Initial progress in symbolic reasoning was mostly discarded by the autonomous/mobile robotics community because robots usually face unpredictable environments and incomplete knowledge. As an alternative, reactive systems have taken over, heavily influenced by the works of Brooks [Brooks, 1991] and others. However, we demonstrate here an application of non-monotonic logic for the solution of localisation problems. While Plausible Logic [Billington and Rock, 2001; Rock and Billington, 2000] is implementable, we show here it is operable in real time on a Sony AIBO in the RoboCup (robotic soccer) context.