Origins of Fair Play

1. Origins ofFair Play Ken Binmore k.binmore@ucl.ac.uk

3. John Mackie’sInventing Right and Wrong Metaphysical moral philosophy is unsound. Look instead at: Anthropology Game theory

4. Social Contracts The social contracts of pure hunter-gatherer societies have two universal properties: No bosses Fair division

5. Pure hunter-gatherers

6. Toy games Adam’s strategies dove dove hawk hawk Prisoners’ Dilemma Stag Hunt

7. Toy games Eve’s strategies dove hawk dove hawk Prisoners’ Dilemma Stag Hunt

8. Toy games Adam’s payoffs dove hawk dove hawk dove dove 4 2 0 0 hawk hawk 3 3 1 2 Prisoners’ Dilemma Stag Hunt

9. Toy games Eve’s payoffs dove hawk dove hawk 2 3 4 3 dove dove 0 1 0 2 hawk hawk Prisoners’ Dilemma Stag Hunt

10. Toy games dove hawk dove hawk 2 3 4 3 dove dove 2 0 4 0 0 1 0 2 hawk hawk 2 3 1 3 Prisoners’ Dilemma Stag Hunt

11. Nash Equilibria dove hawk dove hawk 2 3 4 3 dove dove 2 0 0 4 0 0 1 2 hawk hawk 3 3 1 2 Prisoners’ Dilemma Stag Hunt

12. Coordination Games left right box ball 0 1 1 0 left box 0 1 0 2 0 0 1 2 right ball 0 0 1 1 Battle of the Sexes Driving Game

13. Reciprocal Altruism 2 3 2 3 2 0 2 3 2 0 1 0 2 0 2 3 1 0 3 1 2 0 2 0 3 1 3 1 2 0 0 1 3 1 indefinitely repeated Prisoners’ Dilemma 3 0 1 1 3 1

14. Reciprocal Altruism d 2 3 2 3 2 0 2 3 2 0 1 0 2 0 2 3 d h h 1 0 3 1 2 0 2 0 3 1 3 1 2 0 0 1 3 1 3 0 1 1 Grim strategy 3 1

15. Reputation and Trust Sure I trust him. You know the onesto trust in this business. The oneswho betray you, bye-bye.

16. Vampire bats share blood on a reciprocal basis to insure each other against hunger.

17. Folk Theorem Eve’spayoff efficientequilibria currentstatus quo 0 Adam’spayoff

18. Equilibrium selection Fairness is evolution’s solution tothe equilibrium selection problem.

19. Equilibrium selection Fairness is evolution’s solution tothe equilibrium selection problem. Fairness therefore evolved as a means of balancing power---not as a substitute for power.

20. Deep structure of fairness norms As with language, fairness has adeep structure that is universal in the human species. This deep structure is embodied in Rawls’ original position

21. John Rawls’ original position Veil of ignorance Comparison of welfare Enforcement

22. I might be Adam and Oskar might be Eve. Or Oskar might be Adam and I might be Eve Adam Eve Original Position Oskar John

23. implicit insurancecontracts implicit insurancecontracts deep structure of fairness?

24. implicit insurancecontracts deep structure of fairness? original position original position

25. implicit insurancecontracts Who is right? original position externalenforcement self-policing utilitarianism egalitarianism Harsanyi Rawls

26. Modern Equity Theory What is fair … is what is proportional. Aristotle Eve slope is ratio of the players’context-dependentsocial indices status quo Adam 0

27. implicit insurancecontracts original position cultural evolution externalenforcement self-policing utilitarianism egalitarianism standard ofinterpersonal comparison

28. Utilitarianism and Egalitarianism Eve’spayoff utilitarian outcome egalitarian outcome . state of nature . . Adam’spayoff 0 The slopes are determined by the standard of interpersonal comparison.

29. Utilitarianism and Egalitarianism Eve’spayoff utilitarian outcome egalitarian outcome . . . Adam’spayoff 0 The slopes are determined by the standard of interpersonal comparison.

30. Utilitarianism and Egalitarianism Eve’spayoff utilitarian outcome egalitarian outcome . . Adam’spayoff 0 The slopes are determined by the standard of interpersonal comparison.

31. Utilitarianism and Egalitarianism Nash bargaining solution . . 0 The slopes are determined by the standard of interpersonal comparison.

32. Cultural Evolution: Egalitarian Case Nash bargaining solution . egalitarian solution . . 0 short-run present medium-run past

33. Analogy with language Chomsky discovered that all languages have a deep structure which is universal in the human species, but the particular language spoken in a society is determined by its cultural history. Fairness norms similarly have a common deepstructure, but the standard of interpersonal comparison that is necessary as an input to theoriginal position is culturally determined.

34. Moral relativism • Need • Ability • Effort • Status Social indices always respond to these parameters in the same way, but the degree of response varies with a society’s cultural history.

35. Reform?