Criminal Law · Lexicon

Lexicon

Key terms explained in plain language — filter by letter or search below.

Principle of legality: The rule that a person may not be convicted or punished except in accordance with a clear, pre-existing law: nullum crimen, nulla poena sine praevia lege certa. It comprises five rules — ius acceptum, ius praevium, ius certum, ius strictum, and nulla poena sine lege — and is entrenched by the right to a fair trial (s 35(3) of the Constitution) and the rule of law.
Ius acceptum: The legality rule that conduct is punishable only if the law — statute or existing common law — already recognises it as a crime. Courts may not create new crimes; that is the task of the legislature.
Ius praevium: The legality rule against retrospectivity: a crime (and its penalty) must have existed when the accused acted. A court may develop or extend a common-law crime, but only for the future — never so as to convict the accused before it on a definition that did not exist when they acted (S v Masiya).
Ius certum: The legality rule requiring crimes to be defined clearly and precisely, so that people can know in advance what is prohibited. A crime so vague that its meaning cannot reasonably be ascertained may be struck down (void for vagueness).
Ius strictum: The legality rule that penal provisions are strictly interpreted and may not be extended by analogy to the accused's disadvantage. Ambiguity is resolved in favour of the accused.
Nulla poena sine lege: The legality rule as applied to punishment: no penalty may be imposed that is heavier than the one applicable when the offence was committed (Veldman v DPP; s 35(3)(l) and (n) of the Constitution).
Conduct (act): The requirement of voluntary human conduct — a willed act (or a qualifying omission) capable of being controlled by the will. Reflexes, convulsions and movements during unconsciousness or automatism are not “acts” and cannot found liability.
Automatism: Involuntary conduct performed without conscious control. Sane (non-pathological) automatism (caused by something other than mental illness — e.g. hypoglycaemia, concussion, sleep) leads to an ordinary acquittal (S v Stellmacher). Insane automatism (caused by mental illness) leads to the special verdict under s 78 of the Criminal Procedure Act.
Omission: A failure to act. An omission founds liability only where there was a legal duty to act positively, judged by the legal convictions of the community (the boni mores) — the categories of duty are not a closed list (Minister van Polisie v Ewels, a delict case whose test criminal law adopted by analogy).
Boni mores: The legal convictions of the community — the standard by which unlawfulness (including the existence of a legal duty to act) is judged. Conduct is unlawful when it conflicts with these convictions.
Causation: For crimes defined by a result, the conduct must have caused the result. The enquiry has two stages: factual causation (the conditio sine qua non / but-for test) and legal causation (a flexible policy test that limits liability to consequences sufficiently closely connected to the conduct).
Conditio sine qua non: The but-for test for factual causation: but for the accused's conduct, would the result have occurred? If not, factual causation is established (Minister of Police v Skosana). It is necessary but not sufficient — legal causation must still be shown.
Novus actus interveniens: A new intervening cause that is abnormal, independent and unforeseen, which breaks the chain of causation and relieves the accused of liability. Foreseeable events do not break the chain — e.g. medical treatment of an unlawfully-inflicted wound (S v Tembani), or switching off a ventilator on a brain-dead patient (S v Williams).
Unlawfulness: The element that conduct satisfying the definition of a crime also conflicts with the legal order (the boni mores). Conduct is presumed unlawful, but a ground of justification excludes unlawfulness, making the conduct lawful.
Ground of justification: A circumstance that excludes unlawfulness, so that no crime is committed — e.g. private defence, necessity, consent, official capacity, and obedience to a lawful order. It is distinct from a defence that excludes fault.
Private defence: A ground of justification: warding off an unlawful attack on a legally protected interest (of oneself or another — R v Patel). The attack must be unlawful and imminent/commenced; the defence must be directed at the attacker, necessary, and proportionate.
Necessity: A ground of justification: infringing a legal interest to avert a threat arising from circumstances or from human compulsion (duress). Unlike private defence, the harm may fall on an innocent third party. Necessity can, exceptionally, justify even murder where a reasonable person would also have yielded (S v Goliath).
Putative defence: An honest but mistaken belief that a ground of justification exists (e.g. that one is under attack). It is not a ground of justification — the conduct remains unlawful — but it negates fault (dolus), and may reduce murder to culpable homicide (S v De Oliveira).
Criminal capacity: The mental ability, at the time of the act, both (1) to appreciate the wrongfulness of the conduct and (2) to act in accordance with that appreciation. If either leg is absent (through youth, mental illness, or in a given case intoxication or severe stress) the accused lacks capacity (S v Mahlinza).
Non-pathological criminal incapacity: A lack of criminal capacity not caused by mental illness — e.g. from severe intoxication or provocation/emotional stress. It leads to an ordinary acquittal (unlike pathological incapacity, which yields the s 78 special verdict), but is equated with sane automatism and applied with great caution (S v Eadie).
Fault (mens rea): The blameworthy mental attitude the law requires, in one of two forms — intention (dolus) or negligence (culpa). Fault must exist as to every element of the crime and must coincide with the unlawful conduct (contemporaneity).
Dolus (intention): Intention, in three forms: dolus directus (the result is the aim), dolus indirectus (the result is a substantially certain side-effect of the aim), and dolus eventualis (foresight of the result as a real possibility plus reconciliation with it). Intention also requires knowledge of unlawfulness.
Dolus eventualis: The form of intention consisting of (1) subjective foresight of the real possibility of the result and (2) reconciliation with (taking into the bargain) that possibility. Foresight without reconciliation is conscious negligence (luxuria), not intention (S v Humphreys).
Culpa (negligence): The objective fault form: a reasonable person in the accused's position would have foreseen the reasonable possibility of the result and taken steps to guard against it, and the accused failed to do so (S v Ngubane). For culpable homicide the death itself must be reasonably foreseeable (S v Van As).
Mistake: A genuine mistake of fact or of law that excludes knowledge of a definitional element or of unlawfulness excludes intention. Since S v De Blom, ignorance of the law can be a defence — “ignorance of the law is no excuse” is no longer South African law. An unreasonable mistake may still leave negligence.
Common purpose: The doctrine that where two or more people share a common purpose to commit a crime, the conduct of each in furthering it is imputed to the others — individual causation need not be proved (S v Safatsa). It arises by prior agreement or by active association (the five Mgedezi requirements); it is constitutional (S v Thebus).
Accomplice: A participant who does not satisfy all the definitional elements of the crime (so is not a perpetrator) but consciously furthers its commission, with the required intention. Accomplice liability is accessory — it presupposes a perpetrator who commits or attempts the crime.
Accessory after the fact: A person who, after the crime is completed, unlawfully and intentionally helps the perpetrator to evade justice — e.g. by hiding the offender, destroying evidence, or misleading investigators.
Inchoate crimes: “Anticipatory” crimes that impose liability before (or without) the completed crime: attempt (common law), conspiracy, and incitement (both under s 18(2) of the Riotous Assemblies Act 17 of 1956).
Attempt: A common-law crime: an intention to commit a specific crime plus conduct that goes beyond mere preparation (the commencement of execution), where the crime is not completed. Voluntary withdrawal is a defence only in an uncompleted attempt (R v Schoombie).
Conspiracy: A statutory inchoate crime (s 18(2)(a) of the Riotous Assemblies Act 17 of 1956): an agreement between two or more persons to commit (or aid/procure) a specific offence. The agreement itself is punishable, whether or not the crime follows.
Incitement: A statutory inchoate crime (s 18(2)(b) of the Riotous Assemblies Act 17 of 1956): inciting, instigating, commanding or procuring another to commit an offence. After the EFF case it reaches only the incitement of a serious offence.