1. The sudden and unexpected nature of their appearance: The witches appear to Macbeth and Banquo in a remote and desolate setting, creating an air of mystery and suspense. Their sudden and unexpected arrival startles Macbeth, disrupting his sense of security and control.
2. The ambiguity and cryptic language of their prophecies: The witches' predictions are delivered in a cryptic and ambiguous manner, leaving room for multiple interpretations. Macbeth is startled by this lack of clarity, as he struggles to comprehend the full meaning and implications of their words.
3. The gravity of the predictions: The witches' prophecies suggest that Macbeth will become king, but at a great personal cost. Macbeth is startled by the magnitude and potential consequences of these predictions, as they challenge his moral compass and sense of ambition.
4. The supernatural element: The presence of the witches themselves is a supernatural element that disrupts the rational and orderly world of Macbeth. Macbeth is startled by the encounter with these otherworldly beings, as they represent a realm beyond his understanding and control.
5. The potential fulfillment of the prophecies: Macbeth is startled by the possibility that the witches' predictions may come true. The prospect of becoming king fills him with both excitement and fear, and he begins to contemplate the actions necessary to achieve this goal.
In conclusion, Macbeth is startled by the witches' predictions in Act 1 due to their sudden and unexpected nature, their ambiguity, their gravity, the supernatural element they represent, and the potential for their fulfillment. These elements combine to create a sense of unease and intrigue, setting the stage for the tragic events that unfold throughout the play.