Full Idea
A house would be badly explained if we were to describe only the arrangement of its parts, but not its use.
Gist of Idea
To explain a house we must describe its use, as well as its parts
Source
Gottfried Leibniz (On Body and Force, Against the Cartesians [1702], p.255)
Book Reference
Leibniz,Gottfried: 'Philosophical Essays', ed/tr. Arlew,R /Garber,D [Hackett 1989], p.255
A Reaction
This must partly fall under pragmatics (i.e. what the enquirer is interested in). But function plays a genuine role in artefacts, and also in evolved biological organs.