Paul Edmund Griffiths

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.

Philosophical discussion of molecular and developmental biology began in the late 1960s with the use of genetics as a test case for models of theory reduction. With this exception, the theory of natural selection remained the main focus of philosophy of biology until the late 1970s. It was controversies in evolutionary theory over punctuated equilibrium and adaptationism that first led philosophers to examine the concept of developmental constraint. Developmental biology also gained in prominence in the 1980s as part of a broader interest in the new sciences of self-organization and complexity. The current literature in the philosophy of molecular and developmental biology has grown out of these earlier discussions under the influence of twenty years of rapid and exciting growth of empirical knowledge. Philosophers have examined the concepts of genetic information and genetic program, competing definitions of the gene itself and competing accounts of the role of the gene as a developmental cause. The debate over the relationship between development and evolution has been enriched by theories and results from the new field of 'evolutionary developmental biology'. Future developments seem likely to include an exchange of ideas with the philosophy of psychology, where debates over the concept of innateness have created an interest in genetics and development.

The etiological approach to ‘proper functions’ in biology can be strengthened by relating it to Robert Cummins' general treatment of function ascription. The proper functions of a biological trait are the functions it is assigned in a Cummins-style functional explanation of the fitness of ancestors. These functions figure in selective explanations of the trait. It is also argued that some recent etiological theories include inaccurate accounts of selective explanation in biology. Finally, a generalization of the notion of selective explanation allows an analysis of the proper functions of human artifacts.

David Papineau (2003; 2005) has discussed the relationship between social learning and the family of postulated evolutionary processes that includes ‘organic selection’, ‘coincident selection’, ‘autonomisation’, ‘the Baldwin effect’ and ‘genetic assimilation’. In all these processes a trait which initially develops in the members of a population as a result of some interaction with the environment comes to develop without that interaction in their descendants. It is uncontroversial that the development of an identical phenotypic trait might depend on an interaction with the environment in one population and not in another. For example, some species of passerine songbirds require exposure to species-typical songs in order to reproduce those songs whilst others do not. Hence we can envisage a species beginning with one type of developmental pathway and evolving the other type. If, however, the successive evolution of these two developmental pathways were a mere coincidence, selection first favoring the ability to acquire the trait and later, quite independently, favoring the ability to develop it autonomously, then this would not be a distinctive kind of evolutionary process, but merely two standard instances of natural selection. George Gaylord Simpson pointed this out in the paper that gave us the term ‘Baldwin effect’ (Simpson, 1953). The real interest of the Baldwin effect and its relatives lies in the mechanisms which might link the evolution of the two developmental pathways, so that acquiring the trait through interaction with the environment makes it more likely that later generations will evolve the ability to acquire the same trait without that interaction.

Emotion theory is beset by category disputes. Examining the nature and function of scientific classification can make some of these more tractable. The aim of classification is to group particulars into <<natural>> classes - classes whose members share a rich cluster of properties in addition to those used to place them in the class. Classification is inextricably linked to theories of the causal processes that explain why certain particulars resemble one another and so are usefully regarded as <<of the same kind>>. The need to base categories on underlying causal processes explains why mere careful definition (including operational definition) need not produce categories that are productive objects of scientific study. Because different causal processes produce different patterns of similarity there is unlikely to be a single classification that is optimal for addressing all scientific questions. Cultural categories should not be contrasted to natural categories, but should be treated as natural classes generated by underlying social processes. Our capacity to introduce epistemically optimal categories is often restricted because categories play a role in social and political, as well as epistemic, projects. This account of classification has many implications for emotion theory.

Throughout his career David Hull has sought to bring the philosophy of science into closer contact with science and especially with biological science (Hull 1969, 1997b). This effort has taken many forms. Sometimes it has meant ‘either explaining basic biology to philosophers or explaining basic philosophy to biologists’ (Hull 1996, p. 77). The first of these tasks, simple as it sounds, has been responsible for revolutionary changes. It is well known that traditional philosophy of science, modeled as it was on theoretical physics, proved inadequate when philosophers turned their attention to biological science. Biological examples have driven major revisions of accounts of reduction (Hull 1974; Schaffner 1993, Ch. 9), laws of nature (Beatty et al. 1997), theories (Lloyd 1988) and natural kinds (Wilson 1999, Part III). Nor is explaining basic philosophy to biologists a task to be looked down upon. It is useful, not because philosophy has all the answers, but because scientists must think about how to do science, that is doing philosophy of science and scientists frequently reinvent philosophical views with known flaws. Early in his career Hull found biological systematists in the grip of a crude operationalism about scientific concepts and said so in the pages of Systematic Zoology (Hull 1968). For the next thirty years, as biologists debated the nature of species and the correct principles of classification, Hull added a philosophical note at the same congresses and in the same journals (Hull 1970, 1976, 1980, 1997a, 1999).