Learning Logic Programs by Explaining Failures

Scientists form hypotheses and experimentally test them. If a hypothesis fails (is refuted), scientists try to explain the failure to eliminate other hypotheses. We introduce similar explanation techniques for inductive logic programming (ILP). We build on the ILP approach learning from failures. Given a hypothesis represented as a logic program, we test it on examples. If a hypothesis fails, we identify clauses and literals responsible for the failure. By explaining failures, we can eliminate other hypotheses that will provably fail. We introduce a technique for failure explanation based on analysing SLD-trees. We experimentally evaluate failure explanation in the Popper ILP system. Our results show that explaining failures can drastically reduce learning times.