Which is responsibel for Macbeth's downfall? Fate or free will?
One of the predominant themes explored throughout the play Macbeth concerns fate versus free will. The Three Witches and their fortune-telling abilities represent fate, while Macbeth's ambitious nature and decisions represent his free will. Interestingly, Shakespeare leaves the question of whether Macbeth would have assassinated King Duncan without the witches' intervention up to interpretation. The witches possess the supernatural ability to predict the future and prophesy that Macbeth will one day become the Thane of Cawdor and King of Scotland. After Macbeth learns that he has been given the title Thane of Cawdor, he immediately begins thinking about murdering King Duncan. While Macbeth is contemplating the nature of the prophecy, he says,
If good, why do I yield to that suggestion Whose horrid image doth unfix my hair And make my seated heart knock at my ribs, Against the use of nature? Present fears Are less than horrible imaginings. (1.3.138-142)
Also, there is no indication that Macbeth previously sought to become king before receiving the prophecy from the witches. While Macbeth is an inherently ambitious person, the thought of killing King Duncan does not enter his mind until he speaks with the witches. Before receiving the prophecy, Macbeth is portrayed as a loyal, honorable servant to the king. Therefore, Shakespeare suggests that Macbeth's decision to assassinate the king is his own doing.
However, the fact that Macbeth meets the witches in the first place and their prophecies are accurate suggests that fate is truly responsible for Macbeth's ascension to the throne and eventual downfall. Overall, both interpretations are accepted, and the arguments concerning fate versus free will continue to be discussed and debated.
Macbeth was brought down by his ambition, but it was ambition that was exploited by the witches. Macbeth was never forced into any actions that occurred; he always had free will to choose his actions. The witches merely fed a desire that was already inside Macbeth. In Act 1, sc. 3, when the witches deliver their prophecies to Macbeth, Macbeth's responses indicate that becoming king is something that he has secretly hoped for (he is, after all, a cousin to the king). When he says, in his first aside, "The greatest is behind," he means that the next step is to become king. Then in his next aside, the longer one that begins with. "Two truths are told...." also indicates that the thought of becoming king has crossed his mind and the thought of murdering Duncan has already surfaced in his head. All of this indicates that he is acting on free will. The witches' powers are limited. Look through their words at the beginning of Act 1, sc. 3, as they talk about what they'll do to the woman who refused to share her chestnuts. While they do seem to be able to predict the future, they do not have control of a person's actions. Macbeth has the tragic flaw of "vaulting ambition" which he recognizes in himself (Act 1, sc. 7 soliloquy). Since he knows he has this flaw, he should be able to control it, but he doesn't. That speaks of choice and therefore, free will. So, Macbeth's downfall is brought about by his own free will.
The real answer to this depends on when you lived. To the people watching Macbeth in 1606, they believed that witches were as real as terrorists, and had the power to make good people do bad things. Today, we believe that all people have free will and choose their fate [or have psychological problems and cannot make their own decisions]. In the play, you need to contrast how Macbeth and Banquo each react differently to the witches prophesies. Clearly, Macbeth seems more 'corruptible' than Banquo and to that degree he is an easier target for the witches. We never find out why the witches decided to choose Macbeth in the first place? Was it random? Did they think he had the 'seeds of evil' in him? Could they have corrupted Banquo? How you answer that will determine to what degree you think Macbeth is responsible for his own downfall...