is just one component of the tort. On other occasions, causation is the only requirement for legal liability (other than the fact that the outcome is proscribed). For example, in the law of product liability, the courts have come to apply to principle of strict liability : the fact that the defendant's product caused the plaintiff harm is the only thing that matters. The defendant need not also have been negligent. On still other occasions, causation is irrelevant to legal liability altogether. For example, under a contract of indemnity insurance, the insurer agrees to indemnify the victim for harm not caused by the insurer, but by other parties. Because of the difficulty in establishing causation, it is one area of the law where the case law overlaps significantly with general doctrines of analytic philosophy to do with causation. The two subjects have long been intermingled. Establishing causation Where establishing causation is required to establish legal liability, it usually involves a two-stage inquiry, firstly establishing 'factual' causation, then legal (or proximate) causation. Factual causation must be established before inquiring into legal or proximate causation. Establishing factual causation 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. In New South Wales, this requirement exists in s 5D of the Civil Liability Act 2002 (NSW), reinforcing established common law principles. 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