The “butterfly effect” is a term from nonlinear dynamics, which is a subdomain of physics. It occurs in systems that meet three requirements: the output is not always proportional to the input (“nonlinear”), the progression is dependent on time, but is a function of only the original state (“dynamic”), and randomness is not a factor (“deterministic”: if A, then B). When these three conditions are met, a small change to the initial conditions can lead to large changes in the results. The phrase was coined by the meteorologist Edward Lorenz, who was referring to a butterfly flapping its wings…