Why did Wright design so complex a structure? Why was he so intent on cantilevering? I see Fallingwater as an irregular web of forces skillfully balanced to create floating horizontal levels. It is proper for such a structure to be inserted amid horizontal rock ledges naturally settled by similar adjustments of forces. Moreover, cantilevering is a constituent feature of modern structural technology. For millennia building was dominated by uprights - posts or walls holding up beams, trusses, or vaults to provide shelter. Within the past two hundred years, however, a more scientific understanding of materials and forces gradually led (among several results) to horizontal constructions so strong in themselves that vertical supports can be greatly reduced in number and bulk. Furthermore, supports can be distributed freely between horizontal planes. This technological liberation gave rise to the "open plan" that has preoccupied all major creators of modern architecture,Wright in particular.
- Edgar Kaufmann, Jr.,
Fallingwater: A Frank Lloyd Wright Country House, pp. 90-96.