Fuzzy Rationality as a Basis for Group Decision Making

This paper deals with the group decision making problem, assuming that each individual defines his/her opinion through fuzzy binary preference relations, in parallel to the classical approach due to Prof. Arrow. In particular, it is postulated that the main reason for the discouraging impossibility theorems is neither in the domain of admissible preferences or in the concept of solution (Social Welfare Functions versus Social Decision Functions), but in the underlying idea of rationality under all crisp approaches: non complete irrational aggregations will be possible under a fuzzy approach, in such a way that classical Arrow's theorem should be understood just as an impossibility of getting complete rational aggregations. Kewords: aggregation rules, fuzzy opinions, fuzzy rationality, group decision making.