• Factual causation 事實上因果關係
– But-for test 若不是標準
• Legal causation or proximate causation 法
• In Kramer Service, Inc. v. Wilkins, 1865 So. 625
(Miss. 1939) (SATL 4th ed., p.359), the court held that the plaintiff had failed to introduce sufficient evidence to support a jury finding that a negligently caused cut on the plaintiff’s forehead （前額） had caused the plaintiff to develop cancer. One expert testified that there was no causal relationship between the cut and cancer, and the other estimated the chances at only one in a hundred.
• Based on that evidence, the jury could not find that the cancer more likely than not was caused by the defendant’s conduct.
Moreover, because the case involved a complex medical question, the jury could not rely on common knowledge to remedy the deficiency( 不足、缺乏 ) in expert testimony, and the award of damages for cancer was reversed （撤銷、推翻） .
• Because a defendant’s conduct must more likely than not have caused harm to the plaintiff, it is important to consider what qualifies as harm.
• A substantial majority of the courts that have considered the issue hold that the loss of a chance to cure a disease or other medical problem qualifies as a type of harm for which recovery is available.
• If that is true, then the plaintiff must prove that but for （若沒有） the defendant’s tortious conduct, the chance would not have been lost.
• Many decisions speak of liability for increases risk of harm, rather than for loss of a chance of survival, but the concepts are similar, if not identical （同一） . Courts permitting recovery under the loss-of-achance rule have embraced differing approaches in calculating （計算） damages.
• Some courts leave assessment of damages to the discretion （裁量） of the jury based on evidence of the plaintiff’s opportunity for survival and factors pertinent to （相關） the individual plaintiff’s circumstances.
• Other courts multiply the lost percentage chance of survival by the damages that could be recovered in a wrongful-death case; some of these courts allow additional damages for heightened mental anguish （極度痛苦） or physical pain.