see him moving from species-as-types to species-as-populations, and next to how those populations, through organism-environment interactions, might give rise to new species, some of which rapidly lead to higher taxa.Simpson's participation in the creation of the modern synthesis is more generally evident here by his contribution to what V. B. (...) Smocovitis has recently termed the “quantification of evolution — the attachment of numbers to ‘nature.’” Smocovitis rightly views such quantification as an essential ingredient for the formulation of the evolutionary synthesis; however, she neglects Simpson's role in this regard. As suggested here and demonstrated more fully elsewhere, Simpson's commitment to a positivistic philosophy often found expression in quantitative argumentation, even if the paleontological data upon which such arguments were based were limited in number and precision. (shrink)

Biological taxonomists rely on the so-called ‘type method’ to regulate taxonomic nomenclature. For each newfound taxon, they lay down a ‘type specimen’ that carries with it the name of the taxon it belongs to. Even if a taxon’s circumscription is unknown and/or subject to change, it remains a necessary truth that the taxon’s type specimen falls within its boundaries. Philosophers have noted some time ago that this naming practice is in line with the causal theory of reference and its central (...) notion of rigid designation: a type specimen fixes the reference of a taxon name without defining it. Recently, however, this consensus has come under pressure in the pages of this journal. In a series of articles by Alex Levine, Joseph LaPorte, and Matthew Haber, it has been argued that type specimens belong only contingently to their species, and that this may bode problems for the relation between type method and causal theory. I will argue that this ‘contingency debate’ is a debate gone wrong, and that none of the arguments in defense of contingency withstand scrutiny. Taxonomic naming is not out of step with the causal theory, but conforms to it. However, I will also argue that this observation is itself in need of further explanation, since application of the type method in taxonomic practice is plagued by errors and ambiguities that threaten it with breaking down. Thus, the real question becomes why taxonomic naming conforms to the causal theory in the first place. I will show that the answer lies in the embedding of the type method into elaborate codes of nomenclature. (shrink)

The current widespread belief that taxonomic methods used before Darwin were essentialist is ill-founded. The essentialist method developed by followers of Plato and Aristotle required definitions to state properties that are always present. Polythetic groups do not obey that requirement, whatever may have been the ontological beliefs of the taxonomist recognizing such groups. Two distinct methods of forming higher taxa, by chaining and by examplar, were widely used in the period between Linnaeus and Darwin, and both generated polythetic groups. Philosopher (...) William Whewell congratulated pre-Darwinian taxonomists for not adhering to the rigid ideal of definition used in the mathematical sciences. What he called the method of types is here called the method of exemplars because typology has been equated with essentialism, whereas the use of a type species as the reference point or prototype for a higher category was a practice inconsistent with essentialism. The story that the essentialism of philosophers dominated the development of systematics may prove to be a myth. (shrink)

During the early twentieth century, the Swiss Zoologist Adolf Naef (1883–1949) established himself as a leader in German comparative anatomy and higher level systematics. He is generally labeled an ‘idealistic morphologist’, although he himself called his research program ‘systematic morphology’. The idealistic morphology that flourished in German biology during the first half of the twentieth century was a rather heterogeneous movement, within which Adolf Naef worked out a special theoretical system of his own. Following a biographical sketch, we present an (...) English translation of a previously unpublished typescript from Naef’s estate, which Naef intended as the introduction to a textbook on Comparative Anatomy for which he was unable to find a publisher before his sudden death in 1949. The typescript contains Naef’s mature thoughts with unprecedented conciseness, focus, and clarity. The density of Naef’s text warrants a historical and contextual explication of its content. (shrink)

This article describes how empirical discoveries in the 1930s–1950s regarding population variation for chromosomal inversions affected Theodosius Dobzhansky and Richard Goldschmidt. A significant fraction of the empirical work I discuss was done by Dobzhansky and his coworkers; Goldschmidt was an astute interpreter, with strong and unusual commitments. I argue that both belong to a mechanistic tradition in genetics, concerned with the effects of chromosomal organization and systems on the inheritance patterns of species. Their different trajectories illustrate how scientists’ commitments affect (...) how they interpret new evidence and adjust to it. Dobzhansky was moved to revised views about selection, while Goldschmidt moved his attention to different genetic phenomena. However different, there are significant connections between the two that enrich our understanding of their views. I focus on two: the role of developmental considerations in Dobzhansky’s thought and the role of neutrality and drift in Goldschmidt’s evolutionary account. Dobzhansky’s struggle with chromosomal variation is not solely about competing schools of thought within the selectionist camp, as insightfully articulated by John Beatty, but also a story of competition between selectionist thinking and developmental perspectives. In contraposition, Goldschmidt emphasized the role of low penetrance mutations that spread neutrally and pointed out that drift could result from developmental canalization. This account adds to the dominant story about Goldschmidt’s resistance to the splitting of development from genetics, as told by Garland Allen and Michael Dietrich. The story I tell illustrates how developmental thinking and genetic thinking conflicted and influenced researchers with different convictions about the significance of chromosomal organization. (shrink)

The Human Genome Project (HGP) has been criticised from an evolutionary perspective for three reasons: completely ignoring genetic variation; improperly treating either all or some genetic variation as deviation from a norm; and mistakenly seeking to define species in terms of essential properties possessed by all and only member organisms. The first claim is unfounded; the second and third claims are more on target. Nevertheless, it is a mistake to use the typological-population distinction to oppose molecular genetics and evolutionary genetics (...) in order to characterise HGP mapping and sequencing aims, especially the production of a DNA reference sequence, as 'anti-evolutionary' and 'pre-Darwinian.' These aims are consistent with certain strands in twentieth-century evolutionary thought: Muller's classical theory, Kimura's neutral and 'effectively neutral' theories, and, to a lesser extent, Dobzhansky's balance theory of the genetic structure of natural populations. In practice, population-based approaches to human genetic variation are similarly vulnerable to charges of 'typological' and 'essentialist' thinking in their treatment of genetic variation as deviation. This means that the Human Genome Diversity Initiative will not provide a population-based panacea for an overly typological HGP, as its proponents contend. Substituting related, and less rhetorically-charged, conceptual, empirical, and metaphysical distinctions for the typological-population distinction furnishes a better way to assess the concept of the normal genome from an evolutionary perspective. (shrink)

The use of ‘race’ as a proxy for population structure in the genetic mapping of complex traits has provoked controversy about its legitimacy as a category for biomedical research, given its social and political connotations. The controversy has reignited debates among scientists and philosophers of science about whether there is a legitimate biological concept of race. This paper examines the genetic race concept as it developed historically in the work of Theodosius Dobzhansky from the 1930s to 1950s. Dobzhansky’s definitions of (...) race changed over this time from races as ‘arrays of forms’ or ‘clusters’ in 1933–1939, to races as genetically distinct geographical populations in 1940–1946, to races as genetically distinct ‘Mendelian populations’ in 1947–1955. Dobzhansky responded to nominalist challenges by appealing to the biological reality of race as a process. This response came into tension with the object ontology of race that was implied by Dobzhansky’s increasingly holistic treatment of Mendelian populations, a tension, the paper argues, he failed to appreciate or resolve. (shrink)

This paper questions the prevailing historical understanding that scientific racism "retreated" in the 1950s when anthropology adopted the concepts and methods of population genetics and race was recognized to be a social construct and replaced by the concept of population. More accurately, a "populational" concept of race was substituted for a "typological one"-this is demonstrated by looking at the work of Theodosius Dobzhansky circa 1950. The potential for contemporary research in human population genetics to contribute to racism needs to be (...) considered with respect to the ability of the typological-population distinction to arbitrate boundaries between racist society and nonracist, even anti-racist, science. I point out some ethical limits of "population thinking" in doing so. (shrink)

This paper questions the prevailing historical understanding that scientific racism “retreated” in the 1950s when anthropology adopted the concepts and methods of population genetics and race was recognized to be a social construct and replaced by the concept of population. More accurately, a “populational” concept of race was substituted for a “typological one”—this is demonstrated by looking at the work of Theodosius Dobzhansky circa 1950. The potential for contemporary research in human population genetics to contribute to racism needs to be (...) considered with respect to the ability of the typological-population distinction to arbitrate boundaries between racist society and nonracist, even anti-racist, science. I point out some ethical limits of “population thinking” in doing so. (shrink)

Ernst Mayr's typological/population distinction is a conceptual thread that runs throughout much of his work in systematics, evolutionary biology, and the history and philosophy of biology. Mayr himself claims that typological thinking originated in the philosophy of Plato and that population thinking was first introduced by Charles Darwin and field naturalists. A more proximate origin of the typological/population thinking, however, is found in Mayr's own work on species. This paper traces the antecedents of the typological/population distinction by detailing Mayr's changing (...) views of species between 1942 and 1955. During this period, Mayr struggles to refine the biological species concept in the face of tensions that exist between studying species locally and studying them as geographically distributed collections of variable populations. The typological/population distinction is first formulated in 1955, when Mayr generalizes from the type concept versus the population concept in taxonomy to typological versus population thinking in biology more generally. Mayr's appeal to the more general distinction between typological and population thinking coincides with the waning status of natural history and evolutionary biology that occurs in the early 1950s and the distinction plays an important role in Mayr's efforts to legitimate the natural historical sciences. (shrink)

The classical/balance controversy continued along these lines throughout the first half of the sixties. Then, at about the same time that the classical position lost its leading advocate, the balance position received striking new support from Harry Harris, and independently from Dobzhansky's former student Lewontin, and Lewontin's research partner, Jack Hubby.80 These developments served more to reorient the controversy than to end it — and the resulting “neoclassical”/balance controversy is different enough to be grist for another mill.Social policy considerations no (...) longer play a role in keeping the dispute alive. This particular respect in which the issues have changed is, as Diane Paul suggests in her contribution to this volume, as striking as any other.82 There is, however, little danger of our forgetting that this was once much more than just a narrowly technical controversy — the additional social policy issues were far too blatant.However, although blatant, they were by no means the only, or even the most important, issues. In choosing to concentrate on the social policy considerations, I do not mean to suggest that the empirical issues were irrelevant, or simple and straightforward, or otherwise uninteresting. That is by no means the case. What I have tried to show is that there was much more to the classical/balance stalemate than just the empirical underdetermination of the theoretical issues, and that the empirical issues cannot be treated adequately without taking into account the social policy considerations that were involved. Dobzhansky and Muller both appealed to the dangers of misguided social policy that might have resulted from prematurely resolving their controversy in the other's favor. They called for high empirical standards on those grounds, more than once seeking to forestall the resolution of their dispute in this way. (shrink)

The essentialism story is a version of the history of biological classification that was fabricated between 1953 and 1968 by Ernst Mayr, who combined contributions from Arthur Cain and David Hull with his own grudge against Plato. It portrays pre-Darwinian taxonomists as caught in the grip of an ancient philosophy called essentialism, from which they were not released until Charles Darwin's 1859 Origin of Species. Mayr's motive was to promote the Modern Synthesis in opposition to the typology of idealist morphologists; (...) demonizing Plato served this end. Arthur Cain's picture of Linnaeus as a follower of 'Aristotelian' (scholastic) logic was woven into the story, along with David Hull's application of Karl Popper's term, 'essentialism', which Mayr accepted in 1968 as a synonym for what he had called 'typological thinking'. Although Mayr also pointed out the importance of empiricism in the history of taxonomy, the essentialism story still dominates the secondary literature. The history of the first telling of the essentialism story exposes its scant basis in fact. (shrink)