Contingent Notions in Molecular Scenario: Stochasticity as Insufficiency of Causal Dependence (ICD)

The purpose of this paper is to propose an original definition of stochasticity. It accomplishes this via a molecular case study that has rarely been analyzed in the philosophical literature: mutually exclusive alternative splicing (MEAS). The development of this definition can prove useful for rethinking the epistemological meaning of stochasticity in molecular and cellular biology. Exploring biological practice, I will show that work by Hiesinger and Hassan (Trends Neurosci 41:577–586:2018) is a good starting point for clarifying the stochastic aspect of MEAS as they provide a definition which uses the notions of causal dependence (CD) and unpredictability (U). I then emphasize that this definition is very similar to Gould’s notion of contingency which has been unpacked and clarified by the philosophers such as Beatty (J Philos 103:336–362:2006) and Turner (Biol Philos 26:65–79:2011). Taking this similarity seriously, I developed a definition of stochasticity that I call “insufficiency of causal dependence” (ICD). In ICD, the stochasticity/chanciness of a given phenomenon is characterized by the fact that certain clusters of causes X can be necessary but not sufficient to bring about a given outcome. This definition allows us to move away from defining stochasticity in terms of epistemic limitation (a phenomenon is “chancy” because we do not actually know what is happening), and/or in terms of the intrinsic properties of biological processes (something is “chancy” because we are referring to indeterministic phenomena). I will show that the main advantage of ICD is in helping to untangle the explanatory and predictive dimensions of stochasticity in the context of MEAS and, more generally, in molecular and cellular biology.