The insanity defense is used when a defendant, due to mental illness, lacks the cognitive or volitional capacity to guide conduct according to moral and legal factors so as to avoid injuring legally protected interests of another person or the community. Taken together, mental elements and excuses operate as the law's system for interpreting the quality of respect or disrespect for normative values expressed by the defendant's conduct. Mens rea elements and the voluntariness component of actus reus, including their intricate classification of states of mind and excuses, function as the criminal law's systematic guide for interpreting a defendant's disrespect for legally protected personal and community interests. This focus on the meaning individuals convey through their actions explains why choice, cognition, and volition are relevant in assessing criminal responsibility. 232 footnotes.