Aquinas’ Philosophy: Exploring Faith, Reason, and God’s Existence
Context of Thomas Aquinas’s Thought
Context (Activity 1):
Thomas lived in the thirteenth century, a period of political calm that accompanied the king’s increased power against the feudal lords. This era saw the rise of cities and flourishing trade. There was also significant cultural development for three main reasons:
- The birth of universities.
- The knowledge of Arabic and Jewish thought, primarily through the School of Translators of Toledo.
- The establishment of the Dominicans and Franciscans in Paris, and their access to university professorships.
Rationality and theocentrism were key elements of this century, which were perfectly combined in scholasticism. Scholastic philosophy, aiming to build large systems, was fundamentally concerned with two issues: the relationship between faith and reason, and the nature of universals.
Responses to the first problem varied: some thought that reason and faith were enemies, others that both were needed. Some believed reason was subordinate to faith, others that they were independent. Aquinas, however, believed they were independent but, when their objects matched, they must be harmonized.
The answer to the second problem had two poles: realists, who claimed that universals are things, and nominalists, who claimed they are words.
St. Thomas’s major theological work, the “Summa Theologica”, aimed to make Christian doctrine accessible to beginners. It focused on the relationship between faith and reason, but primarily on God, as the main intention of this doctrine is to know God.
The theme of God contains several problems, one being his existence. The existence of God is not an article of faith but a preamble to the articles of faith, so that truth can be known by natural reason.
According to Aquinas, the existence of God is demonstrated through the collaboration of faith and reason, using five arguments. These arguments follow a similar pattern: starting from the senses, establishing the principle of causality and the impossibility of infinite regress, and concluding that God exists.
Aquinas’s Theory of Knowledge
Activity 2B
Aquinas, following Aristotle, distinguished two types of knowledge:
Sensitive knowledge, which is derived from the senses and sent to the “common sense.” Common sense forms an image of the object with all its peculiarities.
Intellectual knowledge, which is done by the understanding. It operates on the image formed by common sense, capturing the essential features of the thing. This is done through two activities:
- The role of the intellect: to abstract the essential features of the thing, stripping it of its particular elements, thus making the representation universal.
- The role of patient understanding: to realize the abstracted essence, enabling universal knowledge.
First, the intellect knows the essence of things and then, through further work, focuses on their characteristics.
Capturing the universal involves the problem of individuation. If everyone has the same essence, what makes us different? According to Thomas, all have a common subject matter (essence) and a particular subject, which differentiates us.
According to Christianity, God is necessary, while other beings are contingent. This led Aquinas to distinguish between essence (what is it?) and existence (does it exist?) of things. According to him, every created being has essence and existence, but only in a necessary being (God) are both identified. The difference between essence and existence corresponds to the Aristotelian concepts of potency and act: essence is power, and existence is an act.
The existence of a thing depends on the degree of perfection of its essence. Only the essence of God is perfect; therefore, God exists. This truth needs to be demonstrated. To do this, Aquinas used five arguments:
- 1st: From the principle that “everything that moves is moved by another.” Therefore, there must be a first mover that is not moved by anything: God.
- 2nd: Everything has an efficient cause. Since we cannot go back to infinity, there must be a first efficient cause (uncaused cause): God.
- 3rd: There are people in the world that can exist or not exist. This is because their existence is not from themselves, but made by another. Therefore, there must be a necessary being who has self-existence and gives it to others: God.
- 4th: There are things with varying degrees of perfection, so there must be a maximum degree of perfection that causes the lower grades: God.
- 5th: Natural things that have no intelligence are directed to an end, so there must be an intelligent being who directs all natural things to an end: God.