ThoughtTreasure is a commonsense knowledge base and architecture for natural language processing. It contains both declarative and procedural knowledge.
ThoughtTreasure was begun by Erik Mueller in December 1993. The first version was released on April 28, 1996. Mueller established the company Signiform in 1997 to pursue commercial applications of ThoughtTreasure. However, the company was unsuccessful and Signiform closed its doors in 2000. No further development of ThoughtTreasure has been released since then. In 2000, Erik Mueller moved to IBM Research, where he was a member of the team that developed Watson.