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 naked plaster of the ceiling lies bare and empty. 
mnli hypothesis: The naked plaster of the ceiling lies bare and empty.  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.