versión On-line ISSN 1851-9636
The main lines of research that Carlos Alchourrón developed in the Philosophy of Law, were connected, from the beginnings of the 80' s, to some critical problems in the Artificial Intelligence (AI). His contributions to the construction of a logic of norms were rapidly linked to automatic deduction and the Legal Expert Systems. His concerns for the conflict of obligations that could arise in a normative system when a judge has to issue a ruling taking some particular facts into account were associated in his work with the more general notion of "defeasible conditionals" and with the formalization of Non Monotonic Reasoning. But his most relevant contribution was the one derived from the search of a solution to the problem of multiple outcomes resulting from the derogation of a norm in a legal corpus, which may be considered -within an epistemic framework- analogous to the contraction of a set of beliefs. The constructive approach he worked out with David Makinson converged with Peter Gärdenfors' axiomatic, giving rise to the formulation of the theory of Rational Changes of Belief (AGM), which was adopted in AI as a model for the specification of the updates of Knowledge Bases as it usually involves a new belief that may be inconsistent with the old ones.
Palabras llave : AGM; Defeasible conditional; Non Monotonic Reasoning; Artificial Intelligence.