The supernatural elements in Macbeth, including the witches and Banquo's ghost, play a significant role in developing the plot and dramatic tension. While Shakespeare did not express a personal view on witchcraft, he wrote during a time when witches were believed to have real supernatural powers. The witches' prophecies to Macbeth influence his descent into ambition and crime. Their words also symbolize Macbeth's betrayal of himself and the general evil prevailing in the world. The supernatural elements were likely included by Shakespeare to appeal to the superstitious views of his contemporaries.