Thomas Aquinas and Natural Law
Historical Setting: 13th Century Europe
The Awakening of Europe
The 13th century marked a significant turning point in European history, emerging from the Dark Ages into the High Middle Ages. Technological advancements and favorable harvests spurred economic growth, leading to a resurgence of cities, particularly in France, the Netherlands, and Italy. While the economic system remained largely agricultural, the political landscape saw the consolidation of major European monarchies like Castile, Aragon, and England, with the Kingdom of France rising to prominence.
The Clash Between Empire and Papacy
This era also witnessed a clash between the Empire and the Papacy, both vying for supremacy. The concept of universal Christianity became a point of contention, fueling the power struggle.
Feudal Society and the Rise of Burghers
Society remained largely feudal, divided into nobility, clergy, and peasantry, bound by relations of vassalage. However, a new class emerged: the burghers (city dwellers), primarily engaged in crafts and trade. They maintained a relative independence, contributing to the autonomous nature of cities.
The Resurgence of Culture and the Rise of Universities
Within the cities, craft guilds controlled the exercise of various trades. This urban growth coincided with a cultural resurgence, exemplified by the flourishing of Gothic art and the construction of grand cathedrals. Painting and sculpture aimed to imitate natural reality with greater detail. The early 13th century saw the founding of mendicant orders like the Franciscans and Dominicans (to which St. Thomas Aquinas belonged). Members of these orders occupied prominent positions in the first European universities, including Oxford and Paris, where Aquinas himself taught. University education centered on the commentary and discussion of texts from various authorities—philosophical, legal, medical, or religious—such as Aristotle, Avicenna, the Bible, and the writings of Church Fathers. This scholasticism, marked by the reception of Aristotelian philosophy through Arab and Jewish thinkers and its adaptation to Christian religion, became the second great period of Christian philosophy after the Patristic era (the philosophy of the early Church Fathers like St. Augustine, who synthesized Christian doctrine with Platonic philosophy).
Main Lines of Thought of St. Thomas Aquinas
Relationship Between Reason and Faith
Against the Averroists’ doctrine of double truth, Aquinas maintained that truth is singular, though knowable in two ways: through reason and through faith. Reason derives knowledge from sensory data, while faith relies on divine revelation. Both are independent, yet harmonious. Truths of faith, revealed truths beyond human understanding and studied by theology, cannot be rationally demonstrated and must be accepted as they flow directly from God. Truths of reason, the domain of philosophy, are demonstrable through human intellect. Some truths of reason, though demonstrable, are also revealed by God. In this realm, faith and reason, theology and philosophy, converge. Philosophy serves theology, and since truth is one, philosophy and reason err if they reach conclusions incompatible with faith.
Demonstration of the Existence of God
While some truths of faith are revealed, the existence of God can be rationally demonstrated. Aquinas challenged Anselm’s ontological argument and proposed a posteriori demonstrations, moving from effect (the world) to cause (God). He offered five ways (quinque viae) to demonstrate God’s existence, each sharing a common structure: 1) starting from an observed fact, 2) applying the principle of causality, and 3) concluding the necessity of a first cause, which is God. The five ways are: 1) from motion to an unmoved mover, 2) from efficient causes to a first uncaused cause, 3) from contingency to a necessary being, 4) from degrees of perfection to a supremely perfect being, and 5) from the order and purpose of the world to a first ordering intelligence.
Creation of the World
Regarding creation, Aquinas distinguished between essence (the nature of a being, understood as potentiality) and existence (its actual being). In God, essence and existence are identical, as His nature necessitates existence. Other beings are contingent; their essence doesn’t necessitate existence, which they receive through God’s creative act.
Anthropology and Theory of Knowledge
Following Aristotle, Aquinas viewed man as a single substance composed of matter (body) and form (rational soul). However, aligning with Christian doctrine, he maintained the soul’s immortality. Knowledge is an abstraction process where the soul dematerializes forms registered by the senses, involving memory, intellect (which abstracts forms), and finally, the passive intellect, which receives intelligible species and forms general concepts.
Ethics and Politics
Aquinas’ ethics are theological: actions aim towards an ultimate good, happiness, achieved through the rational soul (knowledge and virtue). Since God is the supreme good and knowledge of God is the highest human aspiration, a life dedicated to seeking God is the most perfect and happy. God governs the world through eternal law, which creatures participate in through natural law. Man acts rightly when following natural law, dictated by reason. Natural law is the habit of practical reason, universal, unchanging, and indelible. Its first precept is to do good and avoid evil, the foundation of morality. Politically, Aquinas believed man is naturally social, and human perfection is only possible in society. Positive law, derived from natural law, must aim for the common good. The political order is subordinate to the moral order, and both to the divine order. Legitimate authority respects natural law; otherwise, resistance is justified.
Relationship of the Text with Aquinas’ Thinking
Life and Works
Born in 1225, Aquinas studied under Albert the Great and taught at the University of Paris. He engaged in intellectual controversies with Franciscans and Averroists. His major works include Summa contra Gentiles and Summa Theologica, the latter a comprehensive summary of his philosophical and theological views, synthesizing Christianity and Aristotelianism. It is divided into parts, treatises, and articles, each following a structure: problem, objections, arguments, solution, and responses to objections. Question 94 of Part 1 addresses natural law within ethics.
Natural Law
The core concept is natural law, a practical precept of reason oriented towards the common good. Grounded in theology, it’s a projection of eternal law onto human reason, the basis of morality. It’s called natural law because it’s based on the natural inclination towards good. Since the rational soul defines human nature, natural law is an act of reason, unique, unchanging, and indelible, applying universally. This applies to first principles; secondary precepts can vary due to circumstances. The first principle of natural law equates to the principle of non-contradiction in theoretical reason.
Influence and Impact of Aquinas’ Thought
Influences on Aquinas
Aquinas was heavily influenced by Aristotle’s metaphysics, theory of knowledge, ethics, and politics. He integrated these with Christian doctrine, rejecting incompatible aspects like the mortality of the soul. He also drew from other Christian philosophers like Albert the Great, St. Augustine, Peter Abelard, and William of Moerbeke, as well as Neoplatonic thinkers like St. Isidore of Seville, Boethius, and Pseudo-Dionysius. Arab philosophers Avicenna and Averroes, Jewish philosopher Maimonides, and ancient Stoicism also contributed to his thought.
Aquinas’ Impact
After initial resistance, Aquinas was canonized and his philosophy became official Catholic doctrine. His natural law theory influenced the School of Salamanca and the development of international law. He influenced modern philosophy through figures like Francisco Suarez, though criticized by Descartes and Kant. Neo-Thomism in the 19th and 20th centuries, represented by Jacques Maritain, revived his thought. In Spain, Zubiri incorporated some of Aquinas’ ideas into his notion of sentient intelligence.
Analysis of Articles from Summa Theologica
Article 1: Is Natural Law a Habit?
Aquinas distinguishes between natural law itself, a product of reason, and the habit of practicing it. Natural law is not a habit but an act of reason.
Article 2: Unity of Natural Law
Since reason is one, natural law is also one.
Article 3: Virtuous Acts and Natural Law
Virtuous acts are subject to natural law, as virtues are natural. Virtuous acts align with natural inclinations, while sins oppose them.
Article 4: Universality of Natural Law
Natural law is the same for all, known equally in its universal principles, but particular precepts can differ due to circumstances.
Article 5: Immutability of Natural Law
Natural law cannot be changed, though human laws can be added. These cannot contradict natural law.
Article 6: Indelible Nature of Natural Law
Natural law cannot be erased from the human heart, though secondary precepts can be contradicted due to individual circumstances.