Full Idea
In the past 'what is right' was hardly disentangled from 'what the tribe ordains'; ..'it is the custom' has been accompanied by 'the custom is right', or 'the custom is ordained by someone who has the right to command'.
Gist of Idea
In the past 'right' just meant what is conventionally accepted
Source
W. David Ross (The Right and the Good [1930], §I)
Book Reference
Ross,W.David: 'The Right and the Good' [OUP 1930], p.12
A Reaction
Ross is rejecting this older view, in favour an absolute (and intuitively known) concept of what is right. All right-thinking people should wish Ross luck in his project, no matter how pessimistic the onlooker may be.