Aggregation of Attack Relations: A Social-Choice Theoretical Analysis of Defeasibility Criteria

TOHMÉ, FERNANDO ABEL; BODANZA, GUSTAVO ADRIÁN

Buenos Aires

Jornada; XII Jornadas de Epistemología de las Ciencias Económicas; 2006

Facultad de Cs. Económicas UBA

This paper analyzes the aggregation of different abstract attack relations over a common set of arguments. Each of those attack relations can be considered as the representation of criterion of warrant. It is well known in the field of Social Choice Theory that if some ``fairness´´ conditions are impossed over an aggregation of preferences,  it becomes impossible to yield a result. In the case of attack relations, instead, a positive result may ensue, namely that if the class of winning coalitions in an aggregation process by pairwaise voting is a proper prefilter an outcome exists. This outcome may preserve some features of the competing attack relations, like acicylicity. The downside of this is that in fact the resulting attack relation must be a portion common to the ``hidden dictators´´ in the system, that is, all the attack relations that belong to all the winning coalitions.