It took a reading of Macbeth for me to realize that most of the long-form theorizing ad nauseam I’ve done about time travel in movies applies just as well to any story with prophecies or other sorts of fortune telling. If a character doesn’t traverse time, at least information can.
To summarize my taxonomy of time travel: The only two legitimate sorts of time travel in movies are “closed loop” versions (a common term, evidently) of time travel and, on the other side, what I labeled “open loop” universes. You can go back and read my explanations of those, but the gist of it is that in closed loop universes, fate fixes the future; there is only one future and it has already been determined, even if a temporal tourist attempts to tweak it. In open loop universes, however, time travel itself changes the future so that there’s always some question about what is to come. Of course, this allows a place for free will to trump destiny, where in a closed loop situation you’re pretty much stuck with whatever is going to happen.
Now, to Macbeth: At the beginning of the play, the Weird Sisters tell Macbeth that he’ll be Thane of Cawdor (a “thane” is a title of yore) and then even King of Scotland. Given this information about the future, the astute time travel connoisseur will immediately want to know what sort of universe William Shakespeare is positing — implicitly or explicitly — in Macbeth. Is Shakespeare’s story one in which, once a vision of the future arrives in the past, it has the ability to upset the course of events so that a new, unseen future comes into being instead? (That would be open loop.) Or, alternatively (and, more to the point, mutually exclusive with the open loop), is the Scotland of the play a place where the future is already definite – a future where Macbeth has “already” (so to speak) achieved the crown? (Never mind the paradox that maybe Macbeth only commits the murders that he does because he is prompted by knowledge of a future where he has already done so. That is, he does it because he learns that he will do it. This is actually a pretty okay paradox by time-travel standards.)