Elizabethan theatres were very different to the theatres we know today. There was no special lighting available nor curtains, and scene switchovers could have been quite arduous for the actors. Thus, perhaps the most pragmatic purpose for the scene is that it would allow the characters, specifically Macbeth and Lady Macbeth, to change costumes and prepare for the following scene.
However, it is unlikely that Shakespeare haphazardly inserted this scene simply for practicality, for we see very similar occurrences of such comedic moments in his other tragedies: ‘Hamlet’ – with the gravediggers that follows Ophelia’s suicide – and the humorous interjections of Lear’s Fool in ‘King Lear’. Therefore, the porter scene is probably intended as a piece comic relief, which offers some respite from the otherwise dark material of ‘Macbeth’. Alike the gravediggers in ‘Hamlet’ and the speeches of the Fool in ‘King Lear’, the Porter’s nonsense verbatim aims to relieve the tension and heightens the tragic elements by contrast, making it an important part of the play.
Another reason as to why the scene is important is that it displays normality in the midst of the calamitous story of ‘Macbeth’. It shows the audience that there are other characters in the world in which the play takes place, that live their own lives – work and drink and have fun – in spite of all the happenings concerning Macbeth and the other main characters. This is significant because it reminds the audience that amidst the conflict surrounding the Throne, there is a country to be run. It leads to further question the role of the monarch and whether Macbeth, as a soldier and