Alchourr'on's Defeasible Conditionals and Defeasible Reasoning

this paper will be devoted to showing that Alchourr'on's defeasible conditionals are a cumbersome way to handle defeasibility: these conditionals hide defeasibility's essential procedural aspects, and relegate them to a mere clerical task of explicitating the consequences of the choices made by an external agent. We aver that defeasible reasoning is more than that: it is a process of deliberation that provides constructive justifications and avoids the struggle with complexity, simply because every partial justification counts. More computation may lead to the defeat of a previously justified conclusion. Defeasible reasoning is an open process, where the notions of entscheidung or completeness are no longer relevant. Their importance is overthrown by the relevance of criteria for efficient adjudication. So it seems paradoxical that, the representation of legal reasoning being his main goal, Alchourr'on chose the logical approach instead of defeasible reasoning. In the following sections we will briefly introduce both approaches, in order to compare them and to show why the Zeitgeist favors defeasible reasoning. 2 A Logic for Defeasible Conditional