The Brains and Brawn of Criminal Law: Mens Rea and Actus Reus

Robber is thinking of profit from robbery. Word balloon from Freepix.At the most fundamental level, criminal law is based around a single Latin phrase: “Actus non facit reum nisi mens sit rea”, which translates to “an act does not make a person guilty unless the mind is also guilty”. This means that a crime consists of two elements: the commission of a guilty act, known as actus reus, and the presence of a guilty mind, known as mens rea.

For example, section 322 of the Criminal Code defines theft as follows:

322 (1) Every one commits theft who fraudulently and without colour of right takes, or fraudulently and without colour of right converts to his use or to the use of another person, anything, whether animate or inanimate, with intent (a) to deprive, temporarily or absolutely, the owner of it, or a person who has a special property or interest in it, of the thing or of his property or interest in it…

We can see there are both actus reus and mens rea elements of this offence. The actus reus of theft is taking something without colour of right (something that isn’t yours), the mens rea is intending to deprive the owner of the thing taken.

Actus Reus

For actus reus to be made out there must be a voluntary commission of an unlawful act.  All actions are presumed to be voluntary, but the defence can argue that there was no actus reus because the defendant had no voluntary control of his or her actions. This was the case in R v Parks, where the accused presented evidence that he was sleepwalking at the time he killed his mother and father in law. The Supreme Court of Canada upheld Mr. Park’s acquittal on the basis that he was not acting voluntarily.

Additionally, where the offence charged includes the occurrence of specific result, the fact that those consequences occurred is another element of actus reus. For example, section 222(1) of the Criminal Code provides that “A person commits homicide when, directly or indirectly, by any means, he causes the death of a human being.” Causing death is therefore a necessary requirement for the actus reus of homicide. In determining causation the question we ask is, whether, but for the actions of the accused, would the result have happened?

Mens Rea

Courts presume that criminal offences require some form of subjective mens rea—intent, knowledge, recklessness, or willful blindness—in relation to all aspects of the actus reus unless Parliament clearly indicates otherwise.

For some offences, Parliament has indicated that mens rea is not required. These are known as strict liability offences. For a strict liability offence it is not necessary for the Crown to prove the existence of mens rea—the act itself is the entire offence. If charged with a strict liability offence, the accused may advance the offence that they took all reasonable steps to avoid the act. An absolutely liability offence is similar, but the accused is not able to advance a defence of this nature.

So when you’re wondering if something is a crime, start with “brains and brawn,” and ask yourself if criminal intent and criminal action were both present. As we’ve seen, there are exceptions, but it’s a reasonable place to start.

– Isabelle Crew (3L, Faculty of Law, Queen’s University)

Thought balloon in illustration courtesy Freepik.

Four Key Facts About Canada’s Three Legal Systems

Pop quiz: is the legal system the same in all of Canada?

Common and Civil Law jurisdictions in Canada

Common and Civil Law jurisdictions in Canada

You may be surprised to know that Canada – unlike most nations in the world – doesn’t operate under one set of laws. There are two (actually, three) legal systems in Canada. In Quebec, by grace of the province’s history as a French colony, Civil law is the legal system. In the rest of Canada, Common law holds sway. While they have a lot in common, there are some key differences between the two:

1. Precedent rules in Common Law

Under common law, the law is set through precedent, a doctrine called by its Latin term, stare decisis. This means that judges are obliged to abide by earlier decisions by other judges working in the same court system as them, or by higher-level appeal courts. That means every decision made by a judge in a court becomes part of the common law, until it is appealed or overridden by a higher level court. In common law, legal research skills are paramount: finding a prior decision that supports a specific outcome is an essential skill for lawyers.
Quebec, however, operates under a civil code, itself derived from the Code Napoleon (Napoleonic Code). This means that the province operates under a fixed system of laws, and justices make decisions according to that code. Precedent can be used to help guide decisions for consistency, but precedent is not binding.

2. Academics’ influence varies by system

Since precedent informs, but doesn’t govern the civil law system, academics have a unique voice in Quebec law, compared to the rest of Canada: since judges have more latitude to interpret the civil code as they see fit, the opinions of scholars have more weight than in common law jurisdictions, and judges often turn to the “doctrine” of academic commentary for guidance.
In common law, academic work can be a “secondary source” to precedent, and help judges make new decisions, but does not outweigh clear precedent.

3. Afraid of jury duty? Move to Quebec!

At the provincial level, juries can be a factor at any trial in the common law system. In Quebec, though, under civil law, juries are much more rare, and don’t usually come into play in private disputes.
Criminal law is not affected by the common/civil law split, as criminal law and procedure is federal, public law – the right to a jury trial in criminal matters, particularly serious ones, is governed by federal, not provincial laws.

4. Both terms are confusing as heck

Be sure not to confuse common law, the legal system, with common-law, the relationship status. Common-law relationships can vary in definition according to jurisdiction, but are recognized under both the civil and common law.
While we’re at it, civil law, the system of laws, is not the same as “civil law” as a term related to “public law” – in the latter case, “civil law” is a synonym for “private law,” and describes any legal relationship between a person and other people, as opposed to a person and the state itself.

Wait — didn’t you mention a third legal system?

Aboriginal and treaty rights are recognized as legally binding by the Canadian Constitution – Indigenous laws can be incorporated into these rights, and also form a very important part of the tapestry of Canadian law.

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