Marcelo Auday

Dung’s argumentation frameworks have been applied for over twenty years to the analysis of argument justification. This representation focuses on arguments and the attacks among them, abstracting away from other features like the internal structure of arguments, the nature of utterers, the specifics of the attack relation, etc. The model is highly attractive because it reduces most of the complexities involved in argumentation processes. It can be applied to different settings, like the argument evaluation of an individual agent or the case of dialectic disputes between two agents (pro and con), or even in multi-agent collective argumentation. The latter case involves agents with possibly different arguments and/or opinions on how to evaluate them, leading to the possibility of considering multiple sets of arguments and attack relations. Two basic questions can be asked here, namely ‘what to aggregate’ and ‘how to aggregate’. The former concerns what kinds of entities do the agents intend to choose (arguments, attacks, assessments, etc.), while the second one focuses on which aggregation mechanisms yield rational choices (voting on arguments, merging procedures to obtain a common argumentation framework, deliberation processes, etc.). In particular, the question about the rationality of a collective argument choice relates this topic to Social Choice and Judgment Aggregation theories, while its associated strategic issues relate it to Game Theory. The research efforts on the disparate problems elicited by collective argumentation have generated a considerable corpus of literature that deserves an orderly evaluation. This survey is intended as a contribution to that end.

The usual procedure in the theory of social choice consists in postulating some desirable properties which an aggregation procedure should verify and derive from them the features of a corresponding social choice function and the outcomes that arise at each possible profile of preferences. In this paper we invert this line of reasoning and try to infer, up from what we call social situations the criteria verified in the implicit aggregation procedure. This inference process, which extracts intensional from extensional information can be seen as an exercise in “qualitative statistics”.

We focus on the debate on the external validity of lab results in the area of experimental economics. More specifically, we focus on Colin Camerer’s and John List’s views, who postulate opposite positions on the issue. The problem is that they partially analyze the same empirical evidence and draw from it opposite conclusions. The goal of this work is to analyze such empirical evidence to try to explain the difference in interpretation of results. We argue that the dispute in interpretations can be expressed in terms of difference of criteria used to determine external validity. From our analysis we propose the formulation of different types of external validity.

Kaushik Basu presenta el dilema del viajero como un desafío a la teoría de juegos. El desafío ha sido investigado experimentalmente. Al enfrentarse a la versión de Basu del DV o similares, los participantes se comportan como sugiere Basu. Sin embargo, un pequeño cambio en el juego tiene como consecuencia revertir las tendencias de elección. La cuestión es, entonces, si es posible brindar una explicación de los principales hallazgos empíricos como consecuencias de decisiones racionales. Hay varias propuestas en la literatura pero ninguna provee una explicación satisfactoria de por qué expertos en teoría de juegos jugando entre sí usualmente rechazan la única estrategia no dominada del DV. El objetivo de este artículo es sugerir una propuesta alternativa que solucione este problema.