A tool in modelling disagreement in law: preferring the most specific argument

applied to legal reasoning and used to formulate requirements for legal knowledge-based systems choosing between alternative arguments. It is based on a proposal of Poole, but improves it in two respects: firstly, default Iog”c is shown to be a better underlying Io@”c for defensible reasoning than standard first-order lo~-c; and secondly, specificity is defined iteratively, in order to handle muhiple conflicts and to characterize the set of prefk?red knowledge. lle theory is an example of the fact that Io@”c can be a tool in legal reasoning even if deduction is not regarded as the right way to model it,