M'Naghten test

[muhk-nawt-n]

noun

1. a rule that defines a person as legally insane when that person cannot distinguish right from wrong.

Word History and Origins

Origin of M'Naghten test¹

After Daniel M'Naghten (died 1865), defendant in a murder case adjudicated in England in 1843

Example Sentences

The M’Naghten test was used in most U.S. courts well into the 20th century, before the American Law Institute, a think tank, proposed a more liberal rule.

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New York federal judges then used the old M'Naghten test that a man is legally in sane only if he "did not know right from wrong", or did not understand the nature of his acts at the time of his crime.

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A supplement to the M'Naghten test added "irresistible impulse" but neither test seemed to fit Sheller.

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