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 South Carolina, as in many jurisdictions, the mental state of an individual at the time of committing a crime is crucial in determining their degree of guilt or culpability. The mental states are typically ranked from most to least blameworthy: intentional, knowing, reckless, and criminal negligence. Intentional acts are those committed with a purpose or desire to cause a specific result. Knowing acts are those where the individual is aware that their conduct is almost certain to cause a particular result. Reckless behavior involves conscious disregard of a substantial and unjustifiable risk. Criminal negligence occurs when an individual fails to perceive a substantial and unjustifiable risk, and this failure represents a significant deviation from the standard of care an ordinary person would exercise. In South Carolina, these mental states are defined within the state's penal code, and the prosecution must prove the requisite mental state to secure a conviction for crimes that specify such a requirement.