Since the introduction of mathematical populationgenetics, its machinery has shaped our fundamental understanding of natural selection. Selection is taken to occur when differential fitnesses produce differential rates of reproductive success, where fitnesses are understood as parameters in a populationgenetics model. To understand selection is to understand what these parameter values measure and how differences in them lead to frequency changes. I argue that this traditional view is mistaken. The descriptions of natural selection rendered by (...)populationgenetics models are in general neither predictive nor explanatory and introduce avoidable conceptual confusions. I conclude that a correct understanding of natural selection requires explicitly causal models of reproductive success. *Received May 2006; revised December 2006. †To contact the author, please write to: Department of Philosophy, Kansas State University, 201 Dickens Hall, Manhattan, KS 66506; e‐mail: [email protected] . (shrink)
This article explores the tension between the populationgenetics and sociobiological approaches to the study of evolution. Whereas population geneticists, like Stanford’s Marc Feldman, insist that the genetic complexities of organisms cannot be overlooked, sociobiologists rely on optimization models that are based on the simplest possible genetics.These optimization approaches have their roots in the classical result known as the fundamental theorem of natural selection, formulated by R. A. Fisher in 1930. From the start there was great (...) uncertainty over the proper interpretation of Fisher’s theorem, which became confused with Sewall Wright’s immensely influential adaptive landscape concept. In the 1960s, a new generation of mathematical biologists proved that Fisher’s theorem did not hold when fitness depended on more than one locus. Similar reasoning was used to attack W. D. Hamilton’s inclusive fitness theory. A new theory, known as the theory of long-term evolution, attempts to reconcile the rigorous populationgenetics approach with the long-standing sociobiological view that natural selection acts to increase the fitness of organisms. (shrink)
Populationgenetics attempts to measure the influence of the causes of evolution, viz., mutation, migration, natural selection, and random genetic drift, by understanding the way those causes change the genetics of populations. But how does it accomplish this goal? After a short introduction, we begin in section (2) with a brief historical outline of the origins of populationgenetics. In section (3), we sketch the model theoretic structure of populationgenetics, providing the flavor (...) of the ways in which populationgenetics theory might be understood as incorporating causes. In sections (4) and (5) we discuss two specific problems concerning the relationship between populationgenetics and evolutionary causes, viz., the problem of conceptually distinguishing natural selection from random genetic drift, and the problem of interpreting fitness. In section (6), we briefly discuss the methodology and key epistemological problems faced by population geneticists in uncovering the causes of evolution. Section (7) of the essay contains concluding remarks. (shrink)
Ernst Mayr has criticised the methodology of populationgenetics for being essentialist: interested only in “types” as opposed to individuals. In fact, he goes so far as to claim that “he who does not understand the uniqueness of individuals is unable to understand the working of natural selection” (1982, 47). This is a strong claim indeed especially since many responsible for the development of populationgenetics (especially Fisher, Haldane, and Wright) were avid Darwinians. In order to (...) unravel this apparent incompatibility I want to examine the possible sources and implications of essentialism in this context and show why the kind of mathematical analysis found in Fisher's work is better seen as responsible for extending the theory of natural selection to a broader context rather than inhibiting its applicability. (shrink)
From the 1960s, mathematical and computational tools have been developed to arrive at human population trees from various kinds of serological and molecular data. Focusing on the work of the Italian-born population geneticist Luigi Luca Cavalli-Sforza, I follow the practices of tree-building and mapping from the early blood-group studies to the current genetic admixture research. I argue that the visual language of the tree is paralleled in the narrative of the human diasporas, and I show how the tree (...) was actually mapped onto the surface of the earth. This visual and textual structure is mirrored in the liberal discourse of unity in diversity that has been criticized as running counter to the socio-political effects of human populationgenetics. From this perspective, one may ask how far the phylogenetic diagram in its various forms is a manifestation of the physics of power that according to Michel Foucault consists in mechanisms that analyse distributions, movements, series, combinations, and that uses instruments to render visible, to register, to differentiate and to compare. It is one among other disciplinary technologies that ensure the ordering of human diversity. In the case of intra-human phylogenetic trees, population samples and labels are one issue. Another is that the separated branches seem to show groups of people, who have in reality been interacting and converging, as isolated. Often based on so-called isolated peoples, molecular tree diagrams freeze a hierarchical kinship system that is meant to represent a state before the great historical population movements. (shrink)
This paper suggests that many of the pressing dilemmas of bioethics are global and structural in nature. Accordingly, global ethical frameworks are required which recognize the ethically significant factors of all global actors. To this end, ethical frameworks must recognize the rights and interests of both individuals and groups (and the interrelation of these). The paper suggests that the current dominant bioethical framework is inadequate to this task as it is over-individualist and therefore unable to give significant weight to the (...) ethical demands of groups (and by extension communal and public goods). It will explore this theme by considering the inadequacy of informed consent (the ‘global standard’ of bioethics) to address two pressing global bioethical issues: medical tourism and populationgenetics.Using these examples it will show why consent is inadequate to address all the significant features of these ethical dilemmas. Four key failures will be explored, namely,• That the rights and interests of those related (and therefore affected) are neglected;• That consent fails to take account of the context and commitments of individuals which may constitute inducement and coercion;• That consent alone does not have the ethical weight to negate exploitation or make an unjust action just (‘the fallacy of sufficiency’);• That consent is a single one-off act which is inappropriate for the types of decision being made.It will conclude by suggesting that more appropriate models are emerging, particularly in populationgenetics, which can supplement consent. (shrink)
In what follows, I argue that the semantic approach to scientific theories fails as a means to present the Wright—Fisher formalism (WFF) of populationgenetics. I offer an account of what population geneticist understand insofar as they understand the WFF, a variation on Lloyd's view that populationgenetics can be understood as a family of models of mid-level generality.
Evolutionary biology is a field currently animated by much discussion concerning its conceptual foundations. On the one hand, we have supporters of a classical view of evolutionary theory, whose backbone is provided by populationgenetics and the so-called Modern Synthesis (MS). On the other hand, a number of researchers are calling for an Extended Synthe- sis (ES) that takes seriously both the limitations of the MS (such as its inability to incorporate developmental biology) and recent empirical and theoretical (...) research on issues such as evolvability, modularity, and self-organization. In this article, I engage in an in-depth commentary of an influential paper by population geneticist Michael Lynch, which I take to be the best defense of the MS-populationgenetics position published so far. I show why I think that Lynch’s arguments are wanting and propose a modification of evolutionary theory that retains but greatly expands on populationgenetics. (shrink)
The status of populationgenetics has become hotly debated among biologists and philosophers of biology. Many seem to view populationgenetics as relatively unchanged since the Modern Synthesis and have argued that subjects such as development were left out of the Synthesis. Some have called for an extended evolutionary synthesis or for recognizing the insignificance of populationgenetics. Yet others such as Michael Lynch have defended populationgenetics, declaring "nothing in evolution makes (...) sense except in the light of populationgenetics" (a twist on Dobzhansky's famous slogan that "nothing in biology makes sense except in the light of evolution"). Missing from this discussion is the use of populationgenetics to shed light on ecology and vice versa, beginning in the 1940s and continuing until the present day. I highlight some of that history through an overview of traditions such as ecological genetics and population biology, followed by a slightly more in-depth look at a contemporary study of the endangered California Tiger Salamander. I argue that populationgenetics is a powerful and useful tool that continues to be used and modified, even if it isn't required for all evolutionary explanations or doesn't incorporate all the causal factors of evolution. (shrink)
The recent literature in philosophy of biology has drawn attention to the different sorts of explanations proffered in the biological sciences—we have molecular, biomedical, and evolutionary explanations. Do these explanations all have a common structure or relation that they seek to capture? This paper will answer in the negative. I defend a pluralistic and pragmatic approach to explanation. Using examples from classical populationgenetics, I argue that formal demonstrations, and even strictly “mathematical truths,” may serve as explanatory in (...) different historical contexts. (shrink)
This article is about ‘genogeographic’ maps produced by late-Soviet geneticists and published during post-Soviet time. It focuses on the visual and numerical techniques scientists used to project genetic data onto geographic space. Rather than discussing their representational character, I follow these visuals as ‘folded objects’, describing the layering and realigning of measurements and temporalities as well as the shifts in the practices and meanings of genetics. In the 1970s Soviet biological anthropologists transformed scattered data points by means of spatial (...) statistics into visually coherent maps for a ‘genogeographical atlas’, by interpolating data for the entire USSR territory. Computer-aided modelling rendered ‘populations’ as systemic entities and enacted specific cybernetic versions of population, evolution and difference. Tracing the history of their making helps one in understanding what these folded objects hold in store, in terms of data ranging from Russian imperial and colonial anthropology, through early Soviet traditions, to cold war technologies. Folded into those maps in intricate ways, they have co-shaped post-Soviet human genetics as an ever-active site for possible reinscriptions of difference. (shrink)
The train-set circulation plan problem belongs to the rolling stock scheduling problem and is similar to the aircraft routing problem in airline operations and the vehicle routing problem in the logistics field. However, TCPP involves additional complexity due to the maintenance constraint of train-sets: train-sets must conduct maintenance tasks after running for a certain time and distance. The TCPP is nondeterministic polynomial hard. There is no available algorithm that can obtain the optimal global solution, and many factors such as the (...) utilization mode and the maintenance mode impact the solution of the TCPP. This paper proposes a train-set circulation optimization model to minimize the total connection time and maintenance costs and describes the design of an efficient multiple-population genetic algorithm to solve this model. A realistic high-speed railway case is selected to verify our model and algorithm, and, then, a comparison of different algorithms is carried out. Furthermore, a new maintenance mode is proposed, and related implementation requirements are discussed. (shrink)
Suicidal behavior is an interesting blank space in Keller & Miller's (K&M's) population genetical account on explaining the existence and persistence of common, harmful, heritable mental disorders. I argue that suicidal behavior is yet another of these disorders. It may well be consistent with all three evolutionary models considered by K&M. (Published Online November 9 2006).
Like all community-based public health campaigns, proposals to use genetic information to improve the health and welfare of communities, whether the old eugenic sterilization campaigns or the routinized population screening programs of today's ‘public health genetics’, can involve asking affected individuals to make special sacrifices or assume special responsibilities on behalf of the community's welfare. Moreover, unlike public health interventions that restrict individual liberties in order to prevent health problems which all community members risk more or less equally, (...) genetic prevention strategies always require sacrifices on the part of the community who face the genetic risks in question on behalf of those who do not. The irony of ‘community genetics’ is that most human communities are much too heterogeneous to face universal gene pool disasters. (shrink)
The aim of this paper is to further develop van Fraassen’s diagnosis, expanding a previous analysis of the fundamental law of classical genetics and the status of the so-called ‘Mendel’s laws’.6 According to this diagnosis the Hardy-Weinberg law: 1) cannot be considered as axiom (or fundamental law) for classical populationgenetics, since it is a law that describes an equilibrium that 2) holds only under certain special conditions, and 3) only determines a subclass of models, 4) whose (...) generalized form (and fundamental law) being shading off into logical vacuity, and 5) more complex variants of the fundamental law (and of the Hardy-Weinberg law) can be “deduced” for more realistic assumptions. In order to achieve this, I will use notions of the structuralist view of theories, a version that is related to but different from that of van Fraassen’s. These are the notions of fundamental law, specialization, and special law. Having as a background a structuralist reconstruction of classical populationgenetics, I will show why the Hardy-Weinberg law should not be in fact considered the fundamental law of such a theory, but a special law (and not even a “terminal” specialization, i.e. a “non-terminal” specialization). (shrink)
This paper traces the background to R. A. Fisher's multi-factorial theory of inheritance. It is argued that the traditional account is incomplete, and that Karl Pearson's well-known pre-Fisherian objections to the theory were in fact overcome by Pearson himself. It is further argued that Pearson's stated reasons for not accepting his own achievement has to be seen as a rationalization, standing in for deeper-seated metaphysical objections to the Mendelian paradigm of a type not readily discussed in a formal scientific paper. (...) The apparent, post-Fisherian, continued acceptance of Pearson's objections is presented as an interesting problem for the historian and sociologist. (shrink)
A precise formulation of the structure of modern evolutionary theory has proved elusive. In this paper, I introduce and develop a formal approach to the structure of populationgenetics, evolutionary theory's most developed sub-theory. Under the semantic approach, used as a framework in this paper, presenting a theory consists in presenting a related family of models. I offer general guidelines and examples for the classification of populationgenetics models; the defining features of the models are taken (...) to be their state spaces, parameters, and laws. The suggestions regarding the various aspects of the characterization of populationgenetics models provide an outline for further detailed research. (shrink)
In recent years, several prominent biologists have pointed to the relatively new field of evolutionary developmental biology as evidence of an Extended Synthesis in evolutionary biology. More particularly, these biologists claim that theoretical and empirical EvoDevo research is extending the Modern Synthesis framework of evolutionary theory through investigation of evolutionarily important concepts that are not part of the framework developed during the 20th century. To describe the current changes in evolutionary biology as an Extended Synthesis, however, is incorrect. Through review (...) of Extended Synthesis arguments and analysis of the same biological concepts used to support these arguments, I argue that the foundation of the Modern Synthesis framework, theoretical populationgenetics, faces significant, perhaps insurmountable challenges from the concepts highlighted by EvoDevo research. As the foundation of the Modern Synthesis framework will require considerable remodeling—if possible—in light of the concepts emphasized by EvoDevo, it is incorrect to describe the ongoing changes in evolutionary biology as an Extended Synthesis. (shrink)
In recent years, several prominent biologists have pointed to the relatively new field of evolutionary developmental biology as evidence of an Extended Synthesis in evolutionary biology. More particularly, these biologists claim that theoretical and empirical EvoDevo research is extending the Modern Synthesis framework of evolutionary theory through investigation of evolutionarily important concepts that are not part of the framework developed during the 20th century. To describe the current changes in evolutionary biology as an Extended Synthesis, however, is incorrect. Through review (...) of Extended Synthesis arguments and analysis of the same biological concepts used to support these arguments, I argue that the foundation of the Modern Synthesis framework, theoretical populationgenetics, faces significant, perhaps insurmountable challenges from the concepts highlighted by EvoDevo research. As the foundation of the Modern Synthesis framework will require considerable remodeling—if possible—in light of the concepts emphasized by EvoDevo, it is incorrect to describe the ongoing changes in evolutionary biology as an Extended Synthesis. (shrink)
The reason why populationgenetics is a probabilistic theory has attracted considerable attention from philosophers. In what follows, I offer a novel account of what motivates the introduction of probabilities into classical populationgenetics. Probabilities make the theory easier to apply for researchers given their epistemic limitations and give the theory a recursive structure, thereby making possible inferences about the dynamics of systems over multiple generations. I argue that probabilities in populationgenetics can be (...) given a credentist interpretation according to which the probabilities reflect constraints on confidence or belief. (shrink)
In a recent article, “Wayward Modeling: PopulationGenetics and Natural Selection,” Bruce Glymour claims that populationgenetics is burdened by serious predictive and explanatory inadequacies and that the theory itself is to blame. Because Glymour overlooks a variety of formal modeling techniques in populationgenetics, his arguments do not quite undermine a major scientific theory. However, his arguments are extremely valuable as they provide definitive proof that those who would deploy classical population (...) class='Hi'>genetics over natural systems must do so with careful attention to interactions between individual population members and environmental causes. Glymour’s arguments have deep implications for causation in classical populationgenetics. (shrink)
I criticize some arguments against the causal interpretability of populationgenetics put forward by Denis Walsh ([2007], [2010]). In particular, I seek to undermine the contention that populationgenetics exhibits frame of reference relativity or subjectivity with respect to its formal representations. I also show that classical populationgenetics does not fall foul of some criteria for causal representation put forward by James Woodward ([2003]), although those criteria do undermine some causalist stances. 1 Introduction2 (...) Modularity3 The Crucially Important Point4 The Gillespie Case: Density-Dependent Selection5 Conclusion. (shrink)
A strong case has been made for the role and value of mechanistic reasoning in process-oriented sciences, such as molecular biology and neuroscience. This paper shifts focus to assess the role of mechanistic reasoning in an area where it is neither obvious nor expected: populationgenetics. Population geneticists abstract away from the causal-mechanical details of individual organisms and, instead, use mathematics to describe population-level, statistical phenomena. This paper, first, develops a framework for the identification of mechanistic (...) reasoning where it is not obvious: mathematical and mechanistic styles of scientific reasoning. Second, it applies this framework to demonstrate that both styles are integrated in modern investigations of evolutionary biology. Characteristic of the former, applied population genetic techniques provide statistical evidence for associations between genotype, phenotype, and fitness. Characteristic of the latter, experimental interventions provide causal-mechanical evidence for associations between the very same relationships, often in the same model organisms. The upshot is a richer perspective of how evolutionary biologists build evidence for hypotheses regarding adaptive evolution and a general framework for assessing the scope of mechanistic reasoning across the sciences. (shrink)
: This paper explores the calibration of laboratory models in populationgenetics as an experimental strategy for justifying experimental results and claims based upon them following Franklin (1986, 1990) and Rudge (1996, 1998). The analysis provided undermines Coyne et al.'s (1997) critique of Wade and Goodnight's (1991) experimental study of Wright's (1931, 1932) Shifting Balance Theory. The essay concludes by further demonstrating how this analysis bears on Diamond's (1986) claims regarding the weakness of laboratory experiments as evidence, and (...) further how the calibration strategy fits within Lloyd's (1987, 1988) account of the confirmation of ecological and evolutionary models. (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 populationgenetics to take off and reveals a genealogy of women geneticists grounded in mutual inspiration. Their work also shows that women were present in populationgenetics 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)
On the one hand, much has been written on Theodosius Dobzhansky’s central role in the development of the field of populationgenetics and modern evolutionary theory, as well as on his sociopolitical worldview in the middle of the Twentieth Century. On the other hand, much has also been written on Dobzhansky’s role in the institutionalization of genetics in Brazil, where he spent a considerable amount of time. Unfortunately, these literatures developed without any points of intersection or cross-reference. (...) This article places Dobzhansky’s work in Brazil in the broader contexts of the science and politics of its historical period. (shrink)
Although the category “race” fails as a postulated natural kind, racial, ethnic, national, linguistic, religious, and other group designations might nonetheless be considered projectible insofar as they support inductive inferences in biomedicine. This article investigates what it might mean for group concepts in populationgenetics and genomics to be projectible and whether the projectibility of such predicates licenses the representation of their corresponding classes as natural kinds according to currently prevailing projectibility-based accounts of natural kinds. The article draws (...) on a case study from cancer genetics, specifically, breast cancer risk in Ashkenazi Jewish women. (shrink)
In 1966, Richard Levins argued that there are different strategies in model building in population biology. In this paper, I reply to Orzack and Sober’s (1993) critiques of Levins, and argue that his views on modeling strategies apply also in the context of evolutionary genetics. In particular, I argue that there are different ways in which models are used to ask and answer questions about the dynamics of evolutionary change, prospectively and retrospectively, in classical versus molecular evolutionary (...) class='Hi'>genetics. Further, I argue that robustness analysis is a tool for, if not confirmation, then something near enough, in this discipline. (shrink)
I define a concept of causal probability and apply it to questions about the role of probability in evolutionary processes. Causal probability is defined in terms of manipulation of patterns in empirical outcomes by manipulating properties that realize objective probabilities. The concept of causal probability allows us see how probabilities characterized by different interpretations of probability can share a similar causal character, and does so in such way as to allow new inferences about relationships between probabilities realized in different chance (...) setups. I clarify relations between probabilities and properties defined in terms of them, and argue that certain widespread uses of computer simulations in evolutionary biology show that many probabilities relevant to evolutionary outcomes are causal probabilities. This supports the claim that higher-level properties such as biological fitness and processes such as natural selection are causal properties and processes, contrary to what some authors have argued. (shrink)
In the 1960s molecular population geneticists used Monte Carlo experiments to evaluate particular diffusion equation models. In this paper I examine the nature of this comparative evaluation and argue for three claims: first, Monte Carlo experiments are genuine experiments: second, Monte Carlo experiments can provide an important meansfor evaluating the adequacy of highly idealized theoretical models; and, third, the evaluation of the computational adequacy of a diffusion model with Monte Carlo experiments is significantlydifferent from the evaluation of the emperical (...) adequacy of the same diffusion model. (shrink)
