Thomas E. Davitt — “St. Thomas Aquinas and the Natural Law”
1. Meaning of Law
For Aquinas, law is not merely written rules but a rational ordering in the mind of someone with authority, directing means toward the common good and then promulgated. A speed-limit example shows that the true “law” is the legislators’ rational judgment that a certain speed promotes safety.
2. Meaning of “Natural”
“Natural” refers to the nature of a thing—its built-in principles directing it to fulfillment. These appear as dynamic inclinations (e.g., a rosebush’s drive to produce roses). Human nature likewise expresses itself through characteristic inclinations.
3. Human Inclinations and the Structure of Natural Law
Aquinas identifies three levels of human inclinations:
- Shared with all beings: drive to perfection/happiness.
- Shared with animals: self-preservation, sexual union, species survival.
- Properly human: life in community, use of intellect and will.
These inclinations reveal an ordered structure aimed at personal flourishing and the good of the community. Because ordered tendencies require an intellectual cause, Aquinas infers that this order reflects the Eternal Law, the rational plan of the Creator. Natural law is thus the promulgation of the Eternal Law in human inclinations themselves.
4. How Natural Law Is Known
Humans recognize natural law through connatural knowledge: by knowing their inclinations, they judge immediately that what fulfills them is good (e.g., preserving life, living socially, respecting property, regulating sexuality, using reason rightly). Anthropology shows the universality of these elementary judgments.
5. Does Natural Law Change?
The inclinations do not change, but judgments about how to apply them may vary:
- They may be distorted by bad education, habits, or cultural influence (e.g., suicide cults).
- They may legitimately vary when goods are weighed through reason (e.g., self-sacrifice for a greater good).
Thus the first principles are constant, while secondary applications adapt to circumstances.
6. Natural Law vs. Revealed Law
Natural law does not depend on Scripture or religious authority; it is known by reason, and its core principles were recognized by thinkers like Plato and Cicero. Revelation may coincide with natural law, but it does not define it.
7. Natural Law and Human Legislation
Natural law provides basic direction, not detailed rules. It functions like a compass: it tells lawmakers why to make laws (e.g., protect life), but not how (e.g., what exact speed limit to set). Legislators must use reasoning, precedent, and empirical study to specify laws.
8. Broader Legal Implications
Natural law grounds fundamental rights, supports personal responsibility in crime (mens rea), guides balances in tort and property law, and underlies equity—the resort to principles deeper than statutes when justice requires.
9. Final Insight
Attempts to reject natural law usually smuggle it back in under new terms (“fundamental principles,” “jural postulates”). Aquinas’s account remains a foundational “compass” for moral and legal reasoning because it is rooted in real features of human nature.