The law does not impose on us a duty to care for every person. If the rule were otherwise, we would all, in this interdependent world, be our brothers’ keepers, constantly unsure whether any action we took might subject us to liability for its effect on someone else. The law copes with this difficulty by limiting the number of people toward whom we owe a duty to be careful.
In general, the law imposes no obligation to act in a situation to which we are strangers. We may pass the drowning child without risking a lawsuit. But if we do act, then the law requires us to act carefully. The law of negligence requires us to behave with due regard for the foreseeable consequences of our actions in order to avoid unreasonable risks of injury.
During the course of the twentieth century, the courts have constantly expanded the notion of “foreseeability,” so that today many more people are held to be within the zone of injury than was once the case. For example, it was once believed that a manufacturer or supplier owed a duty of care only to immediate purchasers, not to others who might use the product or to whom the product might be resold. This limitation was known as the rule of privity. And users who were not immediate purchasers were said not to be in privity with a supplier or manufacturer. In 1916, Judge Benjamin N. Cardozo, then on the New York Court of Appeals, penned an opinion in a celebrated case that exploded the theory of privity, though it would take half a century before the last state—Mississippi in 1966—would fall in line.
Determining a duty of care can be a vexing problem. Physicians, for example, are bound by principles of medical ethics to respect the confidences of their patients. Suppose a patient tells a psychiatrist that he intends to kill his girlfriend. Does the physician then have a higher legal duty to warn prospective victim? The California Supreme Court has said yes. 1
Establishing a breach of the duty of due care where the defendant has violated a statute or municipal ordinance is eased considerably with the doctrine of negligence per se, a doctrine common to all US state courts. If a legislative body sets a minimum standard of care for particular kinds of acts to protect a certain set of people from harm and a violation of that standard causes harm to someone in that set, the defendant is negligent per se. If Harvey is driving sixty-five miles per hour in a fifty-five-mile-per-hour zone when he crashes into Haley’s car and the police accident report establishes that or he otherwise admits to going ten miles per hour over the speed limit, Haley does not have to prove that Harvey has breached a duty of due care. She will only have to prove that the speeding was an actual and proximate cause of the collision and will also have to prove the extent of the resulting damages to her.