ABSTRACT
In everyday life people hold beliefs with varying degrees of confidence and
uncertainty. Consider, for example, “If Zoe marks the coursework, it will be
turned around in time”. Perhaps in previous years Zoe marked many essays
within the deadline, but this year there is twice the normal number, so
we cannot be certain. We hold the belief with a reasonably high degree of
confidence, but not with absolute certainty. We can use probability as a
proxy to represent this degree of belief, e.g., .85 to express high confidence.
Moreover, the sentence bears clear psychological value, or utility: the outcome, meeting the marking deadline, is a desirable one. By and large these
two parameters, utility and probability, are the same parameters that drive
decision making.
