Final answer:
The witches in 'Macbeth' propel the theme of fate versus free will, as they present prophecies that ignite Macbeth's ambitions and bring into question his moral autonomy.
Step-by-step explanation:
The witches in Macbeth play a critical role in unraveling the theme of fate versus free will. They are instrumental in setting off events that question the influence of destiny in Macbeth's life, as well as his own personal agency. When devising a thesis statement, it's essential to connect it clearly with the evidence presented in the text. A working thesis statement might be: 'In Macbeth, the witches serve as a catalyst that triggers Macbeth's ambition, leading to a fatal confusion between fateful inevitability and the self-destructive exercise of free will.'
This thesis can be supported by analyzing specific interactions between Macbeth and the witches, such as their prophecies and their cryptic statements that inspire Macbeth's actions. For example, in Act 1, Scene 3, the witches greet Macbeth with prophecies that he will become Thane of Cawdor and eventually king. Macbeth's reaction showcases his initial disbelief, but the subsequent fulfillment of the first prophecy triggers his ambition and subsequent grappling with fate and free will.