Natural Moral Law originates from Aristotle’s concept of telos (purpose) and Stoic ideas of rational order in nature.
Aristotle believed human telos is eudaimonia (flourishing/happiness); Aquinas adapted this to Christian theology.
Stoics argued nature and reason guide proper action; humans have a “divine spark” of reason to discover moral order.
Aquinas and the Four Tiers of Law
Aquinas integrated Aristotle’s ideas with Christian doctrine, emphasizing that ultimate happiness is union with God.
Aquinas described four tiers of law: Eternal Law (in God’s mind), Divine Law (revealed in scripture), Natural Law (discovered by reason), Human Law (societal rules).
Human laws are legitimate only if they are consistent with Natural and Divine Law.
Core Concepts: Cinderesis and Precepts
Cinderesis is the innate human inclination to do good and avoid evil.
The cinderesis principle forms the basis for Aquinas’s five Primary Precepts, from which Secondary Precepts are derived.
Primary Precepts are absolute, universal, and unchanging; Secondary Precepts are more culturally relative.
The Five Primary Precepts
Preserve life — Uphold the sanctity of all human life; influences views on abortion, euthanasia, murder.
Reproduce — Promote procreation; underpins Catholic views on contraception, homosexuality, and masturbation.
Educate children — Parents should ensure education, both secular and religious.
Order society — Maintain law, justice, and societal structure for human flourishing.
Worship God — Acknowledge and honour God as life’s source; debated as not universal in modern secular societies.
Applications and Contemporary Issues
Natural Moral Law opposes acts like abortion, euthanasia, contraception, and homosexuality due to its focus on purpose and preservation of life.
John Finnis provides a secular update, listing seven basic goods and emphasizing practical reason, showing the theory can be adapted without reliance on God.
Strengths and Weaknesses
Strengths: Offers universal, absolute moral standards; underpins human rights; empowers individuals to use reason; still relevant in human rights law.
Weaknesses: Assumes universal purpose and belief in God; possibly outdated (esp. in sexual ethics); too rigid and ignores context; subject to naturalistic fallacy (natural ≠ good).
Key Terms & Definitions
Telos — The final purpose or end goal of something.
Cinderesis — Innate principle to do good and avoid evil.
Precept — Rule intended to regulate behaviour.
Eternal Law — God’s perfect law known only to God.
Divine Law — Law revealed through scripture.
Natural Law — Moral order discoverable by human reason.
Human Law — Laws made by societies/governments.
Action Items / Next Steps
Study the doctrine of double effect and proportionalism for comprehensive understanding.
Review examples of how primary precepts apply to current ethical issues.