Exploring Practical Philosophy: From Action to Values

Dan Egonsson, Jonas Josefsson, Björn Petersson, Toni Rønnow-Rasmussen

• Publisher: Routledge
• Year: 2018
• ISBN:
  9781351815062
• Edition: 1
• Topic: Filosofía
• Subtopic: Historia y teoría filosóficas

This title was first published in 28/11/2001: The broad label 'practical philosophy' brings together such topics as ethics and metaethics as well as philosophy of law, society, art and religion. In practical philosophy, theory of value and action is basic, and woven into our understanding of all practical and ethical reasoning. New essays from leading international philosophers illustrate that substantial results in the subdisciplines of practical philosophy require insights into its core issues: the nature of actions, persons, values and reasons. This anthology is published in honour of Ingmar Persson on his fiftieth birthday.

Prioritarianism and Uncertainty

On the Interpersonal Addition Theorem and the Priority View¹

Wlodek Rabinowicz

This paper takes its point of departure from the Interpersonal Addition Theorem. The theorem, by John Broome (1991), is a re-formulation of the classical result by Harsanyi (1955). It implies that, given some seemingly mild assumptions, the overall utility of an uncertain prospect can be seen as the sum of its individual utilities. In the two sections that follow, I discuss the theorem's connection with utilitarianism and in particular the extent to which this theorem still leaves room for the Priority View. According to the latter, the utilitarian approach needs to be modified: Benefits to the worse off should count for more, overall, than the comparable benefits to the better off (cf. Parfit 1995 [1991]).

Broome (1991) and Jensen (1996) have argued that the Priority View cannot be seen as a plausible competitor to utilitarianism: Given the addition theorem, prioritarianism should be rejected for measurement-theoretical reasons. I suggest, in the third section, that this difficulty is spurious: The proponents of the Priority View would be well advised, on independent grounds, to reject one of the basic assumptions on which the addition theorem is based. I have in mind the Principle of Personal Good for uncertain prospects. If the theorem is disarmed in this way, then, as an added bonus, the Priority View disposes of the aforementioned problems with measurement.

According to the Principle of Personal Good, one prospect is better than another if it is better for everyone or at least better for some and worse for none. That the Priority View, as I read it, rejects this welfarist intuition may be surprising to the reader. Isn't welfarism a common ground for prioritarians and utilitarians? Still, as I will argue, the appearances are misleading: The welfarist common ground is better captured by a restricted Principle of Personal Good that is valid for outcomes, but not necessarily for uncertain prospects. As will become clear, we obtain this surprising result if we take the priority weights imposed by prioritarians to be relevant only to moral, but not to prudential, evaluations of prospects. This makes it possible for a prospect to be morally better (i.e. better overall), even though it is worse (prudentially) for everyone concerned. The proposed interpretation of the Priority View thus drives a sharp wedge between prudence and morality. In the fourth section, I will argue that this divergence between moral and prudential evaluations should be recognized by prioritarians even for Robinson-type cases, in which there is only one person to consider. In that section and in the preceding one, I will also contrast the prioritarian morality, on which each person's welfare makes a separable contribution to the overall good, with egalitarianism, which denies such separability.

Finally, in the last section, I will discuss some underlying conceptual commitments of my interpretation of the prioritarian view. Since this interpretation takes very seriously the distinction between uncertain prospects and uncertainty-free outcomes, it goes against the standard decision-theoretical view according to which the distinction in question is more or less provisional and motivated by practical convenience.

Interpersonal addition

Broome's Interpersonal Addition Theorem is inspired by a formally similar aggregation theorem, due to Harsanyi (1955). While Harsanyi was concerned with aggregation of individual preferences, Broome (1991) considers aggregation of individual betterness orderings.² To state his theorem, we need some preparations. Suppose we start from

• a finite set I of individuals, {i_l, ..., i_n},
• a finite partition Σ of mutually exclusive and jointly exhaustive states of nature, {S_l, ..., S_m}, where it may be uncertain which state in fact obtains,
• a set O of possible outcomes, where an outcome, intuitively, is a specification of what happens to each individual, with respect to the factors that are relevant to his/her welfare.

An (uncertain) prospect is any assignment of outcomes to the states of nature. For each possible state in Σ, a prospect specifies an outcome in O that would be realized if that state were to obtain. A prospect may be seen as a kind of lottery in which outcomes are possible prizes and the actual prize depends on which state happens to obtain. We can represent a prospect x as a vector, x = (0₁, ..., 0_m), where 0₁ is the outcome that results on this prospect if state S₁ obtains, 0₂ is the outcome that results if S₂ obtains, etc.

We assume,

• for each individual i in I, an ordering B_i of prospects that specifies, for any two prospects, which of them is better for i or whether they are equally good for that individual.

Suppose also, in addition, that prospects are comparable in an impersonal way. That is, there exists

• an ordering B of prospects that specifies, for all prospects, which of them is overall better or whether they are overall equally good.

Thus, apart from the set of individual (or personal) betterness relations on prospects, one for each individual, there is also an impersonal, or – to use another label – overall betterness relation on prospects. Note that these betterness relations on prospects indirectly order outcomes as well, since any outcome 0 may be associated with the 'safe' prospect (0, ..., 0), which assigns this outcome to each state of nature. The ordering of safe prospects induces the corresponding ordering of outcomes.

Suppose we make the following assumptions about the betterness relations on prospects:

(P1) Each personal betterness relation B_i satisfies the axioms of expected utility theory. Thus, B_i is representable by a utility function u_i on prospects and a probability distribution p. on states of nature, where u_i is expectational with respect to p_i and as such represents i's betterness relation uniquely up to positive linear transformations.

Similarly,

(P2) The overall betterness relation B satisfies the axioms of expected utility theory. Thus, B is representable by a utility function u on prospects and a probability distribution p on states, where u is expectational with respect to p and as such represents the overall betterness relation uniquely up to positive linear transformations.

That a utility function represents an ordering of prospects means that it assigns higher utility values to better prospects. It is expectational if the utility value it assigns to a prospect is the weighted sum of the utilities it assigns to its possible outcomes under various states,³ with the weights being the probabilities of the states in question. (Given appropriate axioms on the underlying ordering of prospects, the probabilities of the states are uniquely determinable from that...

Table of contents

• Cover
• Title
• Copyright
• Contents
• Preface
• Acting, Trying and Rewiring
• Rationality and Reasons
• What to Do about Dead People
• Genetic Therapy and Identity
• Hume on Himself
• Worries about Continuity, Expected Utility Theory, and Practical Reasoning
• The Resentment Argument
• Intrinsic Value and Individual Worth
• Prioritarianism and Uncertainty: On the Interpersonal Addition Theorem and the Priority View
• Virtue Ethics
• Fractal and Fragile Beauty