"Game theory explained" with too many assumptions. Such as that punishment is so costly that it creates another problem of the commons, as the punishers (who ar

"Game theory explained" with too many assumptions. Such as that punishment is so costly that it creates another problem of the commons, as the punishers (who are a subset of the cooperators) get less our of it than the non-punishing cooperators. I'd say this is wrong: in repeated games punishment is not a cost but an investment. A threat must be carried out in order to be credible in the long run, and thus a cooperator who punishes a defector (or a 'joker' for that matter) is better positioned in subsequent games to be treated fairly.