Puer aeternus in mythology is a child-god who is forever young. In psychology, it is an older person whose emotional life has remained at an adolescent level, not to be confused with Peter Pan syndrome. 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. He or she covets independence and freedom, opposes boundaries and limits, and tends to find any restriction intolerable.

Swiss psychiatrist Carl Gustav Jung developed a school of thought called analytical psychology, distinguishing it from the psychoanalysis of Sigmund Freud (1856–1939). In analytical psychology (or “Jungian psychology”), the puer aeternus is an example of what Jung considered an archetype, one of the “primordial, structural elements of the human psyche.”

The girl in the painting has the stoic empty gaze of an adult, yet her glowing skin and rosy cheeks are those of a young girl. Questioning which came first; the eternal adolescent or the schism that would forever remain.