We hardly see a building without some perspective distortion of its constant form. The constancy of form discounts all these distortions. It is difficult to imagine how difficult our thing recognition would become if we had to discount the perspective distortions and foreshortening of our viewing angle. The repression of the distortions represents an important step forward in making perception serviceable for recognizing reality. All probable reasoning is nothing but a species of sensation because beauty in architecture is not a quality in things themselves but exists merely in the mind which contemplates them. Architecture is a microcosm that integrates ideals of beauty into a system of proportions that corresponds to a world order and to the structure of the human body.