We have had a grand tour of operant behaviorism ranging over evolutionary time and the breadth of human cultures. It has included both verbal and nonverbal behavior, and it has visited both their public and their private domains. To test my understanding of some of the issues discussed and to offer what I hope will be constructive contributions to the treatments, I here address to Professor Skinner several questions and comments on some of the topics stopped at along the way (I will treat his responses as my souvenirs of the trip).

What is selected? Around the turn of the century, Samuel Butler made the point that a hen is only an egg's way of making another egg. He was anticipating the view that the organism is the servant of the gene. But the organism is needed by the gene. Variations occur in genes but must be selected in organisms. If we regard a culture as a social environment that shapes the behavior of new members of a group, then we can say that a culture is simply an individual's way of producing other enculturated individuals. Variations occur in the individual, but it is the culture with its practices that survives. Many practices evolve and survive independently of particular cultures, just as eyes, ears, wings, and legs – the “practices” of species – evolve and survive independently of particular species.

The following is an attempt to make explicit some of the questions to which commentators appear to have furnished default answers of their own, answers that have perhaps given rise to certain misunderstandings. It is hoped that in this explicit form the questions will allow Professor Skinner's position to be equally explicitly formulated. (Please note that there is some overlap with Professor Catania's questions 3, 4, 5, 7, 8, and 10.)

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.