It is argued in this paper that amalgamating confirmation from various sources is relevantly different from social-choice contexts, and that proving an impossibility theorem for aggregating confirmation measures directs attention to irrelevant issues.

This paper provides a philosophical critique of social choice theory insofar as it deals with the normative evaluation of voting and voting rules. I will argue that the very method of evaluating voting rules in terms of whether they satisfy various conditions is deeply problematic because introducing strategic behaviour leads to a violation of any condition that makes a difference between voting rules. I also argue that it is legitimate to make interpersonal comparisons of utilities in voting theory. Combining a (...) realistic account of voters’ behaviour with a utilitarian evaluation of the outcomes then leads to the judgment that strategic voting is beneficial. If it is, then Arrow's theorem does not have far-reaching consequences for democracy because one of its conditions is not normatively acceptable. (shrink)

We characterize seniority rules, also known as lexical dictatorships, under weak consistency constraints on the group’s choice function. These constraints are base triple-acyclicity in the case of binary choices and rationalizability (although not rationality) in the case of choices between an arbitrary number of alternatives. Existing results on these weakened constraints remain silent on the treatment of the group’s most junior individuals and therefore do not yield a complete characterization of seniority rules. We also impose a universal domain, binary strict (...) Pareto optimality, binary Pareto indifference, binary independence of irrelevant alternatives, and the newly introduced condition of conflict resolution. The latter condition requires a social choice rules not to remain indecisive between alternatives for which individuals have conflicting preferences. (shrink)

This paper aims to reexamine the axiom of the independence of irrelevant alternatives in the theory of social choice. A generalized notion of independence is introduced to clarify an informational requirement of binary independence which is usually imposed in the Arrovian framework. We characterize the implication of binary independence.

Kirjasymposio Eerik Lagerspetzin Social Choice and Democratic Values – kirjasta. Kenneth Arrowia seuraten Lagerspetz pitää sosiaalisen valinnan teorian suurimpana vahvuutena sitä, että sen tuloksia voidaan käyttää monissa erilaisissa yhteyksissä. Minä taas pidän teorian suurimpana heikkoutena sen vaikeutta: tutkijat eivät ole päässeet yhteisymmärrykseen erityisesti ns. epärelevanttien vaihtoehtojen riippumattomuusehdon tulkinnasta ja muotoilusta. Lagerspetz hyväksyy kirjassaan nähdäkseni seuraavat väitteet: kaikki demokraattiset äänestyssäännöt rikkovat riippumattomuusehtoa, mutta että tuo ehto on silti normatiivisesti perusteltu. Arrow’n ehdot ovat intuitiivisesti ottaen hyväksyttävissä. Koska riippumattomuusehdon rikkoutumisesta seuraa strategista äänestämistä (...) ja strateginen äänestäminen on normatiivisesti katsottuna ei-toivottavaa tai jopa moraalisesti kyseenalaista, strategisen äänestämisen poissulkeminen olisi paras mahdollinen argumentti riippumattomuusehdon puolesta. Lisäksi säännöt jotka toteuttavat riippumattomuusehdon ovat immuuneja strategiselle käyttäytymiselle. Hyvin toimiva äänestyssääntö luo puhtaasti mekaanisen yhteyden yksilöiden mielipiteiden ja kollektiivisen valinnan välille. Tämän kirjoituksen ensisijainen tavoite on kumota jokainen edellisessä kappaleessa esitetty väite. (shrink)

Arrow's Independence of Irrelevant Alternatives (IIA) has been under criticism for decades for not taking account of preference intensities. Computer-simulation results by Aki Lehtinen concerning strategic voting under various voting rules show that this intensity argument does not need to rest on mere intuition. Voters may express intensities by voting strategically, and that this has beneficial aggregate-level consequences: utilitarian efficiency is higher if voters engage in strategic behaviour than if they always vote sincerely. Strategic voting is thus unambiguously beneficial under (...) a utilitarian evaluation of outcomes. What has been considered the main argument for IIA turns out to be one against it. This paper assesses the implications of these results for interpretations of Arrow's theorem and the Gibbard-Satterthwaite theorem in a discussion on the methodological and philosophical arguments concerning preference intensities and IIA. (shrink)