Causation in murder refers to the legal principle that establishes a direct link between a defendant's actions and the resulting death of the victim. It is essential in determining whether the accused can be held criminally responsible for homicide, as it assesses if the defendant's conduct was a significant factor in causing the death. Understanding causation involves dissecting both factual causation, often expressed as 'but for' the defendant's actions, and legal causation, which considers whether the harm was a foreseeable result of those actions.