Consiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle Richerche

Internal consistency of choice has been a central concept in economics, decision theory, and social choice. This idea is essentially confused. We cannot determine whether a choice function is consistent without referring to something external to choice (e.g., objectives, values). The standard results have to be reexamined in this light. Kenneth J. Arrow's general possibility theorem is extended in this paper without demanding any internal consistency of social choice or any notion of 'social rationality.'

Recent developments in social theory are critically surveyed in the light of a categorization of interpersonal aggregation problems into four distinct types that seem to require varying treatment but typically do not receive it. Informational inadequacy of the usual social framework is discussed in this context. A fairly thorough exploration of the correspondences between consistency conditions for functions and regularity properties of the binary relation of preference leads to a re-examination of the class of impossibility results in social theory, necessitating reinterpretations of various theorems (including Arrow's). SOCIAL CHOICE THEORY is concerned with relationships between individuals' preferences and social choice (Fishburn (1973, p. 3)). But a great many problems fit this general description and they can be classified into types that are fundamentally different from each other. It can be argued that some of the difficulties in the general theory of social arise from a desire to fit essentially different classes of group aggregation problems into one uniform framework and from seeking excessive generality. An alternative is to classify these problems into a number of categories and to investigate the appropriate structure for each category. In a small way, this is what will be done in this paper, and some of the recent developments in the theory of social will be examined in that light.

[Regularity conditions in social welfare analysis can be seen as ways of making specific types of information "inadmissible" in welfare judgements: the evaluation is made invariant with respect to information of those types. In this sense, these conditions--often reflecting "principles" of judgement--serve also as informational constraints. In this lecture alternative approaches to social welfare evaluation are examined in this light. The analysis covers both Arrovian and Bergson--Samualsonian social welfare functions as well as principles underlying utilitarianism, Rawlsian conception of justice, notions of liberty and egality, and "historical" theories of rights and entitlements (e.g., Marx or Nozick).]

The primary aim of this paper is to propose a new measure of poverty, which should avoid some of the shortcomings of the measures currently in use. An axiomatic approach is used to derive the measure. The conception of welfare in the axiom set is ordinal. The information requirement for the new measure is quite limited, permitting practical use.

[The object of this paper is to provide a systematic treatment of aggregation of individual welfare as a basis for social preference. Two polar cases of interpersonal comparability seem to have received all the attention in the literature so far. Either it is assumed that individual welfare measures are fully comparable, e.g., in Marshall [12], or that they are not comparable at all, e.g., in Robbins [15]. It is clear, however, that we frequently make judgments that are not consistent with noncomparability but which do not require full comparability. Part of the object of this paper is to examine the formal basis of such judgements and to develop a continuum of intermediate assumptions.]

Nobel Prize winner Amartya Sen's first great book, now reissued in a fully revised and expanded second edition 'Can the values which individual members of society attach to different alternatives be aggregated into values for society as a whole, in a way that is both fair and theoretically sound? Is the majority principle a workable rule for making decisions? How should income inequality be measured? When and how can we compare the distribution of welfare in different societies?' These questions, from the citation by the Swedish Academy of Sciences when Amartya Sen was awarded the Nobel Memorial Prize in Economics, refer to his work in Collective Choice and Social Welfare, the most important of all his early books. Originally published in 1970, this classic work in welfare economics has been recognized for its ground-breaking role in integrating economics and ethics, and for its influence in opening up new areas of research in social choice, including aggregative assessment. It has also had a large influence on international organizations, including the United Nations, particularly in its work on human development. In its original version, the book showed that the 'impossibility theorems' in social choice theory-led by the pioneering work of Kenneth Arrow-need not be seen as destructive of the possibility of reasoned and democratic social choice. Sen's ideas about social choice, welfare economics, inequality, poverty and human rights have continued to evolve since the book's first appearance. This expanded edition, which begins by reproducing the 1970 edition in its entirety, goes on to present eleven new chapters of new arguments and results. As in the original version, the new chapters alternate between non-mathematical chapters completely accessible to all, and those which present mathematical arguments and proofs. The reader who prefers to shun mathematics can follow all the non-mathematical chapters on their own, to receive a full, informal understanding. There is also a substantial new introduction which gives a superb overview of the whole subject of social choice.