ascertained fact

References in classic literature ?
It was a deliberate attack on the mysticism of the Maeterlinck school - an attack from the citadel of positive science upon the wonder-dreamers, but an attack nevertheless that retained much of beauty and wonder of the sort compatible with ascertained fact.
As fast as the ascertained facts of science have overthrown their subjective explanations of things, they have made new subjective explanations of things, including explanations of the latest ascertained facts.
And as memory, when duly impregnated with ascertained facts, is sometimes surprisingly fertile, Mr.
If 70% to 80% of the Japanese people say they do not support the administration, it is an ascertained fact.
CJP remarked we have ascertained facts and now we have to find who is patronizing the criminals.