Expert System

An expert system is an AI program designed to solve a bounded class of problems using a knowledge base and an inference engine. Specialists encode facts, relationships, and if–then rules, while the inference process applies those rules to a user’s case and may explain how it reached a recommendation. Expert systems were widely used before modern machine learning and remain useful where decisions must follow explicit, auditable logic. They do not automatically learn from data unless combined with other methods, and maintaining the rule base can become difficult as a domain changes. Their reliability depends on complete knowledge, conflict handling, and clear boundaries for cases requiring human judgment.