Step 1: Understanding the Question:
The question asks under what circumstances the defence of "mistake" is recognized as a valid excuse in Indian criminal law. It requires us to distinguish between mistake of fact and mistake of law.
Step 2: Key Concepts and Approach:
The defence of mistake is governed by two fundamental legal maxims:
• ‘Ignorantia facti doth excusat‘: Ignorance of fact excuses. This is recognized as a defence.
• ‘Ignorantia juris non excusat‘: Ignorance of law does not excuse. This is generally not recognized as a defence.
These principles are codified in Sections 76 and 79 of the Indian Penal Code.
Step 3: Detailed Explanation:
• Mistake of Fact (Sections 76 & 79 IPC): The IPC provides a defence for a person who commits an act which would otherwise be an offence, if they were mistaken as to the existence of a state of facts. The mistake must be made in good faith and must be a mistake of fact, not of law. For example, if a soldier fires on a mob by the order of his superior officer, believing in good faith that the order is lawful, he is protected by a mistake of fact.
• Mistake of Law: The law presumes that every person knows the law of the land. Allowing ignorance of the law as a defence would encourage people to remain ignorant and would make the administration of justice impossible. Therefore, claiming that you "did not know the act was illegal" is not a valid defence.
• Analyzing the Options:
- (A) "mistake of law alone" is never a defence.
- (B) A "mixed question" is not a recognized category for this defence. The legal element of the mistake would vitiate the defence.
- (C) "mistake of fact alone" is the correct basis for the defence as provided under the IPC.
Step 4: Final Answer:
Indian criminal law recognizes mistake as a good defence only when it is a mistake of fact made in good faith, and not a mistake of law.