This major study advances an interpretation of criminal justification defenses that views them as an integral component of the structure of the criminal law. The book extends the traditional scope of the legal and philosophical discussion of justification defenses. It integrates philosophical analysis with a consideration of contemporary applications, it shows how these defenses are key components of criminal law, and it explores the relationship between legal and moral justification.

This is a book about the role that psychological impairment should play in a theory of criminal liability. Criminal guilt in the Anglo-American legal tradition requires both that the defendant committed some proscribed act and did so with intent, knowledge, or recklessness. The second requirement corresponds to the intuitive idea that people should not be punished for something they did not do "on purpose" or if they "did not realize what they were doing." Although intuitive, this underlying idea can be highly controversial in practice, especially in cases involving the insanity defense. This...