EVID: A system for interactive defeasible reasoning

Web@IDSS – Argumentation-enabled Web-based IDSS for reasoning over incomplete and conflicting information

“…The new logic is comprised of facts and presumption, absolute rules and defeasible rules, and introduced another kind of weak rule known as a 'defeater'. Causey [39] developed 'EVID'; system for interactive defeasible reasoning and Johnston and Governatori [40] developed an algorithm that integrates defeasible logic into a decision support system by automatically deriving its knowledge from databases of precedents. Dr Prolog [17] is a prolog-based implementation for carrying out defeasible reasoning on the Web.…”

A review of current defeasible reasoning implementations

“…Causey states "We do not want the user to perform epistemologically irrational actions. Obviously we would not want the user to add p and notp and EVID prevents this" [16]. However, we would have to question this restriction in an automated reasoning application.…”

“…Accordingly, he has included other predicates in the EVID shell such as "howdef eatit", which shows how a currently justified conclusion can be defeated and "howgetit" to determine how a currently defeated conclusion could be obtained. EVID also allows a user to defeat any conclusion (promoting Causey's theory of the user being able to always "have the last word" [16]), either relative to particular supporting evidence, or absolutely, providing that the user does not contradict himself in so doing. Causey states "We do not want the user to perform epistemologically irrational actions.…”

“…These test cases are useful, but I do not believe that they provide very good understanding of the typical uses of defeasible reasoning in practical contexts." [16].…”

“…As already discussed Causey argued strongly against the use of "a body of simple and eclectic examples about birds and penguins etc." [16] to test defeasible reasoning systems. However, only around the start of 2001 did authors of defeasible reasoning implementation begin to discuss in depth technical techniques to improve efficiency and include comprehensive experimental results within their work.…”