When Brahman had entered into that other world, he bethought himself: How can I extend myself through these worlds? And he extended himself twofold through these worlds, by Form and Name.
Jung reads the Upanishadic account of Brahman’s self-extension through Form (manas) and Name (vac) as a mythological representation of the two fundamental psychic functions of introversion and extraversion.
, Psychological Types, 1921thesis