It’s high time history majors learned about the best method available for reading their changes. A most curious and revealing thing about complex systems is that the first evidence of emergent change is often a display of the physical property that corresponds to the central mathematical idea of calculus, continuity.
In a mathematical function you can define a slope, and the same is true of almost any real change in complex systems. Complex systems evolve through progressions, and applying a logic like that of calculus to measures of change over time shows you where the progressions emerge from the noise and when they shift.
It reveals a great deal about the nature of a system because it provides direct evidence of it’s creative behavior as a whole.