Showing papers by "Isaac Levi published in 1995"

Desire-as-belief implies opinionation or indifference

Abstract: Rationalizations of deliberation often make reference to two kinds of mental state, which we call belief and desire. It is worth asking whether these kinds are necessarily distinct, or whether it might be possible to construe desire as belief of a certain sort belief, say, about what would be good. An expected value theory formalizes our notions of belief and desire, treating each as a matter of degree. In this context the thesis that desire is belief might amount to the claim that the degree to which an agent desires any proposition A equals the degree to which the agent believes the proposition that A would be good. We shall write this latter proposition 'A"' (pronounced 'A halo'). The Desire-as-Belief Thesis states, then, that to each proposition A there corresponds another proposition A0, where the probability of A0 equals the expected value of A. In 'Desire as Belief', David Lewis presented an argument against this anti-Humean proposal.1 Lewis proved that, on pain of triviality, the Desire-as-Belief Thesis cannot be added to the axioms of expected value theory. Our aim in this paper is to present a simpler proof of Lewis's result. The proof we shall give makes clear that the result is a purely synchronic one that depends in no way on the properties of Jeffrey conditionalization or any other revision method. We shall start by presenting a version of expected value theory like the one developed by Richard Jeffrey [2]. Let X be a Boolean algebra of propositions, with greatest and least elements T and F. An expected value model on X is a set .NM of pairs (P, V), where each P is a probability function over X, and each V is an expected value function defined over X {F}. Each pair (P, V) represents a potential state of belief and desire for the agent. The pairs must satisfy the following four axioms:

Perception as Input and as Reason for Action

Abstract: John McDowell (1979) suggests that virtuous agents have a perceptual sensitivity allowing them to determine reliably what to do in any specific context of deliberation. Moreover, the reliable perception yields an accurate depiction not only of the facts of the situation but of the morally right act to do. Finally, the reliably kind behavior of a kind personis not the outcome of a blind, non-rational habit or instinct, like the courageous behaviour- so called only by courtesy- of a lioness defending her cubs. Rather, that the situation requires a certain sort of behaviour is … his reason for behaving in that way, on each of the relevant occasions (331). Perception delivers a reason for action.