Abstract
Teaching somebody something, assigning yourself the aim of implanting a known fact into another person so that he can say, for example, ‘I know that the Pyramids or Mount Everest …’, ‘I know that two and two make four …’, ‘I know that the Mayor of Paris has held a press conference …’ ‘I know that to get a good polish on wood you should use …’, etc calls for fairly well-proven techniques. If it is impossible to bring about direct experience of things by a pupil, a representation of those things can be given with signs of some kind. These signs can be words or pictures, or other kinds of symbols. According to the way they are presented, in principle they allow access to the world through a go-between — via an ‘authority’. Documents of all kinds are useful for this purpose: articles, sound recordings, films, photographs, manuscripts, etc.