Hughlings Jackson and the "doctrine of concomitance": mind-brain theorising between metaphysics and the clinic.

John Hughlings Jackson (1835-1911) is a major figure at the origins of neurology and neuroscience in Britain. Alongside his contributions to clinical medicine, he left a large corpus of writing on localisation of function in the nervous system and other theoretical topics. In this paper I focus on Jackson's "doctrine of concomitance"-his parallelist theory of the mind-brain relationship. I argue that the doctrine can be given both an ontological and a causal interpretation, and that the causal aspect of the doctrine is especially significant for Jackson and his contemporaries. I interpret Jackson's engagement with the metaphysics of mind as an instance of what I call meta-science-the deployment by scientists of metaphysical positions and arguments which help streamline empirical investigations by bracketing off unanswerable questions and focussing attention on matters amenable to the current tools of experimental research.