Full Idea
If it is our duty to produce one or other of two or more different states of affairs, without its being our duty to produce one rather than the another, then in such a case each of these acts will be right, and none will be our duty.
Gist of Idea
If there are two equally good acts, they may both be right, but neither a duty
Source
W. David Ross (The Right and the Good [1930], §I)
Book Reference
Ross,W.David: 'The Right and the Good' [OUP 1930], p.4
A Reaction
An elegant piece of analytical philosophy, which shows fairly conclusively that 'right' is distinct from 'duty', as well as being distinct from 'good'. We can generalise about right actions, without identifying anyone who has the duty to perform them.