Here’s technology forecaster Paul Saffo from 2008:
Since the mid-1980s, my mantra for this process [forecasting] is “strong opinions, weakly held.” Allow your intuition to guide you to a conclusion, no matter how imperfect — this is the “strong opinion” part. Then — and this is the “weakly held” part — prove yourself wrong. Engage in creative doubt. Look for information that doesn’t fit, or indicators that point in an entirely different direction.1
It sounds a little similar to theatre director Peter Brook who said of ideas: “hold on tightly, let go lightly”. But I very much like Saffo’s statement about attempting to prove one’s self wrong; to find information that doesn’t fit. It seems to involve an ongoing testing of ideas and thoughts, and not allowing them to settle too deeply.