Title:   RULE RATIONALITY VERSUS ACT RATIONALITY

Speaker: ROBERT AUMANN       

Abstract: 

In moral philosophy,  "Utilitarianism" is the doctrine that people should
act so as  to maximize  the total welfare  of Society.  Two  variants are
distinguished:  "Act Utilitarianism,"  in which  each case  is considered 
separately, and "Rule Utilitarianism,"  in which rules are developed that  
maximize welfare  on the whole,  but not  necessarily  in each case.  For
example,  Raskolnikov's  murder  of  the  depraved  old  money-lender  in
Dostoyevsky's  "Crime and Punishment" is justified by act utilitarianism,
because Society  as a whole benefits if she is dead and he has her money;  
but it is not justified by  rule utilitarianism,  as it violates the rule
"thou shalt not murder," which on the whole, benefits Society.   

We  make  a parallel  distinction  between  "Act RATIONALITY"  and  "Rule
RATIONALITY."  Rather than acting to maximize INDIVIDUAL  welfare in each
separate decision,  people -- and other organisms -- develop  RULES  that    
maximize  individual welfare  on the whole,  but not necessarily  in each
separate  instance.  This is because  individual  welfare maximization is
the result more of evolutionary and learning processes  than of conscious
deliberation.  Examples will be discussed.