Introduction
The "but for" test constitutes a fundamental principle within legal causation. It is employed by legal professionals to ascertain whether a defendant's conduct is responsible for the harm suffered by a claimant. This test operates by examining the counterfactual scenario of "but for" the defendant's actions, would the claimant’s loss have occurred? If the harm would not have occurred without the defendant's specific conduct, then that specific conduct is said to be a factual cause. The “but for” concept, therefore, serves as the gateway to legal liability by evaluating whether there is a connection between the conduct of a defendant and an ensuing harm. The accurate application of the test requires clear analytical reasoning and precision when evaluating the facts of a specific situation. This is particularly relevant when complex or multiple factors are involved. The ‘but for’ test is often used in negligence actions to assess causation but also has applications across a wide range of legal topics such as breach of contract, tort, and criminal liability.
Understanding the ‘But For’ Test
The “but for” test is, at its core, a test of factual causation. The fundamental question it aims to address is: "would the harm have occurred even if the defendant did not act as he or she did?" Put another way, would the outcome still have happened if the defendant had not done what they did? If, after analysing the facts, the answer to this is yes, that the harm would have still occurred, then the defendant is not a cause in law. If the harm would not have occurred, however, then causation may be present.
This test is not, however, without its limitations. It can sometimes be difficult to apply in cases involving a series of events in which many different factors influence or contribute to the outcome. There is a difference between factual and legal causation. The courts require both to be satisfied in order for a defendant to be found liable, and this test focuses solely on the ‘factual’ side of causation.
The ‘But For’ Test and Negligence
The tort of negligence offers an excellent example of the workings of the "but for" test. To be liable in the tort of negligence, a defendant must owe a duty of care to the claimant, must have breached that duty of care, and that the breach must have caused the claimant a loss. It is with this third step that the 'but for' test is used. To be liable, the defendant's breach of duty must have directly caused the harm. The breach of duty must be the necessary condition that, without which, the claimant would not have suffered damage. This will often be referred to by way of a two-stage process: factual causation and then legal causation. A defendant will not be liable if the harm would have happened even if they had not been negligent. It is this determination of factual causation that the ‘but for’ test determines. Let us consider this in more specific examples.
Example 1 A driver (D) does not see a red light and crashes his vehicle into another car, injuring the other driver (C). If D had not driven through the red light, C would not have been injured. It was the act of D driving through the red light that directly resulted in C’s injury. Therefore, D is liable for C’s personal injury.
Example 2 An employer (D) fails to provide adequate safety training for his staff. An employee (C), who is working on a ladder without any safety equipment, falls from the ladder and suffers personal injury. It is later discovered that the worker had drunk three bottles of beer in his lunch break. The employer will not be liable for C’s injury. Although, D may be at fault for not having provided adequate training, even with the right equipment and training, C would not have been working at his peak ability, and as such, his accident may have happened even if D were not negligent. Therefore the but-for test is not satisfied. However, if the facts change and we remove the element of intoxication, then the employer would be liable because it is more likely than not that C’s fall would not have occurred had D acted reasonably and had provided the adequate training.
The ‘But For’ Test and Joint Tortfeasors
In situations where there is more than one possible cause of the damage, then the 'but for' test can present some challenges. In many cases such as Fairchild, there was more than one possible defendant who had exposed the claimant to a risk of cancer through his employment and due to medical uncertainty it was not possible to ascertain where the cancer had originated from, from each individual employer. Such problems are often encountered in cases of joint tortfeasors, where a chain of events might involve multiple acts of negligence, or other negligent behaviours. Here, one can distinguish between the ‘but-for’ cause and material contribution. A material contribution is an acknowledgement that the defendant’s actions have been a cause or that its actions have materially contributed to the eventual outcome, when there are two or more possible agents that can have been the factual cause. As long as the contribution of that agent was non-negligible, then the ‘but for’ test is met. To take the example of Bonnington Castings, the defendants actions did not have to be the sole or main source of the claimant’s condition. As long as it was not negligible, then it was deemed that the actions were a factor in producing the claimant’s condition. This approach has been criticised because even by taking the correct measures to reduce exposure, the likelihood of contracting a condition may be so high that such efforts will still ultimately have resulted in the harm. Therefore it may be considered unfair that those who made an effort to reduce exposure are still held liable.
The ‘But For’ Test and the Criminal Law
The "but for" test also has an application within criminal law to determine liability for offences that have a prohibited outcome. In general, if the 'but for' test is not satisfied then the criminal liability will not be present. The defendant has to act and that act must cause the outcome with which they have been charged.
One of the most notable cases that deal with the issue is R v White, in which the defendant poisoned his mother’s drink. As the intention was to kill his mother he was guilty of an attempt, but the case is important on the issue of factual causation. On the facts of the case it was found that the actual cause of her death was not the poison, but another factor which was not in fact the intent of the accused (a heart attack). As such the ‘but for’ test was not satisfied and D was not liable for murder but only attempted murder. This case demonstrates, therefore, that the causal link between the act and consequence must be proven through “but for” causation in order for the substantive crime to be made out. A more recent case in which the ‘but for test was applied is R v Hughes. In Hughes, a driver, with no driving licence or insurance, crashed into a car resulting in the death of the occupant. The Supreme Court held that while Hughes had done something illegal that contributed to death, there was no basis to hold that the ‘but for test’ was satisfied; Hughes was not causally liable as he had not done anything wrong in terms of driving.
Conclusion
The "but for" test is a deceptively simple yet powerful tool for determining liability by establishing a clear factual link between a person's conduct and a resulting harm. However, as this essay has shown, it is not without its limitations. As an exclusive measure it is unlikely to suffice given that many cases involve more than a single cause and the scope of liability would have to be determined by public policy or some other factor. It is the first step, and the entry way into the consideration of causal responsibility and liability within the law of both tort and crime, but it is by no means the only one.
