Belief in ghosts and witches remained widespread in Elizabethan England. Shakespeare may not have believed in the supernatural, but he was certainly aware that such beliefs were held by many and he used the element of supernatural to dramatic ends in many of his tragedies.
The supernatural is introduced to contribute to the action of the play, and is an indispensable part of it. Furthermore, the supernatural is always placed in the closest relation with the character of the protagonist in the way that it gives impetus to the already existent inward movements: to the sense of failure in Brutus, to the stifling workings of conscience in Macbeth, to suspicion in Hamlet. That is by no means to say that we are at any point allowed to feel that the supernatural has removed the characters' responsibility for their actions and capacity to make decisions. So far away are we from feeling this that many go a step further and disregard the supernatural as mere sensationalism.
However, the ghosts and witches cannot in most instances be explained as hallucinations, either individual or collective as some critics have suggested. While the ghosts who appear in Richard III and Macbeth are products of guilt-ridden minds, the ghost in Hamlet and the witches in Macbeth are given real substance.
The witches in Macbeth are named by Shakespeare as the "weird sisters". The expression "weird sisters", as used from the 1400's, means "fatal sisters", the word "weird" was actually a noun meaning Fate.
The Witches describe themselves as fore-tellers of destiny, and they present themselves to Macbeth and Banquo as "The weird sisters, hand in hand". The impression that the Witches leave is that of pure evil. For example, each of them describes her wickedness with pride: when the other two ask the Second...