Does a Judge Always Need Evidence of a Fact?
The Principle of Judicial Notice Allows a Judge to Accept a Fact As True Where the Fact Is So Notoriously As True and Uncontroversial That Evidence Is Unnecessary.
Understanding the Principle Known As Taking Judicial Notice Without Evidence of Notoriously Known Truths
Facts that are notorious known, meaning so known that everyone with common knowledge would agree that the fact is true are facts for which a court may take judicial notice of the fact without requiring proof of the fact via some form of evidence. Examples of notorious facts include common knowledge that water is wet, the Sun is bright, and gasoline is flammable.
The legal requirements for review before a judge takes judicial notice of a fact were well explained within the Taylor v. Hanley Hospitality Inc., 2022 ONCA 376, case wherein it was stated:
 The concept of judicial notice allows a court to receive “facts” that are “so notorious or uncontroversial that evidence of their existence is unnecessary”. This does not allow parties “to put before the court controversial evidence to the prejudice of the opposing party without providing a proper opportunity for its truth to be tested”: Public School Boards’ Assn. of Alberta v. Alberta (Attorney General), 2000 SCC 2,  1 S.C.R. 44, at para. 5. The threshold for judicial notice is strict since the facts are not proved by evidence under oath nor tested by cross-examination: R. v. Find, 2001 SCC 32,  S.C.R. 863, at para. 48.
As shown within the Taylor case, a court is permitted to accept a fact as true without proof, by taking judicial notice, when the fact is so well known as true that proof becomes unnecessary.
The taking of judicial notice involves a court accepting certain facts as true without the need of evidentiary proof and involves things so commonly known.