Authority is binding only within a hierarchy: a court must follow the appellate courts above it in its own jurisdiction. Everything else — courts of the same level, courts of other provinces or countries, academic writing — is persuasive: a judge may adopt it for the strength of its reasoning, but need not.
The common law family's shared inheritance makes persuasive authority unusually portable. A point unresolved in one country is routinely argued with cases from the others, and final courts read each other's judgments — which is how doctrines migrate across the common law world.
Pre-1949 Privy Council decisions once bound Canadian courts as their own hierarchy's rulings; today English authority, like all foreign authority, persuades but does not bind.