Canadian Criminal Evidence/Presumptions
A presumption is a reasoning process whereby to some degree, proof of one fact (including the proven absence of a fact) is taken as evidence of another fact. For example, A is an adult, so it is presumed that A is legally competent.
Anywhere in the criminal code which directs a factual inference unless there is "any evidence to the contrary", is a mandatory presumption.
For example under s. 354(2), an obliterated serial number of a vehicle directs the inference of knowledge that the item was stolen. Where there is no evidence presented to the contrary, the court has no discretion and must conclude knowledge.
Evidence to the contrary "is evidence which is not rejected and which raises a reasonable doubt as to the existence of the presumed fact."
These code provisions will tend to violate s. 11(b) Charter rights by shifting the burden onto the accused. However, can remain in force under s.1 as a reasonable limitation.
- R v Boyle (1983), 5 C.C.C. (3d) 193 (Ont. C.A.)
- R v Boyle
- e.g. R. v. Downey, 1992 CanLII 109 (SCC),  2 S.C.R. 10