David Bau is very familiar with the idea that computer systems are becoming so complicated it’s hard to keep track of how they operate. “I spent 20 years as a software engineer, working on really complex systems. And there’s always this problem,” says Bau, a computer scientist at Northeastern University in Boston, Massachusetts.

But with conventional software, someone with inside knowledge can usually deduce what’s going on, Bau says. If a website’s ranking drops in a Google search, for example, someone at Google — where Bau worked for a dozen years — will have a good idea why. “Here’s what really terrifies me” about the current breed of artificial intelligence (AI), he says: “there is no such understanding”, even among the people building it. — Read More