Editing M'Naghten rules (section)

===Knowledge that the act was wrong===
The interpretation of this clause is a subject of controversy among legal authorities, and different standards may apply in different jurisdictions.

"Wrong" was interpreted to mean ''legally'' wrong, rather than ''morally'' wrong, in the case of ''Windle'' 1952 2QB 826; 1952 2 All ER 1 246, where the defendant killed his wife with an overdose of [[aspirin]]; he telephoned the police and said, "I suppose they will hang me for this." It was held that this was sufficient to show that although the defendant was suffering from a mental illness, he was aware that his act was wrong, and the defence was not allowed. 

Under this interpretation, there may be cases where the mentally ill know that their conduct is legally prohibited, but it is arguable that their mental condition prevents them making the connection between an act being legally prohibited and the societal requirement to conform their conduct to the requirements of the criminal law.

As an example of a contrasting interpretation in which defendant lacking knowledge that the act was ''morally'' wrong meets the M'Naghten standards, there are the instructions the judge is required to provide to the jury in cases in New York State when the defendant has raised an insanity plea as a defence:

<blockquote>
... with respect to the term "wrong", a person lacks substantial capacity to know or appreciate that conduct is wrong if that person, as a result of mental disease or defect, lacked substantial capacity to know or appreciate either that the conduct was against the law or that it was against commonly held moral principles, or both.<ref>{{cite web|title=CJI2d[NY] INSTRUCTIONS OF GENERAL APPLICABILITY
|url=http://www.nycourts.gov/judges/cji/1-General/cjigc.shtml|publisher=New York State Unified Court System|access-date=2018-01-21}}</ref><ref>{{cite web|title=Jury Instructions for trying plea of "INSANITY (LACK OF CRIMINAL RESPONSIBILITY BY REASON OF MENTAL DISEASE OR DEFECT) Penal Law S.40.15"|url=http://www.nycourts.gov/judges/cji/1-General/Defenses/CJI2d.Insanity.pdf|publisher=New York State Unified Court System|access-date=2012-08-05}}</ref>
</blockquote>

There is other support in the authorities for this interpretation of the standards enunciated in the findings presented to the House of Lords regarding M'Naghten's case:

<blockquote>
If it be accepted, as can hardly be denied, that the answers of the judges to the questions asked by the House of Lords in 1843 are to be read in the light of the then existing case-law and not as novel pronouncements of a legislative character, then the [Australian] High Court's analysis in ''Stapleton's Case'' is compelling.  Their exhaustive examination of the extensive case-law concerning the defence of insanity prior to and at the time of the trial of M'Naughten establishes convincingly that it was morality and not legality which lay as a concept behind the judges' use of "wrong" in the M'Naghten rules.<ref>{{cite journal|last=Morris|first=Norval|journal=The Modern Law Review|volume=16|issue=4|pages=435–440|date=October 1953|doi=10.1111/j.1468-2230.1953.tb02133.x|title="wrong" in the M'naughten Rules|doi-access=free}}</ref>
</blockquote>