Glossary of Canadian Tort Law Terms
Negligence
Negligence is the dominant civil cause of action in Canadian tort law. A plaintiff must establish, on a balance of probabilities: (1) that the defendant owed the plaintiff a duty of care; (2) that the defendant breached the applicable standard of care; (3) that the breach caused the plaintiff’s injury, both in fact and in law; and (4) that the resulting harm is not too remote. The modern law of negligence originates in Donoghue v Stevenson [1932] AC 562 (HL), which introduced the neighbour principle as the foundation of a generalised duty of care. Canadian courts have since refined the negligence analysis through a two-stage duty framework, the reasonable person standard for breach, and the but-for test for factual causation.
Duty of Care
A duty of care is a legal obligation to avoid causing foreseeable harm to another. Canadian courts apply the two-stage test from Anns v Merton London Borough Council [1978] AC 728 (HL), as modified by City of Kamloops v Nielsen [1984] 2 SCR 2 and Cooper v Hobart [2001] 3 SCR 537. The first stage asks whether the relationship between plaintiff and defendant discloses sufficient foreseeability and proximity to establish a prima facie duty of care. Proximity is assessed through categories of established relationships (e.g., manufacturer-consumer, doctor-patient, lawyer-client) or through an analysis of factors such as reasonable reliance, physical closeness, or direct causal connection. If a prima facie duty is made out, the second stage asks whether there exist residual policy considerations that ought to negate or limit the duty, such as the potential for indeterminate liability or interference with legitimate government decision-making. The Supreme Court of Canada in Cooper v Hobart emphasised that the Anns/Kamloops framework remains the governing test, though proximity must be grounded in concrete factors rather than abstract notions of fairness.
Standard of Care
The standard of care is the level of caution a reasonably prudent person would exercise in the circumstances. The test is objective: the defendant is expected to conform to the conduct of the reasonable person, not to their own subjective capabilities. In professional negligence, the standard is that of the ordinarily competent member of the profession, not the most skilled (ter Neuzen v Korn, [1995] 3 SCR 674). For children, the standard is that of a reasonably prudent child of the same age (McEllistrum v Etches, [1956] SCR 787). In cases involving novel risks or special skills, the fact-finder may consider expert evidence, custom within an industry, or statutory standards as relevant but not conclusive indicators of the required standard. A breach occurs when the defendant’s conduct falls short of the standard, assessed on the facts as they appeared to the defendant at the time, without the benefit of hindsight.
Breach of Duty
Breach of duty is established when the defendant’s conduct falls below the standard of care expected of a reasonable person in like circumstances. The trier of fact weighs the magnitude of the risk (likelihood of harm and its potential severity) against the burden of precautions required to eliminate or reduce the risk, including any social utility of the defendant’s activity. This balancing exercise, derived from Bolton v Stone [1951] AC 850 (HL) and adopted in Canada, asks whether a reasonable person would have taken additional precautions in the face of a foreseeable risk. Where the defendant’s conduct creates an obvious risk of serious harm, the burden of taking precautions is readily justified; where the risk is slight or the activity socially valuable, a less exacting standard applies.
Causation (But For)
Causation in Canadian tort law comprises two components: factual causation and legal causation (remoteness). The governing test for factual causation is the but-for test: the plaintiff must prove, on a balance of probabilities, that but for the defendant’s negligence, the injury would not have occurred. The Supreme Court of Canada affirmed this test in Clements v Clements, 2012 SCC 32, holding that the but-for test must be applied in a robust and pragmatic manner. The court rejected the material contribution test outside the narrow circumstances where the plaintiff cannot prove but-for causation because it is impossible to disentangle multiple tortious causes, each of which was a necessary element of the harm (Resurfice Corp v Hanke, 2007 SCC 7). In such exceptional cases — typically involving overlapping independent tortious causes — a material contribution test may be used, but only if the plaintiff would otherwise be left without a remedy through no fault of their own.
Remoteness
Remoteness limits a defendant’s liability to harms that are of a kind or type that was reasonably foreseeable at the time of the breach. The leading test is from The Wagon Mound (No 1) [1961] AC 388 (PC), as adopted by Canada. The plaintiff need not foresee the precise manner in which the injury occurred or its full extent; it is sufficient that the general type of harm was within the realm of reasonable foresight. If the injury suffered is of an entirely different kind from what could have been anticipated, the loss is too remote and the defendant is not liable. The thin skull rule qualifies this principle: a defendant must take the plaintiff as they find them, including pre-existing vulnerabilities that exacerbate the injury, provided the type of harm was foreseeable.
Contributory Negligence
Contributory negligence arises when the plaintiff fails to take reasonable care for their own safety and that failure contributes to the damage suffered. At common law, contributory negligence was a complete defence. Under the Negligence Act, RSO 1990, c N.1, and equivalent provincial statutes, the defence now operates to apportion damages in proportion to the degree of fault attributed to each party. The trier of fact assesses the relative contribution of each party’s negligence to the loss. The standard is the same reasonable person test applied to defendants, though a lesser standard may apply to children or persons with disabilities. The plaintiff’s conduct need not be a breach of a duty owed to the defendant; it is sufficient that the plaintiff failed to act reasonably for their own protection.
Voluntary Assumption of Risk (Volenti)
Volenti non fit injuria (to a willing person, no injury is done) is a complete defence barring recovery where the plaintiff voluntarily consented to assume the legal risk of the defendant’s negligence, with full knowledge of the nature and extent of that risk. Canadian courts narrowly construe the defence, requiring the defendant to prove that the plaintiff both knew of the risk and accepted it both physically and legally. The defence is rarely successful in negligence actions arising from ordinary activities, since mere awareness of a risk does not constitute acceptance of legal responsibility for it. In the sporting context, participants accept the ordinary risks inherent in the sport but not risks arising from reckless or intentional misconduct. The defence is distinguished from contributory negligence and from waivers (express contractual exclusions of liability).
Nuisance
Nuisance protects a plaintiff’s interest in the use and enjoyment of land from unreasonable interference. It is divided into public nuisance (an interference with rights common to the public, such as obstruction of a highway) and private nuisance (a substantial and unreasonable interference with the plaintiff’s use or enjoyment of land). Liability is assessed by balancing the severity of the interference against the character of the locality, the timing and duration of the conduct, and the social utility of the defendant’s activity. The test is objective: the interference must be such that the ordinary person would regard it as unreasonable. Unlike trespass, nuisance does not require a physical intrusion and may arise from noise, fumes, odours, or other intangible interferences. The tort is actionable without proof of negligence in cases of Rylands v Fletcher-type strict liability, though Canadian courts have subsumed much of this doctrine within the law of nuisance.
Trespass
Trespass is the direct, intentional, and unprivileged interference with a person or property. Canadian law recognises three principal forms: trespass to the person (assault, battery, false imprisonment), trespass to chattels (interference with goods), and trespass to land (entry upon, or remaining on, land without lawful authority). Trespass to land is actionable per se — without proof of damage — and requires a voluntary act of physical intrusion. The plaintiff need only prove the fact of entry; the defendant bears the burden of establishing lawful authority or consent. Defences include necessity (public or private), consent, and legal authority (e.g., pursuant to a warrant or statute). Trespass is a strict liability tort in the sense that the defendant need not intend to commit a legal wrong; it suffices that the defendant intended the act of physical intrusion.
Products Liability
Products liability in Canada arises primarily in negligence and breach of warranty under sale of goods legislation, and to a more limited extent through the law of nondisclosure. A manufacturer owes a duty of care to the ultimate consumer, as established in Donoghue v Stevenson, to take reasonable care in the design, manufacture, and inspection of products to prevent foreseeable harm. Liability extends to intermediate sellers who fail to inspect or warn of known defects. Canadian courts have not adopted the American theory of strict products liability under s 402A of the Restatement (Second) of Torts; instead, the law of negligence, together with implied warranties under provincial Sale of Goods Acts and the Consumer Protection Act, provides the remedial framework. A consumer expectation test and a risk-utility analysis are used to assess whether a product is defectively designed. Failure to warn of dangers associated with normal use or foreseeable misuse also grounds liability.
Absolute Liability
Absolute liability is a standard of liability imposed without proof of fault and without any available defence, including the defence of due diligence. In Canadian tort law, true absolute liability is rare. It is most commonly encountered in statutory offences of strict or absolute liability under regulatory schemes, particularly environmental protection and workplace safety legislation. In the criminal law context, the Supreme Court of Canada in Reference re Section 94(2) of the Motor Vehicle Act, [1985] 2 SCR 486, held that absolute liability that carries the possibility of imprisonment violates s 7 of the Charter. In tort, the term is often conflated with strict liability, under which a defendant is held liable without proof of negligence but may raise defences such as act of God or fault of the plaintiff. True strict liability torts in Canada are confined to Rylands v Fletcher liability, animals (cattle trespass), and certain ultra-hazardous activities.
Vicarious Liability
Vicarious liability imposes liability on one person for the tortious conduct of another, notwithstanding that the person made no personal fault. In Canada, vicarious liability most commonly arises in the employment context: an employer is liable for torts committed by an employee acting in the course of employment. The modern test, as articulated by the Supreme Court of Canada in Bazley v Curry, [1999] 2 SCR 534, examines whether the wrongful act is sufficiently connected to the employment enterprise to justify holding the employer vicariously liable. The court identified policy rationales for the doctrine: (1) providing a just and practical remedy for the harm; (2) deterring future harm through enterprise liability; and (3) ensuring that the party best able to bear and distribute the loss — the employer — bears the cost. Vicarious liability also applies to principals for agents and, in limited circumstances, to parents for children (if the child was acting under the parent’s direction or in furtherance of the parent’s objectives). The doctrine does not apply to the acts of independent contractors unless the employer retained sufficient control or the activity is inherently hazardous.