Randi on proving negatives, reindeer and the World Trade Center.
Video courtesy of JREF on YouTube.
I would query Randi on one issue from the talk though: the ability to prove a negative.
Here’s an interesting article from Steven D Hales, however, who asserts you can prove a negative.
Or as Stephen Law has eloquently written:
“You can prove a negative in fact (after all “you can’t prove a negative” is a negative, so, if true, unprovable).”
Skeptic News | 
Mark | Friday, 6 November, 2009
By Tracy King, Friday, 6 November, 2009 @ 12:34
Richard Wiseman had an even more succinct rebuttal of the claim “you can’t prove a negative”, simply replying “prove it”.