Below is a long essay I wrote four years ago which I’m reposting. It may be a useful guide for readers who are not aware of my various non-genetic interests….
Peter Turchin’s Historical Dynamics: Why States Rise and Fall showed up a little sooner than I’d thought it would, and it was an even quicker read than War and Peace and War: The Rise and Fall of Empires (see review). There isn’t really anything new verbal in the more technical treatment, but the book is about half the length because so much of the text was condensed into simple differential equations and figures which displayed the results of simulations. The figure to the left was one that I found particularly interesting, the differential equations which this is based on are:
dA/dt = c0AS(1 – A/h) – a
dS/dt = r0(1 – A/[2b])S(1 – S)
Where A = area, c = state’s resources translated into geopolitical power, r is the growth rate, h is the spatial scale of power project, a is the geopolitical pressure from the hinterland and S is average polity-wide level of collective solidarity. You can find the elucidation of the details of the simulation in the appendix of Historical Dynamics.
Turchin was obviously pleased with how similar the dynamics of area of polity vs. time were in the simulation to what the …