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Thesis Format



Doctor of Philosophy




Anderson, Michael L.


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.

Summary for Lay Audience

As organisms develop, one can wonder if their development is guided by some pre-formed plan (i.e. through their genes, evolutionary history, etc), if development is more contingent on circumstance, or perhaps a mixture of both. This is the crux of the Nature/Nurture distinction. Contemporary biology often considers itself to have moved beyond the overly-simplistic Nature/Nurture distinction, but tacitly includes problematic aspects of it. My thesis aims to diagnose this problem and propose a solution based on characterizing development in terms of interaction in a way that gets around the shadows of Nature/Nurture. To formulate the solution, I begin by looking at several different kinds of interaction across various parts of science, examining their strengths and weaknesses. There are a few kinds of interaction that can do useful work for my position, but I focus on coupled interaction, which is where the values of multiple variables are inextricably bound together (and cannot be solved separately). I then pivot to examine genetics, and the notion of inherited/acquired traits in the subsequent chapters. When looking at genetics, I defend the Extended Genome Thesis – the notion that the genome transcends the internal/external divide of the body. I argue that the genome and environment are mutually reactive to each other, meaning genes and environment can be understood as an example of coupled interaction, where the meaning of each depends on its counterpart, and cannot be understood in isolation. Similarly, I argue that there is no real difference between a trait being inherited or acquired; in both cases the trait must be constructed for the organism during development, and this will always rely on both the genome and the environment. My project's central argument culminates in Chapter Five, where I argue that the Nature/Nurture framework is not merely false -given the available evidence – it is incoherent. Things traditionally described as 'Nature' cannot be kept developmentally separate from the things described as 'Nurture', and both sets rely on each other to do the work traditionally ascribed to them. Thus, there is no real difference between the categories, and the Nature/Nurture distinction collapses.

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Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.