# Gossen's laws

Gossen's laws, named for Hermann Heinrich Gossen (1810–1858), are three laws of economics:

${\displaystyle {\frac {\partial U/\partial x_{i}}{p_{i}}}={\frac {\partial U/\partial x_{j}}{p_{j}}}\,\forall \left(i,j\right)}$
where
• ${\displaystyle U}$ is utility
• ${\displaystyle x_{i}}$ is quantity of the ${\displaystyle i}$-th good or service
• ${\displaystyle p_{i}}$ is the price of the ${\displaystyle i}$-th good or service
• Gossen's Third Law is that scarcity is a precondition for economic value.

The citation referenced is the translation by Nicholas Georgescu-Roegen in which the translator names only two laws: 1) ”If an enjoyment is experienced uninterruptedly, the corresponding intensity of pleasure decreases continuously until satiety is ultimately reached, at which point the intensity becomes nil." and, 2) "A similar decrease of the intensity of pleasure takes place if a previous enjoyment of the same kind of pleasure is repeated. Not only does the initial intensity of pleasure become smaller but also the duration of the enjoyment becomes shorter, so that satiety is reached sooner. Moreover, the sooner the repetition, the smaller becomes the initial intensity as well as the duration of the enjoyment." (p.lxxx)