The following excerpt is from R. v. Oakes, [1986] 1 SCR 103, 1986 CanLII 46 (SCC):
52. In Leary v. United States, 395 U.S. 6 (1969), Harlan J. articulated a more stringent test for invalidity at p. 36: ... a criminal statutory presumption must be regarded as "irrational" or "arbitrary", and hence unconstitutional, unless it can at least be said with substantial assurance that the presumed fact is more likely than not to flow from the proved fact on which it is made to depend. Harlan J. also noted that since the statutory presumption was invalid under the above test, "we need not reach the question whether a criminal presumption which passes muster when so judged must also satisfy the criminal `reasonable doubt' standard if proof of the crime charged or an essential element thereof depends upon its use" (footnote 64).
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