We show how a simple nonlinear dynamical system (the discrete quadratic iteration on the unit segment) can be the basis for modelling the embryogenesis process. Such an approach, even though being crude, can nevertheless prove to be useful when looking with the two main involved processes:i) on one hand the cell proliferation under successive divisions ii) on the other hand, the differentiation between cell lineages. We illustrate this new approach in the case of Caenorhabditis elegans by looking at the early (...) stages of embryogenesis, up to several hundreds of cells (lima bean larval stage). We show how the many results that have been obtained by several groups can be interpreted in terms of values for the parameters controlling the dynamical system. Furthermore, we can extend the model to the cases of genetic mutations. More precisely the teratogenetic and lethal effects are associated with abnormal variation of the control parameters with time. (shrink)

: This paper juxtaposes Deleuze's notion of the virtual alongside Oyama's notion of a developmental system in order to explore the promises and perils of thinking bodily identity as indeterminate at a time when new technologies render bodily ambiguity increasingly productive of both economic profit and power relations.

Freedom is first apprehended as the pursuit of an activity which implies the choice to defend a thesis among other possible ones. This translation of the problem of freedom in an articulate language presupposes a complex nervous system and sensory apparatuses which we take for granted. In this study, I try to explore the undergrounds of the problem of freedom along with the suggestion that the notion of coding could enable one to bridge nature and the mind. When organisms invent, (...) are they doing it in a spontaneous manner, inscribing in their hereditary and mnemonic instructions a stochastic contrivance of random accidents, or are they attempting to select among a limited number of schemes endowed with some optimality of functioning? If we consider them as submitted to physical forces, it is to the extent that we make them part of a strategy to extend the "laws" of a nature understood to respond passively. I suggest in this study that the epistemological understanding must regionalize itself and admit a hierarchy of dispositions in relation to the phenomenon of selection. I end by suggesting the pursuit of affirmation instead of negation, as this alone contains the requirement of integration to the knowing subject as well as the form in its act of understanding, without giving it a spontaneist position. (shrink)

Some central ideas associated with developmental systems theory (DST) are outlined for non-specialists. These ideas concern the nature of biological development, the alleged distinction between "genetic" and "environmental" traits, the relations between organism and environment, and evolutionary processes. I also discuss some criticisms of the DST approach.

Developmental systems theory (DST) is a general theoretical perspective on development, heredity and evolution. It is intended to facilitate the study of interactions between the many factors that influence development without reviving `dichotomous' debates over nature or nurture, gene or environment, biology or culture. Several recent papers have addressed the relationship between DST and the thriving new discipline of evolutionary developmental biology (EDB). The contributions to this literature by evolutionary developmental biologists contain three important misunderstandings of DST.

Will a synthesis of developmental and evolutionary biology require a focus on the role of nongenetic resources in evolution? Nongenetic variation may exist but be hidden because the phenotypes are stable (developmentally canalized) under certain background conditions. In this case, those differences may come to play important roles in evolution when background conditions change. If this is so, then a focus on the way that developmental resources are made reliable, and the ways in which reliability fails, may prove to be (...) of crucial importance to linking developmental and evolutionary biology. †To contact the author, please write to: 208 Hovland Hall, Philosophy Department, Oregon State University, Corvallis, OR 97331‐3902; e‐mail: jonathan.kaplan@oregonstate.edu. (shrink)

Recent and not so recent advances in our molecular understanding of the genome make the once prevalent view of the genome as a passive container of genetic information (i.e., genes) untenable, and emphasize the importance of the internal organization and re-organization dynamics of the genome for both development and evolution. While this conclusion is by now well accepted, the construction of a comprehensive conceptual framework for studying the genome as a dynamic system, capable of self-organization and adaptive behavior is still (...) underway. This work deals with the effect of such a conceptual shift on evolutionary thought. Specifically, I try to articulate the conceptual commitments and obligations of views that privilege explanatorily or causally the genome, its dynamics and mechanisms, over genes. I refer to this class of views as belonging to ‘the genome perspective’. (shrink)

In reworking a variety of biological concepts, Developmental Systems Theory (DST) has made frequent use of parity of reasoning. We have done this to show, for instance, that factors that have similar sorts of impact on a developing organism tend nevertheless to be invested with quite different causal importance. We have made similar arguments about evolutionary processes. Together, these analyses have allowed DST not only to cut through some age-old muddles about the nature of development, but also to effect a (...) long-delayed reintegration of development into evolutionary theory. Our penchant for causal symmetry, however (or 'causal democracy', as it has recently been termed), has sometimes been misunderstood. This paper shows that causal symmetry is neither a platitude about multiple influences nor a denial of useful distinctions, but a powerful way of exposing hidden assumptions and opening up traditional formulations to fruitful change. (shrink)

The Modern Synthesis of Darwinism and genetics regards non-genetic factors as merely constraints on the genetic variations that result in the characteristics of organisms. Even though the environment (including social interactions and culture) is as necessary as genes in terms of selection and inheritance, it does not contain the information that controls the development of the traits. S. Oyama’s account of the Parity Thesis, however, states that one cannot conceivably distinguish in a meaningful way between nature-based (i.e., gene-based) and nurture-based (...) (i.e., environment-based) characteristics in development because the information necessary for the resulting characteristics is contained at both levels. Oyama and others argue that the Parity Thesis has far-reaching implications for developmental psychology, in that both nativist and interactionist developmental accounts of motor, cognitive, affective, social, and linguistic capacities that presuppose a substantial nature/nurture dichotomy are inadequate. After considering these arguments, we conclude that either Oyama’s version of the Parity Thesis does not differ from the version advocated by liberal interactionists, or it renders precarious any analysis involving abilities present at birth (despite her claim to the contrary). More importantly, developmental psychologists need not discard the distinction between innate characteristics present at birth and those acquired by learning, even if they abandon genocentrism. Furthermore, we suggest a way nativists can disentangle the concept of maturation from a genocentric view of biological nature. More specifically, we suggest they can invoke the maturational segment of the developmental process (which involves genetic, epigenetic and environmental causes) that results in the biological “machinery” (e.g. language acquisition device) which is necessary for learning as a subsequent segment of the developmental process. (shrink)

The concept of innateness is used to make inferences between various better-understood properties, like developmental canalization, evolutionary adaptation, heritability, species-typicality, and so on (‘innateness-related properties’). This paper uses a recently-developed account of the representational content carried by inheritance systems like the genome to explain why innateness-related properties cluster together, especially in non-human organisms. Although inferences between innateness-related properties are deductively invalid, and lead to false conclusions in many actual cases, where some aspect of a phenotypic trait develops in reliance on (...) a genetic representation it will tend, better than chance, to have many of the innateness-related properties. The account also shows why inferences between innateness-related properties sometimes fail and argues that such inferences are especially misleading when applied to human psychology and behaviour because human psychological development is especially reliant on non-genetic inherited representations. (shrink)

Developmental Systems Theory (DST) emphasises the importance of non-genetic factors in development and their relevance to evolution. A common, deflationary reaction is that it has long been appreciated that non-genetic factors are causally indispensable. This paper argues that DST can be reformulated to make a more substantive claim: that the special role played by genes is also played by some (but not all) non-genetic resources. That special role is to transmit inherited representations, in the sense of Shea (2007: Biology and (...) Philosophy, 22, 313-331). Formulating DST as the claim that there are non-genetic inherited representations turns it into a striking, empirically-testable hypothesis, driving the sort of investigations that are only now beginning to appear in the scientific literature. DST’s characteristic rejection of a gene vs. environment dichotomy is preserved, but without dissolving all potentially explanatory distinctions into an interactionist causal soup, as some have alleged. (shrink)