Full Idea
Thinking about right and wrong is, at the most basic level, thinking about what could be justified to others on grounds that they, if appropriately motivated, could not reasonably reject.
Gist of Idea
Right and wrong concerns what other people cannot reasonably reject
Source
Thomas M. Scanlon (What We Owe to Each Other [1998], Intro)
Book Reference
Scanlon,T.M.: 'What We Owe to Each Other' [Belknap Harvard 1999], p.5
A Reaction
The tricky bit is that the acceptance by others must be 'reasonable', so we need a reasonably objective view of rationality. Don't picture your neighbours, picture the locals when you are on holiday in a very different culture. Other Nazis?
Related Idea
Idea 21005 A human right is not plausible if public scrutiny might reject it [Sen]