Full Idea
Obligation and duty look backwards; the acts they require lie in the future, but the reasons for those acts lie in the fact that I have already promised, the job I have undertaken, the position I am already in.
Gist of Idea
Obligation and duty look backwards (because of a promise or job), although the acts are in the future
Source
Bernard Williams (Ethics and the Limits of Philosophy [1985], Ch. 1)
Book Reference
Williams,Bernard: 'Ethics and the Limits of Philosophy' [Fontana 1985], p.8
A Reaction
Maybe the central issue in morality is forwards versus backwards. It reflects two types of human temperament. Tomorrow is another day. Spilt milk.