The hypnotists and observers present can easily agree on whether the subject's arm moves down at least twelve inches within thirty seconds after the end of the suggestion. Behaviorism is an extremely valuable tool for studying simple behaviors, determining what affects them, and learning how to control them. But it has not been able to deal well with complex and important human experiences, such as happiness, love, religious feelings, purposes. If we are to understand d-SoCs, introspection must become an important technique in psychology in spite of the difficulties of its application. I have primarily used peoples' reports of their internal experiences in developing the systems approach, even though these reports are undoubtedly affected by a variety of biases, limitations, and inadequacies, for such reports are the most relevant data for studying d-SoCs.
Mental phenomena are the most complex phenomena of all.
The physical sciences, by comparison, deal with easy subject matter. I do not understand these psychologies well enough to evaluate the validity of these vocabularies, but it is encouraging that others, working over long periods, have at least developed such vocabularies. The English language is well suited for making reliable discriminations among everyday external objects, but it is not a good language for precise work with physical reality. The physical sciences have developed specialized mathematical languages for such work that are esoteric indeed to the man in the street. Sanskrit, on the other hand, has many presumably precise words for internal events and states that do not translate well into English.