Explaining embryological development: Should integration be the goal?

Two approaches to an integration of evolution and development are often distinguished, one “neo-Darwinian” and the other “structuralist”. Should these approaches in turn be integrated? Kelly Smith recently stated that we need a “more complete” theory of biological order, suggesting integration as the ideal. In response to him, I argue that a recognition of different types of scientific questions and causal explanation is more urgent. Do we understand development when we know the crucial factors in the process of differentiation, or rather when we know the laws that govern the transformations of fields? Without a recognition of these different explanatory ideals, “integration” is likely to have the character of annexation.