What design principle promotes cohesion through shared characteristics and consistency?

The principle that promotes cohesion through shared characteristics and consistency is unity. Unity in design refers to the way different elements work together to create a sense of completeness and wholeness. This can be achieved through the use of similar colors, shapes, materials, or styles throughout a space, helping to form a cohesive aesthetic. When all elements in a design unify, it allows for a fluid and integrative experience, making the space more visually appealing and harmonious.

In contrast, the other concepts—variety, harmony, and opposition—serve different purposes in interior design. Variety introduces differences and contrast to prevent monotony, but without careful balance, it can disrupt cohesion. Harmony, while closely related to unity, focuses more on the relationship between the elements and how they complement each other, rather than on the overall sense of oneness created by unity. Opposition is a technique used to create tension and interest through contrasting elements, which is often the opposite of promoting a unified space.