Abstract

This dissertation is about how cognitive phenomena---cognitive capacities, states, processes, and behavior---are to be characterized for the purposes of psychological explanation. The central claim is two-fold. First, cognitive phenomena must be characterized intentionally---i.e., by appealing to their intentional contents. Second, cognitive phenomena must be characterized by appealing to factors that are external to individuals---i.e., to facts that do not supervene on the local physical properties of an individual. ;Working within the information-processing approach to cognitive psychology, I distinguish between the physical, formal, and intentional levels of explanation and description. I argue that the intentional level---the level at which cognitive phenomena are characterized by what they are supposed to do for the possessing organism---plays more than merely a heuristic role in guiding research at the lower levels. Intentional level descriptions are required to state psychologically interesting generalizations across species, and to individuate properly cognitive capacities and behavior. I distinguish the intentional level from Dennett's Intentional Stance. ;I reject the logical behaviorist's identification of behavior with mere bodily movements, and extend the argument to the psychofunctionalist's attempt to characterize behavior in terms of neurophysiological properties. Instead, I endorse an account of behavior as a process that includes intentionally specified cognitive state causes. I discuss the Twin Earth thought experiments of Putnam and Burge, and endorse the externalist thesis that the contents of thought are wide. Given that cognitive phenomena must be individuated by appealing to their intentional content, it follows that cognitive psychology is, in good part, wide. ;I critically examine four major objections to wide content psychology: the argument from cognitive significance, the replacement argument, the argument from causal powers, and the formality argument. Each of these objections attempts to accomplish two things: show that widely individuated cognitive phenomena are unsuitable for the purposes of psychological explanation, and motivate a different conception of psychology, according to which cognitive phenomena are to be individuated by appealing to narrow content. I argue that none of these arguments ultimately works. Finally, I develop an externalist account of propositional attitudes