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 Missouri, the mental states that determine the degree of guilt or culpability in criminal law are indeed categorized into four primary levels: intentional, knowing, reckless, and criminal negligence. These mental states are crucial in assessing the level of blame or punishment a defendant may face. Specifically, criminal negligence in Missouri is defined as failing to be aware of a substantial and unjustifiable risk that results from one's conduct, where such failure represents a significant departure from the standard of care an ordinary person would exercise in the same situation. This risk must be apparent and serious enough that not recognizing it would be considered a gross deviation from what is expected of a reasonable person. For a prosecutor to secure a conviction, they must prove that the defendant acted with the culpable mental state as defined by the relevant statute for the specific crime. These definitions are typically found in the state's penal or criminal code, and they guide the court in determining the appropriate level of culpability and corresponding legal consequences.