How should one interpretate the Virgin’s depiction as Sedes Sapientiae (Throne of Wisdom)? As an actual source of wisdom, knowlegde?
The point is that Wisdom (Jesus/God) was enthroned in Mary when she was pregnant, and upon Mary whenever she held her Son. So a picture of Mary holding her Son in a certain position is referred to as “Sedes Sapientiae”, or Seat/Throne of Wisdom. (You often get some similarities between this and pictures of Mary reading the Scriptures, btw.)
Since Mary and the Church are close types, this also shows that divine Wisdom is to be found enthroned in the Church.
As we know, bishops and the pope are often seen to preach sitting down, from their “sedes”, seat, from which we get the word “see” for a diocese. This was the way philosophers in ancient times often used to teach their students: sitting down as if enthroned, on a chair on a raised dais – while the students stood in respect (or with permission, sat down on the floor or on lower level chairs through longer discourses).
So a Sedes Sapientiae is also a picture of the Baby Jesus as a philosopher-teacher, teaching the world even while still a babe in His mother’s lap.
Now, since Mary is not a brainless chair, the picture shows that Mary is Jesus’ closest and most diligent student. By being the Seat of Wisdom, she has become wise herself (she is often sitting in a philosopher’s chair as well as acting as such a chair!). So it does indeed show her as being someone to consult for help on divine wisdom, but makes it clear that she is not herself divine. She is a source of wisdom by virtue of her connection to God and doing God’s will, not in and of herself.
(Of course the picture of personified divine Wisdom as a woman, and the picture of the wise and valiant woman of Proverbs who takes good care of her household, are probably also referred to, in this picture. But that’s all to the side, not a main consideration at all. There is probably also a reference to those female saints who are depicted as philosophers sitting on such seats, as is not unknown for Church Mothers and great abbesses involved in such matters. But again, not a major thing.)