AUSTIN, Texas (AP) -- Day after day since 1984, teams of programmers, linguists, theologians, mathematicians and philosophers have plugged away at a $60 million project they hope will transform human existence: teaching a computer common sense.

They have been feeding a database named Cyc 1.4 million truths and generalities about daily life so it can automatically make assumptions humans make: Creatures that die stay dead. Dogs have spines. Scaling a cliff requires intense physical effort.

Though some critics question the potential of this painstaking effort, the inventors believe Cyc will form the brains of computers with supercharged reasoning abilities -- which could help us work more efficiently, make us understand each other better and even help us predict the previously unforeseeable.

Cyc (pronounced "psych") has already helped Lycos generate more relevant results on its Internet search engine. The military, which has invested $25 million in Cyc, is testing it as an intelligence tool in the war against terrorism. Companies use Cyc to unify disparate databases and are examining a new application that warns when computer networks have vulnerabilities hackers can exploit.

This spring, the developers' company, Cycorp Inc., sent their 18-year-old creation off for some higher education, creating a Web link to let the public download Cyc's knowledge base and teach it things, too.

Cycorp's founder and president, Doug Lenat, believes that if enough people log in to share more of the world's collective wisdom, Cyc quickly will become vastly more useful.

For now, Cyc is just a few hundred megabytes that can be stored on a single CD. Someday, Lenat envisions it becoming standard equipment in computers or being placed on a network server to fuel dozens of applications. It could annotate e-mails to put them in better context for their recipients, serve as an instant language translator, even offer humans advice from varying points of view.

"This is the most exciting time we've ever seen with the project. We stand on the threshold of success," Lenat, 51, said recently in Cycorp's offices in a quiet Austin complex. "What people are able to do on a day-by-day basis could be dramatically increased if we are successful."

Such hopes are not new in artificial intelligence, which has to date produced far more disappointment than marvel.

As early as the 1940s, researchers envisioned computers that could hold vast amounts of knowledge, learn from experience and reason for themselves. The fantasy was most famously depicted by HAL, the talking computer that operates a spaceship but turns murderous in "2001: A Space Odyssey."

While early artificial intelligence showed promise, it was of limited use beyond specific tasks.

One 1970s program helped doctors diagnose kinds of meningitis by asking for details about a patient's condition. But the program also would determine that a burned-out car had meningitis, because it had no way of knowing that was ridiculous.

Other programs would fail to find anything wrong with a database entry that showed a 25-year-old with 20 years of job experience.

The problem is that computers are programmed with a series of ironclad statements, and human speech is full of nuance and ambiguity.

When someone says, "Mary and Sue are sisters," we know she probably means the two are siblings. A computer can be taught to understand that, but without proper programming, it might also think "Mary and Sue are mothers" means they are each other's mothers.

In 1983, when Lenat was a professor at Stanford University and a researcher for Atari, he decided artificial intelligence would go nowhere unless someone took the time to create a catalog of common sense that would let a computer recognize absurdities as well as humans can.

With colleagues at Microelectronics Computer Corp., a technology research consortium, Lenat began creating Cyc in 1984.

By typing messages in CycL, a programming language created especially for Cyc, Lenat's team first taught it that there are things in the world, and that some are individual (such as the Parthenon) and others are collections (historic sites).

The programmers eventually took chunks of text and thought about every assumption the author knew readers would make. Upon reading something about how the Duke of Wellington was moved by Napoleon's death, the programmers decided to tell Cyc it could assume Wellington outlived Napoleon, knew him when he was alive, heard about his death -- and so on.

The goal was not just to fill Cyc with straightforward facts but to "generalize as much as possible until further generalization would be false," Lenat said.

The result is that if you ask Cyc whether Lassie has a nose, it would reason that Lassie is a collie, collies are dogs, dogs are macroscopic vertebrates and macroscopic vertebrates have noses, so yes.

The researchers also told Cyc to ask questions if it decides it needs more clarity about a concept.

In 1986 Cyc asked whether it was human. That same year it asked whether any other computers were engaged in such a project.

Lenat's team taught Cyc to make sure everything it was told conformed with everything it already knew -- a protection that should keep Cyc from being filled with erroneous information during its public education, which for now is possible only on computers with the Linux operating system.

Already its knowledge appears wide-ranging. Ask Cyc whether al-Qaida might possess anthrax, and it will tell you it presumes you are not referring to the heavy-metal band Anthrax.

Cycorp was spun off in 1994 into a privately held company, although an atypical one. Rather than distract the 60 employees -- known as Cyclists -- from their mission to make Cyc a gift to the world, Cycorp makes no sales calls, no pitches to investors, no press releases.

Even so, Lenat says Cycorp has been profitable from inception, funded by the government, private investors and side projects such as the Lycos search-engine deal, which ended last year.

Cyc's job at Lycos was to make sense of ambiguous search results. If a user entered "vets," Cyc would ask whether he meant veterinarians or veterans and then have appropriate follow-up questions.

Amusingly, the Lycos stint provided Cyc with an adolescence, because it learned about sex-related terms users typed into the search engine. Cyc's programmers taught it that certain things in the world are salacious and shouldn't be mentioned in everyday applications.

The job ended because of turnover at Lycos after it was bought by Terra Networks. Cyc showed promise and could be brought back, though it can't improve search engines all by itself, said Tom Wilde, Terra Lycos' general manager of search services. Still needed before searching can get smarter, he said, are other technologi