  As an n-prisoner’s dilemma for n ≫ 2, collective action is therefore essentially large-number exchange. Each of us exchanges a bit of effort or resources in return for benefiting from some collective provision. The signal difference is that I can cheat in the large-number exchange by free riding on the contributions of others, whereas such cheating in the two-person case would commonly be illegal, because it would require my taking from you without giving you something you prefer in return.