Hover through the fog and filthy air
This is the famous line which is said by the witches at the beginning of the play. In this scene, three haggar old women, the witches, appear out of thunder and lightening. In chanting tones, they make plans to meet again the heath. Generally, this line creates the main theme of the play which is appearance versus reality. This theme is greatly emphasised from the beginning of the play till its end.
In the beginning of the play, the witches pave the way for this theme. That is, Shakespeare has the witches speak in language of contradiction. Besides their famous line, there are many other prominent examples, such as their characterization of Banquo as "lesser than Macbeth, and greater". Such speech adds to the play's sense of moral confusion by implying that nothing is quite what it seems. Some people learns to hide their feelings and thoughts. Likewise, the witches use statements that depend on the listener who is inclined to believe the most suitable words for him.
Interestingly, Macbeth's first line in the play is "So foul and fair a day I have not seen." This line echoes the witches' words and suggest that Macbeth is the focus of the drama's moral confusion. The direct meaning of this sentence is that this day is "fair" because he is victorious, but it is "foul" because of the witches' thunder. The real meaning comes out with Duncan's words that there is no skill by which one can find the "construction" of a person's mind "in the face". For instance, he trusts Thane of Cawdor while he betrays him. Likewise, Macbeth appears to be loyal and trustworthy while he kills King Duncan. Moreover, he is presented as a brave soldier and a noble character although he is a traitor who kills his guest.
After Duncan names Malcolm as his heir, Macbeth shows the conflict inside him to hide his thoughts. In his soliloquy, he says; "Stars, hide your fire! Let not light see my black and deep desires." Here, he wants to pretend loyalty and hide his evil thoughts. Later on, Lady Macbeth comes and teaches him how to do so. She tells Macbeth that his face is like an open book; so she gives him a lesson of how to be a cheater and a deceiver by hiding his feelings and what in his mind. She tells him to be like an "innocent flower" in front of people, but like a "serpent" in reality at the same time.
Later on, an immense example of the theme of appearance versus reality appears while Duncan meets Lady Macbeth. Comfortably, King Duncan describes Macbeth's castle as having a "pleasant seat" with sweet air". Moreover, Lady Macbeth greets her guests with fulsome compliments. Yet, the gentle pleasure described by the King and Banquo are, to the audience, a complete contradiction of the true air of her evil thoughts. In this "pleasant" castle, the King sees death with his "gentle senses". Generally, the beauty of the place and the natural scenes contrast the real gloomy and deceptive atmosphere.
The contrast between reality and appearance reaches its height with the witches' later prophecies. The witches' prophecies allow Macbeth, whose sense of doom mounts, to tell himself that everything may yet be well. For the audience, that lacks Macbeth's misguided confidence, the strong apparitions acts as symbols that foreshadow the way the prophecies will be fulfilled. Macbeth sees the prophecies that he will be defeated by "none of woman born" when the wood of Birnam moves to Dunsinane as a sign of invincibility. Yet, Macduff, who kills Macbeth, is "ripped" from "his mother's womb", attaching a clear irony to a comment that Macbeth takes at face value. Similarly, the Birnam wood will only seem to move at the end of the play, but it is, in reality, the soldiers bearing trees branches.
In conclusion, Macbeth shows that appearance is always deceitful. In other words, man's face, and outer appearance do not certainly reflect the reality of the inner thoughts and intentions. Thus, both of Duncan and Macbeth lose their lives because they trust the wrong people. That is, Duncan trusts in Macbeth while Macbeth himself trusts in the witches.