A Hempelian Explanatory Shift in Neuropathology: A Study in the History and Logic of Medicine

Abstract

Mechanistic analysis of infarction along the boundary zones between the major arterial territories (watersheds) in the brain is herein described as an example of a scientific explanatory shift. The two explanations for the pathogenesis of watershed infarction were both logically deduced from radicallv different emvirical laws of fluid mechanics. The first explanation became the orthodox or received view only until incompleteness neiessitated the development of an alternative and autonomous explanation which accounted for the empirical phenomenon that the orthodox explanation could not logically infer. Since this explanatory shift emerged to maintain completeness, and used empirical laws (Bernoulli's law and the Fahraeus-Lindqvist effect) as antecedents for the logical deduction of consequents which were empirically testable by experiment, it is suggested that the explanatory shift was of the Hempelian-type.