What is an inference engine primarily used for in an expert system?

An inference engine is primarily used in an expert system to conduct logical deductions. It serves as the core processing unit that applies logical rules to a knowledge base, enabling the system to reason about the data it has been provided. This ability to deduce new information or make conclusions based on existing facts is what allows expert systems to mimic human reasoning in specific domains.

For example, in a medical diagnosis system, the inference engine would analyze symptoms and existing medical knowledge to deduce possible illnesses. The strength of the inference engine lies in its capability to apply various reasoning methods—such as forward chaining and backward chaining—to arrive at conclusions or recommendations based on the rules and data provided. This essential function is what distinguishes expert systems from traditional databases or simple rule-based systems, which may not carry out sophisticated reasoning tasks.