6. ... In view of the plea raised it is desirable to consider the meaning of the expression “unsoundness of mind” in the context of Section 84 of the Indian Penal Code and for its appreciation, we deem it expedient to reproduce the same. It reads as follows:
“84. Act of a person of unsound mind.— Nothing is an offence which is done by a person who, at the time of doing it, by reason of unsoundness of mind, is incapable of knowing the nature of the act, or that he is doing what is either wrong or contrary to law.”
Section 84 of the Indian Penal Code is found in its Chapter IV, which deals with general exceptions.
7. From a plain reading of the aforesaid provision it is evident that an act will not be an offence, if done by a person who, at the time of doing the same by reason of unsoundness of mind, is incapable of knowing the nature of the act, or what he is doing is either wrong or contrary to law. But what is unsoundness of mind? This Court had the occasion to consider this question in the case of Bapu alias Gujraj Singh v. State of Rajasthan, (2007) 8 SCC 66, in which it has been held as follows:
“The standard to be applied is whether according to the ordinary standard, adopted by reasonable men, the act was right or wrong. The mere fact that an accused is conceited, odd, irascible and his brain is not quite all right, or that the physical and mental ailments from which he suffered had rendered his intellect weak and had affected his emotions and will, or that he had committed certain unusual acts in the past, or that he was liable to recurring fits of insanity at short intervals, or that he was subject to getting epileptic fits but there was nothing abnormal in his behaviour, or that his behaviour was queer, cannot be sufficient to attract the application of this section.”
8. The scope and ambit of the Section 84 of the Indian Penal Code also came up for consideration before this Court in the case of Hari Singh Gond v. State of Madhya Pradesh, (2008) 16 SCC 109 = AIR 2009 SC 31 in which it has been held as follows:
“Section 84 lays down the legal test of responsibility in cases of alleged unsoundness of mind. There is no definition of ‘unsoundness of mind’ in IPC. The courts have, however, mainly treated this expression as equivalent to insanity. But the term ‘insanity’ itself has no precise definition. It is a term used to describe varying degrees of mental disorder. So, every person, who is mentally diseased, is not ipso facto exempted from criminal responsibility. A distinction is to be made between legal insanity and medical insanity. A court is concerned with legal insanity, and not with medical insanity.”
9. In our opinion, an accused who seeks exoneration from liability of an act under Section 84 of the Indian Penal Code is to prove legal insanity and not medical insanity. Expression “unsoundness of mind” has not been defined in the Indian Penal Code and it has mainly been treated as equivalent to insanity. But the term insanity carries different meaning in different contexts and describes varying degrees of mental disorder. Every person who is suffering from mental disease is not ipso facto exempted from criminal liability. The mere fact that the accused is conceited, odd, irascible and his brain is not quite all right, or that the physical and mental ailments from which he suffered had rendered his intellect weak and affected his emotions or indulges in certain unusual acts, or had fits of insanity at short intervals or that he was subject to epileptic fits and there was abnormal behaviour or the behaviour is queer are not sufficient to attract the application of Section 84 of the Indian Penal Code.
10. Next question which needs consideration is as to on whom the onus lies to prove unsoundness of mind. In law, the presumption is that every person is sane to the extent that he knows the natural consequences of his act. The burden of proof in the face of Section 105 of the Evidence Act is on the accused. Though the burden is on the accused but he is not required to prove the same beyond all reasonable doubt, but merely satisfy the preponderance of probabilities. The onus has to be discharged by producing evidence as to the conduct of the accused prior to the offence, his conduct at the time or immediately after the offence with reference to his medical condition by production of medical evidence and other relevant factors. Even if the accused establishes unsoundness of mind, Section 84 of the Indian Penal Code will not come to its rescue, in case it is found that the accused knew that what he was doing was wrong or that it was contrary to law. In order to ascertain that, it is imperative to take into consideration the circumstances and the behaviour preceding, attending and following the crime. Behaviour of an accused pertaining to a desire for concealment of the weapon of offence and conduct to avoid detection of crime go a long way to ascertain as to whether, he knew the consequences of the act done by him. Reference in this connection can be made to a decision of this Court in the case of T.N. Lakshmaiah v. State of Karnataka, (2002) 1 SCC 219, in which it has been held as follows:
“9. Under the Evidence Act, the onus of proving any of the exceptions mentioned in the Chapter lies on the accused though the requisite standard of proof is not the same as expected from the prosecution. It is sufficient if an accused is able to bring his case within the ambit of any of the general exceptions by the standard of preponderance of probabilities, as a result of which he may succeed not because that he proves his case to the hilt but because the version given by him casts a doubt on the prosecution case.
10. In State of M.P. v. Ahmadull, AIR 1961 SC 998, this Court held that the burden of proof that the mental condition of the accused was, at the crucial point of time, such as is described by the section, lies on the accused who claims the benefit of this exemption vide Section 105 of the Evidence Act [Illustration (a)]. The settled position of law is that every man is presumed to be sane and to possess a sufficient degree of reason to be responsible for his acts unless the contrary is proved. Mere ipse dixit of the accused is not enough for availing of the benefit of the exceptions under Chapter IV.
11. In a case where the exception under Section 84 of the Indian Penal Code is claimed, the court has to consider whether, at the time of commission of the offence, the accused, by reason of unsoundness of mind, was incapable of knowing the nature of the act or that he is doing what is either wrong or contrary to law. The entire conduct of the accused, from the time of the commission of the offence up to the time the sessions proceedings commenced, is relevant for the purpose of ascertaining as to whether plea raised was genuine, bona fide or an afterthought.”