Behaviorism and mentalism are commonly considered to be mutually exclusive and conjunctively exhaustive options for the psychological explanation of behavior. Behaviorism and mentalism do differ in their characterization of inner causes of behavior. However, I argue that they are not mutually exclusive on the grounds that they share important foundational assumptions, two of which are the notion of an innerouter split and the notion of control. I go on to argue that mentalism and behaviorism are not conjunctively exhaustive either, on the grounds that dropping these common foundational assumptions results in a distinctively different framework for the explanation of behavior. This third alternative, which is briefly described, is a version of non-individualism.