'This is extraordinary evidence I have with me,' Collins insisted.

That's a pretty extraordinary claim, and as we all know, extraordinary claims require extraordinary evidence.

Carl Sagan once said that "extraordinary claims require extraordinary evidence."

"Extraordinary claims require extraordinary evidence, and all the systematics have not been cleared to everyone's satisfaction."

One of his credos, often repeated by experts, was "extraordinary claims require extraordinary evidence."

But what evidence - extraordinary or otherwise - can anyone offer for such claims?

However, we have been given pause by the extraordinary evidence of an extraordinary lady.

That's an extraordinary claim and it requires extraordinary evidence.

He tried to remember that age-old saw: Extraordinary claims require extraordinary evidence.

Carl Sagan used to say that extraordinary claims require extraordinary evidence.