The defendant may defend by simply negating one or more of the prima facie elements of the tort. For example, she may present evidence in a battery case that she never touched the plaintiff, that she did so unintentionally, or that the touching was not one that the reasonable person would find offensive under the circumstances. In other cases, however, the defendant takes the position that, even if the prima facie elements of the tort are shown, she is not liable anyway, because of additional facts that allow her to avoid liability. Such additional facts are often referred to as affirmative defenses.
Some affirmative defenses have nothing to do with the underlying incident itself. For example, if Jones sues Smith for battery, Smith might defend on the ground that the claim is barred by the statute of limitations, the statutory period within which suit must be brought on a claim. This defense asserts that, even if Jones can prove that Smith intentionally inflicted a harmful or offensive touching on her, she is not liable, because the suit was brought too late. Or, Smith might plead that Jones had signed a release from liability (a contractual agreement not to sue on the claim, usually given for a sum of money paid in settlement). Again, this defense does not rely on a showing that no battery occurred, but rather on additional facts that demonstrate that there is no longer a right to sue for the claim.