How can one confirm the benefit that thinking has had in one's life? From my point of view, it's more important to know both the principle and the problems (questions) that determine the results that exist in the world, rather than learning how to think about how to solve problems. It's my experience that I have to think when there's an important fact that I haven't realized.

I don't agree with this dichotomy. Thinking and doing are two activities that inform and reinforce each other - "book learning" and "on the job training" are best when combined in an individual.

Sometimes the best ideas don't come to you until you've worked and struggled with the existing tools and materials to appreciate the difference between practice and theory.

Could you share one or two unknown unknowns to which you were exposed in school?