 The 1980s also saw the birth of <unk> , the first attempt to attack the commonsense knowledge problem directly , by creating a massive database that would contain all the mundane facts that the average person knows . Douglas <unk> , who started and led the project , argued that there is no <unk> <unk> the only way for machines to know the meaning of human concepts is to teach them , one concept at a time , by hand . The project was not expected to be completed for many decades . 
