In this article, I address the question of what Developmental Systems Theory aims at explaining. I distinguish two lines of thought in DST, one that deals specifically with development and tries to explain the development of the individual organism, and the other that presents itself as a reconceptualization of evolution and tries to explain the evolution of populations of developmental systems. I emphasize that, despite the claim of the contrary by DST proponents, there are two very different definitions of the (...) “developmental system,” and therefore DST is not a unified theory of evolution and development. I show that DST loses the most interesting aspects of its reconceptualization of development when it tries to reconceptualize evolutionary theory. I suggest that DST is about development per se, and that it fails at offering a new view on evolution. (shrink)

The self/non-self model, first proposed by F.M. Burnet, has dominated immunology for 60 years now. According to this model, any foreign element will trigger an immune reaction in an organism, whereas endogenous elements will not, in normal circumstances, induce an immune reaction. In this paper we show that the self/non-self model is no longer an appropriate explanation of experimental data in immunology, and that this inadequacy may be rooted in an excessively strong metaphysical conception of biological identity. We suggest that (...) another hypothesis, one based on the notion of continuity, gives a better account of immune phenomena. Finally, we underscore the mapping between this metaphysical deflation from self to continuity in immunology and the philosophical debate between substantialism and empiricism about identity. (shrink)

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)

Dobzhansky argued that biology only makes sense if life on earth has a shared history. But his dictum is often reinterpreted to mean that biology only makes sense in the light of adaptation. Some philosophers of science have argued in this spirit that all work in ‘proximal’ biosciences such as anatomy, physiology and molecular biology must be framed, at least implicitly, by the selection histories of the organisms under study. Others have denied this and have proposed non-evolutionary ways in which (...) biologists can frame these investigations. This paper argues that an evolutionary perspective is indeed necessary, but that it must be a forward-looking perspective informed by a general understanding of the evolutionary process, not a backward-looking perspective informed by the specific evolutionary history of the species being studied. Interestingly, it turns out that there are aspects of proximal biology that even a creationist cannot study except in the light of a theory of their effect on future evolution. (shrink)

Developmental biology is expanding into several new areas. One new area of study concerns the production of adult-onset phenotypes by exposure of the fetus or neonate to environmental agents. These agents include maternal nutrients, developmental modulators (endocrine disruptors), and maternal care. In all three cases, a major mechanism for the generation of the altered phenotype is chromatin modification. Nutrient conditions, developmental modulators, and even maternal care appear to alter DNA methylation and other associated changes in chromatin that regulate gene expression. (...) This brings a new, under-appreciated, dimension of gene regulation into developmental biology, and it also demonstrates the poverty of the nature versus nurture framework for discussing phenotype production. Moreover, while such epigenetic mechanisms undermine genetic determinism, they add a layer of probabilistic biological causality for the maintenance of social inequalities. (shrink)

The nature/nurture debate is not dead. Dichotomous views of development still underlie many fundamental debates in the biological and social sciences. Developmental systems theory offers a new conceptual framework with which to resolve such debates. DST views ontogeny as contingent cycles of interaction among a varied set of developmental resources, no one of which controls the process. These factors include DNA, cellular and organismic structure, and social and ecological interactions. DST has excited interest from a wide range of researchers, from (...) molecular biologists to anthropologists, because of its ability to integrate evolutionary theory and other disciplines without falling into traditional oppositions. The book provides historical background to DST, recent theoretical findings on the mechanisms of heredity, applications of the DST framework to behavioral development, implications of DST for the philosophy of biology, and critical reactions to DST. (shrink)

One of our most brilliant evolutionary biologists, Richard Lewontin has also been a leading critic of those--scientists and non-scientists alike--who would misuse the science to which he has contributed so much. In The Triple Helix, Lewontin the scientist and Lewontin the critic come together to provide a concise, accessible account of what his work has taught him about biology and about its relevance to human affairs. In the process, he exposes some of the common and troubling misconceptions that misdirect and (...) stall our understanding of biology and evolution.The central message of this book is that we will never fully understand living things if we continue to think of genes, organisms, and environments as separate entities, each with its distinct role to play in the history and operation of organic processes. Here Lewontin shows that an organism is a unique consequence of both genes and environment, of both internal and external features. Rejecting the notion that genes determine the organism, which then adapts to the environment, he explains that organisms, influenced in their development by their circumstances, in turn create, modify, and choose the environment in which they live.The Triple Helix is vintage Lewontin: brilliant, eloquent, passionate, and deeply critical. But it is neither a manifesto for a radical new methodology nor a brief for a new theory. It is instead a primer on the complexity of biological processes, a reminder to all of us that living things are never as simple as they may seem. (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)