Concurrence

In Western jurisprudence, concurrence (also contemporaneity or simultaneity) is the apparent need to prove the simultaneous occurrence of both actus reus ("guilty action") and mens rea ("guilty mind"), to constitute a crime; except in crimes of strict liability. In theory, if the actus reus does not hold concurrence in point of time with the mens rea then no crime has been committed.

Discussion

Suppose for example that the accused accidentally injures a pedestrian while driving. Aware of the collision, the accused rushes from the car only to find that the victim is a hated enemy. At this point, the accused joyfully proclaims his pleasure at having caused the injury. The conventional rule is that no crime has been committed. The actus reus is complete, and no rule of ratification applies in the Criminal Law. Whereas in the Law of Agency, a Principal may retrospectively adopt a transaction as if the Agent had originally been authorised to conclude an agreement with a third party ("ratification" of the agent's decision), and so acquires liability under that agreement, an alleged criminal cannot retrospectively adopt an actus reus and acquire guilt. To be convicted, the accused must have formed the mens rea either before or during the commission of the actus reus. In the vast majority of cases, this rule works without difficulty.