Final answer:
Donoghue v Stevenson established a legal precedent for the duty of care relating to product safety. An example of a breach is when an auto manufacturer knowingly sells cars with defective brakes, leading to accidents and injuries. In everyday life, we use judgment to prioritize conflicting prima facie duties.
Step-by-step explanation:
The case of Donoghue v Stevenson established the foundational principle in modern law regarding negligence and the duty of care. In this case, the court set out the requirement that when making a product, manufacturers must prevent foreseeable harm from coming to consumers. An example where this principle applies is when an automobile manufacturer discovers there is a defect in a car's brake system yet proceeds with production. When these defective cars lead to accidents and injuries, the manufacturer could be held liable as they have breached their standard of care towards consumers, having foreseen the potential danger and choosing to ignore it.
In relation to our day-to-day experience, we encounter circumstances where we owe prima facie duties, such as the duty to fulfill a promise or to provide help during emergencies. These duties may conflict, as illustrated in the example of choosing between helping an individual in need or keeping a commitment. In such situations, our duty is determined by the action that yields the 'greatest balance of prima facie rightness', according to philosopher William David Ross. This concept also relates to how we assess obligations in a legal context.