the Peaceful Deities (Tib. ZH—wa) are the personified forms of the sublimest human sentiments, which proceed from the psychic heart-centre. As such, they are represented as the first to dawn, because, psychologically speaking, the heart-born impulses precede the brain-born impulses.
Evans-Wentz establishes the psychic-topological distinction between Peaceful and Wrathful Deities as projections of heart-centre and brain-centre impulses respectively, grounding the entire sequence in a depth-psychological reading of karmic propensities.
, The Tibetan Book of the Dead (Evans-Wentz Edition), 1927thesis