The rule against ungrounded common‑sense assumptions

The Supreme Court of Canada has ruled that he rule against ungrounded common‑sense assumptions should not be recognized as giving rise to an error of law. Such an error of law would represent a radical departure from how appellate courts have typically approached credibility and reliability assessments, especially in the context of sexual assault.

The proposed rule is in no way analogous to the body of law protecting sexual assault complainants from myths and stereotypes, nor can it be justified as necessary to ensure fairness to the accused. It also treats any and all factual assumptions drawn in the course of testimonial assessments as errors of law and thereby represents an unjustified departure from well‑established principles governing testimonial assessment and appellate standards of review.

The faulty use of common‑sense assumptions in criminal trials should continue to be controlled by existing standards of review and rules of evidence. In some cases, a trial judge’s use of common sense will be vulnerable to appellate review because it discloses recognized errors of law. Otherwise, like with other factual findings, credibility and reliability assessments — and any reliance on the common‑sense assumptions inherent within them — will be reviewable only for palpable and overriding error. In the instant cases, assessing the trial judges’ credibility and reliability findings using the proper standard of palpable and overriding error, no such errors were made.

First, the proposed rule against ungrounded common‑sense assumptions is not a logical extension of the prohibition against myths and stereotypes about sexual assault complainants. It reflects a misunderstanding of the distinct body of law associated with myths and stereotypes in sexual assault cases, which has a unique history and a specific remedial purpose: to remove discriminatory legal rules that contributed to the view that women, as a group, were less worthy of belief and did not deserve legal protection against sexual violence.

Second,  the proposed rule is counterproductive to proper testimonial assessment and incompatible with the often inextricable role common‑sense assumptions play in credibility and reliability assessments. By prohibiting ungrounded common‑sense assumptions, the rule interferes with the necessary recourse to common sense as a part of testimonial analysis. It is effectively impossible to draw a clear boundary between using human experience to interpret evidence or draw inferences (which is permissible under the rule) and introducing new considerations into the evidence (which is not). The rule invites appellate courts to substitute their opinions about what generalizations are appropriate or instructive for those of trial judges, improperly transforming their strong opposition to a trial judge’s factual inferences into supposed legal errors, thus creating uncertainty and unfairness on appeal.

The rule also runs contrary to established standards of review and would unduly increase the scope of appellate intervention into the credibility and reliability assessments of trial judges.

Source: R. v. Kruk, 2024 SCC 7 (CanLII)