The statement "A law is void only to the extent of inconsistency or contravention with the relevant Fundamental Right" is a direct articulation of the doctrine of severability (also known as the doctrine of separability) as applied to Article 13 of the Indian Constitution. Article 13 is a cornerstone of fundamental rights, declaring that any law inconsistent with or in derogation of fundamental rights shall be void.

Article 13 and the Doctrine of Severability: Article 13(1) states that "All laws in force in the territory of India immediately before the commencement of this Constitution, in so far as they are inconsistent with the provisions of this Part, shall, to the extent of such inconsistency, be void." Article 13(2) states that "The State shall not make any law which takes away or abridges the rights conferred by this Part, and any law made in contravention of this clause shall, to the extent of the contravention, be void."

The phrase "to the extent of such inconsistency" or "to the extent of the contravention" is crucial. It means that if only a part of a statute is inconsistent with a fundamental right, and that part can be separated from the rest without affecting the legislative intent of the valid portion, then only the inconsistent part will be declared void, and the remaining part will remain operative. The entire law is not struck down unless the invalid part is so intertwined with the valid part that they cannot be separated, or if the remaining valid part would be meaningless or contrary to the legislative intent. This doctrine aims to preserve the legislative will as much as possible while upholding constitutional supremacy.

Key Principles of Severability:

1. Separability of Provisions: If the valid and invalid parts of a law are distinct and separable, only the invalid part is struck down. The court examines whether the valid part can stand independently.
2. Legislative Intent: The primary test is whether the legislature would have enacted the valid part even if it knew that the rest was invalid. If the valid part can stand independently and fulfill the legislative purpose, it is retained.
3. Interdependence: If the invalid part is so integral to the valid part that its removal would render the remaining part unintelligible, unworkable, or fundamentally alter the legislative scheme, then the entire law may be struck down.

Decided Cases Illustrating the Doctrine:

1. A.K. Gopalan v. State of Madras (1950): In this landmark case, the Preventive Detention Act, 1950, was challenged. Section 14 of the Act, which prohibited the disclosure of grounds of detention, was found to be violative of Article 22(5) (right to be informed of grounds of detention and make representation). The Supreme Court applied the doctrine of severability and held that only Section 14 was unconstitutional and void, while the rest of the Act remained valid and enforceable. This demonstrated that the invalid part could be severed without affecting the core purpose of the Act, which was preventive detention itself.

2. R.M.D. Chamarbaugwalla v. Union of India (1957): This case involved the Prize Competitions Act, 1955, which regulated prize competitions. The Act covered both competitions of a gambling nature (which are not protected by Article 19(1)(g) - freedom to practice any profession) and those involving substantial skill (which are protected). The Supreme Court held that the provisions of the Act were severable. It declared that the Act was valid insofar as it applied to competitions of a gambling nature, but it could not be applied to competitions predominantly based on skill, as that would violate fundamental rights. The Court laid down several tests for severability, including whether the valid and invalid parts are distinct, whether the legislative intent would be defeated by severance, and whether the remaining part is a complete code in itself.

3. Minerva Mills Ltd. v. Union of India (1980): While primarily known for reinforcing the basic structure doctrine, this case also implicitly applied severability. The 42nd Amendment Act had inserted Articles 31C (as amended) and 368(4) and 368(5), which sought to give primacy to Directive Principles over Fundamental Rights and remove judicial review of constitutional amendments. The Supreme Court struck down these specific provisions as unconstitutional for violating the basic structure (judicial review and limited amending power), but the rest of the 42nd Amendment remained valid. This illustrates that even within a constitutional amendment, specific offending parts can be severed.

Conclusion: The doctrine of severability, as enshrined in Article 13 and consistently applied by the Indian judiciary, is a pragmatic and essential tool. It prevents the wholesale invalidation of legislation when only a specific part infringes upon fundamental rights. By striking down only the offending portions, it upholds the legislative will to the maximum possible extent while simultaneously safeguarding the fundamental rights guaranteed by the Constitution. This approach reflects a balanced judicial philosophy, preserving valid laws while ensuring constitutional supremacy and protecting individual liberties.