“Empiricism, Rationalism, and Restriction” (2/26/16)

Shahin Kaveh

Abstract: I propose that empiricism (the descriptive view that physicists care about explanation only insofar as it furthers empirical success) and rationalism (the descriptive view that physicists care about explanation for its own sake) are both false descriptions of the regularities in the collective decisions of the physics community. I suggest that a third thesis is a more accurate description of these macro-level regularities, and that therefore preoccupation with explanatory virtues has been a distraction. I will first amass cases from the history of physics to show that while certain explanatory adventures in theoretical physics have been met with remarkable indifference and/or hostility, others have consistently flourished in spite of their lack of added empirical content. Then, to explain this discrepancy, I will isolate six basic patterns of derivation, or “conversion schemes” as I shall call them, each of which trades in one type of mathematical information about the world for another type. This enables us to locate the appeal of extra-empirical theories in the type of conversion scheme they instantiate rather than in their explanatory virtues. One conversion scheme in particular, which I shall call “restriction”, appears to be important. The appeal of restriction, I will propose, is intrinsic, independent of other theoretical virtues including explanatory power, and unlike the latter free from personal preference and controversial concepts such as simplicity and causality.

“The Hodgkin & Huxley Model Revisited” (2/19/16)

Evan Pence

Abstract:  The import of Hodgkin and Huxley’s classic model of the action potential has been much debated in recent years. In particular, there has been a great deal of controversy surrounding claims by several prominent proponents of mechanistic explanation (Bogen, 2008; Craver, 2006; 2008). For these authors, the Hodgkin Huxley (HH) model is an excellent predictive tool, but little more. Most importantly it is not a sufficient causal explanation of the action potential. In support, they have been able to cite the prominent role curve-fitting played in the model’s development and Hodgkin and Huxley’s own assertions that the equations could have varied widely while maintaining goodness of fit and that model’s success “must not be taken as evidence that our equations are anything more than an empirical description of the time-course of the changes in permeability to sodium and potassium” (1952c p.541). In fact, they claim, without importing mechanistic details unknown at the time of the model’s publication, the model lacks causal import completely. I believe these claims rest on a problematic reading of Hodgkin and Huxley’s work. First, contrary to these authors’ assertions, the HH equations specify a clear causal model of the action potential. Examining the equations’ broader experimental context, I argue, yields an unambiguous causal reading. This model, in turn, has a good track record of interventions to its name, giving it a good claim to being a causal explanation (Cf. Weber, 2008). Second, the role played by curve fitting in the development of the model has been overstated. When examining the specific protocols adopted by the researchers, I argue, it becomes clear that the curve fitting involved in the 1952 paper was of a tightly constrained and theoretically justified kind. Finally, Hodgkin and Huxley’s comments within the rest of the paper reveal that, while they did not believe their model was the only one consistent with the existing evidence, they did see it as explanatory.

“Analytic Metaphysics and the Vera Causa Ideal: The Nun’s Priest’s Tale” (02/11/2016)

Aaron Novick

Abstract: L.A. Paul (2012) has argued that the success of science vindicates the methodology of metaphysics, on the grounds that scientists and metaphysicians share a methodology. Specifically, scientists and metaphysicians both develop competing explanatory models, then infer to the truth of the model that maximizes the “theoretical virtues.” I argue that this rests on a mischaracterization of scientific reasoning. In particular, in evolutionary biology, we can recognize adherence to a standard of reasoning, the vera causa ideal, that sets strict limits to the use of theoretical virtues in model evaluation. I argue that metaphysicians probably cannot meet any analogous ideal, and so are forced into a greater reliance on the theoretical virtues than is found in evolutionary biology. This methodological discrepancy undermines Paul’s defense of metaphysical methodology.