Many scholars over the years have analysed these characters, and looked for the deeper symbolism in Shakespeare's Macbeth and it's characters and themes. Appearance versus reality is one of the biggest themes in Macbeth, and it is greatly authenticated by Lady Macbeth and the three witches. These characters take on many faces throughout the play to be able to sympathize themselves better with the other characters, so much in fact, that the reader might never had met their real personalities.
The Weird Sisters, as they were called throughout the play, are witches. With the Gift of Foresight, the sisters are the wheels upon which the play turns. Each prediction more fantastical than the former, the witches control the other characters of the play, and do so with the art of lying by omission. "Fair is four, foul is fair", the theme of appearance versus reality was introduced to the audience in the first scene by the sisters.
It is they that introduce the theme in the play, because it is they that insert it into it, thus making their introduction quite appropriate. In act I scene iii, the witches familiarize Macbeth with his future, "All hail Macbeth! That shalt be King hereafter." (1.3.50) Soon the audience learns the man has already thought of becoming king by taking it into his own hands- their words were nothing but reinforcement.
Throughout the play the Sisters give Macbeth half-truths and plays on words to give him the wrong impression, just as Banquo suspected. "Win us with honest trifles, to betray's/ In deepest consequence." (1.3.125-126) This theory was proven and re-proven time and time again. The Sisters' predictions are at time as valid as those of the horoscope pages in today's tabloids, or those of Miss Cleo. They tell Macbeth that he shall...