Does natural selection act primarily on individual organisms, on groups, on genes, or on whole species? The question of levels of selection - on which biologists and philosophers have long disagreed - is central to evolutionary theory and to the philosophy of biology. Samir Okasha's comprehensive analysis gives a clear account of the philosophical issues at stake in the current debate.

Is the history of life a series of accidents or a drama scripted by selfish genes? Is there an “essential” human nature, determined at birth or in a distant evolutionary past? What should we conserve—species, ecosystems, or something else? -/- Informed answers to questions like these, critical to our understanding of ourselves and the world around us, require both a knowledge of biology and a philosophical framework within which to make sense of its findings. In this accessible introduction to philosophy (...) of biology, Kim Sterelny and Paul E. Griffiths present both the science and the philosophical context necessary for a critical understanding of the most exciting debates shaping biology today. The authors, both of whom have published extensively in this field, describe the range of competing views—including their own—on these fascinating topics. -/- With its clear explanations of both biological and philosophical concepts, Sex and Death will appeal not only to undergraduates, but also to the many general readers eager to think critically about the science of life. (shrink)

The authors demonstrate that unselfish behavior is in fact an important feature of both biological and human nature. Their book provides a panoramic view of altruism throughout the animal kingdom--from self-sacrificing parasites to the human capacity for selflessness--even as it explains the evolutionary sense of such behavior.

The main objective of immunology is to establish why and when an immune response occurs, that is, to determine a criterion of immunogenicity. According to the consensus view, the proper criterion of immunogenicity lies in the discrimination between self and nonself. Here we challenge this consensus by suggesting a simpler and more comprehensive criterion, the criterion of continuity. Moreover, we show that this criterion may be considered as an interpretation of the immune 'self'. We conclude that immunologists can continue to (...) speak of the self, provided that they admit that the self/nonself discrimination is not an adequate criterion of immunogenicity. (shrink)

I analyze a number of widespread misconceptions concerning species. The species category, defined by a concept, denotes the rank of a species taxon in the Linnaean hierarchy. Biological species are reproducing isolated from each other, which protects the integrity of their genotypes. Degree of morphological difference is not an appropriate species definition. Unequal rates of evolution of different characters and lack of information on the mating potential of isolated populations are the major difficulties in the demarcation of species taxa.

Recent years have seen a renewed debate over the importance of groupselection, especially as it relates to the evolution of altruism. Onefeature of this debate has been disagreement over which kinds ofprocesses should be described in terms of selection at multiple levels,within and between groups. Adapting some earlier discussions, we presenta mathematical framework that can be used to explore the exactrelationships between evolutionary models that do, and those that donot, explicitly recognize biological groups as fitness-bearing entities.We show a fundamental set (...) of mathematical equivalences between these twokinds of models, one of which applies a form of multi-level selectiontheory and the other being a form of ``individualism.'' However, we alsoargue that each type of model can have heuristic advantages over theother. Indeed, it can be positively useful to engage in a kind ofback-and-forth switching between two different perspectives on theevolutionary role of groups. So the position we defend is a``gestalt-switching pluralism.''. (shrink)

Biological species have been treated traditionally as spatiotemporally unrestricted classes. If they are to perform the function which they do in the evolutionary process, they must be spatiotemporally localized individuals, historical entities. Reinterpreting biological species as historical entities solves several important anomalies in biology, in philosophy of biology, and within philosophy itself. It also has important implications for any attempt to present an "evolutionary" analysis of science and for sciences such as anthropology which are devoted to the study of single (...) species. (shrink)

With this manifesto, John Dupré systematically attacks the ideal of scientific unity by showing how its underlying assumptions are at odds with the central conclusions of science itself.

Darwin’s classic ‘Origin of Species’ (Darwin 1859) described forces of selection acting upon individuals, but there remains a great deal of controversy about what exactly the status and definition of a biological individual is. Recently some authors have argued that the individual is dispensable – that an inability to pin it down is not problematic because little rests on it anyway. The aim of this paper is to show that there is a real problem of biological individuality, and an urgent (...) need to arbitrate over the current plethora of solutions to it. (shrink)

This chapter develops the idea that the germ-soma split and the suppression of individual fitness differences within the corporate entity are not always essential steps in the evolution of corporate individuals. It illustrates some consequences for multilevel selection theory. It presents evidence that genetic heterogeneity may not always be a barrier to successful functioning as a higher-level individual. This chapter shows that levels-of-selection theorists are wrong to assume that the central problem in transitions is always that of minimizing within-group competition. (...) Evidence of intralevel conflict does not qualify as evidence against the existence of a higher level of selection. (shrink)

Richard Lewontin's (1970) early work on the units of selection initiated the conceptual and theoretical investigations that have led to the hierarchical perspective on selection that has reached near consensus status today. This paper explores other aspects of his work, work on what he termed continuity and quasi-independence, that connect to contemporary explorations of modularity in development and evolution. I characterize such modules and argue that they are the true units of selection in that they are what evolution by natural (...) selection individuates, selects among, and transforms. (shrink)

The central point of this essay is to demonstrate the incommensurability of ‘Darwinian fitness’ with the numeric values associated with reproductive rates used in population genetics. While sometimes both are called ‘fitness’, they are distinct concepts coming from distinct explanatory schemes. Further, we try to outline a possible answer to the following question: from the natural properties of organisms and a knowledge of their environment, can we construct an algorithm for a particular kind of organismic life-history pattern that itself will (...) allow us to predict whether a type in the population will increase or decrease relative to other types? Introduction Darwinian fitness Reproductive fitness and genetical models of evolution The models of reproductive fitness 4.1 The Standard Viability Model 4.2 Frequency-dependent selection 4.3 Fertility models 4.4 Overlapping generations Fitness as outcome 5.1 Fitness as actual increase in type 5.2 Fitness as expected increase in type 5.2.1 Expected increase within a generation 5.2.2 Expected increase between generations 5.2.3 Postponed reproductive fitness effects The book-keeping problem Conclusion. (shrink)

The central point of this essay is to demonstrate the incommensurability of ‘Darwinian fitness’ with the numeric values associated with reproductive rates used in population genetics. While sometimes both are called ‘fitness’, they are distinct concepts coming from distinct explanatory schemes. Further, we try to outline a possible answer to the following question: from the natural properties of organisms and a knowledge of their environment, can we construct an algorithm for a particular kind of organismic life-history pattern that itself will (...) allow us to predict whether a type in the population will increase or decrease relative to other types? 1. Introduction2. Darwinian fitness3. Reproductive fitness and genetical models of evolution4. The models of reproductive fitness4.1 The Standard Viability Model4.2 Frequency-dependent selection4.3 Fertility models4.4 Overlapping generations5. Fitness as outcome5.1 Fitness as actual increase in type5.2 Fitness as expected increase in type5.2.1 Expected increase within a generation5.2.2 Expected increase between generations5.2.3 Postponed reproductive fitness effects6. The book-keeping problem7. Conclusion. (shrink)

Ideas about heredity and evolution are undergoing a revolutionary change. New findings in molecular biology challenge the gene-centered version of Darwinian theory according to which adaptation occurs only through natural selection of chance DNA variations. In Evolution in Four Dimensions, Eva Jablonka and Marion Lamb argue that there is more to heredity than genes. They trace four "dimensions" in evolution -- four inheritance systems that play a role in evolution: genetic, epigenetic, behavioral, and symbolic. These systems, they argue, can all (...) provide variations on which natural selection can act. Evolution in Four Dimensions offers a richer, more complex view of evolution than the gene-based, one-dimensional view held by many today. The new synthesis advanced by Jablonka and Lamb makes clear that induced and acquired changes also play a role in evolution.After discussing each of the four inheritance systems in detail, Jablonka and Lamb "put Humpty Dumpty together again" by showing how all of these systems interact. They consider how each may have originated and guided evolutionary history and they discuss the social and philosophical implications of the four-dimensional view of evolution. Each chapter ends with a dialogue in which the authors engage the contrarieties of the fictional "I.M.," or Ifcha Mistabra -- Aramaic for "the opposite conjecture" -- refining their arguments against I.M.'s vigorous counterarguments. The lucid and accessible text is accompanied by artist-physician Anna Zeligowski's lively drawings, which humorously and effectively illustrate the authors' points. (shrink)

The book presents a new way of understanding Darwinism and evolution by natural selection, combining work in biology, philosophy, and other fields.

What makes a biological entity an individual? Jack Wilson shows that past philosophers have failed to explicate the conditions an entity must satisfy to be a living individual. He explores the reason for this failure and explains why we should limit ourselves to examples involving real organisms rather than thought experiments. This book explores and resolves paradoxes that arise when one applies past notions of individuality to biological examples beyond the conventional range and presents an analysis of identity and persistence. (...) The book's main purpose is to bring together two lines of research, theoretical biology and metaphysics, which have dealt with the same subject in isolation from one another. Wilson explains an alternative theory about biological individuality which solves problems which cannot be addressed by either field alone. He presents a more fine-grained vocabulary of individuation based on diverse kinds of living things, allowing him to clarify previously muddled disputes about individuality in biology. (shrink)

Individuals are a prominent part of the biological world. Although biologists and philosophers of biology draw freely on the concept of an individual in articulating both widely accepted and more controversial claims, there has been little explicit work devoted to the biological notion of an individual itself. How should we think about biological individuals? What are the roles that biological individuals play in processes such as natural selection (are genes and groups also units of selection?), speciation (are species individuals?), and (...) organismic development (do genomes code for organisms)? Much of our discussion here will focus on organisms as a central kind of biological individual, and that discussion will raise broader questions about the nature of the biological world, for example, about its complexity, its organization, and its relation to human thought. (shrink)

The theory of evolution by natural selection is, perhaps, the crowning intellectual achievement of the biological sciences. There is, however, considerable debate about which entity or entities are selected and what it is that fits them for that role. This article aims to clarify what is at issue in these debates by identifying four distinct, though often confused, concerns and then identifying how the debates on what constitute the units of selection depend to a significant degree on which of these (...) four questions a thinker regards as central. (shrink)

The question “What is an organism?”, formerly considered as essential in biology, has now been increasingly replaced by a larger question, “What is a biological individual?”. On the grounds that i) individuation is theory-dependent, and ii) physiology does not offer a theory, biologists and philosophers of biology have claimed that it is the theory of evolution by natural selection which tells us what counts as a biological individual. Here I show that one physiological field, immunology, offers a theory, which makes (...) possible a biological individuation based on physiological grounds. I give a new answer to the question of the individuation of an organism by linking together the evolutionary and the immunological approaches to biological individuation. (shrink)