How can these prophecies be considered a manifestation of Macbeth's thoughts?macbeth went to witches in act 4 scene 1
A major question from the play is if Macbeth's downfall was caused by fate (the prophecies) or by his own ambition. It is very obvious that the witches already knew the evil thoughts Macbeth possessed. The instant that he discovered that there was even the slightest chance of becoming king, Macbeth became ambitious. It could be argued that Macbeth would have suffered the same fate without the witches' prophecies. He had the potential for evil and acted upon it by his own free will.
Banquo, on the other hand, was exposed to the same temptation. He; however, did not succumb to such evil. Although he pondered the thought of his sons becoming kings, he never acted upon it.
Two men were exposed to the same temptations by the witches and only Macbeth acted upon them. This in turn proves that the witches' prophecies were a manifestation of Macbeth's thoughts.
The witches were able to prey upon Macbeth's hidden desires because the potential was already there for them to manipulate him. We see from the beginning of the play that Macbeth is successful and enjoys the adulation of those around him. It is not difficult to predict that he has a desire - even if it is unconscious at first - to taste further success. It is unlikely that so forthright and determined a woman as Lady Macbeth would be so passionate about her 'dearest partner of greatness' if he did not possess the qualities which would make him a determined and ambitious man.