The principle of Functionalism is based on the dictum of which architect?

The principle of Functionalism is closely associated with the work and ideas of Louis Sullivan, who famously coined the phrase "form follows function." This principle emphasizes that the design of a building should be primarily influenced by its intended purpose and function. Sullivan believed that the architecture of a structure should reflect its function, suggesting that design should not only fulfill practical needs but also express the essence of its utility through its form.

Sullivan's approach marked a shift away from decorative styles that did not serve a functional purpose, advocating instead for a direct connection between how a building is used and how it is designed. This philosophy laid foundational ideas for modern architectural practices by encouraging architects to consider the user experience and the inherent purpose of spaces in their designs.

Other architects mentioned have contributed to architectural theory as well; however, they do not encapsulate the specific principle of Functionalism as succinctly as Sullivan does. For instance, Frank Lloyd Wright focused on organic architecture and harmony with the environment, while Walter Gropius emphasized the integration of technology and craftsmanship in the Bauhaus tradition. Louis Kahn, on the other hand, explored the relationship between materials and architectural form, but his principles diverge from the strict functionalist viewpoint that Sullivan exemplified.