Abduction for (Non-Omniscient) Agents

Among the non-monotonic reasoning processes, abduction is one of the most important. Usually described as the process of looking for explanations, it has been recognized as one of the most commonly used in our daily activities. Still, the traditional definitions of an abductive problem and an abductive solution mention only theories and formulas, leaving agency out of the picture. Our work proposes a study of abductive reasoning from an epistemic anddynamicperspective,making special emphasis onnon-ideal agents. We begin by exploring what an abductive problem is in terms of an agent’s information, and what an abductive solution is in terms of the actions that modify it. Then we explore the different kinds of abductive problems and abductive solutions that arise when we consider agents whose information is not closed under logical consequence, and agents whose reasoning abilities are not complete. 1 Abductive reasoning Beyond the obvious facts that he has at some time done manual labour, that he takes snuff, that he is a Freemason, that he has been in China, and that he has done a considerable amount of writing lately, I can [get] nothing else. Sherlock Holmes The Red-Headed League Among the non-monotonic reasoning processes, abduction [1] is one of the most important. Usually described as the process of looking for an explanation, it has been recognized as one of the most commonly used in our daily activities. Observing that Mr. Wilson’s right cuff is very shiny for five inches and the left one has a smooth patch near the elbow, Holmes assumes that he (Mr. Wilson) has done a considerable amount of writing lately. Given the symptoms A and B, a doctor suspects that the patient suffers from C. Karen knows that when it rains, the grass gets wet, and that the grass is wet right now; then, she suspects that it has rained.