The Louis Kahn/I. M. Pei generation of architects were modernists who had dispensed with many of the previously essential aspects of architecture such as ornament, but they still believed in buildings ordered by rules, especially the old rules of geometry, symmetry, centering, axes, and so on. That didn’t mean that they didn’t diverge from those rules—in Pei’s case quite often—but when they they did so they were always aware of the break and compensated in some way. That seems to be what is missing in current architecture. There are no rules, broken or unbroken, which too often results in mere confusion.
Another old rule is that the exterior of a building should prepare you for what happens on the interior. The tripartite façade of a Gothic cathedral, for example, signals the presence of the nave and side aisles. The vaulted porches on the exterior of Kahn’s Kimbell Museum (above) prepare us for the vaulted galleries of the interior. Similarly, the angled exterior of Pei’s East Wing of the National Gallery, despite the symmetrical entrance portico, anticipates the interior. In other words, the experience of a building is conditioned not only by what we see but also by what we remember.