from https://www.academia.edu/41743064/Systemic_Risk_of_Pandemic_via_Novel_Pathogens_-_Coronavirus_A_Note  (Jan 2020)

...owing to “increased connectivity,” the spread will be “nonlinear”—two key contributors to Taleb’s anxiety. For statisticians, “nonlinearity” describes events very much like a pandemic: an output disproportionate to known inputs (the structure and growth of pathogens, say), owing to both unknown and unknowable inputs (their incubation periods in humans, or random mutations), or eccentric interaction among various inputs (wet markets and airplane travel), or exponential growth (from networked human contact), or all three.