As suggested previously, a discussion of the relative autonomy and distinctiveness of individuals and the changing circumstances which affect them is an incomplete account of "human nature as modified in each historical epoch". Among the missing elements are answers to these questions: how do circumstances themselves change, and to what extent do they change because individuals themselves consciously intend to, and do, change them? How do individuals feel about their social relations and themselves, what is their experience of, and knowledge about them, and how do these affect the reproduction or change of the circumstances they encounter?