The Fool begins with innocence and curiosity, gradually learning life’s lessons through encounters with other cards like The Magician, The High Priestess, and so on.
In the system that links the Kabbalistic Tree of Life to the Tarot, the High Priestess goes with the Hebrew letter Gimel (ג).
Aleister Crowley's The Book of Thoth gives the same path, Kether to Tiphareth, and gives the Moon as her planet (pages 24 and 266, as cited on Wikipedia's "The High Priestess" page).
The page reads this as the High Priestess's role: she guides the seeker through the "desert" of the unknown toward deeper understanding.
The High Priestess rules this path.
The High Priestess (Gimel) stands for a mystical path of inner exploration.
The High Priestess is shown in the Rider-Waite-Smith Tarot and other classic decks as a calm, mysterious figure seated between two pillars.
The High Priestess sits between them, balancing them and acting as mediator between the two sides.
II The High Priestess: Intuition, mystery, the subconscious.