Criminal Law

M'Naghten Test

The M'Naghten test, also known as the cognitive test, says that a person is not guilty by reason of insanity when he, at the time he committed the act:

1. Had a mental defect
2. Which either:
   1. Prevented him from knowing the nature and quality of the act he was doing or
   2. From knowing that what he was doing was wrong.
      • Wrongfulness

        Wrongfulness can be understood in one of two ways:

        1. Illegal
        2. Morally wrong
           • Moral wrongfulness can also be determined subjectively or objectively:
             • The objective standard asks whether the actor understood his actions violated society's view of morality.
             • The subjective test asks whether the actor was able to understand that his actions violated his own personal moral code.