Carving the brain at its joints : a commentary on Michael L. Anderson

Abstract

When neuroscientists explain the biological basis of a phenomenon of interest, they usually try to identify the parts of a system that seem do the relevant job, and propose a model of how those parts interact to produce the phenomenon. This mechanistic framework of explanation is widely used and has been investigated from a philosophical point of view by different authors. In his target article, Michael Anderson poses a challenge to the currently dominant version of mechanistic explanation as advocated, e.g., by Carl Craver. Taking empirical results and explanatory models from studies on retinal starburst amacrine cells as a starting point, Anderson suggests that the current framework for mechanistic explanation should be extended to include a differentiation between systems and mechanisms, which would allow more leeway in understanding processing in the nervous system. Mechanisms can then be seen to provide enabling constraints on the functioning of systems, where the mechanisms do not need to be subsumed under the system and do not even have to be on the same organizational level. Although Anderson’s proposal is interesting and worth exploring, I am unconvinced that this extension conforms to real-world explanatory practice and/or is necessary for accommodating the understanding of direction-selectivity in the retina. I examine another sample of research on starburst amacrine cells, where the integration of empirical data and computational models shows that, on close inspection, it is distributed networks to which certain characteristics are ascribed —a situation that can be handled with the available tools of mechanistic explanation.