Introduction
This essay examines the natural law perspective on the maxim “an unjust law is no law” through the lens of key naturalist theorists, alongside a discussion of the core principles of natural law and their relevance to constitutional and human rights adjudication. Natural law theory posits that law derives its authority from universal moral principles, often rooted in reason or divine will, rather than merely from human enactment. The first part explores how theorists such as Thomas Aquinas and Lon Fuller interpret the relationship between justice and law, arguing that laws lacking moral legitimacy may forfeit their status as law. The second part evaluates the principles of natural law and their practical application in modern legal contexts, particularly in safeguarding human rights. By integrating theoretical insights with contemporary relevance, this essay aims to provide a sound understanding of natural law’s role within jurisprudence.
Part 1: “An Unjust Law is No Law” – Naturalist Theorists’ Perspectives
The assertion that “an unjust law is no law” is central to natural law theory, which prioritises moral validity over mere legal enactment. Thomas Aquinas, a foundational natural law thinker, argued that laws must align with the “eternal law” derived from divine reason. In his seminal work, *Summa Theologiae*, Aquinas posits that a law lacking justice—defined as conformity to right reason and the common good—ceases to be a true law and becomes a “corruption of law” (Aquinas, 1947). For Aquinas, such laws do not bind in conscience, though obedience might be pragmatically necessary to avoid societal disorder. This view suggests a critical approach to legal authority, where moral scrutiny is essential.
Similarly, Lon Fuller, a 20th-century natural law theorist, framed the issue through his concept of the “inner morality of law.” Fuller argued that laws must adhere to procedural principles such as clarity, publicity, and non-retroactivity to be considered valid. In The Morality of Law, he contends that a legal system failing these基準—such as through gross injustice—loses its claim to legitimacy (Fuller, 1969). While Fuller’s perspective is less tied to divine principles than Aquinas’, it still underscores that laws devoid of moral integrity cannot command true obedience. Both theorists, despite differing foundations, converge on the idea that justice is intrinsic to law’s validity, reflecting a limited but evident critical approach to legal norms.
Part 2: Principles of Natural Law and Relevance to Constitutional and Human Rights Adjudication
Natural law is underpinned by core principles, including the belief in universal moral truths accessible through reason, the prioritisation of the common good, and the inherent dignity of individuals. These principles have significant relevance in constitutional and human rights adjudication. For instance, natural law’s emphasis on inalienable rights—articulated historically by thinkers like John Locke—underpins modern human rights frameworks, such as the European Convention on Human Rights (ECHR). Courts often invoke concepts of fundamental fairness and human dignity, resonating with natural law ideals, when interpreting constitutional provisions.
In UK jurisprudence, while the legal system is predominantly positivist, natural law principles subtly influence human rights adjudication. The Human Rights Act 1998, incorporating ECHR provisions, enables judges to assess legislation for compatibility with fundamental rights. Cases like R (Pretty) v Director of Public Prosecutions [2001] UKHL 61 illustrate how courts grapple with moral questions—here, the right to die—echoing natural law’s concern for human dignity, even if not explicitly cited. Furthermore, natural law offers a framework for critiquing unjust laws in constitutional contexts, providing theoretical grounding for judicial review when legislation violates universal moral standards (Finnis, 1980). However, its relevance is arguably limited by the dominance of legal positivism and parliamentary sovereignty in the UK, which prioritise enacted law over moral ideals.
Conclusion
In conclusion, natural law theorists like Aquinas and Fuller provide compelling arguments supporting the maxim that an unjust law is no law, asserting that moral legitimacy is essential for legal validity. While their approaches vary—Aquinas grounding law in divine reason and Fuller in procedural morality—they collectively challenge the notion of law as mere authority. Moreover, the principles of natural law, emphasising universal rights and the common good, remain relevant in constitutional and human rights adjudication, offering a moral lens through which to evaluate laws, even in predominantly positivist systems like the UK’s. Though limited by practical constraints, natural law continues to inform debates on justice and legality, underscoring its enduring significance in jurisprudence. This interplay of theory and practice highlights the importance of critically assessing laws against moral benchmarks, ensuring they serve humanity’s broader ethical imperatives.
References
- Aquinas, T. (1947) *Summa Theologiae*. Translated by Fathers of the English Dominican Province. Benziger Bros.
- Finnis, J. (1980) *Natural Law and Natural Rights*. Oxford University Press.
- Fuller, L. L. (1969) *The Morality of Law*. Yale University Press.
