Professor Yoshino explains. "Shakespeare calls this a problem of ocular proof, the idea that we need to see evidence before we believe in it -- and that,oftentimes, when metaphysical questions of guilt or innocence are difficult for us to answer, we have a tendency to reduce them to questions that pertain to physical evidence.

VOA: special.2011.06.06

He says those questions became even more difficult to answer after the 9/11 attacks by a group of Sunni Arab terrorists that killed 3,000 people on American soil, and after the massive U.S.military deployments in Afghanistan and Iraq.

VOA: standard.2010.03.18