Being able to forecast is a big thing for scientists, but not always having
understanding of the system leads to better forecasting. In physics we have
good understanding of celestial dynamics, thus we can make accurate predictions
about the movement of planets. Though we also have a decent understanding of how
the weather works, weather forecasts are not that reliable. And most likely
weather forecasts won't get much better over the time, because we will never be
able to precisely predict large number of minor influences, which get amplified
and then the system deviates from the forecast (the so-called
butterfly effect).
Situation with forecasts in social sciences is even worse, but we can do more to
improve them. In this SciShow video Hank Green tells us about
some of the interesting intricacies.
In this video I especially liked one aspect - open-minded non-experts
outperformed close-minded experts. The non-experts did a better job, because
they more often incorporated evidence contradicting their prior beliefs, while
the experts more often rejected such evidence.
So, the takeaway lesson? I guess I should not trust an "expert" who shows off
his firm beliefs. Nor should I myself be an "expert" who values his beliefs more
than the evidence.