Friedman links the increasing separation from Greek times of the actors from the audience, and the architectural developments of the theatre which accompanied it, to the increasing repression of the themes of incest and parricide which dominated Greek tragedy. This increasing repression involved the increasing individuation of the problems enacted and therefore the necessity for an increasing realism of technique. Thus the theatre of convention came to be replaced by the present theatre of illusion. The watching by a modern audience of the outside world from the darkness of the mother's womb involves a fundamental shift in the method of alleviating basic anxieties.