The basic explanation of causation is that an individual either committed an act which has a direct and unbroken link to harm that resulted from the act. Alternatively, failure to commit an act has a direct and unbroken link to harm that resulted from the failure to act.
A basic example of causation would be when an individual stabs another individual in the heart and the individual dies as a result. There is an act (the stabbing) the harm (death) and a direct link (security cameras captured the entire incident.)
The difficulties in application of causation law are inversely related to the quality of the links between act, the harm caused, and the defendant. In one landmark case, the “thin skull” case, an individual playfully slapped another individual, who subsequently died. Even though the defendant did not know that the victim could not withstand even a playful slap, the act (playful slap) caused the harm (death) and there are no breaks in the linkage between actor, act, and harm.
In another case, (R v Dear) a stabbing victim would have recovered, but reopened his wounds and died. The victim committed suicide by aggravating the harm that the defendant caused. The defendant (actor) was still convicted for the death (harm), based on the direct link between actor, original act and harm. The British courts ruled on the “but for” basis. But for the stabbing, the victim would not have been able to commit suicide by opening the wounds that the defendant caused. Another factor involved was that the defendant opened an artery by stabbing the victim, making his act an “operant and significant contribution” to the death.
The “Thin Skull” case resulted in a rule that is called “take the victim as you find him”. In other words, not having foreknowledge of a medical condition does not constitute a break in the link between the actor, the act, and the resulting harm. The “Thin Skull” rule was applied in the case of a Jehovah’s Witness who was stabbed and would have lived, but refused a blood transfusion because of her religious belief. The defendant’s lack of foreknowledge about the victim’s religious belief did not prevent a conviction.
Conversely, failure to take action constitutes causation in the form of omitting to act. The famous case of R v Miller involved a vagrant who started a mattress fire in a house where he was sleeping. He did nothing to put out the fire, and simply moved to another room. He was convicted for arson. He caused damage to property by an act of omission: failing to to put out the mattress fire that he started.
Another example of causation law where omission includes the harm or death caused by withholding food and proper care to a child or other helpless individual under a person’s care. When the law requires that some actions be taken, failing to act and causing harm as a result, with direct linkage between the actor omitting to act and the harm to the victim, causation may be proved.
The complexities of applying the principles of causation are as endless as the complexities in life. There have been negative reactions by the public in cases where causation resulted in conviction, as in “Thin Skull” cases. The defense is armed with ways to present concepts and evidence which break the linkages between the actor, the act, the harmed structure or individual, and the resulting harm.
Sourcebook on criminal law, pp 67 “R. v Dear”
Sixth Form Law
Free Encyclopedia, “The Role of Causation In The Criminal Law”
Wikipedia “R v Miller”
A Level Law, “Thin Skull Rule-causation”