Discovering social knowledge

In some domains acquiring knowledge has proved successful in ways that have not been equalled elsewhere notwithstanding long-term efforts. As the lack of success in the latter must be due to the combination of approach and content, this suggests searching for new approaches, and interpreting the 'not' as a possibly 'never'. The alternative is to see the 'not' as a 'not yet'. The argument Von Foerster (1970) brings to this dilemma is that in the social domain the 'not' is due to an extra, mainly action-bound, source of variation. Constraining this source will allow for a (reasonable) 'not yet'. To remind of Heinz's surprising and sophisticated argument it is re-used.