The Cave allegory Plato spoke about was not attributed to a ‘cave’ in the literal sense, but rather to an inner ‘cave’ that resides in all individuals. He referenced rows of people at different levels; the first only knows a wall with shadows. On the elevation behind the first row, they are aware of the existence of other and the various objects they carry.
All of the people within the cave, both those facing the wall and those on the elevated wall have one thing in common; they are all ‘prisoners’. Some have knowledge of objects and