Every positive requires a negative; the masculine, a feminine; an "I", a "you". This is the world of "twoness", of polarity. Gnostically-inclined commentators, doubtless helped along by Pythagorean misogyny which claimed that the "feminine" or even numbers are evil, would say that the Fool has well and truly fallen now, into duality, reflection as opposed to essence. "Two" is also a lunar number, and the Chalice pack has accordingly taken note of the dark, Lilith-qualities which must certainly be related to the hidden side of the Moon and to the High Priestess.
Hence the apple, the snake, the spider's web within the design, all of which hint at the hidden or even "forbidden" knowledge that the High Priestess represents. The High Priestess can be frightening for women - let alone men - because the power she represents is far removed from that of Küche, Kirche, and Kinder. She is the menstrual pole of the lunar cycle, representing a sexuality which seeks only to satisfy itself. (This, some feminine anthropologists have suggested, is the real nature of the apple Eve gave to Adam: that once sexuality became removed from oestrus and therefore strict biological determinism, human beings did indeed become something greater than beasts, if still less than angels.) The Priestess is therefore virgin in the original, pagan sense, as her sexual favours involve no sacrifice of her personal autonomy.
The High Priestess also harks back to the old Goddess worship of pagan days. Here, the Priestess becomes the Black Goddess, a form of medieval mariolatry to which attention is drawn especially by Ean Begg. The all-male Christian pantheon was unable to wipe out the voice of the Goddess altogether, something which may help explain the persistence of the Pope Joan myth, where a Pope collapses in the middle of a procession, only for it to be discovered that "he" has given birth! (It is to be wondered at the peculiar psycho-pressures of the time which produced the Maid of Orleans.)
Older goddesses from still further back may have helped create the iconography of the High Priestess. She may be Isis, or Innanna, who has to descend into Hell and be dismembered there in order to find what she seeks; Persephone, the Queen of the Dead, the Gnostic Sophia, or Indwelling Shekhina of certain Jewish mysteries.
What all these goddesses tend to have in common is that each seems to represent a path or a process of initiation, which her devotees or initiates must undergo if they are to discover for themselves the hidden knowledge or inner-felt wisdom that the Priestess represents. Perhaps this is why the card has as much to do with soul-searching and self-honesty as it does with the intuitive understanding the Priestess also promises. Either way, it is a knowledge which has to be sought before whatever the veil or scroll of High Priestess reveals its secrets.
It certainly remains true that the Priestess complements the qualities of the Magician. As symbolic of reflective insight, this card hints at the whys and wherefores to the Magicians endeavours. The High Priestess is a gateway between the conscious mind and that of the subconscious, fulfilling all the qualifications for Jung's anima, and as such is a valuable card for meditations and for the development of psychic gifts. As a card symbolising a gateway, the insights the Priestess has to offer tend to be more easily assimilated into the fabric of the querent's understanding than do later Trumps, symbolising more undisciplined or disruptive energies.
As its most positive, therefore, this card can always be seen to promote deeper understanding and insights for most querents. Negatively however, it may hint at paranoia rather than intuition, psychic gifts poisoned by fear or negativity. This is more likely to happen in those individuals who have a more damaged concept of the Feminine. Then, the Priestess may be "witchy" in a more destructive sense. A more intellectual approach may then be required rather than one which relies more on feelings which may be distorted by prejudice or fear.