Duncan never suspected this man to a traitor and he says that expressions on one’s face can be very misleading as they are not always a true representation of “the Mind’s Construction” (line 13) and that there is no science behind these expressions.
This shows that Duncan may be too trusting and possibly naïve as he may not have thought about the possible gains of a traitor who succeeds.
This trusting nature leads him not to suspect Macbeth though in all fairness none of the Lords suspected that Macbeth would kill the King before Duncan’s murder. The lack of a science to comprehend facial expressions as representations of the true thoughts in the mind crops up again as Macbeth is planning to kill Duncan in a few hours but of course would keep a calm face without a sign of malevolence when speaking to him. This problem is that of the proverb “Appearances can be deceiving” which Duncan does not take heed of.
Rather than learning from Cawdor’s treason Duncan places absolute trust in Macbeth instead because he believes that Macbeth saved him and is very loyal to him. This ironic trust is the King’s demise.
Macbeth is very courteous to the King as would have been expected though he was probably wondering how he would fulfill the witches’ prophecy when speaking to him.
The King tells Macbeth that he will assist especially in becoming more important in society and rising through ranks. He then announces that he has decided Malcolm, his eldest son, will be the heir to the throne which greatly angers Macbeth and places doubt into his mind about the witches’ foretelling.
Macbeth displays this anger, when speaking aside, and he considers this doubt forming in his mind and this again deeply angers him as he is a very ambitious man and so would have wanted to become King very much as most people would have.
After Macbeth has finished speaking his thoughts Duncan describes him as a “peerless kinsman” (line 58) which is a very large compliment. This again is very ironic as this “peerless kinsman” that Duncan is trusting so much had just been thinking about his ambitions to become King which would mean Duncan’s death in some way most probably for them to be achieved and so this again shows Duncan’s grave misplacement of trust though this time he probably won’t be lucky enough to escape harmlessly as Macbeth is a man who would not stop at anything to accomplish his aspirations of becoming King.
Macbeth ambitiousness is emphasized later in the play when he is making important decisions.
Act 1, Scene 4 is the only scene in which one sees the ironic mistakes that he makes that have grave consequences for him and possibly others.
