Saint Thomas Aquinas: Philosophy and Influence

Posted on Dec 13, 2024 in Philosophy and ethics

Historical Framework of Saint Thomas Aquinas’ Thought

The historical framework in which the thinking of Saint Thomas Aquinas unfolds is the 13th century, the “High Middle Ages.” Europe was reaching a high point, marked by struggles between the Emperor and the Pope, culminating in the triumph of the papacy.

Universities and mendicant orders appeared, and there was a reunion of the West with the works of Aristotle.
Economically, there was some improvement due to new techniques and increasing population. Commerce developed, reinforcing the cities and the bourgeoisie.
Politically, power struggles occurred between the temporal (Emperor) and spiritual (Pope). The defeat of the Emperor had two consequences: the success of the papacy under Innocent III and the weakening of the Emperor’s power, which increased the power of monarchies (future modern states). France became the political and cultural center of Europe.

Socio-Cultural Context of the 13th Century

Within the socio-cultural context of the 13th century, the appearance of cities and the development of the bourgeoisie became important.

The currency was stable, favoring the development of trade and the bourgeoisie.
The development of cities promoted the emergence of universities, which were divided into four faculties: Arts, Law, Medicine, and Theology, the latter being the most important.
Mendicant orders also appeared: Franciscans and Dominicans. The mendicants dedicated themselves to preaching, with the city as their center of activity, and within it, the university.
There was a reunion of the West with the works of Aristotle (the most important event of this century).

They presented a rational and philosophical view of the world outside of Christianity.

Philosophical Context

Medieval philosophy went through two stages: the patristic and scholastic. Both focused on the relationship between faith and reason, between theology and philosophy. In previous centuries, Augustine had used Platonism for the first synthesis between faith and reason, achieving harmony between them.

The picture in the 13th century changed with the arrival of the works of Aristotle. These works exposed a knowledge of the world and man outside of faith. Saint Thomas would address the problem of harmonizing Aristotle with Christianity, creating the second-largest medieval synthesis.

Thought of Saint Thomas Aquinas

The text is about ethics, specifically on Natural Law, a key concept in Saint Thomas Aquinas’ philosophy. Saint Thomas, like Aristotle, says that the supreme good of man, the end of all his acts, is happiness. This happiness is the contemplation of God in the hereafter (beatific vision). To achieve this vision, Natural Law is needed.

His starting point would be that God created everything that exists and endowed that creation with a law.

There are two types of law:

Eternal Law: The law or order given by God to the universe.
Natural Law: The expression of eternal law in human nature, which is rational. It is also known as moral law. From it, the principles and standards of human behavior are derived (the Ten Commandments).

The first principle of Natural Law is: “One must do good and avoid evil” – an evident, universal, and unchanging principle. From this principle, three types of rules are derived from human nature (from its tendencies and purposes):

Conservation: People tend to preserve their own life because they are “substance.”
Procreation: Procreation tends to the education of children because they are “animal.”
Knowledge of truth and life in society: It tends to the search for truth and standards of justice because humans are “rational.”

Faith and Reason

In the 13th century, an era of Christendom, a problem arose regarding faith and reason. Saint Thomas fought against Latin Averroism (which asserted the independence of reason concerning faith and the theory of double truth) through the synthesis of faith and reason.

For Saint Thomas, faith and reason are two different sources of knowledge due to their origin (for reason, abstraction from the senses; for faith, divine revelation), evidence (evidence is intrinsic to reason and extrinsic to faith), and perfection (reason is imperfect knowledge, while faith is perfect). Although both are autonomous, they are interdependent: reason has to demonstrate a series of truths that “drive” faith and clarify and defend truths. Faith, because it is imperfect, has to be the extrinsic negative criterion of truth when it comes to correcting erroneous and incompatible conclusions with faith.

Metaphysics

Saint Thomas also performs his synthesis in metaphysics (influenced by Aristotle). The starting point of Saint Thomas would be that God created things from nothing (contingent beings). This is the result of a union between “essence” and “esse” (existence). This gives a double composition of potency and act: a union between matter and form in “essence” and, in the contingent entity, a union of “essence” (potency) and “esse” (Act) in the same body. God is the only being where His essence is His esse. Only He is necessary; the rest of the entities are contingent. The concept of esse has a double meaning: on one side, it is the “perfection” of continuing to receive a capacity, and on the other, the first update of essence (“today”).

The Five Ways

Reason was obligated to demonstrate a series of truths that “drive” faith. Saint Thomas demonstrates the existence of God in his Natural Theology (something necessary, as confirmed by the fact that “God exists” is self-evident, but not for us) through the five ways. In this Thomistic procedure, he uses the “a posteriori” method (from effect to cause), discarding the “a priori” method of Saint Anselm’s ontological argument.

The first way starts from movement to God as the Unmoved Mover; the second, from causality to God as the First Cause; the third, from contingency to God as the Necessary Being; the fourth, from degrees of perfection to God as the absolutely perfect Being; and the fifth, from order to God as the Ordering Intelligence. The structure of the first three ways is as follows: finding a fact of experience, applying the principle of causality, confirming that an infinite series of causes is impossible, applying the principle of sufficient reason, and affirming the existence of God.

Anthropology

Saint Thomas developed his anthropology, stating that man is a created contingent being, but because he is made in the image and likeness of God, he is a person. For him, man is a substantial unity of soul (form or act) and body, but he considers the soul immortal. This soul has three types of functions: vegetative, sensitive, and rational, the latter being specific to man (from Aristotle). Regarding the theory of knowledge, he states that all knowledge starts from the senses. He distinguishes between sensory knowledge (which receives the “sensible form” of things through the senses) and intelligible knowledge (which receives the “intelligible form” through abstraction), with the understanding being unique to each man and also immortal (it comes from the soul).

Influences on Saint Thomas Aquinas

Saint Thomas is the creator of the second great synthesis of medieval philosophy (he was not alien to any philosophical current). His main influence is Aristotle, from whom he receives:

The hylomorphic structure of sentient beings (consisting of matter and form) with the consideration of God as Pure Act.
The distinction between substance and accident.
The definition of change or movement as “passage from potency to act,” the priority of act over potency, and the division of substantial and accidental change.
The theory of the four causes, together with a teleological and essentialist understanding of the world.
The use of the theory of causality and Aristotelian knowledge to demonstrate the existence of God.
The idea of man as a substantial unity and the idea of soul as form or act, although Saint Thomas considered it immortal.
In the Theory of Knowledge, the idea that all knowledge stems from the senses, the distinction between two types of knowledge (sensible and intelligible), and within the latter, the distinction between two understandings (agent and patient), although he identifies the individual soul as immortal.
In ethics, he accepts the idea of happiness as the end of man, which is achieved through contemplation (for our author, the contemplation of God), and the idea that moral norms are based on human nature and knowledge is the starting point for the formulation of moral law.

Other influences include Plato, Neoplatonism, and Augustinianism: the Platonic principle of the participation of beings in God and the Neoplatonist principle of degrees of being.

Finally, he was also influenced by Avicenna (distinction between essence and existence and the notion of being contingent) and many other thinkers such as Seneca, Averroes, and Saint Augustine.

Aftermath of Saint Thomas Aquinas

Thomism was a radical innovation within scholasticism. This synthesis was initially met with opposition from the ecclesiastical hierarchy but was later accepted by Catholic theology and the Church.

Saint Thomas’ thought exerted a strong influence on scholastic philosophy and theology in the 16th century (highlighting Suarez and Vitoria) but subsequently lost importance until the 19th century (due to the advancement of science). Neo-Thomism arose in this century at the University of Leuven (represented by Maritain and Gilson), a current that attempted to overcome the division between faith and reason through modernism.
The influence of Saint Thomas continues until the 20th century, where it influences personalism, especially in Christian personalism (M. Mounier). The concept of natural law has enjoyed the highest prestige, reaching our days.

It should be noted that many fronts have fought against the fundamentals of Thomism: atheistic systems like Nietzsche’s, historicist philosophies, and existentialism (which negates the idea of “human nature” of Thomas).