Natural Law Theory
What do human nature and right reason reveal about the moral order that applies to all human beings, regardless of what any particular law or culture says?
Natural law theory holds that there is an objective moral order discoverable by reason that applies universally, independently of positive law, cultural convention, or individual preference. Rooted in Stoic philosophy and Aristotle's teleology, it was given its most systematic formulation by Thomas Aquinas in the 13th century, who grounded natural law in God's eternal law made accessible to human reason. The tradition holds that human beings have a nature with characteristic goods and ends — life, knowledge, friendship, practical reason, religion — and that actions are right insofar as they accord with these natural goods and wrong insofar as they violate them. Natural law thinking has been enormously influential in political philosophy, human rights theory, Catholic social teaching, and international law.
Historical Context
Natural law thinking emerged in ancient Stoicism as the idea of a rational order pervading the cosmos to which human reason has access. Cicero gave it its classic political formulation: true law is right reason in agreement with nature, universal, unchanging, and everlasting. Aquinas synthesized this with Christian theology and Aristotelian teleology, creating the dominant framework for medieval and early modern European moral and legal thought. Natural law theory underwrote the development of international law (Grotius, Vitoria) and influenced the American founding documents. The tradition was challenged by Hume, Kant, and positivism, but received major revival through John Finnis and the 'new natural law' school in the late 20th century, which attempted to free natural law from metaphysical and theological presuppositions.
Key Ideas
- There is an objective moral order accessible to human reason, not merely to revelation or cultural tradition
- Human beings have a nature with characteristic goods and purposes that ground moral norms
- Positive law (human-made law) is legitimate only insofar as it conforms to natural law; unjust laws lack full moral authority
- Basic goods — life, knowledge, friendship, practical reason, justice — are self-evidently worth pursuing and provide the starting points of moral reasoning
- The common good of political community is a genuine good, not merely the aggregate of private interests
- Reason can discern natural inclinations and distinguish genuine human goods from apparent ones
- Human dignity is grounded in our nature as rational, social beings — not in social agreement or state conferral
Core Concepts
The portion of the eternal divine law that is accessible to human reason; the moral norms that follow from human nature and are binding on all rational beings
In Aquinas, the rational governance of all creation by God; natural law is the rational creature's participation in this divine governance
The good of the political community as a whole, distinct from the aggregate of private interests; the proper end of just governance
In John Finnis's contemporary formulation: self-evident, irreducible goods (life, knowledge, play, aesthetic experience, friendship, practical reason, religion) that provide the foundation for all moral reasoning
The faculty by which human beings grasp moral truths and deliberate about action; natural law is the content of what practical reason discerns about human goods
Key Texts
- Aquinas, Summa Theologica, II-I, qq. 90–97 (13th century)
- Cicero, De Re Publica and De Legibus (1st century BCE)
- Grotius, De Jure Belli ac Pacis (1625)
- Finnis, Natural Law and Natural Rights (1980)
- Grisez, The Way of the Lord Jesus (1983)
Where This Shows Up in Frameworks
Why This Shows Up in Frameworks
When a situation raises questions about human dignity, rights that transcend positive law, or whether a practice or arrangement violates something fundamental about human beings regardless of its legal status or social acceptance, natural law theory provides a framework for articulating why some things are simply wrong.