What principle requires that damages must be proven in a liability claim?

The principle that requires damages to be proven in a liability claim is centered on the concept of "damages." In any legal claim for liability, establishing that the defendant is liable requires the claimant to demonstrate that they have incurred actual damages as a result of the defendant's actions. This means that simply proving that a duty was breached or that negligence occurred is not enough; there must be concrete evidence of harm or loss that the claimant has experienced.

In the context of liability claims, damages serve as the basis for determining the extent of the defendant's responsibility. They can be economic, such as lost wages or medical expenses, or non-economic, such as pain and suffering. The claimant must provide sufficient evidence to quantify these damages, making the concept of damages critical to the outcome of the case.

While the other principles like certainty and proximate cause play important roles in establishing liability and linking the defendant's actions to the claimant's losses, they do not specifically address the necessity of demonstrating actual damages. Therefore, the correct focus is on the principle of damages, which underscores the requirement for proof of loss in liability claims.