The problem the administration faces now is that it is declaring that Iran stopped its nuclear weapons development with the same certainty that it insisted two years ago that the program was speeding ahead.
Can it be tested for, diagnosed and treated with the same certainty as a physical disease?
Similarly, it could be excluded with the same certainty in 49 (39%) of the 125 patients of the validation group.
As these businesses acquire scale, their costs will rise with the same certainty as death and taxes.
But the same cannot be said, or at least not with the same certainty, of the extra-marital engagements either of John Kennedy or Bill Clinton.
Now I can reiterate with the same certainty that I'm sure the advice-giver, whom I chose not to listen to, had back then.
"Everybody acknowledges this is one of the weakest fields," Rush Limbaugh, the conservative talk radio host, declared with his usual certainty in March.
I started my quest by calling the great culinary anthropologist Claudia Roden, who declared with refreshing certainty that the best falafel was to be found in Egypt.
Last Sunday, Mr. Limbaugh declared with absolute certainty that the media had overrated Donovan McNabb, the Philadelphia Eagles quarterback, because he is black, and gave him credit for success that belonged to the team's defense.
In 1992, six years before a finger-wagging Bill Clinton fiercely denied having sex with "that woman", he sat on a bar stool at a Weirton community centre, waved that same scolding index finger, and declared with seeming certainty, "I want to make sure we enforce strictly the anti-dumping laws".
The working classes, he declared with bracing certainty, "have never eaten kale", and only eat "spaghetti out of tins".
