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 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