Natural Law vs. Positive Law

The Role of Determinatio in American Legal Authority

September 07, 2025

Abstract

This article clarifies the classical realist account of how natural and positive law relate through determinatio—the prudential specification of universal moral principles for concrete political life. Drawing from Thomas Aquinas's Summa Theologiae, we argue that positive law has binding force only insofar as it conforms to right reason and participates in the eternal law. We distinguish derivation (logical conclusions from universals) from determination (reasonable choices within universals that admit alternatives). To illustrate, we examine early American statutes: the Tariff Act of 1789 as a legitimate determination of commerce and taxation for the common good, contrasted with the Naturalization Act of 1790, which introduced racial exclusions incompatible with the universal of equal human nature. The analysis shows that lawful authority rests on truth-directed specification, not voluntarist invention.

Introduction

Having established in the American Epistemology Institute's "America's Metaphysical Axiom" (2025) that the founding presupposes one human nature, objective goods, and law above the state, we now examine how human law should prudently specify these universal principles through determinatio rather than contradict them through arbitrary will. As demonstrated in the American Epistemology Institute's "A Fixed Star or Shifting Sands" (2025), the founding contained competing metaphysical frameworks—realist natural law principles alongside anti-realist contractual elements that created tensions from the founding itself. In the realist tradition, law's authority is not created by will but measured by truth: a rule binds in conscience only to the extent it conforms to the objective moral order discoverable by reason. This order—natural law—states universals (e.g., pursue the good; do not kill the innocent). Positive law then specifies how those universals apply here and now. When a specification contradicts the universal (e.g., defining a class of humans outside equal standing), it is not properly law but a perversion of law (Aquinas, 2017).

I. Definitions: Natural Law, Positive Law, and Determinatio

Eternal law: the rational governance of creation that exists in God's mind, by which all things are directed to their proper ends (Aquinas, 2017, I–II, q.93, a.1).

Natural law: the rational creature's participation in the eternal law through reason, by which humans discern universal moral principles grounded in human nature (Aquinas, 2017, I–II, q.91, a.2). As established in our "Realist Lexicon," this eternal, knowable order of creation enables humans to discern good and evil through reason, arising from the rational nature of man, which is permanent and universal.

Positive law (human law): an ordinance of reason for the common good, made by him who has care of the community, and promulgated, meaning that the law must be formally and officially made known to the people it is intended to govern (Aquinas, 2017, I–II, q.90, a.4).

Derivation (conclusio): drawing a conclusion that follows logically from a universal (e.g., from "protect innocent life," it follows that murder must be prohibited) (Aquinas, 2017, I–II, q.95, a.2).

Determination (determinatio): choosing among many reasonable, morally compatible ways to instantiate a universal (e.g., which penalty fits theft; what residency period evidences allegiance). Positive law is, most of the time, determination (a prudential fit of means to ends) not invention of new rights ex nihilo (Aquinas, 2017, I–II, q.95, a.2).

Concrete definition (for readers): Determinatio = a rule-making choice that specifies a universal moral principle in circumstances where several specifications could equally serve that principle without contradicting it (e.g., speed limit 55 vs. 60; residency 2 vs. 5 years).

These distinctions provide concrete analytical criteria: legitimate determinations serve objective human goods, respect rational human nature, and can be universalized without contradiction. Illegitimate departures contradict these standards regardless of procedural correctness.

Aquinas states that law partakes of the eternal law inasmuch as it partakes of right reason; if it deviates from reason, it is unjust (Aquinas, 2017, I–II, q.93, a.3). In a companion passage he adds: "The like are acts of violence rather than laws" (Aquinas, 2017, I–II, q.96, a.4). In short, legal obligation presupposes truth; where truth is denied, coercion remains but law-as-law does not.

The founding generation drew primarily from two compatible realist traditions: Scottish Common Sense Realism (Reid, Witherspoon) emphasizing intuitive moral knowledge (Reclaiming America’s Epistemic Spine: Why Realism Still Matters in 2025, American Epistemology Institute, 2025; Morrison, 2005), and Aristotelian-Thomist natural law jurisprudence as exemplified in James Wilson's treatment of natural law (Wilson, 1790-1791).

III. James Wilson: Metaphysical Insight and Constitutional Error

The founding generation's realist framework found one of its clearest expressions in James Wilson's jurisprudence. Wilson, signer of both the Declaration and Constitution and justice on the first Supreme Court, articulated in his Lectures on Law (1790-1791) the hierarchical relationship between divine law, natural law, and positive law. He correctly grounded human dignity in rational nature as imago Dei, argued that sovereignty is ontological rather than constructed, and insisted that unjust laws lack binding moral force. Wilson's metaphysical contributions remain sound: his refutation of Humean skepticism, his defense of moral realism accessible through common sense, and his insistence that positive law must conform to natural law provide essential foundations for constitutional interpretation.

However, Wilson erred in constitutional architecture. His advocacy for direct popular sovereignty through "We the People" failed to adequately institutionalize the very natural law principles he defended. The Anti-Federalists diagnosed what Wilson missed: unmediated federal authority over individuals would enable consolidated power that natural law reasoning alone could not constrain. In Chisholm v. Georgia (1793), Wilson's Supreme Court opinion argued that states, as artificial bodies, could be sued by citizens in federal court without state consent. The Eleventh Amendment's passage within two years represented the founding generation's rejection of Wilson's application. This rapid constitutional correction reveals that Wilson's contemporaries saw his reasoning as dangerous overreach, even if they agreed with his natural law premises.

Wilson conflated two distinct questions: Ontological sovereignty (metaphysical): Does ultimate authority reside in persons as image-bearers? Yes. Constitutional structure (architectural): How should governmental authority be organized to protect human dignity? Through layered, subsidiary institutions, not direct federal command. The Thomist tradition distinguishes lex naturalis (universal first principles) from determinatio (prudent specification in positive law). Wilson excelled at articulating the former but failed in the latter. Sound metaphysics does not automatically produce sound constitutional design. The path forward requires:

  1. Retaining Wilson's realist natural law framework

  2. Correcting his constitutional architecture through restored subsidiarity

  3. Recognizing that the Anti-Federalist concerns about consolidated federal power were vindicated by subsequent history

IV. Derivation vs. Determination: Two Ways Human Law Relates to Natural Law

Aquinas distinguishes two modes: "derived … as a conclusion" and "by way of determination of certain generalities" (Aquinas, 2017, I–II, q.95, a.2). Derivation yields necessary conclusions (no legitimate alternatives). Determination admits multiple reasonable specifications that still serve the universal.

V. Change and Continuity: Determination Admits Variation, Universal Principles Do Not

The first principles of natural law are unchangeable in terms of subtraction (Aquinas, 2017, I–II, q.94, a.5). For example, the fundamental precepts (preserve life, seek truth, live in community) cannot be removed or negated. By contrast, human law may change prudently for the common good; though not lightly (Aquinas, 2017, I–II, q.97, a.1). As such, variability belongs to determinations (e.g., procedures, penalties, administrative forms), not to the universals (e.g., equal moral standing, prohibition of murder).

VI. Historical Tests: Legitimate Determination vs. Illegitimate Departure

A. Legitimate Determination: Tariff Act of 1789

The preamble states ends including "support of government," "discharge of the debts," and "the encouragement and protection of manufactures" (U.S. Congress, 1789). Levying import duties is a determination of the community's authority to secure revenue and regulate commerce for the common good; specific rates/categories admit multiple reasonable settings.

B. Illegitimate Departure: Naturalization Act of 1790

Section 1 allows naturalization of "any alien, being a free white person" after two years' residence and an oath (U.S. Congress, 1790). Residence/oath = legitimate determinations of allegiance; the racial prerequisite contradicts the universal of one human nature (established in the American Epistemology Institute's "America's Metaphysical Axiom," 2025, and "A Fixed Star or Shifting Sands," 2025) and so is a perversion rather than a law in the full sense. This represents the kind of Continental Enlightenment contamination identified in our earlier analysis, where anti-realist frameworks enabled departures from natural law foundations.

C. Constitutional Authority Structure: 'We the People' as Departure from Founding Principles

The Constitution's preamble "We the People" created structural vulnerabilities that enabled departures from properly ordered authority, even though some Federalists like James Wilson believed it expressed natural law principles.

Wilson's position: Sovereignty resides ontologically in persons, not state governments as corporate entities. "We the People" recognized this metaphysical truth—that government derives authority from human beings as image-bearers, not from artificial political bodies.

The Anti-Federalist diagnosis: Whatever Wilson's intentions, the formula enabled federal government to bypass mediating institutions and act directly on individuals. As Brutus warned, "the idea of confederation is totally lost, and that of one entire republic is embraced" (Brutus, 1787). Patrick Henry opposed changing "We the States" to "We the People" precisely because he recognized this would create direct command relationships between federal government and citizens.

The operational outcome: History vindicated the Anti-Federalist concerns. The "We the People" formula enabled:

  • Federal authority to override state governments

  • Direct taxation and regulation of individuals

  • Expansion of federal power beyond enumerated limits

  • Transformation of state citizens into subjects of consolidated national government

As recognized at the Massachusetts Ratifying Convention, "We the People" represented a fundamental shift: "The language of the confederation is, 'We the states, &c.' The latter is a mere federal government of states" (Massachusetts Ratifying Convention, 1788). The new formula claimed national-level popular sovereignty that bypassed state mediation. The natural law problem: Even if persons possess ultimate ontological sovereignty (they do), this does not mean federal government should exercise operational authority directly over individuals without constitutional mediation. The principle of subsidiarity—that authority should be exercised at the most local level capable of addressing an issue—serves natural law's purposes by:

  • Preventing power concentration

  • Maintaining competitive accountability across jurisdictions

  • Keeping governance close to those governed

  • Preserving space for intermediate associations

Wilson believed his popular sovereignty framework would constrain government through ongoing popular consent. The subsequent two centuries of federal consolidation prove he was wrong. Sound realist metaphysics requires institutional structures that embody subsidiarity, not formulas that enable centralization while invoking popular sovereignty. This represents a specification that violated proper authority relationships—not because popular sovereignty is wrong in principle, but because the constitutional mechanism failed to preserve the layered, covenantal structure that properly orders political authority.

VII. Methodological Summary

The determinatio framework reveals that constitutional disputes often involve competing specifications of shared natural law principles rather than simple departures from them. James Wilson's error illustrates this: he correctly identified sovereignty's metaphysical ground (persons as image-bearers) but incorrectly specified how to constitutionalize that truth ("We the People" enabling consolidated federal power). The Anti-Federalists correctly specified the same principle through layered subsidiarity and state mediation. Both camps affirmed natural law; they disagreed about prudent institutionalization. This distinction—between getting the metaphysics right and getting the constitutional architecture right—remains crucial for contemporary constitutional interpretation.

References

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U.S. Congress. (1789). An Act for laying a duty on goods, wares, and merchandises imported into the United States, 1 Stat. 24. Federal Reserve Bank of St. Louis (FRASER). https://fraser.stlouisfed.org/files/docs/historical/congressional/tariff-act-1789.pdf

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