This chapter contains section titled: The Neutral Theory of Molecular Evolution The Molecular Clock The Neutral Null Model Controversy in Molecular Evolution Acknowledgment References Further Reading.

Recently, a number of philosophers of biology have endorsed views about random drift that, we will argue, rest on an implicit assumption that the meaning of concepts such as drift can be understood through an examination of the mathematical models in which drift appears. They also seem to implicitly assume that ontological questions about the causality of terms appearing in the models can be gleaned from the models alone. We will question these general assumptions by showing how the same equation (...) — the simple 2 = p2 + 2pq + q2 — can be given radically different interpretations, one of which is a physical, causal process and one of which is not. This shows that mathematical models on their own yield neither interpretations nor ontological conclusions. Instead, we argue that these issues can only be resolved by considering the phenomena that the models were originally designed to represent and the phenomena to which the models are currently applied. When one does take those factors into account, starting with the motivation for Sewall Wright’s and R.A. Fisher’s early drift models and ending with contemporary applications, a very different picture of the concept of drift emerges. On this view, drift is a term for a set of physical processes, namely, indiscriminate sampling processes. (shrink)

: Where there are cases of underdetermination in scientific controversies, such as the case of the molecular clock, scientists may direct the course and terms of dispute by playing off the multidimensional framework of theory evaluation. This is because assessment strategies themselves are underdetermined. Within the framework of assessment, there are a variety of trade-offs between different strategies as well as shifting emphases as specific strategies are given more or less weight in assessment situations. When a strategy is underdetermined, scientists (...) can change the dynamics of a controversy by making assessments using different combinations of evaluation strategies and/or weighting whatever strategies are in play in different ways. Following an underdetermination strategy does not end or resolve a scientific dispute. Consequently, manipulating underdetermination is a feature of controversy dynamics and not controversy closure. (shrink)

The neutral and nearly neutral theories of molecular evolution are sometimes characterized as theories about drift alone, where drift is described solely as an outcome, rather than a process. We argue, however, that both selection and drift, as causal processes, are integral parts of both theories. However, the nearly neutral theory explicitly recognizes alleles and/or molecular substitutions that, while engaging in weakly selected causal processes, exhibit outcomes thought to be characteristic of random drift. A narrow focus on outcomes obscures the (...) significant role of weakly selected causal processes in the nearly neutral theory. (shrink)

In the early twentieth century, Tatsuo Aida in Japan, Øjvind Winge in Denmark, Richard Goldschmidt in Germany, and Calvin Bridges in the United States all developed different experimental systems to study the genetics of sex reversal. These locally specific experimental systems grounded these experimenters’ understanding of sex reversal as well as their interpretation of claims regarding experimental results and theories. The comparison of four researchers and their experimental systems reveals how those different systems mediated their understanding of genetic phenomena, and (...) influenced their interpretations of sex reversal. (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)

The vast network of Drosophila geneticists spawned by Thomas Hunt Morgan's fly room in the early 20th century has justifiably received a significant amount of scholarly attention. However, most accounts of the history of Drosophila genetics focus heavily on the "boss and the boys," rather than the many other laboratory groups which also included large numbers of women. Using demographic information extracted from the Drosophila Information Service directories from 1934 to 1970, we offer a profile of the gendered division of (...) labor within Drosophila genetics in the United States during the middle decades of the 20th century. Our analysis of the gendered division of labor supports a reconsideration of laboratory practices as different forms of work. (shrink)

This article offers three contrasting cases of the use of neutrality and drift in molecular evolution. In the first, neutrality is assumed as a simplest case for modeling. In the second and third, concepts of drift and neutrality are developed within the context of population genetics testing and the development and application of the molecular clock.

Richard Goldschmidt was one of the most controversial biologists of the mid-twentieth century. Rather than fade from view, Goldschmidt's work and reputation has persisted in the biological community long after he has. Goldschmidt's longevity is due in large part to how he was represented by Stephen J. Gould. When viewed from the perspective of the biographer, Gould's revival of Goldschmidt as an evolutionary heretic in the 1970s and 1980s represents a selective reinvention of Goldschmidt that provides a contrast to other (...) kinds of biographical commemorations by scientists. (shrink)

During the 1960s and 1970s population geneticists pushed beyond models of single genes to grapple with the effect on evolution of multiple genes associated by linkage. The resulting models of multiple interacting loci suggested that blocks of genes, maybe even entire chromosomes or the genome itself, should be treated as a unit. In this context, Richard Lewontin wrote his famous 1974 book The Genetic Basis of Evolutionary Change, which concludes with an argument for considering the entire genome as the unit (...) of selection as a result of linkage. Why did Lewontin and others devote so much intellectual energy to the “complications of linkage” in the 1960s and 1970s? We argue that this attention to linkage should be understood in the context of research on chromosomal inversions and co-adapted gene complexes that occupied mid-century evolutionary genetics. For Lewontin, the complications of linkage were an extension of this chromosomal focus expressed in the new language of models for linkage disequilibrium. (shrink)

Using an analogy between moths and men, in 1916, Richard Goldschmidt proposed that homosexuality was a case of genetic intersexuality. As he strove to create a unified theory of sex determination that would encompass animals ranging from moths to men, Goldschmidt's doubts grew concerning the association of homosexuality with intersexuality until, in 1931, he dropped homosexuality from his theory of intersexuality. Despite Goldschmidt's explicit rejection of his theory of homosexuality, Theo Lang, a researcher in the Genealogical-Demographic Department of the Institute (...) for Psychiatric Research in Munich, revived it, maintained Goldschmidt's association with it, and argued on its behalf in publications from 1936 to 1960. Lang's appropriation of Goldschmidt's theory did not depend on his resolution of the difficulties Goldschmidt had found with his own theory. Lang and Goldschmidt, I argue, had fundamentally different scientific and social commitments that allowed one to reject this theory of homosexuality and the other to accept it. (shrink)

This chapter contains sections titled: The Bridgeless Gap? Species Selection The Macroevolution Dispute as a Biological Controversy Postscript: Counterpoint Acknowledgments References.

Throughout the 1930s two of Germany’s most senior geneticists were caught up in controversy as they tried to enter the distinctly American culture of Drosophila genetics. When Richard Goldschmidt and Victor Jollos were forced by the Nazis to leave Germany in 1936 and 1933, respectively, this type of conflict intensified. The experiences of Goldschmidt and Jollos as émigré scientists are interpreted in terms of a conflict of scientific styles of thought. Their Americanization, I claim, involved the modification of their scientific (...) styles and consequently the ways in which they conceived of and presented their scientific work. (shrink)

A study of visual culture in the teaching of the life sciences.

Through a case study of the controversies surrounding the molecular clock, this paper examines the role of visual representation in the dynamics of scientific controversies. Representations of the molecular clock themselves became objects of controversy and so were not a means for closure. Instead visual representations of the molecular clock became tools for the further articulation of an ongoing controversy.

Many biologists appeal to the so-called Krogh principle when justifying their choice of experimental organisms. The principle states that “for a large number of problems there will be some animal of choice, or a few such animals, on which it can be most conveniently studied”. Despite its popularity, the principle is often critiqued for implying unwarranted generalizations from optimal models. We argue that the Krogh principle should be interpreted in relation to the historical and scientific contexts in which it has (...) been developed and used. We interpret the Krogh Principle as a heuristic, i.e., as a recommendation to approach biological problems through organisms where a specific trait or physiological mechanism is expected to be most distinctively displayed or most experimentally accessible. We designate these organisms “Krogh organisms.” We clarify the differences between uses of model organisms and non-standard Krogh organisms. Among these is the use of Krogh organisms as “negative models” in biomedical research, where organisms are chosen for their dissimilarity to human physiology. Importantly, the representational scope of Krogh organisms and the generalizability of their characteristics are not fixed or assumed but explored through experimental studies. Research on Krogh organisms is steeped in the comparative method characteristic of zoology and comparative physiology, in which studies of biological variation produce insights into general physiological constraints. Accordingly, we conclude that the Krogh principle exemplifies the advantages of studying biological variation as a strategy to produce generalizable insights. (shrink)

One of the most interesting challenges facing paleobiologists is explaining the Cambrian explosion, the dramatic appearance of most metazoan animal phyla in the Early Cambrian, and the subsequent stability of these body plans over the ensuing 530 million years. We propose that because phenotypic variation decreases through geologic time, because microRNAs (miRNAs) increase genic precision, by turning an imprecise number of mRNA transcripts into a more precise number of protein molecules, and because miRNAs are continuously being added to metazoan genomes (...) through geologic time, miRNAs might be instrumental in the canalization of development. Further, miRNAs ultimately allow for natural selection to elaborate morphological complexity, because by reducing gene expression variability, miRNAs increase heritability, allowing selection to change characters more effectively. Hence, miRNAs might play an important role in shaping metazoan macroevolution, and might be part of the solution to the Cambrian conundrum. (shrink)

What are the conditions that foster true novelty and allow visionaries to set their eyes on unknown horizons? What have been the challenges that have spawned new innovations, and how have they shaped modern biology? In Dreamers, Visionaries, and Revolutionaries in the Life Sciences, editors Oren Harman and Michael R. Dietrich explore these questions through the lives of eighteen exemplary biologists who had grand and often radical ideas that went far beyond the run-of-the-mill science of their peers. From (...) the Frenchman Jean-Baptiste Lamarck, who coined the word “biology” in the early nineteenth century, to the American James Lovelock, for whom the Earth is a living, breathing organism, these dreamers innovated in ways that forced their contemporaries to reexamine comfortable truths. With this collection readers will follow Jane Goodall into the hidden world of apes in African jungles and Francis Crick as he attacks the problem of consciousness. Join Mary Lasker on her campaign to conquer cancer and follow geneticist George Church as he dreams of bringing back woolly mammoths and Neanderthals. In these lives and the many others featured in these pages, we discover visions that were sometimes fantastical, quixotic, and even threatening and destabilizing, but always a challenge to the status quo. (shrink)

The first edition of The Scientific Background to Modern Philosophy took the dialogue of science and philosophy from Aristotle through to Newton. This second edition adds eight chapters, taking the dialogue through the Enlightenment and up to Darwin. This anthology is an attempt to help bridge the gap between the history of science and the history of philosophy.

’For each case against advertising, there is a stronger offsetting argument.’Dr Hyman is Visiting Professor of Marketing at Limburg University, Holland, and guest editor of a forth coming special issue of The Journal of Advertising on advertising ethics. Dr Skipper is Instructor of Philosophy at Southwest Texas State University.

This chapter contains sections titled: The Gods Problem The Evolution of Free Will Is Our Starting Point So Gods Evolved Gods Are Hidden Inside Us The Godless Must Walk the Earth Gods Must Be Made Manifest Religion Mediates Between Free Will and Gods Living in Harmony With Our Actual Gods.

Cet essai met en cause la comparaison historique courante qui relie le traitement husserlien de la conscience du temps à la tradition philosophique occidentale par le biais du livre IX des Confessions d’Augustin. Je soutiens notamment que cette comparaison n’est valable qu’à l’égard des leçons sur le temps de 1905 (qui expliquent l’appréhension du temps par le recours à l’étirement de la conscience opéré par la mémoire) et non pour la théorie husserlienne ultérieure, que l’on peut dater autour de 1908 (...) (qui critique ouvertement les premières leçons à cause la position défectueuse et contre-intuitive qu’y était défendue selon laquelle la mémoire étend la perception). Après avoir pointé les défauts de la théorie du temps partagée par Augustin et par le Husserl de 1905, j’approfondis la distinction, élaborée plus tard par Husserl à partir de 1911, entre mémoire et rétention, et j’examine l’hypothèse selon laquelle la théorie aristotélicienne du temps telle qu’elle est présentée dans le IVème livre de la Physique pourrait représenter une meilleur terme de comparaison historique pour la théorie husserlienne de la maturité, notamment dans la mesure où elle s’appuie sur l’idée que c’est « l’esprit qui dit les “maintenant” comme deux ». (shrink)