The Cyc project begins
Lenat set out to write common sense down by hand: millions of assertions about what people know of the world and never say.
Why it matters
The longest bet in the field's history that brittleness is cured by volume of knowledge rather than by a new method.
The plan followed directly from AM's failure and from the brittleness of expert systems, which broke as soon as a question left the described domain. Cyc was to supply the shared ground: that water is wet, that people sleep at night, that an object is not in two places. The writing went on for decades and cost hundreds of person-years. The project neither reached its stated goal nor was shut down; it remains the longest experiment testing that hypothesis.