I never guess. It is a shocking habit—destructive to the logical faculty.1
—SHERLOCK HOLMES, IN SIGN OF THE FOUR
Unlike Mr. Holmes, the rest of us guess sometimes. When we face something that’s broken or any problem in our lives, our frontal cortex lights up with one or dozens of ideas of what might be wrong and how to fix it. We might jot these down and quickly get to work.
Guessing is a natural brain function. In our evolutionary history, humans had to quickly make decisions with very limited information. We had problems such as “What tool should I use to deal with this saber-toothed tiger trying to separate me from my ...