those spaces in between life, thinking, the physical world, and humanity
“We are indebted to Denis Diderot (1713-1784) for the concept of the fourth wall. His critical writing about the theatre of eighteenth century France was important to the rise of realism in the nineteenth and early twentieth centuries.
With the advance of realism, the demarcation between the audience space and the stage gradually sharpened. In Diderot’s time part of the audience sat or stood upon the stage. As the term is now used, the fourth wall corresponds in physical terms to the proscenium arch, and “traditional” Western theatre features a stage area clearly defined by drapery, lighting, sets, an orchestra pit. There are also strong customs which limit what is considered appropriate audience response. The progress of realism in staging has meant that the participation of audiences has been increasingly controlled and excluded in the service of an illusion of reality.
This movement toward realism in theatre has triumphed in the sense of having made it the norm that theatre is free to focus upon characters of any social standing and to use natural speech, action and setting as the usual mode rather than the exception.”
from Playback Theatre