Harford’s basic lesson is you have to design your life to make effective use of failures. You have to design systems of trial and error, or to use a natural word, evolution. Most successful enterprises are built through a process of groping and adaptation, not planning.
The Russian thinker Peter Palchinsky understood the basic structure of smart change. First seek out new ideas and new things. Next, try new things on a scale small enough so that their failure is survivable. Then find a feedback mechanism so you can tell which new thing is failing and which is succeeding.
That’s the model—variation, survivability, selection.