Presumptions & Burdens

Summary of Presumptions, Burdens, and Reasonable Doubt #

i. Presumptions and burdens #

Where the Crown proves fact A, a presumption permits the court to presume fact B. In many cases, fact B is an element of an offence that is difficult for the Crown to prove but flows logically from proof of fact A.

Most presumptions are rebuttable, some are irrebuttable.

Among the class of rebuttable presumptions, we distinguish between evidentiary legal presumptions.

Evidentiary presumptions: #

Evidentiary presumptions apply in provisions that use the phrase “in the absence of evidence to the contrary” (or something similar).1

They require the accused to adduce (or point to) some evidence to the contrary, but not to prove anything.

An evidentiary presumption gives rise to an evidentiary burden (‘some evidence’).

Test for meeting an evidentiary burden

The test for what constitutes an “air of reality” or “some evidence,” is: “any or some evidence on which a properly instructed jury, acting reasonably, could convict” (Cinous, Fontaine). Whether this test is met is for the judge to decide, not the jury. (i.e., is there a possibility the contrary fact is true? The Crown must prove – must persuade the trier of fact – that there is no reasonable possibility that it is true.)

Legal presumptions apply in provisions that use the phrase “unless he establishes…” (or something similar).2

If the Crown proves fact A, a legal presumption permits the court to presume fact B unless the accused proves otherwise.

Legal presumptions give rise to a persuasive burden on the accused (a ‘reverse onus’). In criminal law, where the persuasive burden falls upon the accused, the standard is proof on a balance of probabilities.

Whenever a provision of law places an accused in a reverse onus (i.e., imposing a persuasive burden) to prove an essential element of an offence, the provision violates section 11(d) of the Charter. (Oakes)

In some cases, the violation might be saved under section 1; in some it may not.3

ii. Presumption of Innocence: #

Sources of the presumption of innocence can be found at common law (Woolmington), section 6 of the Criminal Code, and section 11(d) of the Charter, which guarantees the right:

“to be presumed innocent until proven guilty according to law in a fair and public hearing by an independent and impartial tribunal.”

The SCC in Oakes affirmed that the presumption of innocence in 11(d) requires the Crown to prove the elements of an offence beyond a reasonable doubt.

In Woolmington, the UK House of Lords held that once the Crown establishes a prima facie case for the elements of an offence, the burden does not shift to the accused to prove a defence. The burden remains on the Crown to prove that a defence does not apply.

Woolmington and Oakes note an exception to this rule. An accused seeking to rely on the defence of mental disorder bears the onus of proving it (on a balance of probabilities).4

iii. The requirement of proof beyond a reasonable doubt #

The SCC in Lifchus held that ‘reasonable doubt’ has a special meaning in law, which should be explained to juries:

-it is not based on sympathy or prejudice

-it is logically connected to the evidence or absence of it

-it is based upon reason and common sense

-it is not proof to an absolute certainty; it is not proof beyond any doubt, nor is it an imaginary or frivolous doubt

-it is not met where accused is “probably guilty”

In Starr, the SCC held that the reasonable doubt standard is “much closer to absolute certainty than to proof on a balance of probabilities”.


  1. See Code section 348(2) for an example. ↩︎

  2. See Code section 320.35 for an example. ↩︎

  3. For example, the one in Chaulk is saved (mental disorder); the one in Oakes is not (intention for trafficking). ↩︎

  4. The burden also shifts to the accused where they seek to rely on other defences premised on a lack of voluntariness: extreme intoxication and automatism. Once again, these violate 11(d) but are saved under 1. ↩︎

© Robert Diab, TRU Law, 2022