（4） Finally，architecture must do more than meet the physical requirements of strength and space;it must also content the spirit of man.The building should form an aesthetic unity to which the several parts contribute.Thus,the sides and rear of a structure should bear sufficient correspondence to the front to make them all related parts of a single whole.The major internal divisions,too,require some expression in the external design.The nave,aisles, transepts,apse,and radiating chapels of Gothic cathedrals,for example,are all visible on the exterior,so that the visitor is subconsciously prepared for what he will find inside.
(5) Architecture calls for good proportions-a pleasing relationship of voids to solids,of height to width,of length to breadth.Many attempts have been made to explain good proportions by mathematical formulas,such as the golden section. These efforts have not found general acceptance,however,although good results have been achieved through the repetition of some dimension(for example,a module that is half the diameter of a column)throughout a design.Such repetition help to produce the visible order that the human mind seems to crave.
(6) A building also should have what architects call"scale":that is ,it should visually convey its true size.Such elements as benches,steps,or balustrades,though slightly variable in size,are,by their very purpose,related to the normal dimensions of human beings.They therefore become,almost imperceptibly,units of measurement for gauging the size of the whole edifice.Because these units are so small in comparison to the whole building,other elements of intermediate size are needed.Stairs and a balustrade may give a clue to the size of a doorway;that,in turn,to the height of a colonnade;and finally,the colonnade to the whole structure.The Petit Trianon at Versailles is perfect in scale.The absence of small elements in St.Peter's in Rome makes it difficult to perceive its vastness.
(7) Although all decoration is rejected in some modern architecture,it was employed in the past either for its inherent beauty or to emphasize some point of importance in the building.Decoration or ornament may be used to contribute to character,the visible expression of the purpose of the building.Thus a bank should look like a bank ,and a church should be immediately identifiable as such.Ideally,too,any building should seem to belong on its site,with some relationship to its architectural neighbors and to the local geography.