An expert system is computer software that can handle complex issues and make decisions the same way a human expert can. It pulls knowledge from its knowledge base based on the user's queries, employing reasoning and inference procedures.
The expert system is a type of AI, and the first ES was created in 1970, making it the first successful artificial intelligence approach. An expert solves the most difficult problems by extracting knowledge from their knowledge base. Like a human expert, the system assists in complex problems by employing facts and heuristics. It is so named because it comprises expert knowledge of a certain subject and can solve any complex problem in that domain. These systems are tailored to a particular field, medicine or science.
An expert system's performance is determined by the knowledge stored in its knowledge base by the expert. The more knowledge stored in the KB, the better the system performs. When typing in the Google search box, one of the most common examples of an ES is a suggestion of spelling problems.