From molecules to phenotypes? The promise and limits of integrative biology

Is integrative biology a good idea, or even possible? There has been much interest lately in the unifica- tion of biology and the integration of traditionally separate disciplines such as molecular and develop- mental biology on one hand, and ecology and evolutionary biology on the other. In this paper I ask if and under what circumstances such integration of efforts actually makes sense. I develop by example an analogy with Aristotle’s famous four “causes” that one can investigate concerning any object or phenomenon: material (what something is made of), formal (what distinguishes that particular object from others), efficient (how was the object made) and final (why was the object made). The example is provided by ongoing research on different aspects of flowering time in the model system Arabidop- sis, a small weed belonging to the mustard family. I show that understanding how flowering time is controlled is an epistemologically different sort of question from why and how it evolved, and that the two research agendas can be pursued largely independently of each other. Toward the end, I propose that the real goal of integrative biology is to understand the boundary layers between levels of biologi- cal analysis, something to which modern philosophy of science can contribute significantly.