Mircea Eliade suggests that man's impulse to build stems from the need to physically distinguish the world of culture from the world of nature. Man builds in an attempt to perfect the natural world. It is Henry David Thoreau's assertion that nature, of which man is only a part, is already perfect. In Loren Eiseley's view, man must balance his culture with his irrevocable attachment to nature. Architecture, as an expression of culture, mediates between nature and man. Architecture's creation is inspired through man, and informed by nature. From the earliest civilization this has been true. Thus we may compare the work of Frank Lloyd Wright and Louis I. Kahn, finding that, while their work differs considerably in appearance, in spirit it is remarkably the same. From the work of Wright and Kahn we may conclude that Architecture is indebted to nature as well as to the spirit of man.