HPS Brown Bag - Lane Des Autels. “Thinking About Stochastic Mechanisms”


Location: 105 Pasquerilla Center


“Thinking About Stochastic Mechanisms”
Lane Des Autels 
University of Notre Dame


The primary aim of my research has been to develop some important new resources for explaining probabilistic phenomena in the life sciences. In short, I have undertaken to articulate and defend a novel account of stochastic mechanism for grounding probabilistic generalizations in the life sciences.

In this brownbag talk, I will briefly summarize some of the main components of this project. I first offer some brief remarks on the concept of mechanism in the history of philosophical thought. I then lay out some examples of probabilistic phenomena in biology for which an account of stochastic mechanism seems explanatorily necessary and useful: synaptic transmission in the brain, protein synthesis, DNA replication, evolution by natural selection, and Mendelian inheritance. Next, I examine the concept of regularity as it applies to mechanisms as well as its implications for a recent debate in the philosophy of biology: is natural selection regular enough to count as a mechanism? I then turn my attention to the question of how we should understand the chance we ascribe to stochastic mechanisms. I argue that neither subjectivism, frequentism, nor best-system-style accounts of chance will give us what we want from an account of stochastic mechanism, but some version of propensity theory can. Borrowing from recent propensity accounts of biological fitness and drift, I then go on to explore the prospects for developing a propensity interpretation of stochastic mechanism (PrISM) according to which propensities are (i) metaphysically analyzable and operationally quantifiable viaa function of probability-weighted ways a mechanism might fire and (ii) not causally efficacious but nonetheless explanatorily useful. By appealing to recent analyses of deterministic and emergent chance, I suggest further that this analysis need not be vulnerable to the threat of metaphysical determinism.