Step 1: Understanding the Question:
The question asks about the legal doctrine that the Indian judiciary formally follows, as mentioned in the Constitution.
Step 2: Key Concept:
There are two main concepts here:
- Procedure established by law: A doctrine which means that a law that is duly enacted by the legislature is valid if it has followed the correct procedure. The court will not question the fairness or wisdom of the law itself.
- Due process of law: A broader doctrine which checks not only whether there is a law to deprive a person of their life and personal liberty, but also whether the law is fair, just, and not arbitrary.
Step 3: Detailed Explanation:
Article 21 of the Indian Constitution explicitly states, "No person shall be deprived of his life or personal liberty except according to procedure established by law."
This phrase was borrowed from the Japanese Constitution. Therefore, the formal process under which the Indian judiciary functions is the 'Procedure established by law'.
However, it is important to note that through judicial interpretation, especially since the {Maneka Gandhi v. Union of India} case (1978), the Supreme Court has expanded the meaning of 'procedure established by law' to include principles of fairness and justice, thus incorporating aspects of 'due process of law'. But constitutionally, the explicit phrase remains 'procedure established by law'.
Step 4: Final Answer
The Indian Constitution explicitly provides for the 'Procedure established by law' as the process under which the judiciary functions, particularly in the context of Article 21.