Abstract

I examine the relations of three kinds of mental state--desire, belief, and purpose--to their manifestations in behavior, and derive from these relations certain consequences for the philosophy of mind and the philosophy of value. Part I deals with how a purpose that is actually being acted upon is manifested in behavior. Tolman and Pepper held the thesis T: An agent A acts with purpose G if and only if A "persists until" G and A is "docile" with respect to G. To say A persists until G means that if A's first response is not followed by G, A tends to vary his responses until one of them is followed by G. To say A is docile with respect to G means that on certain subsequent occasions, A tends to reject behaviors which in the past were unsuccessful, and thus to come more quickly to the successful behavior. After making some refinements of T, I consider seven objections. Of these, T successfully meets all but the seventh: If two states of affairs, G and H, are lawfully equivalent, to say that A has goal G does not imply that A has goal H. I then propose a major modification of T which meets this objection. Part II deals with desires considered as dispositions to engage in purposive behavior, and inquires into the role of other desires and of beliefs as conditions for their actualization. Those beliefs which mediate the manifestation of desires in behavior are held to be "means-end readinesses," dispositions to pursue or to prefer certain means on condition of pursuing certain ends. The behavioral expression of preference is found to depend on what the agent believes to be an alternative; therefore, the behavioral equivalent of believing something to be an alternative is defined first, and followed by the behavioristic definitions of various types of preference. I then examine the validity or meaningfulness of several kinds of quantitative representation of mental states: numbers putatively representing the strength, not merely the order, of preference or desire, the probability an event is believed to have, and the strength of a belief. Certain intermediate-level motivational structures called "sentiments" are also discussed. In Part III, the results are applied to problems in two areas: philosophy of mind and philosophy of value. I argue that certain claims of analytical behaviorism are untenable, while others may be acceptable; and that a form of identity-materialism is acceptable, provided, of course, that physical states are the basis of behavior. Finally, I analyze the purposive dynamics of using evaluative sentences and argue that ethical emotivism is self-contradictory.