Until something sets them off

From Harriet Hawkins's Strange Attractors: Literature, Culture, and Chaos Theory:

The long-term behaviour of nonlinear systems is humanly unpredictable because tiny differences in input can very soon result in enormous differences in output, and systems fraught with a variety of positive feedback will often undergo sudden and revolutionary changes in behaviour. Very like certain characters in mythic literature, nonlinear systems tend to behave in a regular, orderly way until something sets them off, a critical point is passed, and they suddenly become chaotic (x).

What Hawkins is describing in her second sentence is the separation stage of Joseph Campbell's "monomyth." Here are more of my monomyth-tagged posts.