There’s some evidence that thinking makes it so—not in the obvious sense that thinking makes you smarter, but in the sense that thinking you’re getting smarter actually makes you smarter. Positive thinking really does have power.
I hesitate to endorse this, because I’ve known plenty of people who thought they were smarter than they really were. But I suspect there’s something to it nevertheless. Your brain makes connections all the time. If you think negatively, react skeptically, or simply lack confidence, you’ll discard most of those connections before you devote any time to thinking about them. Many of course ought to be discarded. But quite a few are worth developing, and it requires positive thinking and a certain degree of tenacity to follow where they lead.
Good teaching, especially in a seminar setting, requires the same thing. You have to think positively and be willing to track ideas for a while, hunting them, noticing them, exploring them, and working through them. Sometimes that takes you off track for a while. But often it leads to something really interesting that you wouldn’t have noticed otherwise. Good research requires the same thing—it just isn’t done as publicly, in real time.