What is structural holes?

Example: In 1892, Arthur Conan Doyle published 'Silver Blaze,' in which Sherlock Holmes solves a crime by noticing what did not happen. A racehorse vanishes from a guarded stable, and Holmes identifies the culprit by observing that the watchdog did not bark during the night — meaning the intruder was someone the dog already knew. Holmes solved the case not by examining what was present, but by identifying what was absent. The missing bark was the most important evidence precisely because no one thought to look for it. Your knowledge maps work the same way. The connections you have not drawn — between ideas, between people, between projects — are not empty space. They are either genuine irrelevancies or critical oversights. Learning to tell the difference is one of the most valuable skills in relationship mapping.

This concept is part of Relationship Mapping in the How to Think curriculum.