Eternal boy, used in mythology to designate a child-god who is forever young; psychologically, it is an older man whose emotional life has remained at an adolescent level.
In analytical psychology the puer aeternus is an example of what Jung called an archetype, one of the “primordial, structural elements of the human psyche”.
The shadow of the puer is the senex (Latin for “old man”), associated with the god Cronus — disciplined, controlled, responsible, rational, ordered. Conversely, the shadow of the senex is the puer, related toHermes or Dionysus — unbounded instinct, disorder, intoxication, whimsy.
Like all archetypes, the puer is bi-polar, exhibiting both a “positive” and a “negative” aspect. The “positive” side of the puer appears as the Divine Child who symbolizes newness, potential for growth, hope for the future. He also foreshadows the hero that he sometimes becomes (e.g. Heracles). The “negative” side is the child-man who refuses to grow up and meet the challenges of life face on, waiting instead for his ship to come in and solve all his problems.