(Disclaimer: everything in this w/u is drawn from my imperfect human memory, from a magazine article I read over ten years ago. YMMV)
CYC (named from enCYClopedia) was an AI knowledge base whose developers were teaching it much in the way one would teach a human child - by teaching it facts and relationships, and how to build them together. The most memorable line from the article was the conclusion drawn by CYC when presented with the fact of Napoleon's death, "Wellington was saddened."