Full Idea
You lose the sense of 'should' if you go on saying 'why should I?' when you've finished the argument about what is rational to do, what you've got reason to do.
Gist of Idea
If you demonstrate the reason to act, there is no further question of 'why should I?'
Source
Philippa Foot (Interview with Philippa Foot [2003], P.34)
Book Reference
-: 'Philosophy Now' [-], p.34
A Reaction
Some people reify the concept of duty, so that they do what is required without caring about the reason. I suppose that would wither if they were shown that no reason exists.