Causation is the “causal relationship between the defendant’s conduct and the result”. In a criminal activity, there are always these three elements namely – actus reus, mens rea and causation. Despite the presence of both actus reus and mens rea, a criminal act can be unsustainable in the eyes of law because of the absence/lack of causation. For example, A intending to murder B puts a bomb in his car, B dies because of the car accident with someone else but not because of that bomb. Now in such a situation, A can’t be held liable despite having that mental element and the act. The simple reason is that A’s action didn’t cause B’s death and therefore, A will only be held liable for an attempt to murder. Therefore, causation is an indispensable element of criminal law.
The doctrine of causation is based on the simple premise that ‘a man can only be held liable for the consequence of his actions’. The entire doctrine is effectively based on the interpretation of a single word: ‘consequence’. It is best illustrated by Illustration (b) of Section 299 of The Indian Penal Code, 1860. “A knows Z to be behind a bush. B does not know it. A, intending to cause or knowing it to be likely to cause Z’s death, induces B to fire at the bush. B fires and kills Z. Here B may be guilty of no offence, but A has committed the offence of culpable homicide.” In this illustration, causation is used to establish the link between actus reus and mens rea.
A person can be held for all the consequences of his actions that can be reasonably expected from him/her.
Relationship between Causation & Liability
Now and again causation is one piece of a multi-arrange test for legal obligation. For instance, for the defendant to be held liable for the tort of negligence, the respondent more likely than not owed the offended party an obligation of care, broke that obligation, by harming the offended party, and that harm must not have been excessively remote. Causation is only one segment of the tort.
On different events, causation is the main necessity for legal liability. For instance, in the law of product obligation, the courts have come to apply to the guideline of strict liability: the way that the respondent’s product caused the offended party harm is the main thing that matters. The respondent need not additionally have been negligent.
On still different events, causation is insignificant to legal liability altogether. For instance, under an agreement of indemnity insurance, the insurer agrees to repay the casualty for hurt/damage not brought about by the insurer, but by different parties.
For establishing the doctrine of causation, one must investigate into ‘factual causation’ and ‘legal causation’, thereby convicting anyone of legal liability.
Firstly, ‘factual causation’ must be established and then followed by ‘legal causation’.
Establishing Factual Causation
There is a test namely ‘but for’ test. It says that but for the defendant’s act the harm would not have occurred. A throw a big stone at B. We ask, ‘But for A’s act, would B have been injured?’ The answer is ‘No. So we conclude that A caused the harm/injury to B. This test is a test for necessity.
One shortcoming in the but-for test emerges in circumstances where every one of a few acts alone is adequate to cause the damage. For instance, if both X and Y fire what might alone be lethal shots at Z at around a similar time, and C dies, it gets difficult to state that but-for X’s shot, or but-for Y’s shot alone, Z would have died. Taking the but-for test truly in such a case would appear to make neither X nor Y liable for Z’s demise.
In the case of R v White, the defendant tried to kill his mother by putting poison in her drink. His mother died shortly afterwards from a heart attack. The poison had not taken effect and therefore he wasn’t liable or guilty of murder. The prohibited result (mother’s death) still would have occurred without the defendant’s actions. He was held liable for an attempt to murder. So, but-for White trying to poison his mother, she still would have died. Here the defendant wasn’t the factual cause.
In another case R v Pagett, the defendant shot at the police, and when the police fired back at him, he used his girlfriend as a human shield. His girlfriend was killed by the shots fired by the police, but he was convicted for manslaughter. The court said that but-for the defendant’s actions (using his girlfriend as a human shield) she wouldn’t have died. Here the defendant was the factual cause.
Establishing Legal Causation
Once factual causation has been proved, then we have to prove legal causation.
It asks that ‘Whether the defendant’s act was the ‘operative’ and ‘substantial’ cause of death. Or was it the main cause or the real cause. It is also based on the principle of common sense.
For example – A hit his leg into B’s chin and bleeding starts, she goes to the hospital in the car and the car is struck by lightning and B dies as a result, so factual causation but-for kicking her in the chin, she would not have been in the car and she would not have died, so A is the factual cause. The question here is that ‘Is A the operative and substantial cause of her death?’. Although A is liable for the initial injuries, A is not liable for the death.
Once such a thing is established, we will have to investigate the things that can break the ‘chain of causation’. It is also called ‘Novus Actus Interveniens’ meaning thereby an intervening act, which breaks the chain of causation. The act could be the victim’s act, the act of a third party or an act of god. However, not every intervening act qualifies as Novus actus interveniens. The intervening act must be such that it is not foreseeable or intended but, in some cases, when the intervening act is a ‘free deliberate and informed act’ of another agent, the original causation breaks despite the consequence being an intended consequence.
Under this doctrine, every criminal act is shown to have linked from the mens rea to the actus reus. As long as the link of causation remains unbroken, the act of accused is assumed/believed to have caused the consequence.
However, in IPC every section has its unusual approach to causation in criminal activity. Because of a lack of a uniform doctrine, there exists an ambiguity. Such ambiguity leads to stupid and absurd results and it needs to be addressed.
“The views of the authors are personal“
 Illustration (b) of S.299 of IPC, 1860.
  2 KB 124.
 76 Cr App R 279.
 Jeremty Horder & Andrew Ashworth, Principles of Criminal Law 104 (7th ed. 2013)