Some things are predictable, but many are not and never will be

From Dan Gardner's Future Babble. Page 41.

These insights have fundamentally changed how science views reality. "The old certainties of the Newtonian world machine, with its impressive capability of predicting and retrodicting the motions of sun, moon, planets, and even comets, unexpectedly dissolved into an evolving, historical, and occasionally chaotic universe," wrote historian WIlliam H. McNeill. In this new universe, some things are predictable, but many are not and never will be. Uncertainty is an ineradicable fact of existence.

[snip]

With natural science increasingly aware of the limits of prediction, and with prediction even more difficult when people are involved, it would seem obvious that social science - the study of people - would follow the lead of natural science and accept that much of what we would like to predict will forever be unpredictable. But that hasn't happened, at least not to the extent it should. In fact, as the Yale University historian John Lewis Gaddis describes in The Landscape of History, "social scientists during the twentieth century embraced a Newtonian vision of linear and therefore predictable phenomena even as the natural sciences were abandoning it." Hence, economists issue wonky forecast, criminologists predict crime trends that don't materialize, and political scientists foresee events that don't happen. And they keep doing it no matter how often they fail. Or how spectacularly.