Goals and Functions

Abstract

Contemporary philosophical debates about biological function started in the early 1970s, and they originated from earlier, related, debates about the nature of goal directed systems. These discussions were rooted in scientific advances in the 1920s and 1930s pertaining to cybernetic machines and homeostatic systems, which appear to be purposeful or goal-directed despite not having any conscious intentions. By the 1950s, there were two major philosophical traditions for analyzing goal directedness, the behavioristic and the mechanistic. According to the behavioristic approach, favored by theorists like Gerd Sommerhoff and Richard Braithwaite, a goal directed system is one that exhibits plasticity and persistence in its outward behavior. According to the mechanistic tradition, favored by Ernest Nagel and Norbert Wiener, a goal directed system must be governed by the right sort of mechanism (such as negative feedback). Both of those traditions faced severe philosophical criticism in the 1960s and 1970s. I begin this chapter by sketching the historical background of the earlier debates about goal directedness. I then present the behavioristic analyses of Sommerhoff and Braithwaite, and enumerate several serious criticisms. I discuss mechanistic approaches, namely those of Nagel and the cyberneticists, and their critics.