Full Idea
No decision can be in accord with right reason unless all can agree on it.
Gist of Idea
If a decision is in accord with right reason, everyone can agree with it
Source
Richard Cumberland (De Legibus Naturae [1672], Ch.V.XLVI)
Book Reference
'British Moralists 1650-1800 Vol. 1', ed/tr. Raphael,D.D. [Hackett 1991], p.102
A Reaction
Personally I think anyone who disagrees with this should get out of philosophy (and into sociology, fantasy fiction, ironic game-playing, crime…). Of course 'can' agree is not the same as 'will' agree. You must have faith that good reasons are persuasive.