What is the principal idea behind "form follows function"?

The principal idea behind "form follows function" is centered on the belief that the design of a building should prioritize its intended purpose. This philosophy suggests that the shape and design of a structure should be largely determined by its function and usability, rather than purely aesthetic considerations. By focusing on how a building will be used and what activities will take place within it, architects can create spaces that are efficient, practical, and serve the needs of the occupants. This approach emphasizes a harmonious relationship between how a space looks and how it operates, advocating that the physical form should naturally evolve from the requirements of its function.

In contrast, some of the other options miss the essence of this principle. For instance, the idea that the appearance of a building is secondary to its cost does not address the relationship between form and function. Additionally, advocating for identical appearances in buildings undermines the unique responses required for different functions and contexts. Lastly, preserving architectural styles regardless of function ignores the adaptive nature of architecture, which should evolve based on the needs it serves rather than binding itself to traditional aesthetics.