&gt; I think I was pretty clear that my goal was to &quot;make everyone happier&quot;<p>How does your behavior achieve your goal, then? How do you know what would make people happy if all of your information about what makes them happy is snapshots of the past? Maybe a better study of the model would yield that the best way to make people happy is to offer them the exact opposite of what they had in the past? I don&#x27;t understand how you can draw conclusions from data without understanding the model the data is a snapshot of.<p>&gt; It&#x27;s an irrelevant one, however, since you can&#x27;t actually predict whether any action will change this distribution.<p>I didn&#x27;t say that. I said that we can&#x27;t predict with certainty and we&#x27;re not trying to make predictions at all, but we do know from history that political and social action does work. That&#x27;s how women were allowed to vote, go to universities, and become doctors and lawyers.<p>&gt; that result in no testable predictions, I&#x27;m sorry for you<p>As I have spent even more years studying mathematics, I can tell you that neither subject was a waste of time, testable predictions or no. I feel sorry for you if testable predictions are the only measure of worth you know, but I hope that you are at least aware that much of the progress humankind has made wasn&#x27;t due to any scientifically-predictable actions (and some of it was).<p>Nevertheless, I never said I can&#x27;t make <i>any</i> testable predictions, only that we can&#x27;t predict the course of history.<p>&gt; Perhaps it might have been a better use of time to spend a semester studying complex systems instead.<p>Well, I did both.<p>&gt; but the nonexistence of good predictions does not follow this - it merely changes the character of the predictions.<p>Really? If your measurement time (of initial conditions) significantly exceeds the time the predicted trajectory is within usable error, then yes -- nonexistence of predictions does follow. That doesn&#x27;t mean, however, that we&#x27;ve seen that societies where social action was taken changed faster than those that didn&#x27;t have social action. If nonlinear equations is your field then you know that, sadly, sometimes we are reduced to making qualitative predictions only.