I look at him. He's Biden in flesh, word, and spirit. What more is there to prove? You think it's easy to prove, then prove he is not Biden. And I mean "prove," not just quibble about earlobes (you types don't seem to grasp the idea that some earlobes are intermediate---or that plastic surgery can result in "tucking") or eye color (which can vary with individuals depending on lighting---my own eyes have a color that is difficult to describe).