Editing Expert system (section)

{{Short description|Computer system emulating the decision-making ability of a human expert}}
[[File:Symbolics3640 Modified.JPG|200px|thumbnail|right|A [[Symbolics]] 3640 [[Lisp machine]]: an early (1984) platform for expert systems]]

In [[artificial intelligence]] (AI), an '''expert system''' is a computer system emulating the decision-making ability of a human [[expert]].<ref name="Jackson1998">{{cite book |last1=Jackson |first1=Peter |year=1998 |title=Introduction To Expert Systems |publisher=Addison Wesley |edition=3 |isbn=978-0-201-87686-4 |page=2}}</ref>
Expert systems are designed to solve complex problems by [[Automated reasoning system|reasoning]] through bodies of knowledge, represented mainly as [[Rule-based system|if–then rules]] rather than through conventional [[procedural programming]] code.<ref>{{cite web |url=https://www.pcmag.com/encyclopedia_term/0,2542,t=conventional+programming&i=40325,00.asp |title=Conventional programming |publisher=Pcmag.com |access-date=2013-09-15 |archive-date=2012-10-14 |archive-url=https://web.archive.org/web/20121014124656/http://www.pcmag.com/encyclopedia_term/0%2C2542%2Ct%3Dconventional+programming%26i%3D40325%2C00.asp |url-status=dead}}</ref>  Expert systems were among the first truly successful forms of AI software.<ref name="Simon & Schuster">{{cite book |last1=Russell |first1=Stuart |last2=Norvig |first2=Peter |title=Artificial Intelligence: A Modern Approach|date=1995 |publisher=Simon & Schuster |isbn=978-0-13-103805-9 |pages=22–23|url=http://stpk.cs.rtu.lv/sites/all/files/stpk/materiali/MI/Artificial%20Intelligence%20A%20Modern%20Approach.pdf|access-date=14 June 2014 |archive-url=https://web.archive.org/web/20140505045226/http://stpk.cs.rtu.lv/sites/all/files/stpk/materiali/MI/Artificial%20Intelligence%20A%20Modern%20Approach.pdf |archive-date=5 May 2014|url-status=dead}}</ref>{{sfn|Luger|Stubblefield|2004|pp=227–331}}{{sfn|Nilsson|1998|loc=chpt. 17.4}}{{sfn|McCorduck|2004|pp=327–335, 434–435}}{{sfn|Crevier|1993|pp=145–62, 197−203}} They were created in the 1970s and then proliferated in the 1980s,<ref name="durkinhistory">{{cite book |first= Cornelius T. |last= Leondes |title=Expert systems: the technology of knowledge management and decision making for the 21st century |year=2002 |isbn=978-0-12-443880-4 |pages=1–22}}</ref> being then widely regarded as the future of AI — before the advent of successful [[artificial neural network]]s.<ref>{{Cite news |date=2024-07-16 |title=A short history of AI |url=https://www.economist.com/schools-brief/2024/07/16/a-short-history-of-ai|access-date=2024-08-14 |newspaper=[[The Economist]]|language=en}}</ref>
An expert system is divided into two subsystems: 1) a ''[[knowledge base]]'', which represents facts and rules; and 2) an ''[[inference engine]]'', which applies the rules to the known facts to deduce new facts, and can include explaining and debugging abilities.