Natural Law as Absolute and Universal Standard

The claim is well-founded in the respect that natural law's absolutism and universality provide a stable, non-relativistic foundation for human rights that consequentialism and relativism cannot supply — and Finnis' secular account demonstrates that this universality does not depend solely on theological premises.

Because natural law is grounded in the fixed, rational nature of human beings designed by God, it offers a cross-cultural and trans-historical moral standard: the same moral norms apply to everyone, everywhere, regardless of what any particular society or government decrees. This is a genuine strength against moral relativism — the view that moral norms are merely cultural conventions with no objective validity. The Nuremberg Trials illustrate the practical importance of this: Nazi war criminals were convicted not for breaking German law (which they often technically obeyed) but for violating universal moral standards — exactly the kind of absolute, universal norms that natural law claims to provide. Finnis, in Natural Law and Natural Rights, develops this into a secular account: by identifying basic goods that all human beings rationally recognise as worth pursuing (life, knowledge, friendship, practical reasonableness, religion, play, and aesthetic experience), he grounds a universal standard for human rights in practical reason rather than in any particular culture or theology.

However, the appearance of universality in natural law is partially misleading: the specific content of Aquinas' primary precepts — particularly the worship of God and the sexual ethics derived from the reproduction precept — is not universally accessible to reason but reflects particular theological commitments that not all humans share. A secular humanist or Buddhist can access the precepts of preserving life and living in an ordered society through reason, but "worship God" is only a moral obligation if God exists — which is precisely what the theory is supposed to establish independently of revelation. Furthermore, Finnis' list of basic goods has been criticised as itself reflecting culturally specific Western liberal assumptions: the inclusion of "play" and "aesthetic experience" while omitting community-specific goods recognised in non-Western traditions suggests that the universality claimed is not fully achieved.

Aquinas can respond that the four tiers of law — eternal, divine, natural and human law — mean that the natural law precepts accessible to reason are distinguished from divine law (accessible through scripture), so the "worship God" precept can be understood as accessible to natural reason without presupposing specific Christian revelation. All rational beings can recognise, through observation of the world and reflection on human nature, that some form of acknowledgement of a transcendent ordering principle is part of human flourishing — a claim supported by the cross-cultural universality of religious practice. Finnis can respond to cultural criticism by arguing that his basic goods are formal rather than content-specific: every culture values life, knowledge and community, even if they give these goods different specific expressions.

Both responses are partially persuasive: the four-tiers distinction does clarify the relationship between natural and divine law, and Finnis' formal account of basic goods is less culturally parochial than critics sometimes suggest. However, the Nuremberg example, while rhetorically powerful, does not strictly vindicate natural law specifically — other theories (Kantian universalisability, basic human dignity) can equally account for the wrongness of Nazi war crimes without invoking Aquinas. The universality of natural law is real but not uniquely guaranteed by natural law theory, and its dependence on a specific (if broadly theistic) account of human nature limits its genuinely neutral, secular application.

Natural law's universalism is therefore a genuine strength — particularly in grounding human rights talk and resisting relativism — but it is not as neutral or comprehensive as the theory claims, since its specific content reflects theological assumptions that not all rational agents will share.

Natural law's absolutism — often cited as its greatest strength — generates serious problems of moral rigidity in applied cases, and the situationist challenge from Fletcher reveals that the universal standard is less practically helpful than it appears.

Because natural law's primary precepts are absolute — applying universally with no exceptions — its secondary precepts are also absolute once derived. The secondary precept that contraception is always wrong (because it violates the primary precept of reproduction by frustrating its natural end) applies universally, regardless of circumstances: a married couple using contraception to space children responsibly, a woman using contraception to prevent pregnancy after rape, and a couple preventing the transmission of HIV all commit the same moral error on natural law's account. This absolutism is precisely what natural law presents as its strength, but it strikes many as a profound weakness: the refusal to permit any exceptions — even in cases of clearly preventable suffering — seems to prioritise abstract principle over genuine human welfare. Joseph Fletcher's situation ethics argues directly against this: agape (unconditional love) requires flexible, context-sensitive moral reasoning, not the mechanical application of fixed precepts.

However, Fletcher's situationism faces its own serious problems that partly vindicate natural law's absolutism: if every moral decision is made entirely on situational grounds, there is no stable protection against rationalised wrongdoing — a torturer could always claim the situation justified the act. Natural law's absolutism, by contrast, provides clear, bright-line protections (do not kill, do not deceive) that cannot be overridden by situational calculation, which is genuinely valuable in legal and political contexts where predictability and consistency matter. The doctrine of double effect also provides natural law with more flexibility than critics acknowledge: it permits actions that foreseeably cause harm (such as giving a terminal patient pain relief that may shorten life) provided the harm is not intended and is proportionate to the intended good.

The doctrine of double effect is a genuine and sophisticated resource, but it does not fully resolve the rigidity problem: it permits unintended harmful side-effects but does not permit directly intended actions that violate primary precepts, even when the harm would clearly be outweighed by consequences. A surgeon who must perform an abortion to save the life of a mother is still prohibited under strict natural law, even though virtually every other moral framework would regard this as not only permissible but obligatory. This case reveals that the absolutism which provides the theory's claimed strength also generates conclusions that are widely experienced as morally counterintuitive — and that a moral standard which produces such conclusions is failing in its primary function of guiding moral life.

Fletcher's challenge is more telling here than the simple assertion of situationism: the absolutism of natural law is both its claimed strength and its practical weakness, because the same feature that provides stability and resistance to rationalisation also generates inflexibility in extreme cases. The most honest verdict is that absolutism is a genuine strength in normal cases — where fixed precepts provide predictable, life-respecting guidance — but a genuine weakness in extreme cases — where rigid application produces manifestly harmful outcomes. The claim that absolutism is "one of the greatest strengths" is therefore half-right: it is a strength in some contexts and a weakness in others, and a moral theory that cannot distinguish between them is not as universally applicable as natural law claims to be.

Natural law's absolutism thus proves to be simultaneously its greatest strength and its most significant practical limitation, confirming that the claim in the title is partially but not unreservedly correct.