ABSTRACT

While the term “mechanism” has a long and continuous use in scientific literature dating from the seventeenth century, the concept of mechanism has only recently become a major subject of discussion among philosophers of science. Mechanist philosophers of science argue that a vast variety of phenomena in the natural world are the product of the operation of mechanisms, and accordingly that any adequate theory of science should give an account of what mechanisms are, how they are discovered and represented, and the role that mechanisms play in scientific explanation. To a significant degree, a mechanistic philosophy of science can be seen as an alternative to an earlier logical empiricist tradition in philosophy of science that gave pride of place to laws of nature. Within that tradition, science was broadly conceived as a search for laws that described regularities in natural phenomena. Theories were understood to be deductive closures of sets of laws, explanations were understood as arguments from covering laws, and reduction was understood as a deductive relationship between laws of different theories. Mechanists argue that this approach is fundamentally at odds with the practice of science, especially in the life and social sciences, but even in many areas of physics and chemistry. “Mechanism” is used to describe two distinct but related sorts of structures. First, mechanisms are systems consisting of a collection of parts that interact with each other in order to produce some behavior. So, for instance, a car’s engine is a mechanism containing many parts whose interaction produces the motion of the drive shaft. Second, mechanisms are temporally extended processes in which sequences of activities produce some outcome of the mechanism’s operation. For instance, photosynthesis is a mechanism in which by a series of activities involving water, carbon dioxide, and energy from light produces oxygen and sugar. There is a natural relationship between processes and systems, for the operation of systems gives rise to processes. Photosynthesis can, for instance, be conceived of as the activity of a system – the chloroplast – whose operation is a mechanical process. The term “mechanism” is most widely associated with the seventeenth-century mechanical philosophy championed by philosophers such as Descartes and Boyle. Mechanism in the seventeenth century can be seen as embodying both a metaphysical

doctrine and a scientific methodology (Des Chene 2001). Methodologically, mechanists sought to explain natural phenomena by identifying mechanisms – systems of interacting parts – that produce those phenomena. Metaphysically, the doctrine was closely related to atomism – the view that ultimately mechanistic operations would reduce to the kinetic interactions between atoms or corpuscles. Contemporary mechanists reject the metaphysical view while retaining much of the methodology. A seventeenth-century mechanist would be committed to the view that interactions governed by chemical, electrical, or gravitational forces would have to be explicable in terms of the operation of some atomistic, kinetic mechanism. Contemporary mechanists recognize that this part of the mechanical philosophy has simply not been borne out by scientific research. Accordingly they retain the strategy of explaining phenomena by identifying mechanisms, but they reject any fixed and limited list of the modes by which parts of mechanisms can act and interact.