A theory is a machine for making testable predictions (i.e., positive claims that are a reason for rejecting the theory should they fail to be true). You go to great effort to NOT make any testable predictions.<p>My point is that if your one testable prediction of slow change is true, then using the past to predict the future will be highly accurate. By &quot;accurate&quot;, I mean that if the predictor says group X will have a 40% default rate, the empirical default rate of group X will be close to 40%. (I&#x27;m assuming a good model is built, etc.) Once in a blue moon (the rapid changes) this will fail, then everyone can re-adjust their models and go back to using the slow change assumption.<p>This is strictly a positive (i.e., value-free) claim about the world. It&#x27;s based on <i>your</i> positive belief.<p>As for your dynamical systems verbiage, feel free to state a testable prediction.