Osama’s voice on tape proves that the leader of al Qaeda is still alive. Or does it? “On January 4, Al Jazeera broadcast yet another audio tape purported to be from Osama bin Laden, in which he exhorted his followers to ‘continue the jihad.’ The voice referred to the capture of Saddam Hussein, proving the tape was recent. An anonymous CIA official confided to the New York Times: ‘It is likely the voice of Osama bin Laden.’ In an interview with CBS, Homeland Security Secretary Tom Ridge agreed.

I pronounced bin Laden dead in my May 2002 and September 2002 columns. Am I ready to retract this claim, and to pay off several bets I made back then? No, not yet. I think Osama bin Laden is still dead. And I don’t think I’m just being stubborn. To understand my logic, consider the following three issues: the state of the antiterrorism effort, the technology of voice identification, and the most likely alternative hypothesis that could explain the audio tape.”

— Richard Muller (a security consultant and Berkeley physicist), MIT Technology Review