Full Idea
Any attempt to provide a social justification of morality runs the risk of the 'free rider' - one who pretends to play the game in order to enjoy the fruits of it.
Gist of Idea
Any social theory of morality has the problem of the 'free rider', who only pretends to join in
Source
Roger Scruton (Modern Philosophy:introduction and survey [1994], 20.6)
Book Reference
Scruton,Roger: 'Modern Philosophy: introduction and survey' [Sinclair-Stevenson 1994], p.291