Mental states that determine the degree of guilt or culpability in criminal law are generally classified from highest (most worthy of blame or punishment) to lowest as: (1) intentional; (2) knowing; (3) reckless; and (4) criminal negligence.

A person acts with criminal negligence, or is criminally negligent, with respect to circumstances surrounding his conduct or the result of his conduct when he ought to be aware of a substantial and unjustifiable risk that the circumstances exist or the result will occur. The risk must be of such a nature and degree that the failure to perceive it constitutes a gross deviation from the standard of care that an ordinary person would exercise under all of the circumstances, as viewed from the accused person’s standpoint at the time of the alleged criminal negligence.

Criminal offenses or crimes often specify the culpable mental state the prosecution is required to prove to convict a defendant of the offense. These culpable mental states are generally defined in the relevant state or federal statutes—usually in the penal or criminal code.

In Oregon, as in many jurisdictions, the mental state of an individual plays a crucial role in determining their degree of guilt or culpability in criminal law. The mental states are typically ranked from most to least blameworthy as follows: (1) intentional, (2) knowing, (3) reckless, and (4) criminal negligence. Criminal negligence in Oregon is defined as failing to be aware of a substantial and unjustifiable risk that results from one's conduct, where such failure is a gross deviation from the standard of care an ordinary person would exercise in the same situation. This definition is codified in the Oregon Revised Statutes (ORS), which detail the elements, including the mental state, that the prosecution must prove beyond a reasonable doubt to secure a conviction for a criminal offense. The specific mental state required varies by crime and is outlined in the relevant statutes within the state's penal or criminal code.