On mental events, disciplinary boundaries, and reductionism: a reply to Plaud

Plaud's (2001) radical behavioral manifesto suggests that a psychological science based exclusively upon the study of environment-behavior functional contingencies would yield a discipline unencumbered by mentalism, vaguely delineated disciplinary boundaries, or inappropriate reductionism. In reply, we note that: (a) mental events-e.g., thoughts and feelings-are increasingly accessible to objective investigation, and provide an observable proximal causal mechanism for the environmental selection of behavior; (b) the call for pristine disciplinary boundaries is anachronistic, inasmuch as progress in the natural sciences has engendered disciplinary boundaries that are increasingly porous; (c) cognitive neuroscience facilitates a comprehensive understanding of complex human behavior by mapping out the relationship between such behavior and underlying brain events, thereby engaging in an appropriate form of reductionism (constitutive reductionism) that has become a hallmark of the natural sciences; and (d) ironically, it is radical behaviorism, in its disavowal of the informational level of complexity instantiated in brain events, that engages in inappropriate eliminative reductionism (i.e., reducing neural information to "nothing but" its underlying bring states).