The project has two goals. The first is the development of a methodology for the development of expert systems in purely case oriented areas of the common law, and the second is to explore methods of evaluating legal theories, and in particular theories about legal reasoning, by testing their usefulness as basic assumptions for the construction of expert systems. One of the factors which sustained sufficient confidence to undertake research in the development of expert systems was the similarity between the way we believed that lawyers reason and the reasoning process in expert systems. The pattern of inference entailed in backward chaining is that the system starts with a goal that it wishes to achieve. It then moves back from the goal down paths of inference seeking a path to the facts which will sustain the goal.
Lawyers follow a somewhat similar pattern of inference.
They start with a specific goal such as recovery for a plaintiff in a specific cause of action. The particular cause of action such as a tort will have certain necessary conditions. The lawyer will reason back through each to discover if a particular set of facts contain all the necessary and sufficient conditions for a successful cause of action. Not only do lawyers engage in reasoning entailing patterns of inference which are remarkably similar to back chaining, but legal rules themselves are either modus ponens rules or are rules which can be put in that form. In spite of its potential fruitfulness, very little work is being done regarding building expert systems for case-based law.