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The Shape of Intelligence

MYCIN diagnoses infections

Shortliffe's MYCIN uses about 600 if-then rules with certainty factors to recommend antibiotics, matching specialists in blind evaluation but never used on a patient.

category
model
significance
3 of 5
people
Edward Shortliffe, Bruce Buchanan
organisations
Stanford University

what had to happen · 3 events back to 1943

Every event this one built on, transitively, in order. Direct influences are marked.

MYCIN was Edward Shortliffe's Stanford doctoral project, finished in 1974, and it is the expert system that most later ones copied. Given a patient's symptoms and laboratory results, it asked questions, applied several hundred rules of the form "if the organism is gram-positive and grows in chains, then there is suggestive evidence it is streptococcus", and recommended an antibiotic and dose. Because medical knowledge is uncertain, each rule carried a certainty factor, a number between minus one and one, and the program combined them with an algebra Shortliffe invented for the purpose.

In a 1979 evaluation, MYCIN's recommendations were judged acceptable by a panel of experts more often than those of the infectious-disease specialists it was compared with. It was never used in a clinic. Liability was unresolved, the program needed a mainframe, and physicians did not want to type answers into a terminal.

MYCIN's real product was its architecture. Separating the rules from the engine that applied them produced EMYCIN, the "empty MYCIN", and the idea of the expert-system shell, sold by the dozen in the 1980s. Its certainty factors were later shown to be a rough approximation of Bayesian reasoning, which Judea Pearl put on firm footing in 1988.

what it led to · 3 events downstream, through 1987

Built on it directly:

  1. 1980XCON goes into production at DECW1
  2. 1984Cyc sets out to write down common senseII

And, through them, by era:

W2 · The second winter · 1
  1. 1987The Lisp machine market collapses

sources · 1

See this era in the exhibition →Back to the timeline