1. Claims of natural law

Apologists sometimes appeal to something called natural law and then use this concept to argue that there exist prescriptive moral or ethical rules that transcend written statutes. Before such claims can be meaningfully evaluated, it is necessary to distinguish clearly between two fundamentally different kinds of “law”:

Scientific laws that are descriptive, as they summarize regularities observed in nature. They do not command anything.
Legal laws that are prescriptive, as they are human constructions that define permitted and forbidden conduct and attach consequences.

These categories are not merely different in subject matter; they differ in logical structure, purpose, and mode of enforcement.

1.1 Scientific laws: descriptions of regularities

Scientific laws summarize observed patterns in nature. They express how physical systems behave under specified conditions. Their defining characteristics are:

They are derived from observation and experiment.
They describe what does happen.
They have no normative force.
They carry no penalties for violation.

Typical examples include:

Universal gravitation: massive bodies attract one another with a force proportional to their masses and inversely proportional to the square of their separation.
Conservation of energy: in an isolated system, energy is neither created nor destroyed.
Ohm’s law: electrical current is proportional to applied voltage and inversely proportional to resistance.

If a stone is released, it falls. Not because it ought to, but because this is how matter behaves under gravity. If resistance increases, current decreases. No ethical content is involved.

Crucially, scientific laws cannot be “broken”. A system that appears to violate them simply indicates either measurement error, incomplete modeling, or that the law has been applied outside its domain of validity. Nature does not punish violations; it makes them impossible.

Scientific laws therefore function as compact descriptions of regularities in the world. They do not instruct particles how to behave. They report how they already behave.

1.2 Models versus laws within science

Before contrasting scientific laws with legal laws, it is useful to make a further distinction within science itself: the distinction between laws and models.

A scientific law simply states that a regularity is observed and is consistent with evidence. It does not attempt to explain why the regularity occurs. It records what occurs. In this sense, a law is a compact summary of facts.

Models, by contrast, are conceptual or mathematical constructions used to represent reality. They provide explanatory structure, offer intuition, and support prediction beyond the immediate observations from which a law was formulated.

For example:

Newton’s law of gravitation expresses gravitational attraction through a formula. It tells us how force scales with mass and distance, but it does not explain what gravity is.
General relativity reinterprets gravity as curvature of space and time. From this perspective, Newtonian gravity can be viewed as a limiting case in which spacetime curvature is small and only spatial effects are appreciable. Newton’s formulation works well whenever masses and energy densities are insufficient to produce noticeable relativistic effects.
Symmetry groups are used in modern physics to model elementary particles. Particle types, charges, and interaction rules are represented through mathematical symmetries, with observable properties emerging from group structure rather than being postulated individually.
In quantum mechanics, complex‑valued functions of real variables (wave functions) are used to model particles. These functions do not directly correspond to physical objects; instead, their magnitudes encode probabilities of measurement outcomes. The model supplies a framework for prediction, even though the underlying reality remains conceptually opaque.

These constructions differ fundamentally from laws. Laws summarize observed regularities. Models attempt to organize those regularities into coherent representations of reality.

In short:

Laws report patterns.
Models propose structure.

A model may change while a law remains approximately valid within its domain. Newton’s law of gravitation remains useful for planetary motion, even though the deeper model supplied by general relativity has replaced its conceptual foundations.

This distinction matters because it emphasizes that even within science, descriptive regularities and explanatory frameworks play different roles.

1.3 Legal laws: prescriptions of conduct

Legal laws are human constructs. They specify acceptable and unacceptable behavior and attach consequences to noncompliance. Their defining characteristics are:

They are created, interpreted, and revised by societies.
They prescribe what people should or must not do.
They are enforced by institutions.
They are contingent on culture, history, and political organization.

Examples include:

Criminal prohibitions against theft or assault.
Traffic regulations such as speed limits and right-of-way rules.
Contract law governing agreements between parties.

A person can exceed a speed limit. A contract can be broken. Property can be stolen. These actions are physically possible; they are socially prohibited. What makes these “laws” is not inevitability, but enforcement through courts, police, and other institutions.

Here, compliance is optional in a physical sense. Consequences arise not from nature itself, but from organized human response.

1.4 Claims of overarching “natural law”

Apologists and some philosophers argue that, beyond scientific laws and beyond written legal statutes, there exists an overarching category called natural law. In this framing, natural law is said to encompass both descriptive regularities of nature and prescriptive principles governing human conduct. The claim is that certain moral rules are woven into reality itself: just as gravity governs falling objects, so too do natural moral laws allegedly govern human behavior.

Within this view, scientific laws provide evidence that the universe is orderly, while selected patterns of successful social organization are presented as further evidence that moral obligations are likewise objective, universal, and transcendent. The same word—law—is used for both domains, and this linguistic overlap is then leveraged to suggest a shared ontological status.

1.5 Commonly cited “natural law” principles as social observations

What are presented as natural moral laws are typically drawn from recurring features of stable societies. Common examples include:

Human beings possess inherent worth or dignity.
Unjustified killing is prohibited.
Theft or unjust taking of property is wrong.
Individuals may defend themselves against aggression.
Promises and agreements ought to be honored.
Deliberate deception is morally discouraged.
Like cases should be treated alike (fairness).
Basic compassion toward others is valued.
People have interests in life, liberty, and personal security.
Individuals seek personal flourishing or happiness.
Parents have obligations toward their children.
Those who cause harm should make restitution.

Notably, none of these are discoveries in the same sense as gravitation or conservation of energy. Rather, they are generalized descriptions of behaviors that correlate with social stability. Societies that adopt these norms tend to persist and function more effectively than societies that do not.

These are therefore better understood as empirical observations about which patterns of behavior support cooperative living. They are subsequently reinterpreted by natural law theorists as timeless moral mandates, rather than as contingent features of human social systems.

1.6 Physiological and neurochemical foundations of social norms

The appeal of these principles does not require appeal to transcendent law. Each can be accounted for through ordinary human biology and psychology.

Recognition of human worth arises from evolved social bonding and empathy, mediated by oxytocin and related neurochemicals that reinforce attachment and group cohesion.
Aversion to unjustified harm reflects pain perception, mirror-neuron responses, and stress-hormone activation when witnessing suffering, producing instinctive avoidance of violence within one’s social group.
Rejection of theft follows from territorial instincts and loss aversion, with cortisol and adrenaline responses reinforcing protection of resources.
Self-defense is rooted in the fight-or-flight response, driven by adrenaline and noradrenaline when threats are perceived.
Promise-keeping is supported by reward circuitry: trust-based cooperation activates dopamine pathways, making reliable behavior psychologically reinforcing.
Truthfulness is socially stabilized because deception increases cognitive load and stress, while honesty supports predictable interactions that reduce uncertainty.
Fairness is strongly linked to reward processing in the brain; perceived unfairness activates regions associated with disgust and anger, while equitable outcomes trigger dopamine release.
Compassion is mediated by empathy circuits and oxytocin, promoting caregiving and mutual support.
Interest in life and liberty reflects basic survival drives regulated by the hypothalamus and limbic system.
Pursuit of flourishing corresponds to reward-seeking behavior shaped by dopamine systems that motivate exploration, achievement, and social connection.
Parental care is reinforced by hormonal changes, including oxytocin and prolactin, that promote attachment to offspring.
Restitution aligns with innate reciprocity mechanisms: repairing harm restores social balance and reduces stress within groups.

In each case, what is labeled “natural law” is more parsimoniously explained as the outcome of evolutionary pressures acting on social mammals.

These behaviors persist because they enhance group survival, reduce internal conflict, and stabilize cooperation. They are biological tendencies refined by culture, not moral edicts embedded in the fabric of the universe.

1.7 Claims of overarching “natural law”

1.8 Commonly cited “natural law” principles as social observations

What are presented as natural moral laws are typically drawn from recurring features of stable societies. Common examples include:

Marriage is intrinsically limited to one man and one woman. This is presented as flowing directly from reproductive biology, with alternative family structures labeled deviations from nature rather than cultural variations.
Homosexual relationships are contrary to nature. Same-sex partnerships are framed as violations of an alleged biological purpose of sexuality, despite their historical and cross‑cultural persistence.
Transgender identities are illegitimate or impossible. Gender diversity is dismissed by appealing to reproductive anatomy, treating complex psychological and neurological realities as irrelevant.
Sexual activity is morally permissible only for reproduction. Pleasure, bonding, and intimacy are subordinated to a single biological function, and non‑procreative sex is characterized as misuse rather than ordinary human behavior.
Contraception is wrong because it “frustrates” natural ends. Preventing conception is portrayed as interference with nature itself, rather than as a medical and social technology.
Divorce is inherently immoral. The stability of marriage is elevated into an absolute rule, even when relationships are harmful or coercive.
Men are naturally dominant because they are, on average, physically stronger. A statistical difference in upper‑body strength is converted into a moral authorization for authority.
Therefore, men ought to be the heads of households. From physical dimorphism is inferred a permanent hierarchy within families.
Certain occupations or leadership roles are inherently reserved for men. Social restrictions are justified by appeal to “created roles” rather than competence or individual aptitude.
Women are naturally suited to caregiving and domestic labor. Biological capacity for pregnancy is generalized into lifelong expectations about temperament and vocation.
Humans are naturally ordered toward religious belief. Faith is presented as an innate requirement for psychological health or social stability, and secular lives are characterized as incomplete.
Distinct gender roles are part of cosmic or moral order. Complementarity is framed as embedded in reality itself, not as a negotiable social arrangement.
Reproductive technologies are immoral because they separate sex from conception. Medical interventions are rejected on the grounds that they bypass an allegedly sacred biological sequence.
Sexual purity norms are universal requirements. Practices such as premarital sex, masturbation, or non‑traditional partnerships are labeled intrinsically disordered rather than culturally regulated.

Lists such as these vary by denomination and culture, but they share a common structure. A descriptive fact (for example, average differences in physical strength, or the biological role of reproduction) is selectively elevated into a prescriptive rule governing identity, relationships, and social hierarchy.

Unlike the earlier principles concerning harm reduction or reciprocity, these claims do not emerge from cross-cultural convergence about what enables cooperative living. Many societies, both historical and contemporary, function with same-sex partnerships, diverse gender roles, non-reproductive sexuality, and shared domestic authority. The persistence of these practices directly contradicts the assertion that such restrictions are required by nature.

These positions are therefore not inferred from broad empirical regularities. They are asserted.

They are called “natural laws” only because they align with pre-existing theological commitments. The label provides rhetorical weight, but the content reflects doctrine rather than observation.

1.9 Refuting restrictive claims presented as “natural law”

The claims listed above do not withstand scrutiny once biology, anthropology, and historical context are taken seriously. They are better understood as products of particular social conditions and religious preferences, not as features of nature itself.

Homosexuality as “against nature.” Same-sex behavior appears across a wide range of species, from birds and mammals to primates. This alone falsifies the claim that such relationships are biologically anomalous. In humans, sexual orientation emerges from complex developmental processes involving neurobiology and environment. Its persistence across cultures and eras indicates a stable feature of human variation, not a deviation requiring moral prohibition.
Sex only for reproduction. Sexual behavior in many social species serves bonding and cohesion as much as reproduction. Bonobos are a well-known example: sexual contact functions to reduce conflict, reinforce alliances, and stabilize groups. Humans likewise use intimacy to form pair bonds, maintain relationships, and regulate stress. Reducing sex to reproduction ignores its demonstrable social and psychological roles.
Gender identity dismissed by anatomy. Appeals to reproductive organs erase the well-documented reality that gender identity has neurological and psychological components. Intersex conditions, transgender identities, and diverse gender expressions have existed throughout history. Treating anatomy as destiny reflects a preference for binary simplicity, not an empirical necessity.
Women “naturally” assigned to caregiving. Pregnancy and childbirth do produce strong attachment responses, mediated by hormones such as oxytocin. This explains statistical tendencies, not moral obligations. From the fact that women often bond intensely with infants, it does not follow that they ought to be confined to domestic roles or excluded from leadership or technical work. Biological predispositions do not generate prescriptions.
Male dominance inferred from physical strength. Average differences in upper-body strength are real, but they do not justify authority structures. Modern societies rely on coordination, communication, and technical competence, not brute force. Elevating strength into hierarchy is a relic of survival conditions in which physical confrontation determined access to resources.
Household headship and restricted occupations. These norms reflect historical economies in which labor was rigidly divided and women were often treated as property. They were convenient for inheritance systems and social control. They persist in religious rhetoric because they benefit existing power structures, not because they are demanded by nature.
Monogamy and sexual restriction as universal mandates. Many ancient societies observed that sexually transmitted diseases spread more easily with multiple partners, while tightly regulated pairings appeared “safer.” Without medical understanding, this correlation was moralized. What began as pragmatic risk management became framed as divine or natural command. With modern medicine, testing, and contraception, the original conditions no longer apply.
Opposition to contraception and reproductive technologies. These positions arise from the idea that biology carries intrinsic purposes that must not be altered. In reality, medicine routinely intervenes in natural processes—vaccination, surgery, anesthesia—without moral objection. Singling out reproduction reflects theological doctrine, not a consistent respect for nature.
Claims that humans are naturally ordered toward religion. While humans possess pattern recognition, agency attribution, and social bonding instincts that make religious ideas compelling, this does not entail that belief is mandatory for flourishing. Secular individuals and societies demonstrably live meaningful, cooperative lives.

Across these cases, a common pattern appears: observations made in medically limited, resource-scarce, patriarchal societies were elevated into timeless rules. What once reduced risk, simplified inheritance, or centralized authority was recast as cosmic order. Women’s subordination eased household control. Sexual regulation reduced disease exposure. Fixed roles simplified survival logistics. These were adaptive strategies under specific historical constraints.

They are not laws of nature. They are contingent social arrangements, later sanctified.

1.10 The category error in appeals to “natural law”

When apologists invoke “natural law” to justify transcendent moral prescriptions, they typically import the rhetorical authority of scientific law into the domain of ethics. This involves a quiet conflation:

From scientific law, they borrow the idea of universality and inevitability.
From legal law, they borrow the idea of obligation and prohibition.

But these features do not coexist in either category.

Scientific laws are universal but non-normative. Legal laws are normative but not universal.

To claim that moral rules are “natural laws” attempts to combine universality with prescription. That combination does not arise automatically from either framework. It requires additional philosophical premises.

In effect, this move treats moral norms as though they were physical regularities: as if ethical obligations were embedded in the fabric of the universe in the same way as gravity or electromagnetism. No such embedding is established by observation. What exists instead are human value systems, cultural practices, and institutional mechanisms of enforcement.

1.11 Conclusion

Scientific laws describe regularities of reality. Legal laws prescribe standards of conduct. They differ not merely in content, but in kind.

Any argument that purports to derive prescriptive moral obligations from descriptive facts must explicitly supply the missing philosophical steps. Simply labeling moral rules as “natural law” does not accomplish this.

Absent that additional argument, appeals to natural law amount to a category error: the projection of human norms onto an indifferent universe.