Establishing causation[edit]
Where establishing causation is required to establish legal liability it is usually said that it involves a two-stage inquiry.

The first stage involves establishing ‘factual’ causation. Did the defendant act in the plaintiff’s loss? This must be established before inquiring into legal causation.

The second stage involves establishing ‘legal’ causation. This is often a question of public policy: is this the sort of situation in which despite the outcome of the factual enquiry we might nevertheless release the defendant from liability or impose liability?

Establishing factual causation[edit]
The usual method of establishing factual causation is the but-for test. The but for test inquires ‘But for the defendant’s act would the harm have occurred?’ A shoots and wounds B. We ask ‘But for A's act would B have been wounded?’ The answer is ‘No.’ So we conclude that A caused the harm to B. The but for test is a test of necessity. It asks was it ‘necessary’ for the defendant’s act to have occurred for the harm to have occurred.

One weakness in the but-for test arises in situations where each of several acts alone are sufficient to cause the harm. For example if both A and B fire what would alone be fatal shots at C at approximately the same time and C dies it becomes impossible to say that but-for A's shot or but-for B's shot alone C would have died. Taking the but-for test literally in such a case would seem to make neither A nor B responsible for C's death.

The courts have generally accepted the but for test notwithstanding these weaknesses qualifying it by saying that causation is to be understood “as the man in the street” would: Yorkshire Dale Steamship Co v Minister of War Transport [1942] AC 691 (HL) or by supplementing it with “common sense”: (March v Stramare (1991) 171 CLR 506 (High Court of Australia).[1]

This dilemma was handled in the United States in State v. Tally 15 So 722 738 (Ala. 1894) where the court ruled that: “The assistance given ... need not contribute to criminal result in the sense that but for it the result would not have ensued. It is quite sufficient if it facilitated a result that would have transpired without it.” Using this logic A and B are liable in that no matter who was responsible for the fatal shot the other "facilitated" the criminal act even though his shot was not necessary to deliver the fatal blow.
facilitate 促进，帮助

21'

transpire 发生，泄露

30'

However legal scholars have attempted to make further inroads into what explains these difficult cases. Some scholars have proposed a test of sufficiency instead of a test of necessity. H. L. A. Hart and Tony Honoré and later Richard Wright have said that something is a cause if it is a ‘necessary element of a set of conditions jointly sufficient for the result’. This is known as the NESS test. In the case of the two hunters the set of conditions required to bring about the result of the victim's injury would include a gunshot to the eye the victim being in the right place at the right time gravity etc. In such a set either of the hunters' shots would be a member and hence a cause. This arguably gives us a more theoretically satisfying reason to conclude that something was a cause of something else than by appealing to notions of intuition or common sense.
inroads：损害，侵害，消费。

24'

Hart and Honore in their famous work Causation in the Law also tackle the problem of 'too many causes'. For them there are degrees of causal contribution. A member of the NESS set is a "causally relevant condition". This is elevated into a "cause" where it is a deliberate human intervention or an abnormal act in the context. So returning to our hunter example hunter A's grandmother's birth is a causally relevant condition but not a "cause". On the other hand hunter A's gunshot being a deliberate human intervention in the ordinary state of affairs is elevated to the status of "cause". An intermediate position can be occupied by those who "occasion" harm such as accomplices. Imagine an accomplice to a murder who drives the principal to the scene of the crime. Clearly the principal's act in committing the murder is a "cause" (on the but for or NESS test). So is the accomplice's act in driving the principal to the scene of the crime. However the causal contribution is not of the same level (and incidentally this provides some basis for treating principals and accomplices differently under criminal law). Leon Green and Jane Stapleton are two scholars who take the opposite view. They consider that once something is a "but for" (Green) or NESS (Stapleton) condition that ends the factual inquiry altogether and anything further is a question of policy.
tackle：处理，抓住

23'

intervention：介入

22'

intermediate：中间的，媒介的

40'

elevated：升起，抬高

88'

accomplice：共犯

25'

🌸🌸🌸法律解读 🌸🌸🌸

因果关系有两个构成要素，事实要素和法律要素。在事实要素中主流的观点是but for test也就是「如果不是a，b是不是会发生」用逻辑学来说就是a是b的充分必要条件。
但是这种理论在出现多种A因素的时候就会产生迷惑，比如说甲乙丙同时在没有共同犯罪的意图下像b开枪，那么谁是凶手呢？
所以又有人提出了充分不必要条件，也就是说a一定可以导致b的发生，但是b的发生不一定是由a导致的，在这种情况下只要甲乙丙的行为能够导致b的发生，他们都构成犯罪。


下期说的是法律因果关系～💪💪💪