Maxims on crime and liability

The essentials

Criminal law is built on the maxim actus non facit reum nisi mens sit rea – an act does not make a person guilty unless the mind is also guilty. Thus a crime generally requires both actus reus (the guilty act or omission) and mens rea (the guilty mind, such as intention, knowledge or recklessness). Some offences of strict liability, such as many regulatory offences, do not need mens rea.

Key points

• Actus reus: the physical element – for example, taking another's property.
• Mens rea: the mental element – for example, a dishonest intention to take it.
• Corpus delicti: "the body of the crime" – proof that a crime has actually been committed. It does not literally mean a dead body; in a theft case it is proof that property was in fact stolen.
• Doli incapax: "incapable of crime". Under Indian criminal law (now the Bharatiya Nyaya Sanhita, 2023), nothing is an offence that is done by a child under seven years; a child above seven and under twelve is protected if he has not attained sufficient maturity to understand the nature and consequences of the act.
• Qui facit per alium facit per se: "he who acts through another acts himself". It is the basis of vicarious liability – an employer or principal is liable for acts of an employee or agent done in the course of employment. In criminal law it explains why a person who uses an innocent agent to commit a crime is himself liable.

Exam tips

• Match "guilty mind" with mens rea and "guilty act" with actus reus.
• Corpus delicti is about proof that a crime occurred, not about the identity of the criminal.

Common mistakes

• Translating corpus delicti as "the dead body" only.
• Thinking doli incapax means a child can never be liable at any age below 18.