For centuries architecture, painting and sculpture have been called the Fine Arts, that is to say the arts which are concerned with "the beautiful" and appeal to the eye, just as music appeals to the ear. And indeed most people judge architecture by its external appearance, just as books on the subject are usually illustrated with pictures of building exteriors.
When an architect judges a building its appearance is only one of several factors which interest him. He studies plans, sections and elevations and maintains that, if it is to be a good building, these must harmonize with each other. Just what he means by this is not easy to explain. At any rate, not everyone can understand it any more than everyone can visualize a building merely by looking at the plans. A man to whom I was explaining a project for a house he wanted to build, said deprecatingly: "I really don't like sections." He was a rather delicate person and I got the impression that the mere idea of cutting into anything was repulsive to him. But his reluctance may have arisen from the correct idea of architecture as something indivisible, something you cannot separate into a number of elements. Architecture is not produced simply by adding plans and sections to elevations. It is something else and something more. It is impossible to explain precisely what it is--its limits are by no means well-defined. On the whole, art should not be explained; it must be experienced. But by means of words it is possible to help others to experience it, and that is what I shall atte1mpt to do here.
The architect works with form and mass just as the sculptor does, and like the painter he works with color. But alone of the three, his is a functional art. It solves practical problems. It creates tools or implements for human beings and utility plays a decisive role in judging it.