4 Excusable Defences

4.1 Infancy (Immaturity)The principle: children below the age of criminal responsibility cannot commit crimes — doliincapax: the law's presumption of incapacity to do wrong. Nepal's Code scheme (by principle): a graded ladder — below the minimum age (10 years under the Code's scheme), no criminal liability at all; then ascending bands of partial capacity with mandatory mitigation (reduced punishment), juvenile-justice procedure under the Children's Act applying to minors (diversion, reformative dispositions, borstal-type custody — the child's welfare principle). Comparative: the doli incapax rebuttable presumption (10–14) of common law's retreat; the ICCPR/Beijing Rules' child-justice standards (rehabilitation over retribution). The analytical points: infancy negates capacity (a status defence, no inquiry into the particular child's understanding below the fixed line); the age at the time of the act governs; the juvenile system's dilemma — protection vs. public alarm at grave juvenile crime.4.2 InsanityThe principle: no punishment where, at the time of the act, disease of the mind deprived the actor of the capacity to know the act's nature, or its wrongness — furiosus nisi furore solum interfici potest — the madman is punished by his madness alone. The M'Naghten Rules (1843 — the common law's charter, still the exam's core): to establish the defence, it must be proved that at the act's time, under a defect of reason from disease of the mind,…