Full Idea
It is the job of the philosopher to distinguish what is fact and what is convention in our theorising about the world.
Gist of Idea
The job of the philosopher is to distinguish facts about the world from conventions
Source
Hilary Putnam (Representation and Reality [1988], §7 p.112)
Book Reference
Putnam,Hilary: 'Representation and Reality' [MIT 1992], p.112
A Reaction
This may well be the entire truth about philosophy. It begins with the Nomos-Physis debate in ancient Athens, and it turns out to be the key issue in almost every area of metaphysics, epistemology, aesthetics and morality.