St. Thomas Aquinas’s Summa Theologica and Philosophy: An Overview
St. Thomas Aquinas
Question 1: Summa Theologica’s Structure and Arguments
The Summa Theologica is divided into three parts. Let’s analyze the arguments presented in the provided excerpt, focusing on the concept of natural law:
- Is “natural law” a habit? No, because one can acquire the habit of being good.
- Is “natural law” composed of many precepts or only one? It can be summarized by the previously mentioned principle: “Man is a rational animal.”
- Are the acts of virtue all of the natural law? No, since one can do the right thing by chance.
- Is the natural law equal for everyone? Yes.
- Can we change the law of nature? No, the three fundamental precepts do not change, but secondary precepts may vary.
- Can natural law be abolished in the human heart? No, it remains within us even if we act against it, because God has granted us free will along with original sin, which accompanies the creation of human beings.
Question 2: Faith, Reason, and Knowledge
According to St. Thomas, we understand the universe through reason within its limits, but beyond those limits, we must rely on faith. There are truths of reason (physical) and truths of faith (theological). It is necessary to support and complement both because there are things that people cannot understand due to lack of time or philosophical knowledge. We must also consider the possibility of error in human reason.
Aquinas concludes that faith and reason are not contradictory. Any apparent contradiction would be an error of reason or a misinterpretation of faith. He also addresses the theory of knowledge by abstraction, explaining how we move from individual sensory perceptions to universal concepts. This is achieved through abstraction, the capacity of the understanding to grasp universal concepts. First, the imagination captures images, then the capacity for abstraction removes individual characteristics and universalizes the concepts. Finally, the potential intellect allows for universal knowledge.
Aquinas’s anthropology divides the human being into body and soul, based on Aristotle’s theory of hylomorphism. He distinguishes three types of souls: the rational soul (humans), the sensitive soul (animals), and the vegetative soul (plants). His metaphysics is based on the concept of substance (body) composed of essence (potency (matter/form)) and existence (act).
Aquinas distinguishes between things that exist essentially and the possibility of their presence or absence (existence). For example, man is a rational animal, but he may cease to exist. While based on the Augustinian tradition that all beings, except God, are composed of matter and form, Aquinas states that they are a composition of essence and existence. Contingent beings have the possibility of existing or not, and existence does not necessarily belong to their essence. Essence is potency, and existence is an act of the essence, with beings participating in degrees of perfection.
Only in God are essence and existence identical, as God’s existence is included in His definition. From this, St. Thomas proves the existence of God through reason and observation of nature. He presents five ways to prove God’s existence:
- The Argument from Motion: Everything that moves is moved by another, leading to a First Mover (God).
- The Argument from Efficient Cause: The world is a chain of causes, requiring a First Efficient Cause (God).
- The Argument from Contingency: Substances can be or not be, implying a Necessary Being (God).
- The Argument from Degrees of Perfection: Things participate in degrees of perfection, implying a Perfect Being (God).
- The Argument from Design: Conscious beings are directed towards an end, implying a Designer (God).
Based on the proof of God’s existence, Aquinas establishes laws that govern human behavior. The eternal law governs by faith and represents the divine order of the universe. It regulates human behavior through physical and moral laws. From this comes the natural law, reflecting the eternal law. It is governed by three fundamental precepts: self-preservation, procreation and care for offspring, and the pursuit of truth and social life. This law is developed in the Summa Theologica.
Finally, there is positive law, required by natural law, which imposes a set of rules to regulate social life. Politics is based on trust (faith and reason).
Question 3: Historical and Sociocultural Context
St. Thomas Aquinas lived during the late Middle Ages (mid-11th to late 15th centuries). This period saw agricultural progress, population growth, and the rise of cities. The crisis of the late 13th century brought hunger, war, and pestilence. Politically, Christianity was dominated by the Emperor and the Pope, leading to conflicts over supremacy. Hereditary monarchies emerged, and cities-state developed. The nobility, devoted to war, held extensive lands. The peasantry formed the majority of the population. Social exclusion affected groups like Jews and lepers.
Philosophical Framework
The Church and Christianity influenced European thought. Monasteries emerged, and new religious orders like the Dominicans (to which Aquinas belonged) and Franciscans arose. Universities replaced monastic schools. Scholasticism, a theological and philosophical movement, dominated intellectual life. The Bible and the Summa Theologica served as primary texts. Philosophy took on a different character compared to Greek philosophy.
Question 4: Philosophical Influences
St. Thomas Aquinas was influenced by his teacher, St. Albert the Great, and Aristotle. He adopted aspects of Aristotle’s ontology, anthropology, theory of knowledge, ethics, and politics. He also drew from Augustinian Platonism, particularly where Aristotelian philosophy clashed with Christianity (e.g., the concept of the immortal soul). He incorporated ideas from philosophers like Avicenna and Maimonides. His distinction between essence and existence has Arab origins, while the concept of natural law is related to Stoic philosophy. He was also influenced by the Bible, Church Fathers, and Averroes (whose doctrines of double truth and the unity of the human intellect he rejected).
Aquinas’s natural law doctrine influenced Spanish scholastics of the 16th and 17th centuries (e.g., Francisco de Vitoria, Domingo de Soto). His concept of the “law of nations” is a significant source of modern human rights doctrine. His thought, recognized as the official doctrine of the Catholic Church, was criticized by modern philosophers like Descartes and Kant. However, his philosophy experienced a resurgence in the 20th century thanks to Neo-Thomism, led by Jacques Maritain.