Fate plays a large role in Shakespeare's Macbeth. Not only do the weird sisters use it to wreak havoc among the Scottish nobility, but many people throughout the play try to tempt fate. Macbeth does it, as does Lady Macbeth. Then, later in the play, even Malcolm, Macduff and the other revolutionaries try to alter fate. Fate can be many things to many different people. To those who believe that fate is an all-encompassing aspect of God, fate is merely an excuse for one's deeds. But to Macbeth and the witches, fate was something much more complicated.
To the weird sisters, fate is not something to be overly concerned with. However, their superior, Hecate, obviously thinks that it was important enough to discipline the weird sisters verbally for abusing it. To the weird sisters, fate, and for that matter it seems, time, is merely as water and bread are to Macbeth: they exist and can be altered.
This view of fate is not as ambivalent as the other view, but is more a view along the lines of Thomas Aquinas or Kurt Vonnegut. According to Aquinas, time is something that you both exist in and are affected by or you not. One is either subject to the limitations of time or one is not. For instance, God is outside the normal limitations of time and is therefore immortal. In Macbeth, it seems, the witches are a transient hybrid of those in time and those not in time. That is to say, they can travel in and out of time at will. This ability allows them to both see the future and to change its very course. This of course proves to be an illogical paradox when examined analytically, but Shakespeare's great work is brimming with paradoxes ("Fair is foul, and foul is fair" I.i.11).
This ability leads to some interesting and important moments in the play. For one, the witches seem to already know the consummation of both Macbeth and Banquo's respective fates. However, they, for some reason unbeknownst to the audience, deem it necessary to interfere with this fate and tell Macbeth and Banquo about their futures. This makes it seem as if the witches have a human like desire for power, personified in their quest to affect the outcome of time. This desire, which seems to be the root of their actions, also becomes the root of Macbeth's eventual fall from power. Macbeth's over-zealousness for political power led him to the murder of Duncan, the assassination of Banquo, and finally the slaughter of MacDuff's family. These events spur the revolution that eventually costs Macbeth his crown and his life, not to mention the wife he loses along the way.
Now, many can argue that Macbeth is to be pitied because of the hand fate deals him, but there are other facets of this situation to be considered. For instance, does Macbeth actually have a choice over what he will do or become? To many the answer might be "No," but in reality, as we all must know from everyday life, the answer is "Yes, Macbeth, and any human being for that matter, does have limited control over the outcome of his or her life based on decisions he or she makes at certain critical times in life." These critical times are momentous occasions; for Macbeth, deciding whether or not to kill Duncan was one of these moments. Other decisions humans make do not seem to have as much impact as the major ones; for instance, whether to be black or red in a game of checkers is not likely to have any impact on whether you die of old age or a decapitation. However, these decisions, as every action does, affect something. These small decisions can lead one slightly off of one path and eventually onto another course.
The witches seem to know that whether or not Macbeth chooses to wear his gold armor or his silver armor will not affect his receiving the crown, and whether or not he kills Duncan will drastically effect when Macbeth will receive the crown. According to fate, the witches cannot directly effect whether or not Macbeth becomes king because that event is already predetermined, but they do, however, have the capability to change the route which Macbeth takes to reach the throne and thus the aftermath of his rise.
Whether Macbeth's rise to power and his decline are directly the fault of the witches, fate does seem to play a major part. Fate does not, however, seem to be an all-encompassing aspect of some superior being, but more or less the embodiment of human lust and greed. Every time Macbeth finds out information from the supernatural about his future, he acts directly on it. By taking the predictions of his success, by believing the warnings of his doom, and by trying to act upon and turn each to his favor thereby bending fate's will, Macbeth does nothing more than solidify fate's hold on him. For every thing Macbeth does only increases the quickness with which his fate strikes him down. Macbeth takes every one of the apparitions and foreshadowing statements of the supernatural beings, known as the weird sisters, as absolute truth. Had Macbeth been a strong and individualistic man, he would have never attained such arrogance as to claim that no one of natural birth could kill him. While this arrogance allowed him to fight with admirable courage at the early part of Malcolm's invasion, this same arrogance and human imperfection was again his downfall when he became terrified of MacDuff and lost the battle that resulted in his decapitation.
While fate can be viewed as something that cannot be altered, the only way a strong person would ever use fate is to his or her advantage. To use fate as a source of stability and grounds for faith in one's own self and one's own abilities is a positive use of fate. However, becoming over confident in or basing one's few momentous decisions on fate rather than fact is not a wise undertaking. Fate is like religion and any other belief based on intangible ideas: it can be a good excuse to not take control of one's own life and one's own decisions. When fate supersedes free will, then chaos is bound to follow.