 The recent debate on mechanistic explanation took its point of departure in reflections on sciences other than physics. Most proponents of a mechanistic turn in the philosophy of explanation oppose a number of mainstream interpretations of core notions in the philosophy of science, especially that of a scientific explanation, a law, the layer-cake model of a hierarchy of sciences (Wimsatt 1976), and the notion of a theory. Most often, mechanistic explanation is characterized as (i) being related to the use of ‘by’ rather than ‘because’ (Craver 2007), (ii) being such that the functioning of a complex entity is explained in terms of the coordinated activation of its constituents, (iii) by being tied to a hierarchical order of local mechanisms, whose constituents can themselves become the target of a mechanistic explanation, and (iv) by the relevance of the notion of organization—mechanisms are organized to do something. This is how Craver puts it: