The vaulted ceiling is a sight in itself a painting symbolizing the arts and sciences, specifically grammar, rhetoric, dialectic, arithmetic, music, geometry, and astronomy.
The color palette of the paintings is exceptionally striking and varied. 
mnli hypothesis: The color palette of the paintings is exceptionally striking and varied.  premise: The vaulted ceiling is a sight in itself a painting symbolizing the arts and sciences, specifically grammar, rhetoric, dialectic, arithmetic, music, geometry, and astronomy.