Theories of Mechanism

Abstract

The contemporary philosophical literature contains different views on what mechanisms are. All approaches agree on certain central assumptions; but they differ in various respects, some of which are crucial when it comes to analyzing the metaphysical commitments of the new mechanistic approach. Roughly, the different approaches to mechanisms can be divided into three categories. First, there are Early Approaches to mechanisms and mechanistic explanation, which differ crucially from the new debate in terms of terminology, concepts, and metaphysical implications, despite having also motivated the new mechanistic thinking (see, for example, Glennan 2002 and Campaner 2013 for a comparison). Wesley Salmon (1984a), Phil Dowe (1999), and Peter Railton (1978) are the main figures here. The second category I label Complex System Approaches to mechanisms. Its main defenders are Stuart Glennan (1996, 2002, 2010b), Nancy Cartwright (1999), William Bechtel and Robert C. Richardson (1993), and Bechtel and Adele Abrahamsen (2005). The central assumption of these approaches is that a mechanism is some kind of a physical object or structure, as exemplified by everyday entities such as hearts, cells, clocks, and toilets. The third category I call Acting Entities Approaches to mechanisms. According to these approaches, mechanisms are not objects but process-like in the sense that they consist of actual manifestations of activities by various entities that causally interact. Most prominently, Peter Machamer, Lindley Darden, and Carl Craver (2000), and Craver (2007a) defend this version of the mechanistic approach. Phyllis M. Illari and Jon Williamson (2012) can also be identified as defenders of this view. In this chapter I present the three types of approaches, focusing on one exemplar of each category without dwelling on the details of the various different approaches that are grouped together. Indeed, the reader should keep in mind that the assignment of each approach to one of the categories is intended to simplify matters for our presentation, and thus glosses over important differences. My main goal is to highlight the metaphysical differences between the most prominent versions of the complex system approach and the acting entity approach, and evaluate their adequacy with regard to the overall goals of the new mechanistic approach.