Atlas record: https://www.aitimeline.dev/en/events/evt-0145/
Milestone · July 1984
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 from the brittleness of expert systems, which broke as soon as a question left the described domain, and from the conviction that learning and language understanding would not scale without a base of real-world knowledge. Cyc was to supply the shared ground that texts never state: that an object cannot be in two places at once, that you have to be awake to eat. By 1995 Lenat counted a person-century of effort and about a million hand-entered axioms, and the writing went on for decades. The project neither reached its stated goal nor was shut down; it remains the longest experiment testing that hypothesis.
Event record
- Event date
- July 1984
- Timeline date
- Event date
- Verification
- Sources gathered automatically · September 17, 2026
- Lines
- ID
- evt-0145
The project began in July 1984 at the MCC consortium; the first published account appeared in AI Magazine in 1985.
Related events
Earlier
- Related Scripts, Plans, Goals and Understanding 1977
Instead of scripts for particular situations, one general base of assertions about the world.
- Builds on AM 1976
The project grew out of the conclusion that AM stalled for want of knowledge about the world.
- Related Programs with Common Sense 1958
An attempt to carry out the advice taker programme by volume: millions of written-down assertions.
Later
- Contrasts WordNet: a dictionary arranged by meanings 1990links to this record
Two answers to the same question, begun almost together: Cyc wrote axioms about the world, WordNet took the lexicon apart. The second is the one that got used.
- Contrasts ConceptNet: common sense assembled from visitors' sentences 2004links to this record
The paper places itself beside Cyc and against it: Cyc is optimised for formalised logical reasoning and written by knowledge engineers, ConceptNet is extracted automatically from sentences typed in by visitors to a website.