• Editor's note: complimenting this Legal Definition of Negligence is Negligence - An Introduction.
Not only are people responsible for the intentional harm they cause (called intentional torts), but their failure to act as a reasonable person would be expected to act in similar circumstances (i.e. "negligence") will also give rise to damages.
Everyone has an ongoing duty to conduct themselves, and manage things under their control, with care as towards other persons. Everybody has a duty to ensure that their actions do not cause harm to others.
In a 1904 case, Northern Pacific Railway v. Adams, Mr. Justice Brewer of the United States Supreme Court noted and relied on these two descriptions of negligence:
"Negligence to create a liability on the part of parties in fault must be a failure to observe the degree of care and prudence that is demanded in the discharge of the duty which the person charged with the negligence owed under the peculiar circumstances of the case to the injured party....
"Negligence is the omission to do something which a reasonable man, guided upon those considerations which ordinarily regulate the conduct of human affairs, would do, or doing something which a prudent and reasonable man would not do, provided, of course, that the party whose conduct is in question is already in a situation that brings him under the duty of taking care."
Negligence, if it causes injury to another, exposes the tort-feasor to tort or personal injury liability.
Negligence is assessed against an objective standard, having regards to the circumstances and to the standard of care which would reasonably be expected of a reasonable person in similar circumstances. The law looks at what a hypothetical reasonably prudent person might have done in similar circumstances.
For experts selling or offering their services to others on that basis, their standard will be elevated to a similar and qualified expert.
Legal theorists, like Canadian law professor Allen Linden in his 2011 Canadian Tort Law,1 have tried to break down what can be a very complex area of the law,2 into an ABC rule, as follows:
"A plaintiff in a negligence action is entitled to succeed by establishing three things to the satisfaction of the court: (A) a duty of care exists; (B) there has been a breach of that duty; and (C) damage has resulted from that breach."
In Ryan v The City of Victoria, Canada's Supreme Court opined that:
"Conduct is negligent if it creates an objectively unreasonable risk of harm. To avoid liability, a person must exercise the standard of care that would be expected of an ordinary, reasonable and prudent person in the same circumstances. The measure of what is reasonable depends on the facts of each case, including the likelihood of a known or foreseeable harm, the gravity of that harm, and the burden or cost which would be incurred to prevent the injury."
Between negligence and the intentional act there lies yet another, more serious type of negligence which is called gross negligence.
Gross negligence is any action or an omission in reckless disregard of the consequences to the safety or property of another [see also contributory negligence, comparative negligence and criminal negligence].
Comparatively, in the civil law, to defer to the example of Quebec's Civil Code, negligence is captured within the term civil liability (responsabilite civile) and as follows, at ¶1457:
"Every person has a duty to abide by the rules of conduct which lie upon him, according to the circumstances, usage or law, so as not to cause injury to another.
"Where he is endowed with reason and fails in this duty, he is responsible for any injury he causes to another person by such fault and is liable to reparation for the injury, whether it be bodily, moral or material in nature. "He is also liable, in certain cases, to reparation for injury caused to another by the act or fault of another person or by the act of things in his custody."
- Duhaime, Lloyd, Negligence - An Introductionduhaime.org, Tort & Personal Injury Law
- Linden, Allen and Feldthusen, Bruce, Canadian Tort Law, 9th Ed. (Toronto: LexisNexis, 2011), page 114 [NOTE 1].
- Northern Pacific Railway Company v. Adams, 192 US 440 (1904)
- NOTE 2: Even the venerable English treatise Charlesworth & Percy on Negligence, 11th Ed. (London: Sweet & Maxwell, 2006), cannot, though in the context of a law book, provide a simple definition of negligence proposing, instead, that there are three and taking almost ten pages to announce that, in law, we are principally concerned with their third meaning, a "breach of a duty to take care" (at page 11).
- Ryan v The City of Victoria,  1 SCR 201