Mens Rea vs Actus Rea: What’s the Difference?

By Last Updated: November 3, 2023

Mens Rea vs Actus ReaFor the Crown to secure a conviction they need evidence that will establish the offence for which the accused is charged, that too beyond a reasonable doubt. Each offence in the Criminal Code is broken down into “elements” that are known as the actus reus and the mens rea. Both the actus reus and mens rea are considered essential elements that must be proven, beyond a reasonable doubt, before a judge can return a guilty verdict.

The specific elements of the actus reus and mens rea are derived from the explicit working of the offence in the Criminal Code. In other cases, the act or acts constituting an offence are not defined by statute, and determining what qualifies as criminal conduct is left to the common law. Sometimes this is straightforward enough, either because there can be no dispute about what a term means, or because it is merely a matter of applying some dictionary definition. In other cases, however, the task is much more difficult. For example, while sexual assault is a distinct offence, nowhere in the Criminal Code4 is there a definition of “sexual”, which has required the courts to create a somewhat intricate definition of their own.

What is Actus Reus?

Actus reus is Latin for “guilty act.” The actus reus is the event, action, consequence or situation prohibited by the offence provision. The actus reus generally consists of an act bringing about a prohibited consequence — for example, death.

The actus reus often refers to more than simply the act itself. The actus reus refers to a bundle of components that together form the guilty component. The onus is on the Crown to prove that the accused committed the prohibited act beyond a reasonable doubt.

The actus reus or ‘prohibited act’ requires:

  • Voluntariness
  • Acts or Omissions
  • Circumstances of the Act or Omission; or
  • Consequences of the Act or Omission.


As a general rule, an act must be the voluntary act of an accused in order for the actus reus to exist. This is fundamental to criminal liability as voluntariness only punishes those who can conform to the law.  However, this is a general rule of criminal law, but it is not absolute. For example, one well-recognized exception is made relating to the defence of non-insane automatism.


An omission can make out an actus reus where there is a legal duty to act. Several Code provisions criminalize omissions based on duties set out in the offence provision itself—for example, section 129(b): failing to assist a police officer when requested, or section 252(1): failing to stop, give ID, and render assistance after being involved in an accident. Other offence provisions include as part of the actus reus the breach of a legal duty set out elsewhere in the law, For example, s. 220 – criminal negligence causing death. This offence draws on the definition of criminal negligence in 219:

Circumstances of the Act or Omission

Certain offences only criminalize acts that occur only within certain circumstances. Where the circumstances in which the conduct takes place are an essential element to the offence these are referred to as the “attendant circumstances” or “external circumstances”. For example, an external circumstance is the required proof of lack of consent in assault-based offences.

Consequences of the Act or Omission

The code definition of the Offence will sometimes describe necessary consequences that must arise for the Offence to be complete. This requires the crown to prove that the consequence occurred and that the consequence was caused by the Accused’s conduct.

Where the actus reus of an offence includes the element of causation (“dangerous driving causing death”), the Crown must prove causation BARD.

If the accused’s actions are the direct or main cause (i.e., the factual cause), then causation is made out. No need to go further.

But if the accused’s actions are only a contributing cause, the court must consider whether those actions are the ‘legal cause.’ The test for legal causation is whether the actions of the accused were a “contributing cause beyond the de minimus”. (Smithers)

Legal causation refers to a person’s moral responsibility for a prohibited consequence where his or her acts were a significant cause but not necessarily the only or main cause. (Smithers, Nette)

Examples of Actus Reus

Some examples of actus reus include the following:

  • Theft = taking or converting something
  • Assault =applied force to another person
  • Sexual interference = touching the complainant, under the age of 16, with a part of your body or object
  • Mischief = damaged property

What is Mens Rea?

Mens rea is Latin for “guilty mind.” An offence cannot be complete without proof of the requisite blameworthy state of mind, the “mens rea”.

Subjective mens rea

Subjective mens rea is concerned about what is going on in the individual’s mind at the time that the guilty act occurs. When an individual is charged with a subjective mens rea crime, the Crown must satisfy the judge that the accused subjectively intended to commit the prohibited act.

The types of subjective mens rea include the following:

  • Intent
  • Knowledge
  • Wilful blindness
  • Recklessness


Intent focuses on an individual’s desire to bring about a specific consequence. This means that intent focuses on the accused’s desire to commit the dangerous or guilty act.

In R v Théroux, [1993] 2 SCR 5, it was indicated that “subjective awareness of the consequences can be inferred from the act itself, barring some explanation casting doubt on such inference.”

For example, if a person plans to assault someone and finds a target, that person will possess intent.


Knowledge relates to the awareness of a fact or circumstance. This means that knowledge focuses on what the accused knew, not what the accused should have known.

For example, if a person gets mad at someone and pushes them, inflicting harm may not have been their primary goal. However, if the person was aware that the harm would be a predictable result of the action, then it can be said there was knowledge.

Wilful Blindness

Wilful blindness is a substitute for knowledge as it attributes knowledge to individuals as it arises in circumstances where the accused virtually knows what is happening, but they intentionally look the other way.

However, it is important to note that, as indicated in R v Briscoe, 2008 ABCA 327, wilful blindness “serves to override attempts to self-immunize against criminal liability by deliberately refusing to acquire actual knowledge” and the courts are indicating that the accused should have known something.

For example, if you have a strong suspicion that you are engaged in criminal activity but you prevent yourself from learning about the situation, you are wilfully blind.


Recklessness focuses on the accused’s awareness and his irresponsibility. It is when an accused is aware that the conduct could bring about the prohibited criminal act, but they persist despite the risk.

For example, if you are drinking and driving and you cause injury to another because of this, you are reckless.

Objective mens rea

Objective mens rea looks at the accused’s actions from an objective standard. This means that it focuses on what the accused should have known and the standard is that of a reasonable person.

Examples of Mens Rea

Some examples of mens reas include the following:

  • Theft = intention
  • Assault = intent
  • Sexual interference = intent
  • Mischief = willfull blindess or recklessness

Simultaneous Principle

As a general principle, the actus reus and mens rea must concur. However, it is important to note that the simultaneous principle is not to be applied strictly. This means that both the actus reus and men’s rea do not need to be “completely concurrent” throughout the commission of an offence but it is important that they must coincide at some point.


What is the difference between mens rea and actus reus in criminal law?

Actus reus refers to the “guilty act” whereas mens rea refers to the “guilty mind”.

What is actus reus in criminal law?

Actus reus is Latin for “guilty act.” The actus reus element of an offence is in effect the required act of the offence.

What is mens rea in criminal law?

Mens rea is Latin for “guilty mind.” The mens rea element of an offence refers to the intent or awareness of wrongdoing behind the crime.

About The Author

Michael Oykhman

Managing Partner

Michael Oykhman is a senior lawyer and founder of Strategic Criminal Defence, a full-service criminal law firm with central law offices across Western Canada and Ontario.

My professional experience consists of countless court appearances and thousands of successful defences and satisfied clients. Over the last 10 years, I have worked to build a law office where all the lawyers share our collective experience, resources, and passion to help people. Our team approach to legal representation is client–rather than only law–centred. We look for opportunities to add value to our clients through strategic thinking and creative solutions.

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