For quite some time, philosophers, economists, and statisticians have
endorsed a view on rational choice known as Bayesianism. The work on
this book has grown out of a feeling that the Bayesian view has come to
dominate the academic com- nitytosuchanextentthatalternative,
non-Bayesianpositionsareseldomextensively researched. Needless to say, I
think this is a pity. Non-Bayesian positions deserve to be examined with
much greater care, and the present work is an attempt to defend what I
believe to be a coherent and reasonably detailed non-Bayesian account of
decision theory. The main thesis I defend can be summarised as follows.
Rational agents m- imise subjective expected utility, but contrary to
what is claimed by Bayesians, ut- ity and subjective probability should
not be de?ned in terms of preferences over uncertain prospects. On the
contrary, rational decision makers need only consider preferences over
certain outcomes. It will be shown that utility and probability fu-
tions derived in a non-Bayesian manner can be used for generating
preferences over uncertain prospects, that support the principle of
maximising subjective expected utility. To some extent, this
non-Bayesian view gives an account of what modern - cision theory could
have been like, had decision theorists not entered the Bayesian path
discovered by Ramsey, de Finetti, Savage, and others. I will not discuss
all previous non-Bayesian positions presented in the literature
