Academia.eduAcademia.edu

Which preferences shall be the basis of rational decision

1998, Preferences. Berlin; New York: de Gruyter

Abstract

Theories of rational decision normally distinguish basic and other preferences, using only the former for calculating the utility function of an agent. The idea behind the distinction is that, on the one hand, a theory of rational decision must allow criticism of at least a part of the agent's actual preferences; on the other hand, so as not to lose touch with the agent's real interests, it must rely on his factual preferences. Different decision theories have declared as basic various sets of preferences, thereby arriving at very different utility functions. Therefore, the question of which preferences shall be basic is of large practical importance. Nonetheless, it has rarely been discussed.

Key takeaways

  • Every theory of rational decision distinguishes a certain utility (or desirability) function which is basic at least relative to that theory, and an expected utility (or desirability) function which is derived from the basic utility and the subjective probability function of the agent.
  • Jeffrey sets aside the difference between desirability and estimated desirability for normal objects of a valuation, and considers all desirabilities as estimated ones; the argument for this view is that any object a of valuation can be split up into the parts a&b and a&¬b from which the estimated desirability of a can be calculated by means of the probability-weighted average (Jeffrey (1983), p. 87).
  • In fact, internal desirabilities can be dependent on the circumstances, and sometimes are: E. g. for me personally, my being in a good mood has a positive internal desirability; but this desirability differs according to whether or not this good mood has occurred naturally, or if it has occurred as a result of taking drugs; in the latter case the desirability is lower.
  • The amount of intrinsic desirability of all the objects is a sum of intrinsic desirabilities of a set of objects with the following features: the set must, in a certain way, include all the objects having an intrinsic desirability and accompanying p; but these objects in pairs may not overlap like the objects p&q and q&r would overlap; otherwise the overlapping parts would be counted twice.
  • Both conditions, uniqueness and additivity, in a weaker form are also required for the preferential basis of intrinsic desirabilities: AQPB10, AQPB11: Uniqueness and additive coherence of the preferential basis: The desirability functions taken as preferential basis for the intrinsic desirability must be such that there is an interpretation of them not garbling their underlying intention and fulfilling the following conditions: 1.