Aquinas and the harmony of faith and reason

Program / Course 13: Foundations of Apologetics / Lesson 6.2

What you will learn

• Explain Aquinas’s claim that truth is one and that faith and reason cannot truly conflict.
• Distinguish the preambles of faith, which reason can reach, from the articles of faith, which depend on revelation.
• State what Aquinas meant by saying that grace perfects nature.
• Describe objections to his approach from Protestant, Orthodox and secular thinkers.

The big idea

Thomas Aquinas, a Dominican friar who taught in the thirteenth century, argued that faith and reason are two ways of knowing that come from the same God and therefore cannot contradict each other. Some truths about God, he held, can be reached by reason alone, such as that God exists. Others, such as the Trinity, can be known only because God has revealed them. Reason can defend and clarify these but cannot prove them. His synthesis shaped Catholic teaching and influenced many others, and it has also been challenged on several grounds.

Key terms

Natural reason

The human power to know and argue from experience of the world, without relying on revelation.

Revelation

What God has made known, especially through Israel, Jesus Christ and Scripture.

Preambles of faith

Truths about God, such as his existence, that Aquinas thought could be known by reason and that prepare the way for faith.

Articles of faith

Truths, such as the Trinity and the Incarnation, that Aquinas held can be known only through revelation.

Grace perfects nature

A principle in Aquinas that grace does not destroy or replace human nature and reason but completes and elevates them.

Sacred doctrine

Aquinas’s term for the teaching based on divine revelation, which he treats at the start of his Summa Theologiae.

Scholasticism

The method of teaching and study used in medieval schools, based on careful definitions, distinctions and structured argument.

Background

Thomas Aquinas lived from about 1225 to 1274. He taught at the University of Paris and elsewhere, and wrote a vast body of work, including the Summa Theologiae and the Summa Contra Gentiles. He lived at a moment when the writings of Aristotle, preserved and commented upon by Muslim and Jewish scholars, had recently become available in Latin Europe. Some Christians feared that Aristotle would undermine faith. Aquinas believed that careful study could show the opposite.

His thought was not accepted without question in his own day, and in later centuries it was honored, criticized and reinterpreted. In the Catholic Church it gained a special place: Pope Leo XIII in 1879 recommended his philosophy for Catholic schools, and the Church has called him the Common Doctor. This lesson describes his main claims about faith and reason, as best they can be summarized.

Step-by-step explanation

Step 1: One truth, one source

Aquinas started from the claim that God is the source of all truth. Reason, which God gave to human beings, and revelation, which God gave in history, both come from God. Therefore, if a conclusion of sound reasoning seems to contradict a truth of revelation, one or the other has been misunderstood. A genuine contradiction cannot exist.

This is not a naive trust in either side. Aquinas knew that reasoning can fail and that Scripture can be misread. His principle is a guide to inquiry: when the two appear to conflict, look again at both. The idea was later stated in Catholic teaching at the First Vatican Council in 1870, which affirmed that faith and reason cannot truly disagree.

Step 2: What reason can reach and what it cannot

Aquinas distinguished two kinds of truth about God. Some, he said, can be known by natural reason, such as that God exists, that God is one and that God is the cause of everything else. These are the preambles of faith, because a person must have some knowledge of them to make sense of what is revealed. Others, such as the Trinity, the Incarnation and the resurrection of the dead, exceed what human reason could discover and are known only because God has spoken. These are the articles of faith.

Aquinas gave his famous Five Ways as arguments for the first kind, and he treated them as brief outlines of reasoning. He did not argue that reason can prove the articles. He argued instead that reason can show that they are not contradictory, can answer objections to them and can find fitting reasons for them, without claiming to demonstrate them.

Step 3: What faith is

For Aquinas faith is an act of the intellect, moved by the will, under the influence of grace. A person assents to what God has revealed, not because the evidence compels it, as in a mathematical proof, but because he trusts God as the one who reveals. Faith is therefore firm, since it rests on God, and yet it is not seeing: it is a kind of knowing in the dark, held by trust.

In this view faith is not irrational. It rests on reasons that make belief credible, such as miracles and the lives of the saints, but its final basis is the authority of God. Reason prepares the way, defends what is believed and explores its meaning. The assent itself is a gift.

Step 4: Grace perfects nature

A principle often repeated in Thomist writing is that grace does not destroy nature but perfects it. In the area of knowledge, this means that revelation does not replace human reason but raises and completes it. Philosophy has its own proper territory and methods, and theology builds on it. Aquinas learned from non-Christian thinkers like Aristotle, Avicenna and Maimonides, and cited them with respect, while correcting them where he thought they were wrong.

This stance has been called a confidence in creation. If the world and the mind were made by God, then they are fit for knowing him in part. It also explains why Catholic education has valued philosophy, science and the arts as allies of faith.

Step 5: Objections and responses

Protestant critics, especially in the Reformed tradition, have said that Aquinas gives too much credit to fallen reason. Karl Barth rejected the idea that human beings can know God apart from revelation in Christ. Orthodox theologians have asked whether the scholastic method treats God as an object of concepts, and have stressed the need for direct experience of God and for apophatic caution. Some also dispute aspects of his teaching on divine simplicity.

Secular philosophers, following Hume and Kant, argue that the Five Ways do not succeed. Within the Catholic tradition, there are debates between those who follow Aquinas closely and those who think his work needs updating. Defenders reply that the critics often misread Aquinas, who did not claim that reason could replace revelation, and that his arguments should be judged in their medieval context and on their own merits.

1. Why does Aquinas hold that faith and reason cannot contradict one another?
2. What is the difference between a preamble and an article of faith?
3. In what sense is faith firm, and in what sense is it not seeing?
4. What does it mean to say that grace perfects nature?
5. Why do some Protestants and Orthodox thinkers question his approach?
6. How might a skeptic respond to the Five Ways?

Examples

Different perspectives

Roman Catholic

Catholic teaching treats Aquinas as a model theologian. The Church teaches, as in the First Vatican Council, that God can be known by natural reason and that faith is a gift beyond reason. The relation is described as harmony, not conflict.

Reformed Protestant

Reformed theologians have often criticized natural theology as given too large a role in Catholic thought, stressing the noetic effects of sin. Others, such as the Protestant scholastics and modern writers like Sproul and Geisler, have defended a version of the classical approach.

Lutheran

Luther spoke sharply about reason when it is set against the gospel, and called its abuse harmful. Lutheran thought distinguishes the use of reason in ordinary matters, which is good, from its use in judging God’s word, which is limited.

Eastern Orthodox

Orthodox writers appreciate some parts of Aquinas but have often found the scholastic method too confident about describing God. Gregory Palamas, in the fourteenth century, stressed the experience of God’s uncreated energies and the distance between God’s essence and human concepts.

Secular and Jewish philosophers

Many philosophers admire the clarity of Aquinas while disputing his premises. Jewish thinkers like Maimonides, whom Aquinas read, had worked on the same relation between reason and revelation, and often reached similar conclusions about its harmony.

Why it matters

Aquinas gives one of the most influential answers to the question of faith and reason, and anyone who studies apologetics will meet it. It supports the idea that Christians can reason publicly without fear, and it offers a model of how to learn from thinkers outside the church. Its critics raise real concerns about overconfidence and about the role of grace, so that a student who knows both is better placed to think independently.

Common misunderstandings

Knowledge check

Think it through

1. Do you believe that reason and faith can never truly conflict? What do you do when they seem to?
2. Which truths about God do you think can be reached without revelation?
3. What is gained and what is risked by learning from thinkers outside your tradition?
4. How does Aquinas’s view of faith differ from the claim that faith is believing without evidence?

Independent assignment

Read and report

In your own notebook, write 500 to 700 words. Read the short text of the Five Ways in the library. Choose one and write a paragraph on how Aquinas understands its place: what it claims to show, what it does not claim to show. Then write a paragraph on how that fits his teaching on preambles and articles. Add a short note on one objection from this lesson. Keep this for yourself.

Further study

• Thomas Aquinas, Summa Theologiae I, Q. 2: The Existence of God Read the whole short text and note how little it claims to show.
• Thomas Aquinas, Summa Theologiae Read the first question on sacred doctrine, and notice how Aquinas defines the relation of reason and revelation.
• Stanford Encyclopedia of Philosophy, Thomas Aquinas A scholarly overview of his thought, including faith and reason.
• First Vatican Council, Decrees of the First Vatican Council (including Pastor Aeternus on papal primacy and infallibility) Read the section on faith and reason for the Catholic teaching as formally stated.
• Vladimir Lossky, The Mystical Theology of the Eastern Church An Orthodox approach that contrasts with scholastic method.
• Romans 1:20 A verse often cited in support of natural knowledge of God.