Cogitationis poenam nemo patitur

The Latin expression cogitationis poenam nemo patitur is used in the field of criminal law to express that only a conduct, and not a simple thought, can constitute a crime. This phrase originally appeared in the "Institutions" of the jurist Ulpian (170-228). Later, it appeared in the Digest, a compilation of Roman legal texts carried out by order of the Byzantine emperor Justinian in the sixth century.

Its translation would be "no one can be punished for their thoughts". According to this, thinking about stealing something is not punishable, while committing a robbery is. This principle of Roman law assumes that no thought or desire of a human being can be a criminal, until this manifestation of thought or desire is externalized, causing unjust conduct that causes damage to a protected legal asset.