Legal insanity under Section 84 can be proved from total circumstances showing incapacity to know the act's nature.

A plea of legal insanity under Section 84 of the Indian Penal Code is made out when the accused, on a preponderance of probabilities, shows that at the time of the act he was incapable of knowing its nature or that it was wrong or contrary to law. The burden under Section 105 of the Indian Evidence Act lies on the accused, but it is assessed on the civil standard and may be discharged from the totality of circumstances before, during, and after the . On the evidence of longstanding paranoid schizophrenia and conduct consistent with delusion, the conviction and sentence could not be sustained.

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Issues: Whether the appellant was entitled to the benefit of the general exception for unsoundness of mind under Section 84 of the Indian Penal Code in respect of the offence of murder.

Analysis: The evidence showed a long history of paranoid schizophrenia, family history of psychiatric illness, prior and subsequent treatment, and conduct consistent with delusion rather than a mere transient anger reaction. The governing rule is that the accused must show circumstances bringing the case within Section 84, and under Section 105 of the Indian Evidence Act the burden is on the accused, though it is only the burden applicable in civil proceedings. The decisive inquiry is the accused's state of mind at the time of the act, which may be inferred from the circumstances preceding, attending, and following the occurrence. On the totality of the evidence, a reasonable doubt arose whether the appellant was incapable of knowing the nature of the act by reason of unsoundness of mind.

Conclusion: The appellant was entitled to the benefit of Section 84 of the Indian Penal Code, and the conviction and sentence could not be sustained.

Ratio Decidendi: In a plea of legal insanity, the accused may establish entitlement to Section 84 of the Indian Penal Code by showing, on a preponderance of probabilities and from the totality of circumstances, that at the time of the act he was incapable of knowing its nature or that it was wrong or contrary to law.

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