In Act 3, scene 4, Macbeth causes chaos at a celebratory banquet at his castle when he suddenly starts to behave very oddly indeed. Everything starts quite normally. The guests are greeted and they all sit down ready for the meal. One man is absent: Macbeth's old friend, Banquo. The reason why he is absent is very simple - Macbeth has just had him murdered. Where Banquo should be sitting at the banquet, Macbeth sees instead his ghost. Imagine his horror and his reaction, and remember that no one else at the feast can see this ghost. Lady Macbeth tries her best to cover up for her husband, but in the end, has to send the guests away in chaos. What can we learn from this key scene? The first point is about order. The scene opens with Macbeth telling the guests: 'You know your own degrees, sit down.' By 'degrees', he means their places in the social hierarchy. The guests would sit around the table in order of their social standing, with the most important lords sitting nearest the king. A banquet is in itself an occasion of formality and convention. These words heighten this sense of ceremony. This sense of social order was even more important to the people of Shakespeare's time than it is today. There was a whole Chain of Being in society, with god at the top, then the king, then the lords, followed by men, women and animals at the very bottom. The banquet is designed to reinforce this sense of social hierarchy, but ends in disarray: 'Stand not upon the order of your going, But go at once.' This serves to underline the terrible effect that Macbeth has had on Scotland. In murdering the king he has disturbed the natural order and hierarchy of the country. The chaos at the banquet is just one metaphor for the distress he has caused in the country as a whole. What does the appearance of the ghost tell us about Macbeth's state of mind? It might show guilt. We can see the appearance of the ghost as a sign of Macbeth's conscience working. Although on the surface Macbeth is happy to kill, deep down he is troubled by it. The appearance of the ghost is evidence of this conscience. Another way of viewing this apparition is that it shows that Macbeth cannot achieve the purity of murder that he so desires. He longed to be able to kill Duncan and be assured that there would be no adverse consequences for him. The appearance of the ghost is yet another step in Macbeth's path to learning that life is not as he would wish. He cannot achieve what he wants through more and more brutality. He thinks he can get what he wants just through the kind of manly heroism for which he was praised in the opening scenes of the play: 'What man dare, I dare.' It is one of the great ironies of the play. The more he tries to act in a way that he thinks is fitting of a great man, the more his behaviour resembles that of a brutal animal. He will not listen to the voice of humanity. Instead, he goes on blindly trying to secure his kingship: 'I am in blood Stepp'd in so far, that, should I wade no more, Returning were as tedious as go o'er.' This is a powerful metaphor. He imagines that he has created a river of blood through his murders. He rejects the idea of trying to wade back to where he started - in effect trying to turn the clock back and make amends. Instead, he asserts that since he is about halfway across the river, it is just as easy to keep going and reach the opposite bank. In terms of the metaphor, this means reaching a position where he is safe and he has secured his kingship. There is something that we have to admire in this reckless determination. Yet with all the inevitability of tragedy, we also know that he can never be secure in the evil he has created, and that his death can be the only outcome. At the beginning of the play, his wife told him that his face was like 'a book' to her; she could read everything that was going on in his mind. Now he sees ghosts that she cannot; he plans to visit the witches without her; he has secrets of which she knows nothing. The distance between a husband and wife who were once so close is just one more tragedy in this most tragic of plays.