Full Idea
Ross held that moral principles are self-evident to us, meaning that no more is needed to reveal their truth to us as general guides to behaviour than what is the case before us, not that we can discover a moral truth just by thinking about it.
Gist of Idea
Ross said moral principles are self-evident from the facts, but not from pure thought
Source
report of W. David Ross (The Right and the Good [1930]) by Jonathan Dancy - Intuitionism
Book Reference
'A Companion to Ethics', ed/tr. Singer,Peter [Blackwell 1993], p.412
A Reaction
This seems to be a crucial distinction between two types of intuitionism, one that is purely a priori, and one that chimes in with the 'particularist' reading of virtue theory. The former is implausible and much attacked; the latter is more interesting.