Jung places images and instinct on a psychological continuum, like a spectrum… ranging from an infrared end, the bodily action of instinctual desire, to the ultraviolet blue end of fantasy images. These fantasy images, according to Jung’s model, are the pattern and form of desire.
This passage articulates Jung’s foundational structural claim that fantasy images are not epiphenomenal but are the very form and patterning of instinct, positioning them at the ultraviolet pole of a psychic spectrum.
, Mythic Figures, 2007thesis