In law, knowledge is one of the degrees of mens rea (the "guilty mind") that constitute part of a crime. It refers to the actor's awareness that their conduct is of a particular nature, that attendant circumstances exist, or that it is practically certain to cause a specified result. The mens rea of knowledge concerns knowledge about certain facts rather than knowledge of the law itself. It is defined as "a positive belief that a state of affairs exists."
Knowledge in the legal context is generally categorized into three types: actual, constructive, and imputed.
Actual knowledge exists when a defendant is subjectively aware of a fact. The standard is subjective, and the defendant's belief need not be reasonable, only honest. For example, in R v. Williams, a defendant who intervened in what he thought was a mugging (but was actually a citizen's arrest) had his mistake upheld as a defence against assault charges. In Beckford v. R, a police officer who shot and killed a person claimed he honestly believed the victim was shooting at him; the court held that the correct test was whether the defendant "honestly believed" facts that, if true, would establish a defence.
Constructive knowledge arises where a defendant suspects that circumstances exist and "deliberately decides not to make any further enquiries" in case their suspicions prove well-founded. A common example is a person who purchases significantly inexpensive and unprovenanced but desirable items from a stranger; such a person is likely to be fixed with constructive knowledge that the items were stolen.
Imputed knowledge is relevant in strict liability offences and in corporate crime. For instance, if a bar manager delegates duties to others and those others know of unlawful activities on the premises, the manager can be fixed with imputed knowledge of those unlawful activities.
In English law, a specific example is the offence of knowingly being a passenger in a vehicle taken without consent (TWOC) under section 12 of the Theft Act 1968. The prosecution must prove not only that the defendant was a passenger and that the vehicle was taken without consent, but also that the defendant knew it was taken without consent.
The concept distinguishes knowledge from other mental states such as intention (higher culpability) and recklessness (lower culpability), forming part of the hierarchy of fault elements in criminal law.
