Few issues within behavior therapy have aroused as much debate as the causal status of cognitions. We briefly trace the history of the debate, provide recent exemplars of misunderstanding, and seek to clarify important epistemological distinctions between radical and cognitive behaviorism. It is suggested that cognitive and radical behavioral therapists share a pragmatic interest in effecting and demonstrating behavior change, but differ significantly with respect to how change is explained. Less certain is the extent to which the practices of radical behavioral and cognitive therapists differ. It is concluded that radical (contextual) and cognitive (mechanistic) views, though distinct, are both scientifically respected approaches to studying human behavior with important roles to play in the future of behavior therapy. The multigenerational enterprise called behavior therapy stands to be enriched by promoting shared values, acceptance of our differences, and encouraging healthy competition.