The priority of form: Anti-reductionism and the concept of organization in twentieth-century embryology and developmental biology

Reductionism is one of the central issues in contemporary philosophy of biology. In very general terms this issue concerns the question of whether biological phenomena can be fully explained by reference to more “fundamental” processes studied by chemistry and physics. The primary focus of philosophers examining this issue has been on evolutionary biology and genetics. But in the biological sciences it is the fields of embryology and developmental biology that have been the natural home to non-reductionist views. This dissertation examines the role of anti-reductionist concepts of organization in twentieth-century experimental embryology and developmental biology. The principle results of this examination are (1) to show a continuity between earlier organicism (anti-reductionism) in experimental embryology and some features of more current theoretical developmental biology, especially with regard to the concept of organization and its role in explanation of developmental phenomena; (2) to develop an analysis of organization in terms of the causal capacities of constituent parts of biological systems; and (3) to show that explanation incorporating such a concept of organation are non-reductive in a limited sense. The analysis (2) employs a distinction between the inherent causal capacities and the formal causal capacities of the component parts of a system. Organizational properties are then understood as involving interdependent formal capacities of component parts. Some current approaches to modelling and explaining development are examined to show how they implicitly incorporate this kind of organization. Explanations employing this concept of organization are non-reductive in some sense. They do not deny “ontological reductionism” because organizational properties are not construed as emergent properties in a strict sense. In other words developmental processes are the result of interactions between the component parts of the system. However, while the behavior of the larger system can be explained by reference to the behavior of its molecular components, the behavior of those components must be explained by reference to the organizational features of the system. As the explanatory process is extended, explanation does not always go from lower level to higher level. In this sense explanations that refer to organizational properties does not correspond to “methodological reductionism.”...