A. What is the current status of theory in radical behaviorism? Radical behaviorism is antitheoretical in the sense that it attacks and rejects traditional explanations of behavior in terms of internal initiating causes. It is anti-creationist. It turns instead, as Darwin did, to the selection of presumably random variations by contingencies of survival (ethology) and contingencies of reinforcement (the experimental analysis of behavior). In that analysis, rate of responding is taken as a basic datum and studied as a function of many contingencies of reinforcement. The results are factual, not theoretical. The analysis has “matured” by successfully analyzing more and more complex arrangements of variables. If rate of responding is taken as a measure of probability of response, an element of theory no doubt arises, and theory may be necessary in interpreting facts about behavior which are out of reach of precise prediction and control. As in modern astronomy, a laboratory science of behavior will continue, I believe, to give the best possible explanation of facts beyond experimental control – events in the world at large in the case of behavior, the waves and particles reaching the earth from outer space in the case of astronomy. The depth and breadth of both fields depend not upon improvements in theory but upon success in the analysis of presumably similar phenomena where some degree of prediction and control is possible.