Full Idea
In practical affairs one always follows the decision rule in accordance with which one ought to seek the maximum or the minimum: namely, one prefers the maximum effect at the minimum cost, so to speak.
Gist of Idea
We follow the practical rule which always seeks maximum effect for minimum cost
Source
Gottfried Leibniz (On the Ultimate Origination of Things [1697], p.150)
Book Reference
Leibniz,Gottfried: 'Philosophical Essays', ed/tr. Arlew,R /Garber,D [Hackett 1989], p.150
A Reaction
Animals probably do that too, and even water sort of obeys the rule when it runs downhill.