Kaamesh Singam

Chapter 6 contains a nascent proposal for a concept of emergence that also derives its meaning through relation to scientific practice. It begins with a question of whether the accounts of emergence and downward causation discussed in the previous chapter are fruitful in the new mechanist framework. The concepts of electric potential and electric field as they are employed in physics are used to argue that there is no way to verify the empirical claim that the membrane potential has a downward determinative influence on the electric fields associated with the ions in the membrane, as was suggested in the previous chapter. Following this, to address the question of fruitfulness of the concepts of emergence and downward causation, an operational definition of emergence is proposed, according to which any attribution of emergence (understood as the qualitative and/or quantitative difference at a higher level) should lead to the experimental identification of a species of downward causation/determination (different from the structural constraints) from the higher level in the mechanism governing the phenomenon and as a result the experimental identification of novel empirical interventions and detections with respect to the phenomenon. The requirement of novel empirical interventions and detections essentially implies that incorporating emergence in our explanation should lead to novel means of manipulation and control of the phenomenon under study. This harks back to the ontic conception of explanation discussed in Chapter 1. If emergence as a concept is to be employed meaningfully in our research such that it refers to something that exists in the world, it needs to have practical consequences, i.e., changes in scientific practice (new ways of manipulating and controlling phenomena in which emergence is proposed to be present). If it doesn’t lead to any change in scientific practice, then it is not a fruitful concept. This is the conclusion that is reached in the final chapter of this dissertation. Then different questions related to the operational definition of emergence such as how a researcher identifies the presence of qualitative/quantitative difference at a higher level, how interventions and detections can be performed at different levels in a complex mechanism, etc., are analysed, and finally the possibility of applying the definition to other potential examples of downward causation is discussed.

In Chapter 5, using the developed new mechanist framework and the account of levels in mechanisms, the arguments provided by James Woodward and Denis Noble for the presence of downward causation in the HH model are analysed. As a response to Woodward’s argument, the chapter argues that the membrane potential (V) and the overall ionic conductances (gK and gNa) are not at different levels and therefore there is no downward causation in the HH model as Woodward suggested. As a response to Noble’s argument, the chapter argues that the structural constraints at any level in a mechanism cannot be considered to provide any sort of downward causal or determinative influence within the new mechanist framework. However, if we use Gillett’s account of emergence in the form of downward determination, we can show that it is possible for the membrane potential to have a downward determinative influence on the electric fields and a species of mediated downward causation on the individual ion channel conductances (not the overall conductances gK and gNa).

In Chapter 4, the notion of ‘being at the same level’ is further defined using the notions of production (thick causation) as discussed by Gillett, Glennan and other mechanists and conditional independence as introduced by James Woodward. The goal here is to come up with an objective set of criteria grounded in scientific practice based on which one could identify the levels in a mechanism and the things present at each level. This chapter also discusses in detail the interventionist framework developed by Woodward and shows how interventionist (thin) causation is different from production (thick causation) in the new mechanist framework. It also discusses to which things in mechanisms interventions can be introduced, whether the variables used in interventionist causal models strictly refer to things in mechanisms and whether causation can exist between unrelated mechanisms. This chapter shows how interventionism, as a methodological thesis about causation, is useful in identifying the presence of downward causation in mechanisms.