I.  Terminology


            1.  INDIVIDUALISTICALLY RATIONAL (IR) = to Maximize One's Expected Return (Total Expected Benefits Less Total Expected Costs).  This sense of rationality is the twentieth-century development of the concept of INSTRUMENTAL RATIONALITY.  It is the notion of rationality that is employed in economics.  (Note that to be INDIVIDUALISTICALLY RATIONAL does not require that one be an egoist.)



                                                                        Everyone else







I Cooperate (C)









I Defect (D)









A Collective Action Problem

Involving A Decision to Cooperate (C) or Defect (D). 


            2.  COLLECTIVE ACTION PROBLEM = A situation in which everyone (in a given group) has a choice between two alternatives and where, if everyone involved chooses the alternative act that is Individualistically Rational (IR), the outcome will be worse for everyone involved, in their own estimation, than it would be if they were all to choose the other alternative (i.e., than it would be if they were all to choose the alternative that is not IR).



            By convention, in any Collective Action Problem, the IR alternative is referred to as "Defection" ("D"); and the non-IR alternative is referred to as "Cooperation" ("C").





In a Collective Action Problem:

(1) Consider only the outcomes in which everyone does the same thing;

(2) Define Cooperation as the alternative that would produce the best outcome (in everyone's estimation) from among the outcomes in which everyone does the same thing;

(3) Choose to Cooperate, if you have reason to believe that enough others (e.g., most others) are also willing to Cooperate.


FREERIDING.  In a Collective Action Problem in which most agents choose to Cooperate, Defectors are referred to as FREERIDERS, because they benefit from the Cooperation of others, but are unwilling to reciprocate Cooperation. 


REASONABLE (in Rawls's sense) = being willing to Cooperate on fair terms of social cooperation.  In a Collective Action Problem, a REASONABLE person will Cooperate if enough others will Cooperate also.  In a CollectiveAction Problem, a REASONABLE person would not choose to FREERIDE on the Cooperation of others, even if s/he could get away with it.  A REASONABLE person is willing to do his/her fair share in a cooperative arrangement.