The goal of evolutionary theory is to (a) specify the general causal structure of evolving systems and (b) analyze evolutionary consequences that are expected to result from the proposed structure of the model systems. Biologists frequently emphasize the hypothetico-deductive method in evolutionary theory. I will show that this method primarily provides a tactical device for (b), while evolutionary synthesis requires a foundation of a unifying conceptual model for (a). Therefore, any successful strategy for a new synthesis requires both a new (...) conceptual insight of evolving systems, and tactical devices for analyzing new specific aspects of the evolutionary process. (shrink)

Given the amount of literature devoted to the reasoning used in Darwin’s Origin of Species, an interpretation seeking to revise the standard take on Darwin’s methodology is unexpected. Yet,, and challenges the view that Darwin drew an analogy in the Origin on the grounds that such a strategy could not support the possibility of a new species emerging. I suggest, however, that how one interprets causal efficacy is intimately connected with Darwin’s use of analogy. A more robust conception of natural (...) selection, as found in the Origin, supports the standard interpretation, significantly weakening Richards’ charge of a paradox. (shrink)

Here I reply to Jean Gayon's, Tim Lewens's, and Samir Okasha's comments on Did Darwin write the Origin backwards? The topics addressed include: Darwin's thinking that common ancestry is "evidentially prior" to natural selection; how Darwin uses phylogenetic trees to test hypotheses concerning natural selection; how group and indivdiual selection should be defined, and how each is related to the concept of adaptation.

Several stages can be identified in Darwin's effort to formulate natural selection. The first stage corresponded, roughly speaking, to the period up to 1844. It was characterized by Darwin's attempt to base his model of geographic speciation on an individualistic dynamics, with species understood as reproductively isolated populations. Toward the end of this period, Darwin's ignorance of the laws of variations and heredity led him to adopt varieties and species as the units of variations. This had the extremely important effect (...) of stimulating him to consider the process of speciation as involving populations. At the end of this period, Darwin also began to regard adaptation as being exclusively toward places in the economy of nature. Thus he faced the problem of integrating the process of natural selection with the process of speciation. Individual variants were the units that fueled the first process, whereas varieties produced new speices. There was no link between adaptation and speciation, except whatever could be supplied by a quasi-historical, developmental idea of optimizing the amount of life.In the second stage, I contend, Darwin's reading of Milne-Edwards crystallized his previous insights into a coherent whole. Milne-Edwards' comments on the advantage of functional specialization could readily be understood in terms of the advantage accruing to the individual, relative to other members of its species, from occupying a different niche. Milne-Edwards' discussion of the division of labor suggested that organisms which moved into unoccupied niches would enjoy reduced competition, and hence a differential advantage in survival and reproduction; thus they would induce the species to do likewise. Rather than base his explanation on an analogy with the artificial economy, Darwin chose the principle of the optimalization of the amount of life per unit area as the overall explanatory principle. The difficulties connected with integrating different levels of description were therefore circumvented, insofar as the problem of diversity and speciation was concerned. Although natural selection considered individuals as the units of selection, and the units of variations were varieties and species, the dynamics of the process understood in terms of natural selection, competition, division of labor and niches could give a plausible account of how individual advantage could be transferred to the species, and how diversity resulted from this mechanism. The problem of the different levels of descriptions was confined to how the properties of variations in individuals (in particular, the frequency of variations and their transmission) were responsible for the assumed variability characteristic of varieties and species. This problem Darwin never solved.A third stage occurred in 1858 with the amalgamation of the tree-of-life vizualization of the process of speciation. Speciation, geographic distribution, and systematics were all then embedded in a conceptual matrix with vast explanatory powers. (shrink)

The Evolutionary Synthesis is often seen as a unification process in evolutionary biology, one which provided this research area with a solid common theoretical foundation. As such, neo-Darwinism is believed to constitute from this time onward a single, coherent, and unified movement offering research guidelines for investigations. While this may be true if evolutionary biology is solely understood as centred around evolutionary mechanisms, an entirely different picture emerges once other aspects of the founding neo-Darwinists’ views are taken into consideration, aspects (...) potentially relevant to the elaboration of an evolutionary worldview: the tree of life, the ontological distinctions of the main cosmic entities , the inherent properties of self-organizing matter, evolutionary ethics, and so on. Profound tensions and inconsistencies are immediately revealed in the neo-Darwinian movement once this broader perspective is adopted. This pluralism is such that it is possible to identify at least three distinct and quasi-incommensurable epistemological/metaphysical frameworks as providing a proper foundation for neo-Darwinism. The analysis of the views of Theodosius Dobzhansky, Bernhard Rensch, and Ernst Mayr will illustrate this untenable pluralism, one which requires us to conceive of the neo-Darwinian research agenda as being conducted in more than one research programme or research tradition at the same time. (shrink)

Natural selection explains how living forms are fitted to theirconditions of life. Darwin argued that selection also explains what hecalled the gradual advancement of the organisation, i.e.evolutionary progress. Present-day selectionists disagree. In theirview, it is happenstance that sustains conditions favorable to progress,and therefore happenstance, not selection, that explains progress. Iargue that the disagreement here turns not on whether there exists aselection-based condition bias – a belief now attributed to Darwin – but on whether there needs to be such a bias (...) for selection to count as explaining progress. In Darwin''s own view, selection explained progressso far as more complex organisms have the selective advantage whenselection operates unimpeded. I show that these two explanations ofevolutionary progress, selection and happenstance, answer for theirobjectivity to different standards, and for their truth or falsehood todifferent features of the world. (shrink)

What should human languages be like if humans are the products of Darwinian evolution? Between Darwin’s day & like the peoples speaking them are higher or lower in an evolutionarily generated scale This paper charts some of the changes in the Darwinian tradition that transformed the notion of human linguistic equality from creationist heresy., our own, expectations about evolution’s imprint on language have changed dramaticallyIt is now a commonplace that, for good Darwinian reasons, no language is more highly evolved than (...) any otherBut Darwin, in The descent of man, defended the opposite view: different languages. (shrink)

In what follows, I consider the role of analogy in the first edition of Darwin’s Origin. I argue that Darwin follows Herschel’s methodology and hence exploits an analogy between artificial and natural selection that allows him generalize selection as a cause of evolutionary change. This argument strategy is not equivalent to an argument from analogy. Reading Darwin’s argument as conforming to Herschel’s two-step methodology of causal analysis followed by generalization allows us to understand the role and placement of Darwin’s discussion (...) of artificial selection in the Origin, without making the mistake of portraying Darwin’s argument for the existence and character of natural selection as an analogical argument. (shrink)

Work throughout the history and philosophy of biology frequently employs ‘chance’, ‘unpredictability’, ‘probability’, and many similar terms. One common way of understanding how these concepts were introduced in evolution focuses on two central issues: the first use of statistical methods in evolution (Galton), and the first use of the concept of “objective chance” in evolution (Wright). I argue that while this approach has merit, it fails to fully capture interesting philosophical reflections on the role of chance expounded by two of (...) Galton's students, Karl Pearson and W.F.R. Weldon. Considering a question more familiar from contemporary philosophy of biology—the relationship between our statistical theories of evolution and the processes in the world those theories describe—is, I claim, a more fruitful way to approach both these two historical actors and the broader development of chance in evolution. (shrink)

There are a bewildering variety of claims connecting Darwin to nineteenth-century philosophy of science—including to Herschel, Whewell, Lyell, German Romanticism, Comte, and others. I argue here that Herschel’s influence on Darwin is undeniable. The form of this influence, however, is often misunderstood. Darwin was not merely taking the concept of “analogy” from Herschel, nor was he combining such an analogy with a consilience as argued for by Whewell. On the contrary, Darwin’s Origin is written in precisely the manner that one (...) would expect were Darwin attempting to model his work on the precepts found in Herschel’s Preliminary Discourse on Natural Science. While Hodge has worked out a careful interpretation of both Darwin and Herschel, drawing similar conclusions, his interpretation misreads Herschel’s use of the vera causa principle and the verification of hypotheses. The new reading that I present here resolves this trouble, combining Hodge’s careful treatment of the structure of the Origin with a more cautious understanding of Herschel’s philosophy of science. This interpretation lets us understand why Darwin laid out the Origin in the way that he did and also why Herschel so strongly disagreed, including in Herschel’s heretofore unanalyzed marginalia in his copy of Darwin’s book. (shrink)

Berichte zur Wissenschaftsgeschichte, EarlyView.

In the title chapter of Did Darwin Write the Origin Backwards?, Sober argues for an asymmetry between facts about genealogy and facts about natural selection, which has the result that evidentially Darwin's book is the wrong way round. Here I make three points about Sober's argument in that chapter. First, it is not clear that Darwin employs what Sober calls 'tree thinking' as frequently as Sober himself suggests. Second, I argue that Darwin's reason for structuring the Origin as he did (...) can be understood if we think of the Origin's argument as an inference to the best explanation. Third, I show circumstances where, even if selection is the only important evolutionary force, we would still be able to infer common ancestry. (shrink)

Darwin’s claim about natural selection is reconstructed as an empirical claim about a causal connection leading from the match of the physiology of an individual and its environment to leaving surviving progeny. Variations in this match, Darwin claims, cause differences in the survival of the progeny. Modern concepts of fitness focus the survival side of this chain. Therefore, the assumption that evolutionary theory wants to explain reproductive success in terms of a modern concept of fitness has given rise to the (...) so-called tautology problem. It is shown that the tautology problem reappears in the treatment of fitness proxies in today’s experimental evolutionary biology when these proxies are considered to indicate fitness only. Taking Darwin’s empirical claim seriously suggests, by contrast, that fitness proxies are first of all measures of the match between organism and environment, which I call the organism’s ‘fittedness’. At the same time, they are indeed related to reproductive success. Thus looking in both directions, at fitness and at fittedness, they are janiform. Acknowledging this situation not only allows for rejection of the tautology objection, but also for integration of Darwin’s argument into current evolutionary biology. It is suggested that this helps reframe and alleviate the dispute between the Modern Synthesis and the Extended Evolutionary Synthesis. (shrink)

Recently, the nature of science (NOS) has become recognized as an important element within the K-12 science curriculum. Despite differences in the ultimate lists of recommended aspects, a consensus is emerging on what specific NOS elements should be the focus of science instruction and inform textbook writers and curriculum developers. In this article, we suggest a contextualized, explicit approach addressing one core NOS aspect: the human aspects of science that include the domains of creativity, social influences and subjectivity. To illustrate (...) these ideas, we have focused on Charles Darwin, a scientist whose life, work and thought processes were particularly well recorded at the time and analyzed by scholars in the succeeding years. Historical facts are discussed and linked to core NOS ideas. Creativity is illustrated through the analogies between the struggle for existence in human societies and in nature, between artificial and natural selection, and between the division of labor in human societies and in nature. Social influences are represented by Darwin’s aversion of criticism of various kinds and by his response to the methodological requirements of the science of that time. Finally, subjectivity is discussed through Darwin’s development of a unique but incorrect source for the origin of variations within species. (shrink)

Almost any modern reader's first encounter with Darwin's writing is likely to be the "Historical Sketch," inserted by Darwin as a preface to an early edition of the Origin of Species, and having since then appeared as the preface to every edition after the second English edition. The Sketch was intended by him to serve as a short "history of opinion" on the species question before he presented his own theory in the Origin proper. But the provenance of the "Historical (...) Sketch" is somewhat obscure. Some things are known about its production, such as when it first appeared and what changes were made to it between its first appearance in 1860 and its final form, for the fourth English edition, in 1866. But how it evolved in Darwin's mind, why he wrote it at all, and what he thought he was accomplishing by prefacing it to the Origin remain questions that have not been carefully addressed in the scholarly literature on Darwin I attempt to show that Darwin's various statements about the "Historical Sketch," made primarily to several of his correspondents between 1856 and 1860, are somewhat in conflict with one another, thus making problematic a satisfactory interpretation of how, when, and why the Sketch came to be. I also suggest some probable resolutions to the several difficulties. (shrink)

Almost any modern reader's first encounter with Darwin's writing is likely to be the "Historical Sketch," inserted by Darwin as a preface to an early edition of the Origin of Species, and having since then appeared as the preface to every edition after the second English edition. The Sketch was intended by him to serve as a short "history of opinion" on the species question before he presented his own theory in the Origin proper. But the provenance of the "Historical (...) Sketch" is somewhat obscure. Some things are known about its production, such as when it first appeared and what changes were made to it between its first appearance in 1860 and its final form, for the fourth English edition, in 1866. But how it evolved in Darwin's mind, why he wrote it at all, and what he thought he was accomplishing by prefacing it to the Origin remain questions that have not been carefully addressed in the scholarly literature on Darwin I attempt to show that Darwin's various statements about the "Historical Sketch," made primarily to several of his correspondents between 1856 and 1860, are somewhat in conflict with one another, thus making problematic a satisfactory interpretation of how, when, and why the Sketch came to be. I also suggest some probable resolutions to the several difficulties. (shrink)

In the wake of recent attempts at alternate history (Bowler 2013), this paper suggests several avenues for a pluralistic approach to Charles Darwin and his role in the history of evolutionary theory. We examine in what sense Darwin could be described as a major driver of theoretical change in the history of biology. First, this paper examines how Darwin influenced the future of biological science: not merely by stating the fact of evolution or by bringing evidence for it; but by (...) discovering natural selection, and giving it pre-eminence over any other mechanism for evolution; and also by proposing a masterful and quite unique synthesis of many scientific fields. Contrasting Darwin’s views with those of A.R. Wallace, I conclude that “natural selection” is clearly an original contribution, that it had no forerunners or co-discoverers, and could barely have appeared after Darwin conceived of it. This specificity of Darwin’s contribution is an invitation to be strongly presentist (Loison 2016) and to adopt only weak counter-factuals. In contrast, there are possible ways to use strong counter-factuals as attempts to “pluralize” the history of biological theory: i.e. imagine new possible avenues for the development of evolutionary biology. The idea that evolution was a theory “in the air” suggests that evolutionary theory could have developed in a world without Darwin, especially if we accept to delete not only “Darwin” but “England”. France and Germany are examined as possible countries where evolutionary ideas would have thrived even with no contribution from the English scientists. Finally, the paper suggests another counter-factual hypothesis: deleting not Darwin and his Origin but the Darwin Industry itself. This may allow us to read the Origin of Species with fresh eyes and to discover Darwin’s life-long interest in variation and its laws, as many of his early readers did. (shrink)

Various claims have been made, recently, that Darwin's argumentation in the Origin instantiates and so supports some general philosophical proposal about scientific theorizing, for example, the "semantic view". But these claims are grounded in various incorrect analyses of that argumentation. A summary is given here of an analysis defended at greater length in several papers by the present author. The historical and philosophical advantages of this analysis are explained briefly. Darwin's argument comprises three distinct evidential cases on behalf of natural (...) selection, cases, that is, for its existence, its adequacy and its responsibility. Theorizing, today, about evolution by natural selection involves a similar structure of evidential and explanatory concerns. (shrink)

We develop an account of laboratory models, which have been central to the group selection controversy. We compare arguments for group selection in nature with Darwin's arguments for natural selection to argue that laboratory models provide important grounds for causal claims about selection. Biologists get information about causes and cause-effect relationships in the laboratory because of the special role their own causal agency plays there. They can also get information about patterns of effects and antecedent conditions in nature. But to (...) argue that some cause is actually responsible in nature, they require an inference from knowledge of causes in the laboratory context and of effects in the natural context. This process, cause detection, forms the core of an analogical argument for group selection. We discuss the differing roles of mathematical and laboratory models in constructing selective explanations at the group level and apply our discussion to the units of selection controversy to distinguish between the related problems of cause determination and evaluation of evidence. Because laboratory models are at the intersection of the two problems, their study is crucial for framing a coherent theory of explanation for evolutionary biology. (shrink)

This work takes a stand on whether Wallace should be regarded as co-author of the theory of natural selection alongside Darwin as he is usually considered on behalf of his alleged essential contribution to the conception of the theory. It does so from a perspective unexplored thus far: we will argue for Darwin’s priority based on a rational reconstruction of the theory of natural selection as it appears in the writings of both authors. We show that the theory does not (...) appear in exactly the same manner in the writings of each of its alleged co-discoverers: tough we find the same fundamental elements in both works, even in Darwin’s early texts, we discern a more complex unifying and ramified structure than the one we find in Wallace’s Ternate manuscript. Even when we think the badge of the “Darwin–Wallace” theory is well deserved, the unifying force of Darwin’s version has proved to be one of the keys for the ulterior success of the so-called Darwinian revolution in Biology. (shrink)

Darwin used artificial selection extensively and variedly in his theorizing. Darwin used ASN as an analogy to natural selection; he compared artificial to natural varieties, hereditary variation in nature to that in the breeding farm; and he also compared the overall effectiveness of the two processes. Most historians and philosophers of biology have argued that ASN worked as an analogical field in Darwin’s theorizing. I will argue rather that this provides a limited and somewhat muddled view of Darwinian science. I (...) say “limited” because I will show that Darwin also used ASN as a complex experimental field. And I say “muddled” because, if we concentrate on the analogical role exclusively, we conceive Darwinian science as rather disconnected from contemporary conceptions of “good science”.I will argue that ASN should be conceived as a multifaceted experiment. As a traditional experiment, ASN established the efficacy of Darwin’s preferred cause: natural selection. As a non-traditional experiment, ASN disclosed the nature of a crucial element in Darwin’s evolutionary mechanics: the nature of hereditary variation. Finally, I will argue that the experiment conception should help us make sense of Darwin’s comments regarding the “monstrous” nature of domestic breeds_traditionally considered to be problematic. (shrink)

Charles Darwin and C. Lloyd Morgan forward two influential principles of cognitive ethological inference that yield conflicting results about the extent of continuity in the cognitive traits of humans and other animals. While these principles have been interpreted as reflecting commitments to different senses of parsimony, in fact, both principles result from the same vera causa inferential strategy, according to which “We ought to admit no more causes of natural things, than such as are both true and sufficient to explain (...) their appearances”. Instead, the conflict stems from Darwin’s and Morgan’s views about the true causes of human psychology. Darwin holds a thoroughly Humean philosophy of the human mind, from which he infers significant continuity between human and animal minds. In contrast, Morgan argues that Humean cognitive mechanisms cannot account for a class of uniquely human behaviors, and therefore, he concludes that there is a significant discontinuity between human and animal cognition. This historical debate is informative for current controversies in comparative psychology. (shrink)

In the Origin, Darwin forwards two incompatible lines of attack on special creationism. First, he argues that imperfect or functionless traits are evidence against design. Second, he argues that since special creationism can be made compatible with any observation, it is unscientific and explanatorily vacuous. In later works, Darwin shifts to an argument that he finds much more persuasive and which would undermine theistic evolutionism as well. He argues that variation is random with respect to selection and that this demonstrates (...) that there is no design in the biological world. I examine why Darwin found the argument from independence of variation and selection more compelling than the argument from imperfection. I argue that Darwin utilized general principles of causal inference, akin to those used in modern causal modeling, to rule out any unified cause behind the evolutionary process. (shrink)

This paper discusses some philosophical and historical connections between, and within, nineteenth century evolutionism and microscopical research. The principal actors are mainly Darwin, Schleiden, Whewell and the "London Doctors," Arthur Henfrey and Edwin Lankester. I demonstrate that the apparent alliances—particularly Darwin/Schleiden (through evolutionism) and Schleiden/Whewell (through Kantian philosophy of science)—obscure the deep methodological differences between evolutionist and microscopical biology that lingered on until the mid-twentieth century. Through an understanding of the little known significance of Schleiden's programme of microscopical research and (...) by comparing certain features of his methodology to the activities of the "London Doctors," we can identify the origin of this state of affairs. In addition, the outcome provides an insight into a critique of Buchdahl's view on Schleiden's philosophical conception. (shrink)

This paper discusses some philosophical and historical connections between, and within, nineteenth century evolutionism and microscopical research. The principal actors are mainly Darwin, Schleiden, Whewell and the “London Doctors,” Arthur Henfrey and Edwin Lankester. I demonstrate that the apparent alliances—particularly Darwin/Schleiden (through evolutionism) and Schleiden/Whewell (through Kantian philosophy of science)—obscure the deep methodological differences between evolutionist and microscopical biology that lingered on until the mid-twentieth century. Through an understanding of the little known significance of Schleiden’s programme of microscopical research and (...) by comparing certain features of his methodology to the activities of the “London Doctors,” we can identify the origin of this state of affairs. In addition, the outcome provides an insight into a critique of Buchdahl’s view on Schleiden’s philosophical conception. (shrink)

In the 1940s, the ‘modern synthesis’ (MS) of Darwinism and genetics cast genetic mutation and recombination as the source of variability from which environmental events naturally select the fittest, such ‘natural selection’ constituting the cause of evolution. Recent biology increasingly challenges this view by casting genes as followers and awarding the leading role in the genesis of adaptations to the agency and plasticity of developing phenotypes—making natural selection a consequence of other causal processes. Both views of natural selection claim to (...) capture the core of Darwin’s arguments in On the Origin of Species. Today, historians largely concur with the MS’s reading of Origin as a book aimed to prove natural selection the cause (vera causa) of adaptive change. This paper finds the evidence for that conclusion wanting. I undertake to examine the context and meaning of all Darwin’s known uses of the phrase vera causa, documenting in particular Darwin’s resistance to the pressure to prove natural selection a vera causa in letters written early in 1860. His resistance underlines the logical dependence of natural selection, an unobservable phenomenon, on the causal processes producing the observable events captured by the laws of inheritance, variation, and the struggle for existence, established in Chapters 1–3 of Origin. (shrink)

Recent Darwin scholarship has provided grounds for recognising the Origin as a literary as well as a scientific achievement. While Darwin was an acute observer, a gifted experimentalist and indefatigable theorist, this essay argues that it was also crucial to his impact that the Origin transcended the putative divide between the scientific and the literary. Analysis of Darwin's development as a writer between his journal-keeping on HMS Beagle and his construction of the Origin argues the latter draws on the pattern (...) of the Romantic or Kantian sublime. The Origin repeatedly uses strategies which challenge the natural-theological appeal to the imagination in conceiving nature. Darwin's sublime coaches the Origin's readers into a position from which to envision nature that reduces and contains its otherwise overwhelming complexity. As such, it was Darwin's literary achievement that enabled him to fashion a new 'habit of looking at things in a given way' that is the centrepiece of the scientific revolution bearing his name. (shrink)

Recent Darwin scholarship has provided grounds for recognising the Origin as a literary as well as a scientific achievement. While Darwin was an acute observer, a gifted experimentalist and indefatigable theorist, this essay argues that it was also crucial to his impact that the Origin transcended the putative divide between the scientific and the literary. Analysis of Darwin’s development as a writer between his journal-keeping on HMS Beagle and his construction of the Origin argues the latter draws on the pattern (...) of the Romantic or Kantian sublime. The Origin repeatedly uses strategies which challenge the natural-theological appeal to the imagination in conceiving nature. Darwin’s sublime coaches the Origin’s readers into a position from which to envision nature that reduces and contains its otherwise overwhelming complexity. As such, it was Darwin’s literary achievement that enabled him to fashion a new ‘habit of looking at things in a given way’ that is the centrepiece of the scientific revolution bearing his name. (shrink)

Seventy-two Internet documents promoting creationism, intelligent design, or evolution were selected for analysis. The primary goal of each of the 72 documents was to present arguments for creationism, I.D., or evolution. We first identified all arguments in these documents. Each argument was then coded in terms of both argument type and argument topic. We then provided a quantitative summary of each argument type and topic for each of the three positions. Three clear patterns were revealed by the data. First, websites (...) promoting evolution were characterized by a narrow focus on appeals to empirical evidence, whereas websites promoting creationism and I.D. were quite heterogeneous in regards to argument type. Second, websites promoting evolution relied primarily on a small number of empirical examples, while websites promoting creationism and I.D. used a far greater range of arguments. Finally, websites promoting evolution were narrowly focused on the topic of descent with modification. In contrast, websites promoting creationism tackled a broad range of topics, while websites promoting I.D. were narrowly focused on the issue of the existence of God. The current study provides a quantitative summary of a systematic content analysis of argument type and topic across a large number of frequently accessed websites dealing with origins. The analysis we have used may prove fruitful in identifying and understanding argumentation trends in scientific writing and pseudo-scientific writing. (shrink)

Newton’s Regulae philosophandi—the rules for reasoning in natural philosophy—are maxims of causal reasoning and induction. This essay reviews their significance for Newton’s method of inquiry, as well as their application to particular propositions within the Principia. Two main claims emerge. First, the rules are not only interrelated, they defend various facets of the same core idea: that nature is simple and orderly by divine decree, and that, consequently, human beings can be justified in inferring universal causes from limited phenomena, if (...) only fallibly. Second, the rules make substantive ontological assumptions on which Newton’s argument in the Principia relies. (shrink)

This Ph.D. thesis provides a pilosophical account of the structure of the evolutionary synthesis of the 1930s and 40s. The first, more historical part analyses how classical genetics came to be integrated into evolutionary thinking, highlighting in particular the importance of chromosomal mapping of Drosophila strains collected in the wild by Dobzansky, but also the work of Goldschmidt, Sumners, Timofeeff-Ressovsky and others. The second, more philosophical part attempts to answer the question wherein the unity of the synthesis consisted. I argue (...) that it exemplifies a weak of form of explanatory unification. (shrink)

A number of areas of biology raise questions about what is of value in the natural environment and how we ought to behave towards it: conservation biology, environmental science, and ecology, to name a few. Based on my experience teaching students from these and similar majors, I argue that the field of environmental ethics has much to teach these students. They come to me with pent-up questions and a feeling that more is needed to fully engage in their subjects, and (...) I believe some exposure to environmental ethics can help focus their interests and goals. I identify three primary areas in which environmental ethics can con- tribute to their education. The first is an examination of who (or what) should be considered to be part of our moral community (i.e., the community to whom we owe direct duties). Is it humans only? Or does it include all sentient life? Or all life? Or ecosystems considered holistically? Often, readings implicitly assume one or more of these answers; the goal is to make the student more sensitive to these implicit claims and to get them to think about the different reasons that support them. The second area, related to the first, is the application of the different answers concerning the extent of the ethical community to real environmental issues and problems. Students need to be aware of how the different answers concerning the moral community can imply conflicting answers for how we should act in certain cases and to think about ways to move toward conflict resolution. The third area in which environmental ethics can contribute is a more conceptual one, focusing on central concepts such as biodiversity, sustainability, species, and ecosystems. Exploring and evaluating various meanings of these terms will make students more reflective and thoughtful citizens and biologists, sensitive to the implications that different conceptual choices make. (shrink)

After clarifying how Darwin understood natural selection and common ancestry, I consider how the two concepts are related in his theory. I argue that common ancestry has an evidential priority. For Darwin, arguments about natural selection often make use of the assumption of common ancestry, whereas defending common ancestry does not require the assumption that natural selection has been at work. In fact, Darwin held that the key evidence for common ancestry comes from characters whose evolution is not caused by (...) natural selection. This raises the question of why Darwin puts natural selection first and foremost in the Origin. (shrink)