Historical Dynamics Quotes

“There is a heuristic “rule of thumb” in modeling dynamical systems: do not attempt to encompass in your model more than two hierarchical levels.”
― Peter Turchin, Historical Dynamics: Why States Rise and Fall

“physicists traditionally choose to deal with systems and phenomena that are very different from those in history. Physicists tend to choose very simple systems with few interacting components (such as the solar system, the hydrogen atom, etc.) or systems consisting of a huge number of identical components (as in thermodynamics). As a result, very precise quantitative predictions can be made and empirically tested. But even in physical applications such systems are rare, and in social sciences only very trivial questions can be reduced to such simplicity. Real societies always consist of many qualitatively and quantitatively different agents interacting in very complex ways.”
― Peter Turchin, Historical Dynamics: Why States Rise and Fall

“Mathematical models are particularly important in the study of dynamics, because dynamic phenomena are typically characterized by nonlinear feedbacks, often acting with various time lags. Informal verbal models are adequate for generating predictions in cases where assumed mechanisms act in a linear and additive fashion (as in trend extrapolation), but they can be very misleading when we deal with a system characterized by nonlinearities and lags. In general, nonlinear dynamical systems have a much wider spectrum of behaviors than could be imagined by informal reasoning (for example, see Hanneman et al. 1995). Thus,”
― Peter Turchin, Historical Dynamics: Why States Rise and Fall