Full Idea
Asserting that the good is 'the useful', or 'what is choiceworthy for its own sake', or 'that which contributes to happiness', does not teach us what good is but states its accidental property.
Gist of Idea
Saying the good is useful or choiceworth or happiness-creating is not the good, but a feature of it
Source
Sextus Empiricus (Against the Ethicists (one book) [c.180], II.35)
Book Reference
Sextus Empiricus: 'Against the Physicists/Against the Ethicists', ed/tr. Bury,R.G. [Harvard Loeb 1997], p.403
A Reaction
This seems to be a pretty accurate statement of Moore's famous Open Question argument. I read it in an Aristotelian way - that that quest is always for the essential nature of the thing itself, not for its role or function or use.
Related Idea
Idea 11057 It is always an open question whether anything that is natural is good [Moore,GE]