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Reasonable Foreseeability:
Principles Regarding Whether an Advance Risk of Harm Arising Could Be Recognized
Last Updated: August 23 2026
Question: How is reasonable foreseeability determined in a negligence claim in Ontario?
Answer: In Ontario negligence cases, courts use an objective “reasonable foresight” test to ask whether, in the defendant’s position before the incident, a reasonable person ought to have seen a real risk that their conduct could cause the type of harm that happened, rather than judging with hindsight after the fact. The analysis also addresses remoteness, meaning the harm must not be too unrelated to the wrongful conduct to fairly hold the defendant liable, and it can consider how a person of “ordinary fortitude” would likely respond when the alleged injury is mental injury. For help applying these foreseeability principles to your situation, paralegal and property management support is available through Mole Legal Services at (647) 709-5157.
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Understanding Foreseeability Principles
Negligence law includes the principle of reasonable foreseeability. Reasonable foreseeability involves the question of whether a reasonable person could envision the risk of harm arising from the specific conduct in question. As a fundamental component of negligence law principles requires an analysis of what a reasonable person would do or avoid doing, analyzing what a reasonable person would view as risky becomes necessary within a negligence liability discussion.
Note: Please contact Mole Legal Services by phone at: (647) 709-5157 to discuss any specific questions that you may have.
The Law
The concept of reasonable foreseeability was explained by the Supreme Court within the cases of Rankin (Rankin’s Garage & Sales) v. J.J., [2018] 1 S.C.R. 587, and Mustapha v. Culligan of Canada Ltd., [2008] 2 S.C.R. 114, as follows:
[53] Whether or not something is “reasonably foreseeable” is an objective test. The analysis is focussed on whether someone in the defendant’s position ought reasonably to have foreseen the harm rather than whether the specific defendant did. Courts should be vigilant in ensuring that the analysis is not clouded by the fact that the event in question actually did occur. The question is properly focussed on whether foreseeability was present prior to the incident occurring and not with the aid of 20/20 hindsight: L. N. Klar and C.S.G. Jefferies, Tort Law (6th ed. 2017), at p. 212.
[12] The remoteness inquiry asks whether “the harm [is] too unrelated to the wrongful conduct to hold the defendant fairly liable” (Linden and Feldthusen, at p. 360). Since The Wagon Mound (No. 1), the principle has been that “it is the foresight of the reasonable man which alone can determine responsibility” (Overseas Tankship (U.K.) Ltd. v. Morts Dock & Engineering Co., [1961] A.C. 388 (P.C.), at p. 424).
[13] Much has been written on how probable or likely a harm needs to be in order to be considered reasonably foreseeable. The parties raise the question of whether a reasonably foreseeable harm is one whose occurrence is probable or merely possible. In my view, these terms are misleading. Any harm which has actually occurred is “possible”; it is therefore clear that possibility alone does not provide a meaningful standard for the application of reasonable foreseeability. The degree of probability that would satisfy the reasonable foreseeability requirement was described in The Wagon Mound (No. 2) as a “real risk”, i.e. “one which would occur to the mind of a reasonable man in the position of the defendan[t] . . . and which he would not brush aside as far-fetched” (Overseas Tankship (U.K.) Ltd. v. Miller Steamship Co. Pty., [1967] A.C. 617 (P.C.), at p. 643).
[14] The remoteness inquiry depends not only upon the degree of probability required to meet the reasonable foreseeability requirement, but also upon whether or not the plaintiff is considered objectively or subjectively. One of the questions that arose in this case was whether, in judging whether the personal injury was foreseeable, one looks at a person of “ordinary fortitude” or at a particular plaintiff with his or her particular vulnerabilities. This question may be acute in claims for mental injury, since there is a wide variation in how particular people respond to particular stressors. The law has consistently held — albeit within the duty of care analysis — that the question is what a person of ordinary fortitude would suffer: see White v. Chief Constable of South Yorkshire Police, [1998] 3 W.L.R. 1509 (H.L.); Devji v. Burnaby (District) (1999), 180 D.L.R. (4th) 205, 1999 BCCA 599; Vanek. As stated in White, at p. 1512: “The law expects reasonable fortitude and robustness of its citizens and will not impose liability for the exceptional frailty of certain individuals.”
As per the Rankin and Mustapha cases, foreseeability revolves around whether a person could reasonably view the possibility that certain actions might lead to harm of another person. Additionally, per Rankin and Mustapha, when reviewing whether harm was foreseeable a court must consider the incident from the perspective of foresight rather than in hindsight.
Conclusion
Negligence law encompasses the assessment of whether an individual behaved with an unreasonable lack of care and should be deemed responsible for harm brought about by such lack of care. Within the inquiry of whether the behavior lacked due care is the question regarding whether the ensuing harm could be reasonably anticipated. If the harm was reasonably unforeseeable, then liability for the harm fails to arise.
NOTE: A considerable amount of online searches featuring “lawyers nearby” or “top lawyer in” frequently indicate a desire for prompt and competent legal assistance rather than a particular professional designation. In Ontario, licensed paralegals are governed by the same Law Society responsible for lawyers and are permitted to represent clients in certain legal matters. Key aspects of this role include advocacy, legal analysis, and procedural expertise. Mole Legal Services provides legal representation within its licensed parameters, focusing on strategic approaches, evidence preparation, and effective advocacy to secure timely and advantageous outcomes for clients.
