First Principles of Business Law

6. Causation

6.2.6. Assessing the full extent of harm

Case study: A is a young and successful stage actor. One night, during a performance, she is struck on the head by a falling stage set that was not properly secured in position by the stage crew. The blow injures A's optic nerve, causing her to become permanently blind and unable to work. A sues B, the theatre owner, for damages. Six months later, before the case comes to trial, A develops a hereditary illness that weakens her spine and leaves her permanently unable to walk.  Consider both of the arguments below. Which of them do you think is correct?

(a) Since the first injury to A was sufficient on its own to end her working career, B should be liable for the full loss that A has suffered, without regard to the effects of the later illness.

(b) Since the effects of the illness suffered by A were sufficient to end her working career, B's liability for A's loss should be adjusted because the extent of harm actually caused by B's conduct is affected by A's disease.