Why can design rules about proportion not replace a designer’s judgment?

In the fields of interior design and architecture, rules regarding proportion—such as the golden section or Le Corbusier’s Modulor—serve only as guidelines rather than absolute mandates. These rules cannot replace a designer’s judgment for several critical reasons:1

• Subjectivity and Context: Design success often relies on subjective judgment and experimentation rather than rigid laws. A designer must account for the specific human body and the unique relationship between the observer and the space, which varies based on scale and purpose.21
• Functional Expression: Modern design prioritizes the expression of a building's purpose and function over adherence to traditional, dogmatic rules. For example, while symmetry was a hallmark of the Renaissance, contemporary design recognizes that balance can be achieved through asymmetry to better serve a space's intended use.1
• Complexity and Cohesion: A successful interior requires a cohesive sequence of interrelated spaces that relate to the total architectural concept. This level of integration requires critical analysis and creative sensitivity that automated or formulaic approaches cannot replicate.13

Ultimately, design is a creative process rooted in research and analysis, where the designer’s eye is essential to achieving aesthetic unity and appropriateness.13