archetypes are not determined as regards their content, but only as regards their form and then only to a very limited degree. A primordial image is determined as to its content only when it has become conscious and is therefore filled out with the material of conscious experience.
Jung's foundational claim that archetypes are semantically empty formal structures whose content is supplied only through the interface with conscious experience.
, The Archetypes and the Collective Unconscious, 1959thesis