Legal Maxims

Principle of legality

no one can be convicted of, or punished for, a crime unless the law defined the crime and prescribed the punishment before the person engaged in the behavior that was defined as a crime.

Titius semper est errare acquitando quam in puniendo

It is always safer to err in acquitting than in punishing.

Blackstone's Ratio

It is better that ten guilty persons escape than that one innocent person suffer.

Melior est justitia vere praeveniens, quam severe puniens

Justice truly preventing is better that severely punishing.

ignorantia legis non excusat

Latin: ignorance of the law is not an excuse

Culpae poena par esto

Let the punishment equal the crime.

Dura lex sed lex

The law is hard, but it is the law.

actus non facit reum nisi mens sit rea

An act does not make a person guilty unless the mind is guilty.

Actus me invito factus non est meus actus

An act done by me against my will is not my act. (No person can be held liable for an involuntary act)

Mistake of Fact

Any mistaken belief other than a mistake of law. Examples include erroneous beliefs about the meaning of some term or about the identity of some person. In criminal law, a mistake of fact can usually operate as a defense so long as it is reasonable.

El que es cuesa de la causa es causa del mal causado

He who is the cause of the cause is the cause of the evil caused.

Ignorantia facti excusat

Ignorance of a fact excuses.

In dubio, pro reo

In doubt, for the accused

Cogitationis poenam nemo meretur

No man deserves punishment for a thought.

Nemo bis punitur pro una et eodem delicto

No one can be punished for one and the same offense.

mala prohibita

Offenses prohibited by law but not wrong in themselves; Do not require criminal intent.

Mala in se

Offenses that are wrong by their very nature; Requires criminal intent.

Presumption of innocence

The accused shall be presumed innocent until the contrary is proved beyond reasonable doubt.

Mens Rea

The required criminal state of mind that the accused should have at the time of the commission of the offense.

Nullum crimen sine lege, nulla poena sine lege

There is no crime without a law; there is no penalty without a law.

Actus Reus and Mens Rea

guilty act and guilty mind