Step 1: Understanding the Concept:
In the law of evidence, a presumption is a rule that allows a court to assume a fact is true until it is rebutted. Presumptions are of two main types:
- Presumption of Fact (Presumptio hominis or naturalis): These are inferences that are naturally and logically drawn from the observation of a course of human conduct. They are rebuttable and the court has discretion whether to raise the presumption or not (often indicated by the phrase "may presume"). Example: A person in possession of stolen goods soon after the theft is either the thief or has received the goods knowing them to be stolen.
- Presumption of Law (Presumptio juris): These are rules of law that direct a certain conclusion to be drawn from a set of established facts. They can be either rebuttable (indicated by "shall presume") or irrebuttable/conclusive (indicated by "conclusive proof").
Step 2: Detailed Explanation:
Section 82 of the Indian Penal Code (IPC) states: "Nothing is an offence which is done by a child under seven years of age."
This is the principle of \textit{doli incapax} (incapable of forming criminal intent).
This is an irrebuttable presumption of law or a conclusive proof. The law conclusively presumes that a child below the age of seven is incapable of committing a crime. No evidence can be admitted to prove that the child had the maturity to understand the nature and consequences of their act. The court has no discretion; if the child is under seven, they cannot be held criminally liable.
Since it is a mandatory rule laid down by the law and it cannot be rebutted, it is a clear example of a (conclusive) presumption of law.