“Judicial notice” refers to commonly known information that is not required to be formally proven in court. Rather, the information is accepted as being noted by the judiciary, hence the name.

Generally, only indisputable facts can be judicially noted. For example, historical facts, geographic locations, and the meanings of words are often judicially noted. Similarly, well-known medical opinions (such as smoking causes lung cancer) and well-established scientific theories (”battered woman syndrome”)^ may be included in a proceeding as judicial notice.

There are also statutory enactments requiring judges to take judicial notice of domestic laws.#

In contrast, “delegated legislation” (such as corporation by-laws, condominium corporation declarations) is not well-known enough for the judge to take judicial notice. In this case, it must be proven as fact, generally through an affidavit.

What about personal knowledge? Can a judge use his or her own personal knowledge to adjudicate a case?

At common law, the judges can only utilize general knowledge commonly known to the community to decide a case. Numerous appellate decisions in Canada indicate that a judge should not rely on his or her own opinion.*

^R. v. Lavallee, [1990] 1 S.C.R. 852

#See e.g. Canada Evidence Act, R.S.C. 1985 c. C-5 ss. 17, 18., Legislation Act, S.O. 2006, c. 21, Sch. F.

*See e.g. R. v. W.(S.) (1991), 6 C.R. (4th) 373 (Ont. C.A.), R. v. Dickson (1973), 5 N.S.R. (2d) 240 (C.A.)