Elevation
A pyramid may quite generally symbolize unification: the set of points forming the base pass into the single point at the top, the apex. This kind of transformation is fundamentally important for knowledge.
It is part of what we have called the “act of knowing”. A certain pattern crystallizes into one thing that multiplies as a whole — and so constitutes a new plane or space of knowledge.
This move into a new dimension is nicely depicted by the pyramid shape, too.