Title

The naturalistic foundations of intentional action

Date of Completion

January 2001

Keywords

Philosophy

Degree

Ph.D.

Abstract

Philosophical interest in intentional action has flourished in recent decades. Typically, writers in the field of action theory seek necessary and sufficient conditions for a movement's being an action, conditions derived from a conceptual analysis of everyday action ascriptions. However, only a naturalistic account of intentional action, an account whose methods and aims are continuous with those of the empirical sciences, will truly help further our understanding of action as a biological phenomenon. ^ Action is naturalized as a species of movement that is both purposive and self-controlled, using these terms in novel senses. Various psychological and physiological models of purposiveness have been offered, including negative feedback, motor program, and dynamical systems models. However, while such non-historical models offer valuable insights into the nature of how organisms control their movements, they fail as general models of purposiveness because consideration of a movement's selectional history is required in order to classify movements as unitary behaviors rather than merely accidental motions. Non-historical models also fail to cover instances of unsuccessful purposive movements and cases of “functionally emergent behaviors.” For such reasons, purposiveness must be seen as an historical property of movements; a movement is purposive insofar as it has a Millikanian proper function. ^ An agent's capacity to exert a high degree of control over its movements (i.e. self-control) marks the second key underlying property of action. I highlight an aspect of behavior-control which empirical theorists have largely ignored, namely the extent to which agents “could have done otherwise” than how they have in fact acted upon particular occasions. Self-control in this “could have done otherwise” sense is naturalized in terms of “modulatory interconnectivity.” Modulatory interconnectivity involves the extent to which an agent's internal behavior-control modules facilitate behavioral interruptability via the interaction of informational links of inhibition and/or suppression. The greater the extent to which an agent's behavior-control modules have the capacity to modulate one another's activities, the more the agent has the capacity for self-control in the “could have done otherwise” sense. This view is elucidated and supported with the aid of models from robotics and neurophysiology. ^