There is an experiment in which fleas are placed inside a jar with a lid. Initially, the fleas will attempt to jump out of the jar, as it is their natural behavior to escape confinement. However, due to the height of the jar and the presence of the lid, the fleas repeatedly hit the lid when they jump, which causes them to experience discomfort or pain.
Over time, the fleas learn from this repeated failure and adjust their behavior. They begin to jump just below the height of the lid, avoiding collision and minimizing discomfort. Even if the lid is later removed, the fleas continue to jump at the lower height, as they have developed a conditioned response.
This book aims to make it known that humanity is in a similar predicament to that of the flea, previously we were bound, however, now such confinements have been removed. Now only one question is left to be answered, are we human or flea?