Arrow's Theorem holds that no constitution can satisfy certain properties. In annex to that theorem, Arrow claims that those properties are reasonable and morally desirable. In his view there thus is the difficulty that people desire a constitution that cannot exist. While the Theorem stands as...

Fuzzy set theory has been explicitly introduced to deal with vagueness and ambiguity. One can also use probability theory or techniques borrowed from philosophical logic. In this chapter, we consider fuzzy preferences and we survey the literature on aggregation of fuzzy preferences. We restrict...

Any procedure of social choice makes use of some types of information and ignores others. For example, the method of majority decision concentrates on people's votes, but pays no direct attention to, say, their social standings, or their prosperity or penury, or even the intensities of their...