The Scope of Biology

When new technology pushes the frontier of a scientific discipline, often our understanding of the nature of that discipline needs to be revised. My dissertation explores how biological technologies challenge common views about the nature of causal selection in biology as discussed in the philosophy of biology literature. Causal selection is the practice of ontologically privileging some causal conditions over others for investigative and explanatory reasons. For causal selection to be justified, two conditions must be met. First, the causal conditions that get singled out as ontologically significant must possess a causal or explanatory property that sets them apart from others. Second, the property identified must be one whose biologists regard as genuinely illuminating and particularly relevant to their domain of inquiry. The first condition justifies causal selection on ontological grounds; the second accounts for what is unique to the domain of biology. I consider two recently proposed accounts of causal selection: the actual difference making approach and the biologically normal approach. Although both adequately satisfy the first condition, they fall short in meeting the second. I demonstrate that the causal selection literature gets the full scope of biology wrong by failing to account for how biologists make genuinely new things happen with technology. When developing new technologies like orthogonal transfer RNA, green fluorescent protein, the CRISPR-Cas gene editing system, and DREADDs, biologists must often imagine and hypothesize the nonactual and the non-normal. This practice suggests that biologists expect their domain of inquiry to extend significantly beyond both the actual and the biologically normal. I defend a more nuanced account of causal selection that better accommodates biological technology. The core of this account is that factors capable of having fine-grained influence over processes characteristic to life and living things are ontologically significant causes in biology.