Abstract

For many, the Nature/Nurture approach to development is a quaint figment of the past. We have moved on, one might think; everyone thinks that both categories are important for development, not merely one. The reality, however, is not so simple. In this dissertation, I argue that contemporary biology has not succeeded in getting out from under the shadow of Nature/Nurture, despite everyone being some sort of interactionist about development. The central aim of my project is to offer a form of developmental interactionism worth having, which succeeds in shedding the pernicious aspects of Nature/Nurture. I begin by giving an overview of several candidate notions of interaction. One particularly promising notion is coupled interaction, where multiple variables co-determine each others' products, and cannot be well understood in isolation. I follow this up by examining the Central Dogma of genetics, and argue that the evidence supports the Extended Genome Thesis – the notion that the genome partially extends beyond the body in a sense that is analogous to coupled interaction. I then extend the analysis to the inherited/acquired distinction and argue that the distinction is meaningless. Traits are not inherited wholesale; they must be constructed anew in ontogeny. This means there is not a principled difference between whether the trait is inherited or acquired. My project culminates with an argument that the Nature/Nurture distinction itself is incoherent, based on the available evidence. The world simply isn't separable into distinct categories in the way Nature/Nurture implies; the reality tramples these conceptual boundaries. Neither category can do the work traditionally ascribed to it without its counterpart, and so those results should be understood as emerging from a coupled system. This system transcends the traditional internal/external divide, and so cannot be decomposed. Thus, Nature/Nurture is incoherent because there is no real difference between the components of one category and the components of another. Instead, the parts are coupled to form the ontogenetic (developmental) niche. To round out the project, I canvas some areas of science that I think are worth keeping a close eye on, given their capacity to enhance or harm the way understand development.