Book Description
This dissertation is about the extent to which natural selection has causal power. In Chapter 1, I articulate and defend a version of an interventionist account of causation. Put simply, I claim that some event e causes another event e’ in a causal system S just in case a precise manipulation to the value of e, while holding various other events in S fixed, results in a change to the probability of e’. Also in Chapter 1, I endorse a recent constraint on causal relata that James Woodward has endorsed, which requires that it be possible in principle to manipulate each relatum in a causal system while simultaneously holding fixed the other relata in the causal system at arbitrary values. In Chapter 2, I use this account of causation to determine the extent to which natural selection can be treated as a cause of other evolutionary phenomena. Through a variety of examples, I show that natural selection can cause trait evolution, as well as the origin of novel traits. I also show that, given various assumptions, there are cases in which natural selection can cause a particular individual to have one trait, rather than another. In Chapter 3, I analyze the extent to which natural selection can operate at various levels of the biological hierarchy, in particular among individuals within a group and between groups in a group-structured population. For reasons that I describe, while “group selection” is a coherent concept, I am dissatisfied with various accounts of that concept. As I develop my own account, I comment more broadly on the way in which we can understand natural selection and causation in a group-structured population, given the variety of non-causal dependency relationships that exist in such a setting.
