The introduction of probability and certainty allows human reviewers to accurately identify responsive data in large populations while examining only a small percentage of the total data population.

WHEN Denmark was overrun by the Germans various British subjects were caught, Mr. among them. He was interned in a camp under Danish control and spent part of his enforced leisure in coin-tossing ...

"Yes or no: was there once life on Mars?" I can't say. "What about intelligent life?"' That seems most unlikely, but again, I can't really say. The simple yes-or-no framework has no place for shadings ...