The Principle of Proportionality Applied to Design

In law, "the concept of proportionality is used as a criterion of fairness and justice in statutory interpretation processes, especially in constitutional law, as a logical method intended to assist in discerning the correct balance between the restriction imposed by a corrective measure and the severity of the nature of the prohibited act. Within municipal (domestic) law, it is used to convey the idea that the punishment of an offender should fit the crime."

From Proportionality [wikipedia]

A beautiful design is the one that uses just the right amount of solution elements to solve a given problem.

A design that does not provide enough features to successfully solve a problem falls short on its objective as a product and and can be declared a functional failure: users can't satisfy their needs with it and need to eventually acquire another product that actually works as they hopped.

A design that provides a big and overblown solution to a minimal problem has no design credibility and is a ethical failure: users have been led to believe that they needed such a product when in reality something simpler would have sufficed. In addition to cheating users with more gaudy and expensive products, there is also the excess of product material that is unnecessary and violates the most basic fundamental sustainable design principles.

In design, the proportional law should be used to convey the idea that the magnitude of a solution should fit the problem.

Image: Powers of 10, Charles and Ray Eames