The Archetypes and The Collective Unconscious (Collected Works of C.G. Jung Vol.9 Part 1)
Puer aeternus. Latin for “eternal child,” used in mythology to designate a child-god who is forever young; psychologically it refers to an older man whose emotional life has remained at an adolescent level, usually coupled with too great a dependence on the mother.[The term puella is used when referring to a woman, though one might also speak of a puer animus-or a puella anima.]
The puer typically leads a provisional life, due to the fear of being caught in a situation from which it might not be possible to escape. His lot is seldom what he really wants and one day he will do something about it-but not just yet. Plans for the future slip away in fantasies of what will be, what could be, while no decisive action is taken to change. He covets independence and freedom, chafes at boundaries and limits, and tends to find any restriction intolerable.
[The world] makes demands on the masculinity of a man, on his ardour, above all on his courage and resolution when it comes to throwing his whole being into the scales. For this he would need a faithless Eros, one capable of forgetting his mother and undergoing the pain of relinquishing the first love of his life.[The Syzygy: Anima and Animus,”CW9ii, par. 22.]
Common symptoms of puer psychology are dreams of imprisonment and similar imagery: chains, bars, cages, entrapment, bondage. Life itself, existential reality, is experienced as a prison. The bars are unconscious ties to the unfettered world of early life.
The puer’s shadow is the senex (Latin for “old man”), associated with the god Apollo-disciplined, controlled, responsible, rational, ordered. Conversely, the shadow of the senex is the puer, related to Dionysus-unbounded instinct, disorder, intoxication, whimsy.
Whoever lives out one pattern to the exclusion of the other risks constellating the opposite. Hence individuation quite as often involves the need for a well-controlled person to get closer to the spontaneous, instinctual life as it does the puer’s need to grow up.
The “eternal child” in man is an indescribable experience, an incongruity, a handicap, and a divine prerogative; an imponderable that determines the ultimate worth or worthlessness of a personality.[The Psychology of the Child Archetype,”CW9i, par. 300.]