“Stairs” are alleged to have a well-established sexual meaning: they represent the sexual act because of the rhythmic climbing… If I attach a symbolic value to the ascent of the stairs, I must also attach a symbolic value to the images called mother, sister, and baby.
Jung challenges the Freudian reduction of stairs to sexual symbolism by demonstrating that selective symbolic interpretation is logically incoherent, opening stairs to a more differentiated hermeneutic.
, Collected Works Volume 4: Freud and Psychoanalysis, 1961thesis