Title: The Narrow Door
Course: Science Fiction: Dune > Section: Book II

The following excerpt is from page 296:

The prescience, he realized, was an illumination that incorporated the limits of what it revealed--at once a source of accuracy and meaningful error. A kind of Heisenberg indeterminacy intervened: the expenditure of energy that revealed what he saw, changed what he saw.

And what he saw was a time nexus within this cave, a boiling of possibilities focused here, wherein the most minute action--the wink of an eye, a careless word, a misplaced grain of sand--moved a gigantic lever across the known universe. He saw violence with the outcome subject to so many variables that his slightest movement created vast shiftings in the pattern.

The vision made him want to freeze into immobility, but this, too, was action with its consequences.

The countless consequences--lines fanned out from this cave, and along most of these consequence-lines he saw his own dead body with blood flowing from a gaping knife wound.

Assignment:
Explain what all of this means in your own words. Also, Who is Heisenberg, and what does he have to do with any of this (focus on his Uncertainty Principle)? (Hint: he was a real person)