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:
- Had a mental defect
- Which either:
- Prevented him from knowing the nature and quality of the act he was doing or
- From knowing that what he was doing was wrong.
Wrongfulness can be understood in one of two ways:
- 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.