He is also credited with demonstrating the non-linear relationship between psychological sensation and the physical intensity of a stimulus via the formula: S = K ln ⁡ I {\displaystyle S=K\ln I} , which became known as the Weber–Fechner law.
Han er mest kendt for at have demonstreret den ikke-lineære relation mellem psykologisk følelse og den fysiske intensitet af en stimulus via formlen: "S = K Log  I", der blev kendt som Fechners lov.