RALPH-MEA's reasoning is guided by the Maximum Expected Utility (MEU) principle. This principle can be summarized as "Do the Right Thing". Each execution architecture produces its own plan according to its own knowledge types. In particular, the Action-Utility and the Decision-Theoretic architectures utilize an MEU function to evaluate the best actions given knowledge of current and future states. The meta-level arbitrator evaluates the expected utility of action, planning and replanning . The architecture that is chosen by the meta-level arbitrator to provide the plan for a designated task in the current state can create the highest quality plan (i.e. with the most desirable long-term effects) within the evaluated time constraints.
Go to a discussion of this property for multiple architectures.