Online research in philosophy

The concept of population thinking was introduced by Ernst Mayr as the right way of thinking about the biological domain, but it is difficult to find an interpretation of this notion that is both unproblematic and does the theoretical work it was intended to do. I argue that, properly conceived, Mayr’s population thinking is a version of trope nominalism: the view that biological property-types do not exist or at least they play no explanatory role. Further, although population (...) thinking has been traditionally used to argue against essentialism about biological kinds, recently it has been suggested that it may be consistent with at least some forms of essentialism—ones that construe essential properties as relational. I argue that if population thinking is a version of trope nominalism, then, as Mayr originally claimed, it rules out any version of essentialism about biological kinds. (shrink)

This paper explores the intersections between national identity and the production of medical/population genomics in Mexico. The ongoing efforts to construct a Haplotype Map of Mexican genetic diversity offers a unique opportunity to illustrate and analyze the exchange between the historic-political narratives of nationalism, and the material culture of genomic science. Haplotypes are central actants in the search for medically significant SNP’s (single nucleotide polymorphisms), as well as powerful entities involved in the delimitation of ancestry, temporality and variability (www.hapmap.org). (...) By following the circulation of Haplotypes, light is shed on the alignments and discordances between socio-historical and bio-molecular mappings. The analysis is centred on the comparison between the genomic construction of time and ethnicity in the laboratory (through participant observation), and on the public mobilisation of a “Mexican Genome” and its wider political implications. Even though both: the scientific practice and the public discourse on medical/population genomics are traversed by notions of “admixture”, there are important distinctions to be made. In the public realm, the nationalist post-revolutionary ideas of Jose Vasconcelos, as expressed in his Cosmic Race (1925), still hold sway in the social imaginary. In contrast, admixture is treated as a complex, relative and probabilistic notion in laboratory practices. I argue that the relation between medical/population genomics and national identity is better understood as a process of re-articulation (Fullwiley Social Studies of Science 38:695, 2008), rather than coproduction (Reardon 2005) of social and natural orders. The evolving process of re-articulation conceals the novelty of medical/population genomics, aligning scientific facts in order to fit the temporal and ethnic grids of “Mestizaje”. But it is precisely the social and political work, that matches the emerging field of population genomics to the pre-existing projects of national identity, what is most revealing in order to understand the multiple and even subtle ways in which population genomics challenges the historical and identitarian frames of a “Mestizo” nation. (shrink)

Analysing the demands of global justice for the distribution of resources is a complex task and requires consideration of a broad range of issues. Of particular relevance is the effect that different distributions will have on global population growth and individual welfare. Since changes in the consumption and distribution of resources can have major effects on the welfare of the global population, and the rate at which it increases, it is important to establish meaningful principles to ensure a (...) just distribution of resources. In order to establish such principles we must consider the scope of any reproductive rights, and rights to other goods, such as food and health care, as well as examine the extent of duties correlating to those rights. In addition to the impact that distributions of global goods have on the welfare of current generations, it is also important to consider what duties we have, if any, to future generations. (shrink)

Ernst Mayr has argued that Darwinian theory discredited essentialist modes of thought and replaced them with what he has called "population thinking". In this paper, I characterize essentialism as embodying a certain conception of how variation in nature is to be explained, and show how this conception was undermined by evolutionary theory. The Darwinian doctrine of evolutionary gradualism makes it impossible to say exactly where one species ends and another begins; such line-drawing problems are often taken to be the (...) decisive reason for thinking that essentialism is untenable. However, according to the view of essentialism I suggest, this familiar objection is not fatal to essentialism. It is rather the essentialist's use of what I call the natural state model for explaining variation which clashes with evolutionary theory. This model implemented the essentialist's requirement that properties of populations be defined in terms of properties of member organisms. Requiring such constituent definitions is reductionistic in spirit; additionally, evolutionary theory shows that such definitions are not available, and, moreover, that they are not needed to legitimize population-level concepts. Population thinking involves the thesis that population concepts may be legitimized by showing their connections with each other, even when they are not reducible to concepts applying at lower levels of organization. In the paper, I develop these points by describing Aristotle's ideas on the origins of biological variation; they are a classic formulation of the natural state model. I also describe how the development of statistical ideas in the 19th century involved an abandoning of the natural state model. (shrink)

Ascertaining the optimum global population raises not just substantive moral problems but also philosophical ones, too. In particular, serious problems arise for utilitarianism. For example, should one attempt to bring about the greatest total happiness or the highest level of average happiness? This article argues that neither approach on its own provides a satisfactory answer, and nor do rights-based or Rawlsian approaches, either. Instead, what is required is a multidimensional approach to moral questions—one which recognises the plurality of our (...) values. Such an approach can be formalised by employing multidimensional indifference-curves. Moreover, whereas classical utilitarianism might be thought to enjoin us to bring about a larger global population, a multidimensional approach clearly suggests a significant reduction in human numbers. (shrink)

It has been known for quite a while now that the on-going project of constructing an acceptable population axiology has gloomy prospects. Already in Derek Parfit’s seminal contribution to the topic, an informal paradox was presented and later contributions have proved similar results.1 All of these contributions invoke, however, some version of a principle – the Mere Addition Principle – which is controversial.2 In Arrhenius (1998), I presented a theorem which didn’t invoke this controversial principle but replaced it with (...) logically and intuitively weaker conditions. Still, however, one of the conditions in my theorem shares with these earlier results the presupposition that welfare can be measured on at least an interval scale.3 One can deny this and, as a matter of.. (shrink)

This paper is about mechanisms and models, and how they interact. In part, it is a response to recent discussion in philosophy of biology regarding whether natural selection is a mechanism. We suggest that this debate is indicative of a more general problem that occurs when scientists produce mechanistic models of populations and their behaviour. We can make sense of claims that there are mechanisms that drive population-level phenomena such as macroeconomics, natural selection, ecology, and epidemiology. But talk of (...) mechanisms and mechanistic explanation evokes objects with well-defined and localisable parts which interact in discrete ways, while models of populations include parts and interactions that are neither local nor discrete in any actual populations. This apparent tension can be resolved by carefully distinguishing between the properties of a model and those of the system it represents. To this end, we provide an analysis that recognises the flexible relationship between a mechanistic model and its target system. In turn, this reveals a surprising feature of mechanistic representation and explanation: it can occur even when there is a mismatch between the mechanism of the model and that of its target. Our analysis reframes the debate, providing an alternative way to interpret scientists’ mechanism-talk , which initially motivated the issue. We suggest that the relevant question is not whether any population-level phenomenon such as natural selection is a mechanism, but whether it can be usefully modelled as though it were a particular type of mechanism. (shrink)

I claim that the balance of nature metaphoris shorthand for a paradigmatic view of natureas a beneficent force. I trace the historicalorigins of this concept and demonstrate that itoperates today in the discipline of populationecology. Although it might be suspected thatthis metaphor is a pre-theoretic description ofthe more precisely defined notion ofequilibrium, I demonstrate that balance ofnature has constricted the meaning ofmathematical equilibrium in population ecology.As well as influencing the meaning ofequilibrium, the metaphor has also loaded themathematical term with (...) values.Environmentalists and critics use thisconflation of meaning and value to theiradvantage. This interplay between the balanceof nature and equilibrium fits aninteractionist interpretation of the role ofmetaphor in science. However, it seems theinteraction is asymmetric, and the balance ofnature metaphor has had a larger influence onmathematical equilibrium than vice versa. Thisdisproportionate influence suggests that themetaphor was and continues to be a constitutivepart of ecological theories. (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)

Homeostatic Property Cluster (HPC) theory suggests that species and other biological taxa consist of organisms that share certain similarities. HPC theory acknowledges the existence of Darwinian variation within biological taxa. The claim is that “homeostatic mechanisms” acting on the members of such taxa nonetheless ensure a significant cluster of similarities. The HPC theorist’s focus on individual similarities is inadequate to account for stable polymorphism within taxa, and fails properly to capture their historical nature. A better approach is to treat distributions (...) of traits in species populations as irreducible facts, explained in terms of selection pressures, genealogy, and other evolutionary factors. We call this view Population Structure Theory (PST). PST accommodates the view, implicit in biological systematics, that species are identified by reference to particular historical populations. (shrink)

Recent discussions in the philosophy of biology have brought into question some fundamental assumptions regarding evolutionary processes, natural selection in particular. Some authors argue that natural selection is nothing but a population-level, statistical consequence of lower-level events (Matthen and Ariew [2002]; Walsh et al. [2002]). On this view, natural selection itself does not involve forces. Other authors reject this purely statistical, population-level account for an individual-level, causal account of natural selection (Bouchard and Rosenberg [2004]). I argue that each (...) of these positions is right in one way, but wrong in another; natural selection indeed takes place at the level of populations, but it is a causal process nonetheless. (shrink)

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 population genetics 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-population genetics 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 population genetics. (shrink)

“ The Origins of Genome Architecture ” by Michael Lynch (2007) may not immediately sound like a book that someone interested in the philosophy of biology would grab off the shelf. But there are three important reasons why you should read this book. Firstly, if you want to understand biological evolution, you should have at least a passing familiarity with evolutionary change at the level of the genome. This is not to say that everyone interested in evolution should be a (...) geneticist or a bioinformatician, but that a working knowledge of genetic change is an essential part of the intellectual toolkit of modern evolutionary biology, even if your primary focus is the evolution of behaviour or the diversity of communities. Secondly, this book provides excellent examples of another important tool in the biologist’s intellectual toolkit, but one that is rarely explained or illustrated to such an extent: null (or neutral) models. The role null models play in testing hypotheses in evolution is a central focus of this book. Thirdly, as an accomplished work of advocacy for a strictly microevolutionary view of evolution, this book provides grist for the mill for the important debate about whether population genetic processes are the sine qua non of evolutionary explanations. (shrink)

Population genetics 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 population genetics. In section (3), we sketch the model theoretic structure of population genetics, providing the flavor of the ways in (...) which population genetics theory might be understood as incorporating causes. In sections (4) and (5) we discuss two specific problems concerning the relationship between population genetics 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)

In this paper, I answer a fundamental question facing any view according to which natural selection is a population‐level causal process—namely, how is the causal process of natural selection related to, yet not preempted by, causal processes that occur at the level of individual organisms? Without an answer to this grounding question, the population‐level causal view appears unstable—collapsing into either an individual‐level causal interpretation or the claim that selection is a purely formal, statistical phenomenon. I argue that a (...) causal account of realization provides an answer to the grounding question. By applying this account of realization to the natural selection of melanism in rock pocket mice, I show how an alternative, formal account of realization, favored by proponents of the statistical interpretation, misses biologically important features. More generally, this paper shows how metaphysical issues about realization normally discussed in the philosophy of mind apply to debates in philosophy of biology. Thus, it is a first step toward fleshing out the oft‐noted similarities between debates in these areas. (shrink)

A wide range of ecological and evolutionary models predict variety in phenotype or behavior when a population is at equilibrium. This heterogeneity can be realized in different ways. For example, it can be realized through a complex population of individuals exhibiting different simple behaviors, or through a simple population of individuals exhibiting complex, varying behaviors. In some theoretical frameworks these different realizations are treated as equivalent, but natural selection distinguishes between these two alternatives in subtle ways. By (...) investigating an increasingly complex series of models, from a simple fluctuating selection model up to a finite population hawk/dove game, we explore the selective pressures which discriminate between pure strategists, mixed at the population level, and individual mixed strategists. Our analysis reveals some important limitations to the ESS framework often employed to investigate the evolution of complex behavior. (shrink)

Ernst Mayr has criticised the methodology of population genetics 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 population genetics (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)

Where there is a fixed population (i.e., who exists does not depend on what choice an agent makes), the deontic version of anonymous Paretian egalitarianism holds that an option is just if and only if (1) it is anonymously Pareto optimal (i.e., no feasible alternative has a permutation that is Pareto superior), and (2) it is no less equal than any other anonymously Pareto optimal option. We shall develop and discuss a version of this approach for the variable (...) class='Hi'>population case (i.e., where who exists does depend on what choice an agent makes). More specifically, we shall develop and discuss it in the context of a person-affecting framework—in which an option is just if and only if it wrongs no one according to certain plausible conditions on wronging. (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)

and Overview In an earlier book, Weighing Goods1, John Broome gave a sophisticated defense of utilitarianism for the cases involving a fixed population. In the present book, Weighing Lives, he extends this defense to variable population cases, where different individuals exist depending on which choice is made. Broome defends a version of utilitarianism according to which there is a vague positive level of individual wellbeing such that adding a life with more than that level of wellbeing makes things (...) morally better and adding a life with less than that level makes things morally worse. This version of utilitarianism avoids the extreme—but perhaps not all— forms of the repugnant conclusion that the usual total version faces. As usual, Broome’s work combines logical rigor with deep philosophical insight. There is much to learn from it. Nonetheless, I shall identify some problematic conditions used by Broome to derive utilitarianism and suggest that Broome’s version of utilitarianism has implausible implications. (shrink)

The standard mathematical models in population ecology assume that a population's growth rate is a function of its environment. In this paper we investigate an alternative proposal according to which the rate of change of the growth rate is a function of the environment and of environmental change. We focus on the philosophical issues involved in such a fundamental shift in theoretical assumptions, as well as on the explanations the two theories offer for (...) some of the key data such as cyclic populations. We also discuss the relationship between this move in population ecology and a similar move from first-order to second-order differential equations championed by Galileo and Newton in celestial mechanics. (shrink)

Following Wallace’s suggestion, Darwin framed his theory using Spencer’s expression “survival of the fittest”. Since then, fitness occupies a significant place in the conventional understanding of Darwinism, even though the explicit meaning of the term ‘fitness’ is rarely stated. In this paper I examine some of the different roles that fitness has played in the development of the theory. Whereas the meaning of fitness was originally understood in ecological terms, it took a statistical turn in terms of reproductive success throughout (...) the 20th Century. This has lead to the ever-increasing importance of sexually reproducing organisms and the populations they compose in evolutionary explanations. I will argue that, moving forward, evolutionary theory should look back at its ecological roots in order to be more inclusive in the type of systems it examines. Many biological systems (e.g. clonal species, colonial species, multi-species communities) can only be satisfactorily accounted for by offering a non-reproductive account of fitness. This argument will be made by examining biological systems with very small or transient population structures. I argue this has significant consequences for how we define Darwinism, increasing the significance of survival (or persistence) over that of reproduction. (shrink)

I shall briefly evaluate the common claim that ethically acceptable population policies must let individuals to decide freely on the number of their children. I shall ask, first, what exactly is the relation between population policies that we find intuitively appealing, on the one hand, and population policies that maximize procreative freedom, on the other, and second, what is the relation between population policies that we tend to reject on moral grounds, on the one hand, and (...) population policies that use coercive methods such as laws or economic incentives and deterrents, on the other. I shall argue that when changing a population policy, it may be morally desirable to affect people's procreative decisions more rather than less, and that sometimes it may be morally desirable to prefer a population policy that does not maximize procreative freedom to a population policy that does maximize it. I shall also point out that indirect population policies that use incentives and deterrents are not necessarily incompatible with liberal principles. Finally, I try to show what is assumed by those who defend the view that coercive population policies are morally wrong in all circumstances. (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 population genetics, I argue that formal demonstrations, and even strictly “mathematical truths,” may serve as explanatory in different (...) historical contexts. (shrink)

In “‘Population’ is Not a Natural Kind of Kinds,” Jacob Stegenga argues against the claim that the concept of “population” is a natural kind and in favor of conceptual pluralism, ostensibly in response to two papers of mine (Millstein 2009, 2010). Pluralism is often an attractive position in the philosophy of science. It certainly is a live possibility for the concept of population in ecology and evolutionary biology, and I welcome the opportunity to discuss the topic further. (...) However, I argue that the case for conceptual pluralism has not yet been made. In what follows, I first clarify the issues at stake before taking up the topic of conceptual pluralism and responding to Stegenga’s criticisms of the causal interactionist population concept. (shrink)

The debate between legal constitutionalists and critics of constitutional rights and judicial review is an old and lively one. While the protection of minorities is a pivotal aspect of this debate, the protection of disenfranchised minorities has received little attention. Policy-focused discussion—of the merits of the Human Rights Act in Britain for example—often cites protection of non-citizen migrants, but the philosophical debate does not. Non-citizen residents or ‘denizens’ therefore provide an interesting test case for the theory of rights as trumps (...) on ordinary representative politics. Are they the ultimate success story of the human rights framework? Or was Michael Walzer correct to describe government of denizens by citizens as a modern form of ‘tyranny’? This paper argues that neither liberal rights theorists nor democratic republicans provide a coherent response to the existence of denizens. Liberal rights theorists overstate the extent to which a politically powerless status can secure individual rights, while democratic republicans idealise the political process and wrongly assume that all those affected by laws are eligible for political participation. The paper outlines an alternative model for assessing the accountability of states to their non-citizen population, informed by the republican ideal of non-domination. It identifies gaps in state accountability to denizens–such as where there is inadequate diplomatic protection—and argues that these gaps are particularly troubling if their exit costs of leaving the state are high. (shrink)

I criticize some arguments against the causal interpretability of population genetics put forward by Denis Walsh ([2007], [2010]). In particular, I seek to undermine the contention that population genetics exhibits frame of reference relativity or subjectivity with respect to its formal representations. I also show that classical population genetics 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)

Group-structured populations, of the kind prominent in discussions of multilevel selection, are contrasted with ‘neighbor-structured’ populations. I argue that it is a necessary condition on multilevel description of a selection process that there should be a nonarbitrary division of the population into equivalence classes (or an approximation to this situation). The discussion is focused via comparisons between two famous problem cases involving group structure (altruism and heterozygote advantage) and two neighbor-structured cases that resemble them. Conclusions are also drawn about (...) the role of correlated interaction in the evolution of altruism. 1 Introduction 2 Two Kinds of Population Structure 3 Objections and Replies 4 Particles on a Line 5 Conclusion Appendix: Neighborhoods and Selection CiteULike Connotea Del.icio.us What's this? (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 genetics. Further, (...) I argue that robustness analysis is a tool for, if not confirmation, then something near enough, in this discipline. (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 population genetics, 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 population genetics 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 population genetics models provide an outline for further detailed research. (shrink)

The status of population genetics has become hotly debated among biologists and philosophers of biology. Many seem to view population genetics 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 population genetics. Yet others such as Michael Lynch have defended population genetics, declaring "nothing in evolution makes sense except in the (...) light of population genetics" (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 population genetics 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 population genetics 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)

In this essay, I argue for four related claims. First, Richard Levins’ classic “The Strategy of Model Building in Population Biology” was a statement and defense of theoretical population biology growing out of collaborations between Robert MacArthur, Richard Lewontin, E. O. Wilson, and others. Second, I argue that the essay served as a response to the rise of systems ecology especially as pioneered by Kenneth Watt. Third, the arguments offered by Levins against systems ecology and in favor of (...) his own methodological program are best construed as “pragmatic”. Fourth, I consider limitations of Levins’ arguments given contemporary population biology. (shrink)

The project of this paper is to understand what a phylogenetic tree represents and to discuss some of the implications that this has for the practice of systematics. At least the first part of this task, if not both parts, might appear trivial—or perhaps better suited for a single page in a textbook rather than a scholarly research paper. But this would be a mistake. While the task of interpreting phylogenetic trees is often treated in a trivial way, their interpretation (...) is tied to foundational conceptual questions at the heart of systematics—questions whose answers are hotly disputed. I have previously argued that widely shared ideas about the meaning and interpretation of phylogenetic trees are inconsistent with species concepts other than some genealogical version of a phylogenetic species concept (Velasco 2008). Here I rely on a similar approach and concentrate on the implications of the necessary conditions underlying the inferences that we make using phylogenetic trees. I argue that common practices for the interpretation and use of trees are in conflict and that unacceptable principles about species as units of phylogeny must be given up. According to the view that I will develop, all phylogenetic trees depict the history of populations. The branches on trees represent collections of population lineages through time and the splits represent population lineage splits. This is true regardless of whether the tips of the trees are themselves populations, or are species or higher taxa. Although this conclusion might be paired naturally with a view that species must be monophyletic groups, this population-centric view of trees is independent of that view of species. If we still want to have species that are paraphyletic groups of populations, this is permissible as long as we also do not treat species as the units of phylogeny. This population-centric view opposes a species-centric view of phylogeny and might be called a “rank-free” approach since it entails that we do not need to determine which groups are species (which is partly a ranking question) in order to build a tree. This conclusion and the argument for it are meant to be consistent with, but not require, acceptance of the conclusions of Velasco (2008) regarding species. (shrink)

In a recent article, “Wayward Modeling: Population Genetics and Natural Selection,” Bruce Glymour claims that population genetics 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 population genetics, 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 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 population genetics. (shrink)

Ecologist Richard Levins argues population biologists must trade‐off the generality, realism, and precision of their models since biological systems are complex and our limitations are severe. Steven Orzack and Elliott Sober argue that there are cases where these model properties cannot be varied independently of one another. If this is correct, then Levins's thesis that there is a necessary trade‐off between generality, precision, and realism in mathematical models in biology is false. I argue that Orzack and Sober's arguments fail (...) since Levins's thesis concerns the pragmatic features of model building not just the formal properties of models. (shrink)

University of Montreal, Canada, walter.bossert{at}umontreal.ca ' + u + '@' + d + ' '//--> David Donaldson University of British Columbia, Canada, dvdd{at}telus.net ' + u + '@' + d + ' '//--> This article examines several families of population principles in the light of a set of axioms. In addition to the critical-level utilitarian, number-sensitive critical-level utilitarian, and number-dampened utilitarian families and their generalized counterparts, we consider the restricted number-dampened family and introduce two new ones: the restricted critical-level (...) and restricted number-dependent critical-level families. Subsets of the restricted families have non-negative critical levels, avoid the `repugnant conclusion' and satisfy the axiom priority for lives worth living, but violate an important independence condition. Key Words: population ethics • axiomatic methodology. (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)

Jan Österberg is one of the pioneers in the field of population ethics. He started thinking about this issue already in the late 60s and he has developed one of the most original and interesting population axiologies.1 I’ve discussed the problems and drawbacks of Österberg’s theory elsewhere, and I don’t think that this is the place and time to discuss them again.2 Rather, I shall show that Österberg’s theory has a feature in common with the population axiologies (...) of such luminaries like Plato, Aristotle, Kant, Nietzsche, Wittgenstein and Heidegger, had they developed such a theory: None of these theories simultaneously satisfy five weak adequacy conditions. We shall show this by proving that no population axiology satisfies these five conditions. As a fringe benefit, this theorem also shows that the on-going project of constructing an acceptable population axiology has very gloomy prospects. 3.. (shrink)

The aim of this work is to present aggregation methods of hierarchically organized systems allowing one to replace the initial micro-system by a macro-system described by a few global variables. We also study the relations between the fast micro-dynamics and the slow macro-dynamics which can produce global properties. Emergence corresponds to a bottom-up coupling that is the result effected by a micro-level at a macro-level. As an example, we present prey-predator models with different time scales in an heterogeneous environment. A (...) fast time scale is associated to the migration process on spatial patches and a slow time scale is associated to growth and interactions between the populations. Preys must go on spatial patches where resources are located and where predators can attack them. The efficiency of the predators to catch preys is patch dependent. Perturbation methods allow us to aggregate the initial system of differential equations for the patch sub-populations into a macro-system of two differential equations governing the total population densities. We study the case of density independent and density dependent migrations. In the latter case, we show that different functional responses can emerge in the macro prey-predator model as a result of the coupling between the slow and fast systems. (shrink)

A deflationary perspective on theories of cultural evolution, in particular dual-inheritance theory, has recently been proposed by Lewens. On this ‘pop-culture’ analysis, dual-inheritance theorists apply population thinking to cultural phenomena, without claiming that cultural items evolve by natural selection. This paper argues against this pop-culture analysis of dual-inheritance theory. First, it focuses on recent dual-inheritance models of specific patterns of cultural change. These models exemplify population thinking without a commitment to natural selection of cultural items. There are grounds, (...) however, for doubting the added explanatory value of the models in their disciplinary context—and thus grounds for engaging in other potentially explanatory projects based on dual-inheritance theory. One such project is suggested by advocates of the theory. Some of the motivational narratives that they offer can be interpreted as setting up an adaptationist project with regard to cumulative change in cultural items. We develop this interpretation here. On it, dual-inheritance theory features two interrelated selection processes, one on the level of genetically inherited learning mechanisms, another on the level of the cultural items transmitted through these mechanisms. This interpretation identifies a need for further modelling efforts, but also offers scope for enhancing the explanatory power of dual-inheritance theory. (shrink)

Sigmoid functions have been applied in many areas to model self limited population growth. The most popular functions; General Logistic (GL), General von Bertalanffy (GV), and Gompertz (G), comprise a family of functions called Theta Logistic ( $$ \Uptheta $$ L ). Previously, we introduced a simple model of tumor cell population dynamics which provided a unifying foundation for these functions. In the model the total population ( N ) is divided into reproducing ( P ) and (...) non-reproducing/quiescent ( Q ) sub-populations. The modes of the rate of change of ratio P / N was shown to produce GL, GV or G growth. We now generalize the population dynamics model and extend the possible modes of the P / N rate of change. We produce a new family of sigmoid growth functions, Trans-General Logistic (TGL), Trans-General von Bertalanffy (TGV) and Trans-Gompertz (TG)), which as a group we have named Trans-Theta Logistic ( T $$ \Uptheta $$ L ) since they exist when the $$ \Uptheta $$ L are translated from a two parameter into a three parameter phase space. Additionally, the model produces a new trigonometric based sigmoid ( TS ). The $$ \Uptheta $$ L sigmoids have an inflection point size fixed by a single parameter and an inflection age fixed by both of the defining parameters. T $$ \Uptheta $$ L and TS sigmoids have an inflection point size defined by two parameters in bounding relationships and inflection point age defined by three parameters (two bounded). While the Theta Logistic sigmoids provided flexibility in defining the inflection point size, the Trans-Theta Logistic sigmoids provide flexibility in defining the inflection point size and age. By matching the slopes at the inflection points we compare the range of values of inflection point age for T $$ \Uptheta $$ L versus $$ \Uptheta $$ L for model growth curves. (shrink)

In this paper, we present a deterministic time discrete mathematical model based on multiregional periodic matrices to describe the dynamics of Sardina pilchardus in the Central Atlantic area of the Moroccan coast. This model deals with two stages (immature and mature) and three spatial zones where sardines are supposed to migrate from one zone to another. The population dynamics is described by an autonomous recurrence equation N ( t + 1) = A . N ( t ), where A (...) is a positive matrix whose entries are estimated using data collected during biannual acoustic surveys carried out from 2001 to 2003 onboard the Norwegian research vessel “Dr Fridtjof Nansen”. The dominant eigenvalue λ of A that gives the long-term growth rate of fish population is smaller than one. This agrees with the stock decrease observed in the data collected. We show that λ is highly sensitive to the recruitment rate and much less sensitive to the reproduction rate. These results can clearly be used to define an efficient scenario in order to fight for instance against a stock decrease. (shrink)

Why do societies collapse? We use an individual-based evolutionary model to show that, in environmental conditions dominated by low-frequency variation (“red noise”), extirpation may be an outcome of the evolution of cultural capacity. Previous analytical models predicted an equilibrium between individual learners and social learners, or a contingent strategy in which individuals learn socially or individually depending on the circumstances. However, in red noise environments, whose main signature is that variation is concentrated in relatively large, relatively rare excursions, individual learning (...) may be selected from the population. If the social learning system comes to lack sufficient individual learning or cognitively costly adaptive biases, behavior ceases tracking environmental variation. Then, when the environment does change, fitness declines and the population may collapse or even be extirpated. The modeled scenario broadly fits some human population collapses and might also explain nonhuman extirpations. Varying model parameters showed that the fixation of social learning is less likely when individual learning is less costly, when the environment is less red or more variable, with larger population sizes, and when learning is not conformist or is from parents rather than from the general population. Once social learning is fixed, extirpation is likely except when social learning is biased towards successful models. Thus, the risk of population collapse may be reduced by promoting individual learning and innovation over cultural conformity, or by preferential selection of relatively fit individuals as models for social learning. © 2009 Elsevier Inc. All rights reserved. (shrink)

This book of selected papers covers population research and banking as well as accompanying confidentiality, and governance concerns.

Since the introduction of mathematical population genetics, 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 population genetics 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 population (...) genetics 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: glymour@ksu.edu . (shrink)

We propose a way to achieve across-population sharing within the authors' model in a way that is plausibly in accordance with human evolution, and also a simple way to capture ecological structure. Finally, we briefly reflect on the model's scope and limits in modeling linguistic communication.

Despite evidence indicating that public health services are the most effective means of improving the population's health status, health care services receive the bulk of funding and political support. The recent passage of the Affordable Care Act, which focused on improving access to health care services through insurance reform, reflects the primacy of health care over public health. Although policymakers typically conceptualize health care and public health as two distinct systems, gains in health status are most effectively and cost-efficiently (...) achieved through their integration into a single health system. The Act does little to compel integration; however, there are numerous opportunities to encourage the coordination of public health and health care in the Act's implementation. (shrink)

There is no way literally to measure health, because health is multi-dimensional, and there is no metric whereby one person who is healthier than a second with respect to one dimension but less healthy with respect to another counts as healthier, less healthy or equally healthy overall. Health analysts instead measure how good or bad health states are in some regard. If these values are measures of health states, then identical health states must have identical values. But in different circumstances, (...) the same health state may have different values. It may be better or worse. Uniform values can nevertheless be assigned to kinds of health states, either as a weighted average of the values of their tokens or as the value of the performance in a standard environment of the capacity the health state constitutes. These uniform values are not well suited for some of the purposes for which summary measures of population health have been intended, and a set of non-evaluative indicators may be an attractive alternative. (shrink)

Ecologist Richard Levins (1966, 1968) argues population biologists must trade-off the generality, realism and precision of their models since biological systems are complex and our limitations are severe. Elliott Sober and Steven Orzack (1993) argue that there are cases where these model properties cannot be varied independently of one another. If this is correct, then Levins` thesis that there is a necessary trade-off between generality, precision, and realism in mathematical models in biology is false. I argue that Sober and (...) Orzack`s arguments fail since Levins` thesis concerns the pragmatic features of model building not just the formal properties of models. (shrink)

Where there is a fixed population (i.e., who exists does not depend on what choice an agent makes), the deontic version of anonymous Paretian egalitarianism holds that an option is just if and only if (1) it is anonymously Pareto optimal (i.e., no feasible alternative has a permutation that is Pareto superior), and (2) it is no less equal than any other anonymously Pareto optimal option. We shall develop and discuss a version of this approach for the variable (...) class='Hi'>population case (i.e., where who exists does depend on what choice an agent makes). More specifically, we shall develop and discuss it in the context of a person-affecting framework—in which an option is just if and only if it wrongs no one according to certain plausible conditions on wronging. (shrink)

The purpose of this essay is to investigate the properties of singular causal systems and their population manifestations, with special concern for the thesis of methodological individualism, which claims that there are no properties of social groups that cannot be adequately explained exclusively by reference to properties of individual members of those groups, i.e., at the level of individuals. Individuals, however, may be viewed as singular causal systems, i.e., as instantiations of (arrangements of) dispositional properties. From this perspective, methodological (...) individualism appears to be an ambiguous thesis: some properties of collections of (independent) systems of the same kind are reducible, but other properties of collections of (dependent) systems of the same kind are not. In cases of the first kind, therefore, methodological individualism is true, but trivial; while in cases of the second kind, it is significant, but false. Hence, if the arguments that follow are correct, at least some of the properties of social groups should qualify as emergent. (shrink)

Comparing alternative scientific theories obviously is relevant to theory assessment, but are comparativists (like Laudan) correct when they also make it necessary? This paper argues that they are not. Defining rationality solely in terms of theories' comparative problem-solving strengths, comparativist philosophers of science like Laudan subscribe to what I call the irrelevance claim (IC) and the necessity claim (NC). According to IC, a scientific theory's being well or poorly confirmed is "irrelevant" to its acceptance; NC is the claim that "all (...) evaluations of research traditions and theories must be made within a comparative context," how any theory "compares with its competitors" (Laudan 1977, 21, 120). Using current competing theories (T1 and T2) of population viability assessment (PVA) for the Florida panther, the paper investigates IC/NC. In part because dominant T2 panther biologists accept IC/NC (which T1 theorists reject), the paper argues that they appear both to have accepted flawed T2 and to have contributed to flawed panther science and policy. Correcting Laudan's Comparativist Philosophy of Science (LCPS), underlying the T1-versus-T2 debate, thus may hold promise for helping resolve both the scientific and policy controversy over panther PVA. (shrink)

Background In Japan, discussion concerning advance directives (ADs) has been on the rise during the past decade. ADs are one method proposed to facilitate the process of communication among patients, families and health care providers regarding the plan of care of a patient who is no longer capable of communicating. In this paper, we report the results of the first in-depth survey on the general population concerning the preferences and use of ADs in Japan. Method A self-administered questionnaire was (...) sent via mail to a stratified random sampling of 560 residents listed in the residential registry of one district of Tokyo, Japan (n = 165,567). Association between correlating factors and specific preferences toward ADs was assessed using contingency table bivariate analysis and multivariate regression model to estimate independent contribution. Results Of the 560 questionnaires sent out, a total of 425 participants took part in the survey yielding a response rate of 75.9 %. The results of the present study indicate that: 1) the most important components to be addressed are the specifics of medical treatment at the end of life stage and disclosure of diagnosis and prognosis; 2) the majority of participants found it suitable to express their directives by word to family and/or physician and not by written documentation; 3) there is no strong need for legal measures in setting up an AD; 4) it is permissible for family and physician to loosely interpret one's directives; 5) the most suitable proxy is considered to be a family member, relative, or spouse. Multivariate analysis found the following five factors as significantly associated with preferences: 1) awareness regarding living wills, 2) experience with the use of ADs, 3) preferences for end-of-life treatment, 4) preferences for information disclosure, and 5) intentions of creating a will. Conclusions Written ADs might be useful in the Japanese setting when the individual either wishes: 1) to not provide a lot of leeway to surrogates and/or caregivers, and/or 2) to ensure his or her directives in the cases of terminal illness, brain death, and pain treatment, as well as regarding information disclosure. (shrink)

This communication presents a very simple model for the global growth of the human population. It is shown that the solution of the simple equation.

This paper aims to illustrate one of the primary goals of the philosophy of biology⎯namely, the examination of central concepts in biological theory and practice⎯through an analysis of the concepts of population and metapopulation in evolutionary biology and ecology. I will first provide a brief background for my analysis, followed by a characterization of my proposed concepts: the causal interactionist concepts of population and metapopulation. I will then illustrate how the concepts apply to six cases that differ in (...) their population structure; this analysis will also serve to flesh out and defend the concepts a bit more. Finally, I will respond to some possible questions that my analysis may have raised and then conclude briefly. (shrink)

A major debate in the philosophy of biology centers on the question of how we should understand the causal structure of natural selection. This debate is polarized into the causal and statistical positions. The main arguments from the statistical side are that a causal construal of the theory of natural selection's central concept, fitness, either (i) leads to inaccurate predictions about population dynamics, or (ii) leads to an incoherent set of causal commitments. In this essay, I argue that neither (...) the predictive inaccuracy nor the incoherency arguments successfully undermine the causal account of fitness. (shrink)

: This paper explores the calibration of laboratory models in population genetics 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)

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 population genetics.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 population genetics, which can supplement consent. (shrink)

The Person Affecting Restriction, in its slogan form, states that an outcome can only be better than another if it is better for someone.1 It has a strong intuitive appeal and several theorists have suggested that the paradoxical implications in population ethics of “impersonal” welfarist theories, such as classical utilitarianism, could be avoided by adopting the restriction.

A chronic difficulty for functionalism is the problem of instantiations of a functionalist theory of mind which seem to lack some or all of the mental states--especially qualitative--we want to attribute to minds the theory describes. Here I discuss one such counterexample, Block’s system S, consisting of the population of China organized to simulate a single mind as described by some true, adequate, psychofunctionalist theory. I then defend a version of functionalism against this example, in part by an adaptation (...) of Dennett’s notion of “stances”. A true, adequate theory, as Block understands it, would be appropriate to Dennett’s “design” or (at best) “intentional” stance; but a genuinely true and adequate theory should instead coincide with a “personal” stance. Hence, if system S does instantiate such a theory, we must impute to it mental states, even qualitative, whether or not it “really" has them. Hence Block’s counterexample lacks force. (shrink)

Literature on ethical behavior has paid little attention to the mechanism between macro-environmental variables and environmental performance. This study aims at constructing a model to examine the relationships which link cultural values, population growth, economic development, and environmental performance by incorporating the mediating role of education. The multiple linear regression model was employed to test the hypotheses on a 3-year-pooled sample of 51 countries. Empirical results conclude that national culture, economic development, and population growth would significantly influence environmental (...) performance directly. In addition, through the mediating effect of education, population growth and national culture would significantly affect environmental performance indirectly. These findings provide theoretical and managerial implications for constructing the mechanism of cultural values and ethical behavior in general and environmental management in particular. (shrink)

The debates over the future of human population and the earth’s environment, and similar large issues, usually take place without reference to explicit models. Debate would be clarified if such models were employed. We propose that the logistic equation and its extensions like the generalized logistic and the Lotka-Volterra equations, so familiar to ecologists, can easily be modified to model the important "macro" questions that motivated the three thinkers of our title. The long term rate of population growth (...) must normally be controlled by the rate of improvement in K, the carrying capacity of the earth. K will in turn be controlled by the rate of technological progress. The present situation, in which technological improvement (but also perhaps environmental deterioration) are increasing at rates above r, the Malthusian intrinsic rate of natural increase, is probably unique in human history. Can present levels of human prosperity and population growth be sustained? What processes are most likely to determine the answer to this and similar questions? We here sketch a model that endogenizes technological progress and environmental deterioration in the logistic framework. We discuss extensions of the logistic approach to multiple populations, such as other species, and sub-populations, such as human social classes, using the Lotka-Volterra equations. (shrink)

The definition of the study population for a clinical trial via the criteria for trial eligibility has implications for the validity of the study and its applicability to clinical practice. Though issues of equity regarding the selection of subjects for research have long been a concern of ethicists, issues regarding the impact of subject selection on a trial's generalizability have only recently attracted ethical scrutiny. After a review of the history of the ethics of subject selection, I focus on (...) three empirical questions regarding the generalizability of clinical trials. (1) What proportion of diseased populations are studied in clinical trials? (2) How are subjects selected for clinical trial participation (and what are the main barriers to participation)? (3) Are clinical trial participants comparable to non-participants? Finally, the role of the Institutional Review Board--Research Ethics Board in Canada--in assessing the generalizability of clinical research is discussed. (shrink)

A survey of three types of cell population models is presented in this paper. The main issue in all the surveyed words is whether or not there exists astable type distribution (s.t.d.). In the last few years, many efforts were directed towards describing the most general models which still exhibits.t.d. Progress made in the case ofsize density models are discussed. A slightly extended version of atime continous daughter cell model, studied in Arino et al. (1991), is presented. Recently, some (...) authors have undertaken the task of comparing models of various origins and types. Such works are alluded to in a discussion. (shrink)

Sober (1984) presents an account of selection motivated by the view that one property can causally explain the occurrence of another only if the first plays a unique role in the causal production of the second. Sober holds that a causal property will play such a unique role if it is a population level cause of its effect, and on this basis argues that there is selection for a trait T only if T is a population level cause (...) of survival and reproductive success. Sterelny and Kitcher (1988) claim against Sober that some traits directly subject to selection will not satisfy the probabilistic condition on population level causation. In this paper I show that Sober has the resources to resist the Sterelny-Kitcher complaint, but I argue that not all traits that satisfy the probabilistic condition play the required unique role in the production of their effects. (shrink)

A model is proposed for the population dynamics of an annual plant (Sesbania vesicaria) with a seed bank (i.e. in which a proportion of seeds remain dormant for at least one year). A simple linear matrix model is deduced from the life cycle graph. The dominant eigenvalue of the projection matrix is estimated from demographic parameters derived from field studies. The estimated values for population growth rate () indicates that the study population should be experiencing a rapid (...) exponential increase, but this was not the case in our population.The addition of density dependent effects on seedling survivorship and adult fecundity, effects for which field studies provide evidence, considerably improves our model. Depending on the demographic parameters, the model leads to stable equilibrium, oscillations, or chaos. Study of the behaviour of this model in the parameter space shows that the existence of a seed bank allows higher among-year variation of adult fecundity, without leaving the region of demographic stability. Field data obtained over 3 years confirm this prediction. (shrink)

Group beneficial norms are common in human societies. The persistence of such norms is consistent with evolutionary game theory, but existing models do not provide a plausible explanation for why they are common. We show that when a model of imitation used to derive replicator dynamics in isolated populations is generalized to allow for population structure, group beneficial norms can spread rapidly under plausible conditions. We also show that this mechanism allows recombination of different group beneficial norms arising in (...) different populations. (shrink)

Ethical issues arise in the world’s first population-level treatment of severe lead poisoning caused by small-scale mining for gold in rural Nigeria. Emergency medical intervention and environmental cleanup have reduced the mortality in children younger than 5 years from lead poisoning from over 40 to 2.5 per cent leaving little evidence of the harms caused by lead poisoning. In the absence of obvious sequelae, family adherence to long-term intensive therapy to remove accumulated lead reservoirs in children wanes and some (...) community miners challenge safer mining interventions to prevent recontamination of the environment with lead. This letter raises questions regarding community versus individual rights in public health interventions and patient autonomy. (shrink)

The axiom of extensionality of set theory states that any two classes that have identical members are identical. Yet the class of persons age i at time t and the class of persons age i + 1 at t + l, both including same persons, possess different demographic attributes, and thus appear to be two different classes. The contradiction could be resolved by making a clear distinction between age groups and cohorts. Cohort is a multitude of individuals, which is constituted (...) within a time interval, and endures throughout part of the time continuum. Age group, on the other hand, is only a reference term to which empirical measurement relates, as in birth or death rates. Accordingly, the two concepts, age group i at t, and age group i + 1 at t + 1, are different. The standard population growth model of Leslie and Lotka, however, does not support such a distinction in age groups. An alternative model, proposed recently, implies precisely such a distinction. (shrink)

In this work we consider a structured population with groups and subgroups of individuals. The intra-group dynamics is assumed to be fast in comparison with the inter-group dynamics. We study linear discrete models where the slow dynamics is represented by a single matrix and the fast dynamics is described by means of the first k terms of a converging sequence of different matrices. The number k can be interpreted as the ratio between the two time scales.The aim of this (...) work is to extend aggregation techniques to the case of fast changing environments. The main idea of aggregation is to build up a new system, with lower dimension, that summarizes the information concerning the fast process. This "aggregated" system provides essential information on the original one. It is shown that the asymptotic behavior of the original system can be approximated by the asymptotic behavior of the aggregated system when the ratio between the two time scales is large enough. (shrink)

Group beneficial norms are common in human societies. The persistence of such norms is consistent with evolutionary game theory, but existing models do not provide a plausible explanation for why they are common. We show that when a model of imitation used to derive replicator dynamics in isolated populations is generalized to allow for population structure, group beneficial norms can spread rapidly under plausible conditions. We also show that this mechanism allows recombination of different group beneficial norms arising in..

Vallortigara & Rogers (V&R) propose a fundamental role of the environment in determining population-level lateralisation and suggest that genes play no primary function in this phenomenon. Here I argue that genes involved in the coordination of visceral organ laterality and in coupling of different forms of lateralisation do play a role in the control of lateralisation within the population.

Direction of the embyro's head rotation is determined by asymmetrical expression of several genes (such as shh, Nodal, lefty, and FGF8) in Hensen's node. This genetically determined head-turning bias provides a base for light-aligned population lateralization in chicks, in which the direction of the lateralization is determined by genetic factors and the degree of the lateralization is determined by environmental factors.

Ives, Rosslyn Review(s) of: Bigger or better: Australia's population debate, by Ian Lowe, University of Queensland Press, 2012, $34.95.

This paper attempts to take seriously the claim that we can look for causes in order to understand the reality we live (in), and focuses therefore primarily on 'the natural world'. It will be argued that even if we were to fully endorse the programme of looking for antecedents, a dominant driver for many educational researchers, this would still not solve the problems they commonly set out to address. It will illustrate the problem of contextualisation in using an example of (...) educational research that uses the methodology of the randomised field trial. In these kind of studies the paradigm of causality and its experimental laboratory approach is modified to incorporate the exigencies of real life situations. The claim that these studies too do not put one in a position to derive straightforward conclusions for policy makers or more generally for educational practitioners will be substantiated. Finally, some concluding remarks will be offered that indicate what may be expected from large-scale population studies and what their epistemological basis is. (shrink)

A basic model of hierarchical structure, expressed by simple, linear differential equations, shows that the pattern of population growth is essentially determined by conditions of redundancy in the sub-structure of individuals. There does not exist any possible combination between growth rate and accident rate that could balance population numbers and/or the level of redundancy within the population; all possible combinations either lead to extinction or to positive population growth with a decline of the fraction of individuals (...) with redundant substructure. Declining populations, however, can be held fluctuating between certain limits by periodic phases of sub-unit repair. These results are particularly pertinent to the population dynamics of diploid (polyploid) organisms. (shrink)

The Problem Background Some Political History, Pre-1790 Federalist and Republican Principles Some Demographic History, 1790-1980 To What Extent Have the Possible Dangers Become Actual? The Discriminatory Impact and Prospects for Future Amendments Remedies Conclusion Appendix Table 1. The Possibility of Federalist Minority Amendment: Decade by Decade Table 2. The Possibility of Federalist Minority Amendment: Amendment by Amendment Table 3. Discriminatory Impact of Population Changes Table 4. Relative Strength of Voice of Citizens of the Various States Notes Second Thoughts..

As the result of the complexity inherent in nature, mathematical models employed in ecology are often governed by a large number of variables. For instance, in the study of population dynamics we often deal with models for structured populations in which individuals are classified regarding their age, size, activity or location, and this structuring of the population leads to high dimensional systems. In many instances, the dynamics of the system is controlled by processes whose time scales are very (...) different from each other. Aggregation techniques take advantage of this situation to build a low dimensional reduced system from which behavior we can approximate the dynamics of the complex original system.In this work we extend aggregation techniques to the case of time dependent discrete population models with two time scales where both the fast and the slow processes are allowed to change at their own characteristic time scale, generalizing the results of previous studies. We propose a non-autonomous model with two time scales, construct an aggregated model and give relationship between the variables governing the original and the reduced systems. We also explore how the properties of strong and weak ergodicity, regarding the capacity of the system to forget initial conditions, of the original system can be studied in terms of the reduced system. (shrink)

Background The broad topic of research ethics is one which has been relatively well-investigated and discussed. Unique ethical issues have been identified for such populations as pediatrics, where the issues of consent and assent have received much attention, and obstetrics, with concerns such as the potential for research to cause harm to the fetus. However, little has been written about ethical concerns which are relatively unique to the population of patients seen by the practitioner of rehabilitation medicine. Discussion This (...) paper reviews unique ethical concerns in conducting research in this population, including decision-making capacity, communication, the potential for subject overuse, the timing of recruitment, hope for a cure and therapeutic misconception and the nature of the health care provider-research subject relationship. Summary Researchers in the area of rehabilitation medicine should be aware of some of the unique ethical challenges posed by this patient population and should take steps to address any potential concerns in order to optimize subject safety and ensure that studies meet current ethical guidelines and standards. (shrink)

Multiple endogenous and exogenous prenatal influences interact to form a system that induces the development of individual lateralization across a range of perceptual and motor abilities in precocial birds. As these influences are nearly invariant for all species members, they produce a phylogenetic influence that creates high levels of population laterality and social cohesion in the postnatal state.

I shall briefly evaluate the common claim that ethically acceptable population policies must let individuals to decide freely on the number of their children. I shall ask, first, what exactly is the relation between population policies that we find intuitively appealing, on the one hand, and population policies that maximize procreative freedom, on the other, and second, what is the relation between population policies that we tend to reject on moral grounds, on the one hand, and (...) population policies that use coercive methods such as laws or economic incentives and deterrents, on the other. I shall argue that when changing a population policy, it may be morally desirable to affect people's procreative decisions more rather than less, and that sometimes it may be morally desirable to prefer a population policy that does not maximize procreative freedom to a population policy that does maximize it. I shall also point out that indirect population policies that use incentives and deterrents are not necessarily incompatible with liberal principles. Finally, I try to show what is assumed by those who defend the view that coercive population policies are morally wrong in all circumstances. (shrink)

The House Sparrow (Passer domesticus), formerly a common bird species, has shown a rapid decline in Western Europe over recent decades. In The Netherlands, its decline is apparent from 1990 onwards. Many causes for this decline have been suggested that all decrease the vital rates, i.e. survival and reproduction, but their actual impact remains unknown. Although the House Sparrow has been dominant in The Netherlands, data on life history characteristics for this bird species are scarce: data on reproduction are non-existent, (...) and here we first present survival estimates based on live encounters and dead recoveries of marked individuals over the period 1976–2003, 14 years before and 14 years during the decline, reported to the Dutch Ringing Centre. We show that there is an indication that both juvenile and adult survival are lower during the period of decline. Secondly, to be able to analyse the relative impact of changes in the vital rates, we formulated a general matrix model based on a range of survival values between zero and one with a step size of 0.01 (both juvenile and adult yearly survival) and a range of realistic reproduction values (one, three or five fledglings per pair per year). With the matrix model, we calculated the finite rate of population change (λ) and applied elasticity analysis. To diagnose the cause of the decline in the Dutch House Sparrow, we parameterised the model with estimates of survival values before and during the decline and present the resulting λ. With the survival estimates from the declining period, λ < 1 only if reproduction is relatively low. We discuss this result within the light of available literature data on survival in the House Sparrow. Finally, we evaluate which of the suggested causes of population decline should be reversed to mitigate the decline and how this can be achieved. (shrink)

Although there is empirical evidence of neural filling-in, this does not necessarily entail “isomorphic” theory. Most cortical neurons do not respond to a uniform surface and are instead sensitive to surface size and quality. I propose that a population of such neurons encodes the presence of a surface. This scheme is different from either the “cognitive” or “isomorphic” theories.

This paper presents a novel view of the concept of cognitive enhancement by taking a population health perspective. We propose four main modifiable healthy lifestyle factors for optimal cognitive functioning across the population for which there is evidence of safety and efficacy. These include i) promoting adequate sleep, ii) increasing physical activity, iii) encouraging a healthy diet, including minimising consumption of stimulants, alcohol and other drugs including nicotine, iv) and promoting good mental health. We argue that it is (...) not ethical to promote or sanction the use of pharmaceutical drugs as putative cognitive enhancers without acknowledging the adverse effects on population cognitive health of failing to encourage the pursuit of healthy behaviours. We conclude with recommendations to increase the public health relevance of bioethical analyses of the cognitive enhancement debate. (shrink)

Recent research governance documents say that the body of research evidence must reflect population diversity. The response to this needs to be more sophisticated than simply ensuring minorities are present in samples. For quantitative research looking primarily at treatment effects of drugs and devices four suggestions are made. First, identify where the representation of minorities in samples matters—for example, where ethnicity may cause different treatment effects. Second, where the representation of a particular group matters then subgroup analysis of the (...) results will usually be necessary. Third, ensuring representation and subgroup analysis will have costs; deciding on whether such representation is worthwhile will involve cost benefit analysis. Fourth, the representation of minorities should not be seen as mainly a locality issue. For qualitative research it is argued that the representation of diversity is often important. Given the small samples of many qualitative projects, however, the best way to ensure representation occurs is to allow a proliferation of such research, not to stipulate such representation in samples. (shrink)

Spatial and temporal heterogeneity are often described as important factors having a strong impact on biodiversity. The effect of heterogeneity is in most cases analyzed by the response of biotic interactions such as competition of predation. It may also modify intrinsic population properties such as growth rate. Most of the studies are theoretic since it is often difficult to manipulate spatial heterogeneity in practice. Despite the large number of studies dealing with this topics, it is still difficult to understand (...) how the heterogeneity affects populations dynamics. On the basis of a very simple model, this paper aims to explicitly provide a simple mechanism which can explain why spatial heterogeneity may be a favorable factor for production. We consider a two patch model and a logistic growth is assumed on each patch. A general condition on the migration rates and the local subpopulation growth rates is provided under which the total carrying capacity is higher than the sum of the local carrying capacities, which is not intuitive. As we illustrate, this result is robust under stochastic perturbations. (shrink)

Many ecologists have dismissed alleged ecological laws as tautological or trivial. This essay investigates the epistemological status of one prominent such "law," the population-growth thesis, and argues for 4 claims: (1) Once interpreted, the thesis cannot be denied the status of empirical law on the grounds that it is always and everywhere untestable. (2) Contrary to Peters' (1991) claim, some interpretations of the thesis have significant heuristic power. (3) One can use the reasoning of Brandon (1990), Lloyd (1987), and (...) Sober (1984) to show that some interpretations of the thesis are not a priori. (4) Even if the thesis is a priori, it has explanatory power as a "schematic law.". (shrink)

Millstein (2009) argues against conceptual pluralism with respect to the definition of “population,” and proposes her own definition of the term. I challenge both Millstein's negative arguments against conceptual pluralism and her positive proposal for a singular definition of population. The concept of population, I argue, does not refer to a natural kind; populations are constructs of biologists variably defined by contexts of inquiry.

Thomson, Kelvin You might be surprised to learn that China, home of the much derided one-child policy, has a higher birth rate than Italy, home of the Vatican. This suggests Chinese families are quietly defying their political leaders and Italian families are quietly defying their religious ones. But the overall global picture is one of rapid population growth.

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).

The aim of this work is twofold. First, we survey the techniques developed in Perthame and Zubelli (Inverse Probl 23(3):1037–1052, 2007 ), Doumic et al. (Inverse Probl 25, 2009 ) to reconstruct the division (birth) rate from the cell volume distribution data in certain structured population structured population models. Secondly, we implement such techniques on experimental cell volume distributions available in the literature so as to validate the theoretical and numerical results. As a proof of concept, we use (...) the experimental data experimental data reported in the classical work of Kubitschek (Biophys J 9(6):792–809, 1969 ) concerning Escherichia coli in vitro experiments measured by means of a Coulter transducer-multichannel analyzer system (Coulter Electronics, Inc., Hialeah, FL, USA). Despite the rather old measurement technology, the reconstructed division rates still display potentially useful biological features. (shrink)

The balance between births and deaths in an age-structured population is strongly influenced by the spatial distribution of sub-populations. Our aim was to describe the demographic process of a fish population in an hierarchical dendritic river network, by taking into account the possible movements of individuals. We tried also to quantify the effect of river network changes (damming or channelling) on the global fish population dynamics. The Salmo trutta life pattern was taken as an example for.We proposed (...) a model which includes the demographic and the migration processes, considering migration fast compared to demography. The population was divided into three age-classes and subdivided into fifteen spatial patches, thus having 45 state variables. Both processes were described by means of constant transfer coefficients, so we were dealing with a linear system of difference equations. The discrete case of the variable aggregation method allowed the study of the system through the dominant elements of a much simpler linear system with only three global variables: the total number of individuals in each age-class. (shrink)

Proposed here is that an overriding principle of nature governs all population behavior; that a single tenet drives the many regimes observed in nature—exponential-like growth, saturated growth, population decline, population extinction, and oscillatory behavior. The signature of such an all embracing principle is a differential equation which, in a single statement, embraces the entire panoply of observations. In current orthodox theory, this diverse range of population behaviors is described by many different equations—each with its own specific (...) justification. Here, a single equation governing all the regimes is proposed together with the principle from which it derives. The principle is: The effect on the environment of a population’s success is to alter that environment in a way that opposes the success. Experiments are suggested which could validate or refute the theory. Predictions are made about population behaviors. (shrink)

Marking a major development in Foucault's thinking, this book derives from the lecture course which he gave at the Collège de France between January and April, 1978. Taking as his starting point the notion of "bio-power," introduced in his 1976 course Society Must be Defended , Foucault sets out to study the foundations of this new technology of power over population. Distinct from punitive, disciplinary systems, the mechanisms of power are here finely entwined with the technologies of security, and (...) it is to 18th century developments of these technologies with which the first chapters of the book are concerned. By the fourth lecture however Foucault's attention turns, focusing on a history of "governmentality" from the first centuries of the Christian era to the emergence of the modern nation state. As Michel Sennelart explains in his afterword, the effect of this change of direction is to "shift the center of gravity of the lectures from the question of biopower to that of government, to such an extent that the former almost entirely eclipses the former ..." Consequently, in light of Foucault's later work, it is tempting to see these lectures as the moment of a radical turning point at which the transition to the problematic of the "government of self and others" would begin. (shrink)

Marking a major development in Foucault's thinking, this book derives from the lecture course which he gave at the Collège de France between January and April, 1978. Taking as his starting point the notion of "bio-power," introduced in his 1976 course Society Must be Defended , Foucault sets out to study the foundations of this new technology of power over population. Distinct from punitive, disciplinary systems, the mechanisms of power are here finely entwined with the technologies of security, and (...) it is to 18th century developments of these technologies with which the first chapters of the book are concerned. By the fourth lecture however Foucault's attention turns, focusing on a history of "governmentality" from the first centuries of the Christian era to the emergence of the modern nation state. As Michel Sennelart explains in his afterword, the effect of this change of direction is to "shift the center of gravity of the lectures from the question of biopower to that of government, to such an extent that the former almost entirely eclipses the former ..." Consequently, in light of Foucault's later work, it is tempting to see these lectures as the moment of a radical turning point at which the transition to the problematic of the "government of self and others" would begin. (shrink)

The prevalence, course and prognosis of diseases in patients referred to tertiary medical centers frequently differ from those treated in primary care settings. Extrapolation of findings from one population to another may therefore be unwarranted. Other factors that contribute to misinterpretation of medical literature include failure to distinguish statistical from clinical significance and advocacy of medical interventions prior to adequate clinical trials.

This paper analyses the broad methodological structure of population-biological theorising. In it, I show that the distinction between initial exploratory, hypothesis-generating research and the subsequent process-reconstructing, hypothesis-testing type of research is not being made. Rather, the hypotheses generated in population biology are elaborated in such detail that students confound the initial research phase with the subsequent hypotheses-testing phase of research. In this context, I therefore analyse some testing procedures within the exploration phase and show that, as an extreme (...) form of confusion, statistical null-models are mistakenly given the status of causal population-biological theory. (shrink)

This paper addresses the application of the ethical concept of trust and the legal and political concept of public trust to population genomics projects in Iceland, Estonia, and Tonga. Focusing on trust and public trust, the paper explores analogies between the genomics projects and the treatment of other common-pool resources, making use of the notion of trust as an ethical demand, derived from the works of Emmanuel Levinas and Knud Eljer Lgstrup. The paper discusses the degree to which the (...) ethical demands for trust and public trust have been established and maintained in the three national population genomics projects. (shrink)