Introduction: The Relevance of Rational Decision Theory for Ethics

Abstract

Rational decision theory (including rational game theory) has played important roles in more formally oriented ethics, from providing the definition of ‘utility’ in welfare ethics to much more substantial contributions, like the justification of morals in game-theoretic reconstructions of contractarian ethics. Further uses of rational decision theory in ethics include: the justification of morals by means of rational decisions in an original position; the axiomatic justification of utilitarianism; risk ethics etc. So there are many ways in which rational decision theory has actually been used in ethics. These various endeavours are rather intricate, and it is far from clear which role(s) rational decision theory should play in ethics. There is a role for empirical (psychological or economic) decision theory in ethics too. However this introduction as well as this whole issue of Ethical Theory and Moral Practice deals with rational decision theory only; therefore, the addendum “rational” in the following will often be omitted. During the last decades, several proposals have been made to justify certain systems of morals in a decision-theoretic fashion (e.g. by Harsanyi, Rawls, Gauthier, Broome); and, because of the purely formal character of rational decision theory, such proposals are held to be rather strong justifications of morals. However, as is usual in ethics, all these proposals have been contested—in part precisely because of their too formal nature. How much rational decision theory can and should contribute to ethics largely depends on which kind of justification of morals (or parts of morals) by decisiontheoretic means in the end turns out to be valid and sound. The various justificatory uses of decision theory in ethics can be ordered according to the strength of the claims these arguments try to prove. The stronger the most ambitious justificatory project that in the end turns out to be valid and sound, the more important the role of rational DOI 10.1007/s10677-010-9228-9