Moral judgments, ideas about good or bad, remain the building block of cooperation in a large group.
A rule of thumb for promoting cooperation is to help those who have a good reputation and not those who have a bad reputation, yet that determination requires time, effort and money. What about moral "free riders" who evade the cost associated with moral judgment (e.g. by not paying taxes for police and court) so are better off than those who shoulder the cost?
Philosophers debate voluntary reactive policing of the moral free riders, which is costly, too, and thus can be exploited by higher order moral free riders. This leads to an infinite regression of opportunities to free ride.
Can the moral free rider problem really be solved?