假设因果关系问题指的是特定损害已因加害行为（真正原因）而发生，然而若该加害行为不存在，该特定损害的全部或者一部仍会因为另一原因（假设原因）而发生。该问题的解决在我国法上是一个损害赔偿范围的计算问题。我国损害赔偿法以补偿为基本功能，以“完全赔偿主义”为理想，采取“差额说”认定损害，而实务中在确定损害时又趋向客观、保守。根据我国损害赔偿法立法、理论和实务的现状，解决假设因果关系问题应当采取区分“直接损害”和“间接损害”为基本思路，原则上，只存在直接损害案件的赔偿范围的计算不考虑假设因果关系，假设原因的存在不对其产生影响；存在间接损害的案件损害赔偿范围的计算应当考虑假设因果关系对赔偿范围可能产生影响。根据假设因果关系类型的不同，案件在具体处理中的思路和关键点有各自特色。另外，假设因果关系的处理中还有法律政策和利益衡量的考虑。法律上认可假设因果关系对损害赔偿责任范围的修正不会引起拖延诉讼、迟延赔偿的风险。当“完全赔偿原则”和“禁止获益原则”在个案中产生冲突时，斟酌假设因果关系应当站在保护受害人的立场，通过解释“禁止获益”来优先实现“完全赔偿”；当加害人故意或者重大过失实施加害行为时，有必要引入过错评价而不考虑假设因果关系的修正作用；对假设因果关系的适用范围可以考虑以“紧迫性”进行限制。假设原因作为减免责事由而由加害人承担证明责任；以“高度盖然性”的民事诉讼证明一般标准来要求假设因果关系的证明有过于松弛的嫌疑。假设原因是一种抗辩，诉讼中出现假设原因被告应当作为“新证据”提出并完成证明。判决生效之后出现假设原因，被告不能再提起新诉讼。
The hypothetical causation issue is whether a defendant who has tortiously caused injury to the plaintiff nevertheless should be absolved from liability if the particular injury would have occurred anyway as a result of independent preempted conditions. In tort law this issue is most appropriately placed under the heading of damages. With the function of compensation as the main purpose of tort law, Chinese compensation mechanism takes "full compensation doctrine", and uses "direct damage theory" to define damage. To solve the hypothetical causation issue, one should first distinguish between "direct damages" and "collateral damages". In principle, the hypothetical causation affects the claim of the plaintiff only when there are collateral damages. In addition, the detailed calculation method differs when the independent preemptive condition is a condition inside the victim, a wrongful act from an third party, and a natural force. On the other hand, logic does not always have the last word in the law. And when as here it might lead to a result not morally justifiable, moral considerations have prevailed. Moral considerations discussed in this article are "for the sake of the victim", "fault" and "remoteness". In the lawsuit, the defendant should prove the existence of the hypothetical causation and the damages it might cause, and thus the defendant should bear the burden of proof. At last, if the hypothetical causation exists after judgement coming into effect, the defendant will not have a new claim against the plaintiff based on unjust enrichment.
