It's way past 2001 now, where the heck is HAL? For several decades now we've had high hopes for computers amplifying our mental abilities not just giving us access to relevant stored information, but answering our complex, contextual questions. Even applications like human-level unrestricted speech understanding continue to dangle close but just out of reach.

What's been holding AI up? The short answer is that while computers make fine idiot savants, they lack common sense: the millions of pieces of general knowledge we all share, and fall back on as needed, to cope with the rough edges of the real world. I