Unions are for 'collective bargaining,' not individual bargaining. It follows that most of the achievements of a union, even if they were more impressive than the staunchest unionist claims, could offer the rational worker no incentive to join; his individual efforts would not have a noticeable effect on the outcome, and whether he supported the union or not he would still get the benefits of its achievements.

THE LOGIC OF COLLECTIVE ACTION (ed. Harvard University Press, 2009) - ISBN: 9780674041660