extent of the liability to compensate the plaintiff(s) will be determined by what was reasonably foreseeable. So if, for example, the plaintiff unexpectedly contributed to the extent of the loss suffered, that additional element would not be included in the damages award even though the plaintiff would not have had the opportunity to make this mistake had it not been for the defendant's breach. In cases involving the partitioning of damages between multiple defendants, each will be liable to the extent that their contribution foreseeably produced the loss. Risk Sometimes the reverse situation to a novus actus occurs, i.e. factual causation cannot be proved but the court nevertheless does want to hold the defendant liable. In Sindell v. Abbott Laboratories, the plaintiff's mother consumed diethylstilbestrol as a miscarriage preventive. The medicine, later recalled from the market, caused the defendant to develop a malignant bladder tumor due to its negligent manufacture. However, there were many manufacturers of that drug in the market. The manufacturer of the particular medication that caused the injury could not be ascertained for certain. The court held that the defendant was liable in proportion to its market share. They departed from traditional notions of pure cause and adopted a ‘risk based’ approach to liability. The defendant was held liable because of the amount of risk it contributed to the occasioning of the harm. Note that a risk theory is not strictly a theory built on notions of cause at all, as, by definition, the person who caused the injury could not be ascertained for certain. However, it does show that legal notions of causation are a complex mixture of factual causes and ideas of public policy relating to the availability of legal remedies. In R v Miller , the House of Lords said that a person who puts a person in a dangerous position, in that case a fire, will be criminally liable if he does not adequately rectify the situation. Evidence proving causation To be acceptable, any rule of law must be capable of being applied consistently, thus a definition of the criteria for this qualitative analysis must be supplied. Let us assume a purely factual analysis as a starting point. A injures B and leaves him lying in the road. C is a driver who fails to see B on the road and by running over him, contributes to the cause of his death. It