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Course 14 · Lesson 1.1

What natural theology attempts and what it does not

12 minute read

Lessons in this course

Course 14 outline

Module 1: Arguments, Existence and Necessity

  1. What natural theology attempts and what it does not
  2. Necessary and contingent existence
  3. How to read and test an argument for God
  4. Philosophy of religion today: a map of the field

Module 2: The Ontological Argument

  1. Anselm and the argument of the Proslogion
  2. Gaunilo and the perfect island objection
  3. Kant: existence is not a real predicate
  4. What the ontological argument would show if it worked

Module 3: Cosmological Arguments

  1. Aquinas: the first three ways
  2. Infinite regress: what is the problem?
  3. Leibniz, the principle of sufficient reason and the argument from contingency
  4. Objections: the brute fact reply and the fallacy of composition

Module 4: The Kalam Cosmological Argument

  1. The kalam tradition: Philoponus, al-Ghazali and Bonaventure
  2. The modern argument: whatever begins to exist has a cause
  3. Did the universe begin? Philosophy and cosmology
  4. Objections and replies, and what follows about the cause

Module 5: Teleological and Fine-Tuning Arguments

  1. From Aquinas’s fifth way to Paley’s watch
  2. Hume and the Dialogues Concerning Natural Religion
  3. Darwin and the change in the design argument
  4. The fine-tuning argument: what is claimed and what is debated
  5. The multiverse and other replies

Module 6: The Moral Argument and Divine Hiddenness

  1. The moral argument: Kant, Lewis and contemporary forms
  2. The Euthyphro question and moral realism without God
  3. Evolution and moral knowledge
  4. The argument from divine hiddenness and Christian replies

Module 7: Contemporary Modal Arguments and Evaluation

  1. Possible worlds and modal logic in plain language
  2. Plantinga’s modal ontological argument
  3. Assessing the modal argument: what it needs and what it shows
  4. Weighing the arguments together, and what none of them prove

All courses

Program / Course 14: Arguments for the Existence of God / Lesson 1.1

What you will learn

  • Define natural theology and distinguish it from revealed theology.
  • Explain what a philosophical argument for God can and cannot be expected to show.
  • Describe the main Christian positions on whether reason alone can reach God.
  • State the fair objections of those who think natural theology fails or does not matter.

The big idea

Natural theology is the attempt to learn something about God by reason and ordinary experience, without appealing to a sacred book or a church’s authority. Its arguments, even when they work, aim at a modest result: that a God of some kind exists. They do not reach the full Christian message of Christ, the Trinity or salvation. Christians disagree about how much weight reason should carry here, and non-believers disagree about whether the arguments succeed at all.

Key terms

Natural theology
The study of what can be known about God from reason and observation of the world, without relying on a claimed revelation.
Revealed theology
Teaching about God that is received from what God is believed to have made known, in Scripture, in Christ and in the life of the church.
Argument
A set of statements called premises offered as reasons for another statement called the conclusion.
Theism
The belief that there is one God who is the personal creator and sustainer of everything else.
Fideism
The view that religious faith does not need rational support, or that reason should not be trusted on questions about God.
Evidentialism
The view that a belief is justified only if it is supported by good evidence or argument.
Preamble of faith
A truth about God, such as that God exists, which Aquinas held that reason can reach and which the creeds then presuppose.

Background

Almost every culture has asked whether the world points beyond itself. Greek philosophers such as Plato and Aristotle argued about a highest cause or highest good. Jewish, Christian and Muslim thinkers of the Middle Ages took over these arguments and reworked them in the light of their own scriptures. The phrase natural theology came to name this whole effort. It is called natural because it starts from nature and human reason, not from a text received as revelation.

Scripture itself makes two remarks that later thinkers took as support. The psalmist says that “the heavens declare the glory of God” (Psalm 19:1). Paul writes that “the invisible things of him from the creation of the world are clearly seen” (Romans 1:20), and in Athens he speaks of God as the one in whom people live and move (Acts 17:28). These passages do not set out arguments. Whether they imply that reason alone can reach God is itself debated, as the perspectives below show.

The course studies arguments in their best forms, then studies the strongest objections. That balance is deliberate. A student who has only heard the arguments in a sermon, or only the objections in a skeptic’s book, has not yet met either at full strength.

Step-by-step explanation

Step 1: Separate two questions

The first question is whether anything can be shown about God by reason. The second is what follows for a person’s life if something can. These are different. A person might accept an argument for a first cause and still never pray. Another person might reject every argument and still worship with full confidence. Keep the two questions apart as you read.

Step 2: Know what an argument for God claims

A philosophical argument for God does not say “believe because the Bible says so.” It says: here are premises that you may accept on grounds open to everyone, and here is a conclusion that follows. If the premises are true and the reasoning is valid, the conclusion is true. An argument is only as strong as its least believable premise, so most of the work in this course is spent testing premises.

Notice also what the conclusion usually is. It is something like “there is a first cause,” or “there is a necessary being,” or “there is a designer.” These conclusions are far from the doctrine of the Trinity or the resurrection of Jesus. Defenders such as Aquinas knew this and said so.

Step 3: Learn the different goals people have for the arguments

Some defenders hope for proof that should persuade any honest person. Others, such as many modern philosophers, think more modestly: an argument may make belief in God more reasonable than it was, even if it does not compel. Others use the arguments to remove obstacles, showing a doubter that belief is not irrational. Others, in the tradition of Anselm, treat the argument as faith seeking understanding, a way for a believer to see more clearly what is already believed.

When you evaluate an argument, ask which of these goals its author has. An argument can fail as a proof and still succeed as a way of showing that belief is intellectually respectable.

Step 4: Hear the objections to the whole project

Some objections target the whole effort, not a single argument. The skeptic says that after centuries of debate no argument has won general agreement among philosophers, which suggests none is decisive. Some believers raise a different worry: a God reached by a chain of reasoning may look like a conclusion of philosophers, not the living God of Abraham, Isaac and Jacob, a phrase Pascal made famous in a note about his own experience. Others hold that to prove God is to place God under human judgment.

These objections are serious. A fair student states them before beginning, and returns to them in the final lesson of the course.

Step 5: Set your own plan for the course

Write in your notebook what you currently think about whether God’s existence can be argued, and why. Return to it at the end. The aim of the course is to give you the tools to judge, not to hand you a verdict.

  1. What would count for you as a good reason to believe something about God?
  2. If an argument concludes only that a first cause exists, what is left to be learned from revelation?
  3. Is there a difference between an argument being valid and being persuasive?
  4. Why might a believer be wary of trying to prove God?
  5. Why might a skeptic still find the arguments worth studying?
  6. What would it take to change your mind about the strength of an argument?

Examples

Two readers of Psalm 19

One reader hears the psalm as a report that anyone who looks at the sky can sense a maker. Another hears it as the song of a person who already knows God and therefore sees the sky differently. Both can quote the same verse. They disagree on whether the sky leads to God or whether knowing God shapes how the sky is seen. (A constructed example.)

Aquinas on what reason reaches

Aquinas teaches that some things about God, such as that God exists, can be known by reason, while the Trinity and the Incarnation cannot be discovered that way. He calls the first group preambles to faith. The creeds assume them but do not rest on them alone.

A doubter and a friend

A student tells a friend that she cannot believe because she has never seen a good reason. The friend does not present a proof. He asks which reasons she has looked at and which seemed weakest. The conversation turns from slogans to specific premises. (A constructed example.)

Different perspectives

Catholic

The Catholic Church teaches that God can be known with certainty by the natural light of human reason from created things. The First Vatican Council (1870) stated this, and the Catholic Catechism repeats it. The same teaching holds that revelation is needed for what reason cannot reach and so that even natural truths about God can be known by all without error. Aquinas is the classic model of the approach.

Orthodox

Orthodox writers generally affirm that creation reveals God and that the mind can recognize a creator, but they are wary of treating God as the conclusion of an argument. The tradition stresses that God is known by participation and prayer, and that God lies beyond all concepts. Many Orthodox theologians therefore see the arguments as limited tools at best, and prefer the language of encounter.

Protestant (Reformed and Lutheran)

The Reformers affirmed a general knowledge of God from creation, with Calvin speaking of a sense of the divine in every person. They also held that sin darkens this knowledge so that, without grace, people misuse it. Some twentieth-century Reformed theologians, notably Karl Barth, rejected natural theology as a path around Christ. Others, such as Alvin Plantinga, argue that belief in God can be reasonable without arguments at all.

Protestant (evangelical apologetics)

Many evangelical philosophers and apologists use the arguments actively. William Lane Craig and Richard Swinburne defend versions of them as part of a case for Christianity. They regard the arguments as helpful but as only the first stage of a case that goes on to the evidence for Jesus.

Skeptical and secular views

Many secular philosophers hold that none of the arguments succeeds, either because a premise is doubtful or because the conclusion is smaller than believers suppose. Some regard the question of God as meaningful but unsettled. Others, following Hume and Kant, hold that human reason cannot reach beyond experience to such a conclusion.

Why it matters

The arguments are the most careful attempt that thinkers of many faiths and none have made to say why belief in God might be reasonable. Studying them trains patience, precision and fairness. It also guards against two opposite mistakes: thinking that belief is only emotion, and thinking that faith is a conclusion that logic alone can deliver.

Common misunderstandings

Misunderstanding: Natural theology tries to prove the Christian faith.

Correction: Its conclusions are about a God of some kind. They do not by themselves reach Christ, the Trinity or the church. Christians who value the arguments see them as a first stage.

Misunderstanding: All Christians think the arguments are important.

Correction: They do not. Catholic teaching values them highly. Barth and many Orthodox writers are cautious. Reformed epistemologists argue that belief in God needs no argument to be reasonable.

Misunderstanding: If an argument has been criticized, it has been refuted.

Correction: Most philosophical arguments in this field are still defended and still disputed. A criticism shows where the debate lies, not that it is over.

Misunderstanding: A skeptic who rejects the arguments has proved that God does not exist.

Correction: To show that an argument fails is not to show that its conclusion is false. Atheism needs its own supporting reasons.

Knowledge check

What is natural theology, and how does it differ from revealed theology?

Natural theology tries to learn about God from reason and observation of the world, without relying on a claimed revelation. Revealed theology begins from what God is believed to have made known, through Scripture, Christ and the church. The two are often combined, as when a thinker argues for God by reason and then turns to revelation for what reason cannot reach.

Why do the conclusions of these arguments fall short of Christian doctrine?

The arguments aim at conclusions such as a first cause, a necessary being or a designer. None of these says anything about the Trinity, the Incarnation or salvation. Even Aquinas, a strong defender of reason, taught that these doctrines are known only by revelation. Natural theology prepares the way but does not replace the gospel.

Name two different goals a person might have in using an argument for God.

One goal is proof meant to compel any reasonable person. Another is a more modest case that belief is reasonable, or that it removes obstacles for a doubter. A third, in Anselm’s tradition, is to help a believer understand what is already believed. The goal affects how the argument should be judged.

Why do some Christians distrust natural theology?

Some, like Barth, think it leads away from Christ as the center of knowledge of God. Some Orthodox writers think God cannot be the conclusion of a syllogism. Some Reformed thinkers hold that sin damages human reasoning about God. Others think belief in God needs no argument at all to be rational.

Think it through

  1. Which is more convincing to you, an argument about the world or a personal encounter, and why?
  2. Can a belief be reasonable if the person holding it cannot state an argument for it?
  3. What would it mean to treat an argument fairly if you wanted its conclusion to be false?
  4. How might a believer and a skeptic each profit from studying the same argument?

Independent assignment

Your starting position

In your own notebook, write 300 to 400 words. State what you now think about whether reason can say anything about God, and give two reasons. Then name the one argument for God that you have heard most often and write what you think its strongest and weakest point is. Keep this page and compare it with your view after the final lesson. Do not send it to anyone.

Further study