Microsoft co-founder Paul Allen has been pondering artificial intelligence since he was a kid. In the late '60s, eerily intelligent computers were everywhere, whether it was 2001's HAL or Star Trek's omnipresent Enterprise computer. As Allen recalls in his memoir, "machines that behaved like people, even people gone mad, were all the rage back then." He would tag along to his father's job at the library, overwhelmed by the information, and daydream about "the sci-fi theme of a dying or threatened civilization that saves itself by finding a trove of knowledge." What if you could collect all the world's information in a single computer mind, one capable of intelligent thought, and be able to communicate in simple human language?

Forty years later, with nearly 9 billion dollars to Allen's name, that idea is beginning to seem like more than just fantasy. Much of the technology is already here. We talk to our phones and aren't surprised when they talk back. A web search can answer nearly any question, undergirded by a semantic understanding of the structure of online information. But while the tools are powerful, the processes behind them are still fairly basic. Siri only understands a small subset of questions, and she can't reason, or do anything you might call thinking. Even Watson, IBM's Jeopardy champ, can only handle simple questions with unambiguous phrasing. Already, Google is looking to the Star Trek computer as a guiding light for its voice search — but it's still a long way off. If technology is going to get there, we'll need computers that are better at talking and, more crucially, better at reasoning.