Thomas Aquinas, a prominent medieval theologian and philosopher, wrote extensively on various topics, including law. One of his most notable works on this subject is the Summa Theologiae, which includes discussions on different aspects of law. Aquinas's views on law are primarily found in his treatises on law within the Summa Theologiae. These treatises can be divided into four parts: eternal law, natural law, human law, and divine law.
Eternal law: Aquinas believed that eternal law is the divine plan or order that governs the universe. It is the highest and most fundamental form of law and is the source of all other laws. Eternal law is the expression of God's wisdom and providence, directing all of creation toward its ultimate purpose.
While humans cannot directly access eternal law, they can discern it through their understanding of natural law and divine revelation.
Natural law: Aquinas argued that natural law is derived from eternal law and is imprinted on the human soul. It is the moral law that is accessible to human reason and is common to all people, regardless of their cultural or religious backgrounds. Natural law is based on the idea that human beings have certain inherent inclinations, such as self-preservation and the desire to live in society, and these inclinations guide moral behaviour.
Human law: Human law, according to Aquinas, is created by humans to supplement and enforce natural law. It includes civil laws, laws of nations, and specific legal systems. Human laws should be in accordance with natural law. If a human law contradicts natural law, it is not truly a law but rather an unjust decree. The authority to make human laws is derived from the natural law and, ultimately, from God.
Divine law: Divine law, as described by Aquinas, includes both the Old Testament law (Mosaic law) and the New Testament law (the teachings of Jesus Christ). It provides additional guidance and rules for believers to follow, in addition to natural law. Divine law complements natural law, helping individuals understand their moral duties and obligations more explicitly.
Aquinas's treatise on law is a significant part of his overall philosophy and theology. He firmly believed in the importance of aligning human laws with natural law and divine law to ensure justice and moral conduct. His ideas on law have had a lasting influence on legal and moral philosophy, and they continue to be subjects of study and discussion in both theological and philosophical circles.
You can learn more about this topic with our Jurisprudence and Legal Theory notes.
