If each member of a group of defendants negligently contributes to an indivisible injury, should courts impose liability upon the entire group? Plaintiff was severely and permanently retarded due to brain damage suffering at birth. Evidence proved that defendant obstetrician had committed eight separate acts of medical malpractice during the birth, and that the defendant pediatrician had committed three separate acts of medical malpractice after the birth. Expert witnesses maintained that the brain damage could have been caused by either one of the defendants’ negligence, or by the combined negligence of both. However, the experts did not believe that they could accurately tell what “percentage” of the plaintiff’s brain damage was due to obstetrician’s wrongful acts, as opposed to the pediatrician’s.