In 1921, Jung had described the four functions of thinking, feeling, sensing and intuiting in Psychological Types.
INSCRIPTION TRANSLATION :
Inscription at top:
“Amor triumphat.” [Love triumphs]
Inscription at bottom:
“This image was completed on 9 January 1921, after it had waited incomplete for 9 months. It expresses I know not what kind of grief, a fourfold sacrifice. I could almost choose not to finish it. It is the inexorable wheel of the four functions, the essence of all living beings imbued with sacrifice.”