Demystifying Downward Causation in Biology

The concept of downward causation is frequently used in an explanatory capacity in biology to account for certain regularities and processes. Some philosophers, however, argue that downward causation is metaphysically incoherent, providing three main objections. Underlying these objections is the assumption that entities are connected by compositional hierarchies of levels of organization. In this paper, I introduce the notions of weak and strong compositional relations using examples from evolutionary developmental biology. I argue that downward causation becomes unproblematic if we use features of interventionist theories of causation to explain the causal relations between levels. I show that an interventionist account of downward causation successfully responds to the three central objections to downward causation in the philosophical literature and I clarify the explanatory usefulness of the concept in biology. As such, this paper provides an epistemic solution to demystify downward causation in the context of scientific practice. The solution proposed is compatible with how biologists seem to use a concept of downward causation fruitfully in their work.